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Decker SM, Bruza P, Zhang R, Williams BB, Jarvis LA, Pogue BW, Gladstone DJ. Technical note: Visual, rapid, scintillation point dosimetry for in vivo MV photon beam radiotherapy treatments. Med Phys 2024. [PMID: 38598093 DOI: 10.1002/mp.17071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 03/07/2024] [Accepted: 03/26/2024] [Indexed: 04/11/2024] Open
Abstract
BACKGROUND While careful planning and pre-treatment checks are performed to ensure patient safety during external beam radiation therapy (EBRT), inevitable daily variations mean that in vivo dosimetry (IVD) is the only way to attain the true delivered dose. Several countries outside the US require daily IVD for quality assurance. However, elsewhere, the manual labor and time considerations of traditional in vivo dosimeters may be preventing frequent use of IVD in the clinic. PURPOSE This study expands upon previous research using plastic scintillator discs for optical dosimetry for electron therapy treatments. We present the characterization of scintillator discs for in vivo x-ray dosimetry and describe additional considerations due to geometric complexities. METHODS Plastic scintillator discs were coated with reflective white paint on all sides but the front surface. An anti-reflective, matte coating was applied to the transparent face to minimize specular reflection. A time-gated iCMOS camera imaged the discs under various irradiation conditions. In post-processing, background-subtracted images of the scintillators were fit with Gaussian-convolved ellipses to extract several parameters, including integral output, and observation angle. RESULTS Dose linearity and x-ray energy independence were observed, consistent with ideal characteristics for a dosimeter. Dose measurements exhibited less than 5% variation for incident beam angles between 0° and 75° at the anterior surface and 0-60∘ $^\circ $ at the posterior surface for exit beam dosimetry. Varying the angle between the disc surface and the camera lens did not impact the integral output for the same dose up to 55°. Past this point, up to 75°, there is a sharp falloff in response; however, a correction can be used based on the detected width of the disc. The reproducibility of the integral output for a single disc is 2%, and combined with variations from the gantry angle, we report the accuracy of the proposed scintillator disc dosimeters as ±5.4%. CONCLUSIONS Plastic scintillator discs have characteristics that are well-suited for in vivo optical dosimetry for x-ray radiotherapy treatments. Unlike typical point dosimeters, there is no inherent readout time delay, and an optical recording of the measurement is saved after treatment for future reference. While several factors influence the integral output for the same dose, they have been quantified here and may be corrected in post-processing.
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Affiliation(s)
- Savannah M Decker
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Rongxiao Zhang
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
| | | | - Lesley A Jarvis
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth Health, Lebanon, New Hampshire, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth Health, Lebanon, New Hampshire, USA
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Kanouta E, Bruza P, Johansen JG, Kristensen L, Sørensen BS, Poulsen PR. Two-dimensional time-resolved scintillating sheet monitoring of proton pencil beam scanning FLASH mouse irradiations. Med Phys 2024. [PMID: 38569159 DOI: 10.1002/mp.17049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 03/14/2024] [Accepted: 03/20/2024] [Indexed: 04/05/2024] Open
Abstract
BACKGROUND Dosimetry in pre-clinical FLASH studies is essential for understanding the beam delivery conditions that trigger the FLASH effect. Resolving the spatial and temporal characteristics of proton pencil beam scanning (PBS) irradiations with ultra-high dose rates (UHDR) requires a detector with high spatial and temporal resolution. PURPOSE To implement a novel camera-based system for time-resolved two-dimensional (2D) monitoring and apply it in vivo during pre-clinical proton PBS mouse irradiations. METHODS Time-resolved 2D beam monitoring was performed with a scintillation imaging system consisting of a 1 mm thick transparent scintillating sheet, imaged by a CMOS camera. The sheet was placed in a water bath perpendicular to a horizontal PBS proton beam axis. The scintillation light was reflected through a system of mirrors and captured by the camera with 500 frames per second (fps) for UHDR and 4 fps for conventional dose rates. The raw images were background subtracted, geometrically transformed, flat field corrected, and spatially filtered. The system was used for 2D spot and field profile measurements and compared to radiochromic films. Furthermore, spot positions were measured for UHDR irradiations. The measured spot positions were compared to the planned positions and the relative instantaneous dose rate to equivalent fiber-coupled point scintillator measurements. For in vivo application, the scintillating sheet was placed 1 cm upstream the right hind leg of non-anaesthetized mice submerged in the water bath. The mouse leg and sheet were both placed in a 5 cm wide spread-out Bragg peak formed from the mono-energetic proton beam by a 2D range modulator. The mouse leg position within the field was identified for both conventional and FLASH irradiations. For the conventional irradiations, the mouse foot position was tracked throughout the beam delivery, which took place through repainting. For FLASH irradiations, the delivered spot positions and relative instantaneous dose rate were measured. RESULTS The pixel size was 0.1 mm for all measurements. The spot and field profiles measured with the scintillating sheet agreed with radiochromic films within 0.4 mm. The standard deviation between measured and planned spot positions was 0.26 mm and 0.35 mm in the horizontal and vertical direction, respectively. The measured relative instantaneous dose rate showed a linear relation with the fiber-coupled scintillator measurements. For in vivo use, the leg position within the field varied between mice, and leg movement up to 3 mm was detected during the prolonged conventional irradiations. CONCLUSIONS The scintillation imaging system allowed for monitoring of UHDR proton PBS delivery in vivo with 0.1 mm pixel size and 2 ms temporal resolution. The feasibility of instantaneous dose rate measurements was demonstrated, and the system was used for validation of the mouse leg position within the field.
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Affiliation(s)
- Eleni Kanouta
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Jacob Graversen Johansen
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Line Kristensen
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Brita Singers Sørensen
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Per Rugaard Poulsen
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
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Vasyltsiv R, Rahman M, Harms J, Clark M, Gladstone DJ, Pogue BW, Zhang R, Bruza P. Imaging and characterization of optical emission from ex vivotissue during conventional and UHDR PBS proton therapy. Phys Med Biol 2024; 69:075011. [PMID: 38422545 PMCID: PMC10945384 DOI: 10.1088/1361-6560/ad2ee6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 02/21/2024] [Accepted: 02/29/2024] [Indexed: 03/02/2024]
Abstract
Objective. Imaging of optical photons emitted from tissue during radiotherapy is a promising technique for real-time visualization of treatment delivery, offering applications in dose verification, treatment monitoring, and retrospective treatment plan comparison. This research aims to explore the feasibility of intensified imaging of tissue luminescence during proton therapy (PT), under both conventional and ultra-high dose rate (UHDR) conditions.Approach. Conventional and UHDR pencil beam scanning (PBS) PT irradiation of freshex vivoporcine tissue and tissue-mimicking plastic phantom was imaged using intensified complementary metal-oxide-semiconductor(CMOS) cameras. The optical emission from tissue was characterized during conventional irradiation using both blue and red-sensitive intensifiers to ensure adequate spectral coverage. Spectral characterization was performed using bandpass filters between the lens and sensor. Imaging of conventional proton fields (240 MeV, 10 nA) was performed at 100 Hz frame rate, while UHDR PBS proton delivery (250 MeV, 99 nA) was recorded at 1 kHz frame rate. Dependence of optical emission yield on proton energy was studied using an optical tissue-mimicking plastic phantom and a range shifter. Finally, we demonstrated fast beam tracking capability of fast camera towardsin vivomonitoring of FLASH PT.Main results. Under conventional treatment dose rates optical emission was imaged with single spot resolution. Spot profiles were found to agree with the treatment planning system calculation within >90% for all spectral bands and spot intensity was found to vary with spectral filtration. The resultant polychromatic emission presented a maximum intensity at 650 nm and decreasing signal at lower wavelengths, which is consistent with expected attenuation patterns of high fat and muscle tissue. For UHDR beam imaging, optical yield increased with higher proton energy. Imaging at 1 kHz allowed continuous monitoring of delivery during porcine tissue irradiation, with clear identification of individual dwell positions. The number of dwell positions matched the treatment plan in total and per row showing adequate temporal capability of iCMOS imaging.Significance. For the first time, this study characterizes optical emission from tissue during PT and demonstrates our capability of fast optical tracking of pencil proton beam on the tissue anatomy in both conventional and UHDR setting. Similar to the Cherenkov imaging in radiotherapy, this imaging modality could enable a seamless, independent validation of PT treatments.
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Affiliation(s)
- Roman Vasyltsiv
- Thayer School of Engineering, Dartmouth College, Hanover, NH, United States of America
| | - Mahbubur Rahman
- UT Southwestern Medical Center, Dallas, TX, United States of America
| | - Joseph Harms
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Megan Clark
- Thayer School of Engineering, Dartmouth College, Hanover, NH, United States of America
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, NH, United States of America
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH, United States of America
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, NH, United States of America
- Department of Radiation Oncology, New York Medical College, Valhalla, NY, United States of America
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, NH, United States of America
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Dai T, Sloop AM, Rahman MR, Sunnerberg JP, Clark MA, Young R, Adamczyk S, Von Voigts-Rhetz P, Patane C, Turk M, Jarvis L, Pogue BW, Gladstone DJ, Bruza P, Zhang R. First Monte Carlo beam model for ultra-high dose rate radiotherapy with a compact electron LINAC. Med Phys 2024. [PMID: 38493501 DOI: 10.1002/mp.17031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 03/04/2024] [Accepted: 03/04/2024] [Indexed: 03/19/2024] Open
Abstract
BACKGROUND FLASH radiotherapy based on ultra-high dose rate (UHDR) is actively being studied by the radiotherapy community. Dedicated UHDR electron devices are currently a mainstay for FLASH studies. PURPOSE To present the first Monte Carlo (MC) electron beam model for the UHDR capable Mobetron (FLASH-IQ) as a dose calculation and treatment planning platform for preclinical research and FLASH-radiotherapy (RT) clinical trials. METHODS The initial beamline geometry of the Mobetron was provided by the manufacturer, with the first-principal implementation realized in the Geant4-based GAMOS MC toolkit. The geometry and electron source characteristics, such as energy spectrum and beamline parameters, were tuned to match the central-axis percentage depth dose (PDD) and lateral profiles for the pristine beam measured during machine commissioning. The thickness of the small foil in secondary scatter affected the beam model dominantly and was fine tuned to achieve the best agreement with commissioning data. Validation of the MC beam modeling was performed by comparing the calculated PDDs and profiles with EBT-XD radiochromic film measurements for various combinations of applicators and inserts. RESULTS The nominal 9 MeV electron FLASH beams were best represented by a Gaussian energy spectrum with mean energy of 9.9 MeV and variance (σ) of 0.2 MeV. Good agreement between the MC beam model and commissioning data were demonstrated with maximal discrepancy < 3% for PDDs and profiles. Hundred percent gamma pass rate was achieved for all PDDs and profiles with the criteria of 2 mm/3%. With the criteria of 2 mm/2%, maximum, minimum and mean gamma pass rates were (100.0%, 93.8%, 98.7%) for PDDs and (100.0%, 96.7%, 99.4%) for profiles, respectively. CONCLUSIONS A validated MC beam model for the UHDR capable Mobetron is presented for the first time. The MC model can be utilized for direct dose calculation or to generate beam modeling input required for treatment planning systems for FLASH-RT planning. The beam model presented in this work should facilitate translational and clinical FLASH-RT for trials conducted on the Mobetron FLASH-IQ platform.
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Affiliation(s)
- Tianyuan Dai
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Austin M Sloop
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | | | - Jacob P Sunnerberg
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Megan A Clark
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Ralph Young
- IntraOp Medical Corporation, Sunnyvale, California, USA
| | | | | | - Chris Patane
- IntraOp Medical Corporation, Sunnyvale, California, USA
| | - Michael Turk
- IntraOp Medical Corporation, Sunnyvale, California, USA
| | - Lesley Jarvis
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
- Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin, USA
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Department of Radiation Medicine, New York Medical College, Valhalla, New York, USA
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Petusseau AF, Streeter SS, Ulku A, Feng Y, Samkoe KS, Bruschini C, Charbon E, Pogue BW, Bruza P. Subsurface fluorescence time-of-flight imaging using a large-format single-photon avalanche diode sensor for tumor depth assessment. J Biomed Opt 2024; 29:016004. [PMID: 38235320 PMCID: PMC10794045 DOI: 10.1117/1.jbo.29.1.016004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 12/06/2023] [Accepted: 12/20/2023] [Indexed: 01/19/2024]
Abstract
Significance Fluorescence guidance is used clinically by surgeons to visualize anatomical and/or physiological phenomena in the surgical field that are difficult or impossible to detect by the naked eye. Such phenomena include tissue perfusion or molecular phenotypic information about the disease being resected. Conventional fluorescence-guided surgery relies on long, microsecond scale laser pulses to excite fluorescent probes. However, this technique only provides two-dimensional information; crucial depth information, such as the location of malignancy below the tissue surface, is not provided. Aim We developed a depth sensing imaging technique using light detection and ranging (LiDAR) time-of-flight (TOF) technology to sense the depth of target tissue while overcoming the influence of tissue optical properties and fluorescent probe concentration. Approach The technology is based on a large-format (512 × 512 pixel ), binary, gated, single-photon avalanche diode (SPAD) sensor with an 18 ps time-gate step, synchronized with a picosecond pulsed laser. The fast response of the sensor was developed and tested for its ability to quantify fluorescent inclusions at depth and optical properties in tissue-like phantoms through analytical model fitting of the fast temporal remission data. Results After calibration and algorithmic extraction of the data, the SPAD LiDAR technique allowed for sub-mm resolution depth sensing of fluorescent inclusions embedded in tissue-like phantoms, up to a maximum of 5 mm in depth. The approach provides robust depth sensing even in the presence of variable tissue optical properties and separates the effects of fluorescence depth from absorption and scattering variations. Conclusions LiDAR TOF fluorescence imaging using an SPAD camera provides both fluorescence intensity images and the temporal profile of fluorescence, which can be used to determine the depth at which the signal is emitted over a wide field of view. The proposed tool enables fluorescence imaging at a higher depth in tissue and with higher spatial precision than standard, steady-state fluorescence imaging tools, such as intensity-based near-infrared fluorescence imaging, optical coherence tomography, Raman spectroscopy, or confocal microscopy. Integration of this technique into a standard surgical tool could enable rapid, more accurate estimation of resection boundaries, thereby improving the surgeon's efficacy and efficiency, and ultimately improving patient outcomes.
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Affiliation(s)
- Arthur F Petusseau
- Dartmouth College, Thayer School of Engineering and Dartmouth Cancer Center, Hanover, New Hampshire, United States
| | - Samuel S Streeter
- Geisel School of Medicine at Dartmouth, Department of Orthopaedics, Hanover, New Hampshire, United States
| | - Arin Ulku
- Ecole polytechnique fédérale de Lausanne, Advanced Quantum Architecture Laboratory, Neuchâtel, Switzerland
| | - Yichen Feng
- Geisel School of Medicine at Dartmouth, Department of Surgery, Hanover, New Hampshire, United States
| | - Kimberley S Samkoe
- Geisel School of Medicine at Dartmouth, Department of Surgery, Hanover, New Hampshire, United States
| | - Claudio Bruschini
- Ecole polytechnique fédérale de Lausanne, Advanced Quantum Architecture Laboratory, Neuchâtel, Switzerland
| | - Edoardo Charbon
- Ecole polytechnique fédérale de Lausanne, Advanced Quantum Architecture Laboratory, Neuchâtel, Switzerland
| | - Brian W Pogue
- Dartmouth College, Thayer School of Engineering and Dartmouth Cancer Center, Hanover, New Hampshire, United States
- University of Wisconsin-Madison, Department of Medical Physics, Madison, Wisconsin, United States
| | - Petr Bruza
- Dartmouth College, Thayer School of Engineering and Dartmouth Cancer Center, Hanover, New Hampshire, United States
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Alexander DA, Majji S, Jermyn M, Byrd BK, Bruza P, Li T, Zhu TC. Characterization of Cherenkov imaging parameters and positional constraints on an O-ring linear accelerator. Phys Med Biol 2023; 68:10.1088/1361-6560/acfdf2. [PMID: 37757840 PMCID: PMC10693929 DOI: 10.1088/1361-6560/acfdf2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 09/27/2023] [Indexed: 09/29/2023]
Abstract
Objective. With the introduction of Cherenkov imaging technology on the Halcyon O-ring linear accelerator platform, we seek to demonstrate the imaging feasibility and optimize camera placement.Approach. Imaging parameters were probed by acquiring triggering data Cherenkov image frames for simplistic beams on the Halcyon and comparing the analyzed metrics with those from the TrueBeam platform. Camera position was analyzed by performing 3D rendering of patient treatment plans for various sites and iterating over camera positions to assess treatment area visibility.Main results. Commercial Cherenkov imaging systems are compatible with the pulse timing of the Halcyon, and this platform design favorably impacts signal to noise in Cherenkov image frames. Additionally, ideal camera placement is treatment site dependent and is always within a biconical zone of visibility centered on the isocenter. Visibility data is provided for four treatment sites, with suggestions for camera placement based on room dimensions. Median visibility values were highest for right breast plans, with values of 80.33% and 68.49% for the front and rear views respectively. Head and neck plans presented with the lowest values at 26.44% and 38.18% respectively.Significance. This work presents the first formal camera positional analysis for Cherenkov imaging on any platform and serves as a template for performing similar work for other irradiation platforms. Additionally, this study confirms the Cherenkov imaging parameters do not need to be changed for optimal imaging on the Halcyon. Lastly, the presented methodology provides a framework which could be further expanded to other optical imaging systems which rely on line of sight visibility to the patient.
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Affiliation(s)
- Daniel A. Alexander
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia PA
| | | | - Michael Jermyn
- DoseOptics LLC, Lebanon NH
- Thayer School of Engineering, Dartmouth College, Hanover NH
| | - Brook K. Byrd
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia PA
| | - Petr Bruza
- DoseOptics LLC, Lebanon NH
- Thayer School of Engineering, Dartmouth College, Hanover NH
| | - Taoran Li
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia PA
| | - Timothy C. Zhu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia PA
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Pogue BW, Decker SM, Zhang R, Bruza P, Gladstone DJ, Jarvis LA. Cherenkov and Plan Integration for Real-Time Delivery Verification: The Opportunity for Automated Visualization and Guidance of All Treatments in EBRT. Int J Radiat Oncol Biol Phys 2023; 117:e706. [PMID: 37786068 DOI: 10.1016/j.ijrobp.2023.06.2198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) Initiatives in the national radiation oncology incident learning system (RO-ILS) have been exceptionally useful in discovery of factors that lead to incidents and learning of best practices that can help make the national practice of RO safer as a whole. Incident learning systems come from the flight industry, where both visual cues and instrument control are essential parts of implementation, and similarly both human and instrument tools are used in RO. However, numerous RO studies have reported that human factors are a leading cause of incidents discovered and that timelines, such as QA, setup, delivery, and verification are areas where most incidents are found. Tools such as Cherenkov imaging and SGRT can be used to automate many of the riskiest human decisions and/or providing both human vision and instrument-guided oversight in these areas of treatment delivery process. MATERIALS/METHODS The value of continuous online imaging is reviewed and the two parts have been tested towards complete automation. The conceptual framework of comparing images to the patient treatment plan is outlined with software examples. Development towards a combined SGRT & Cherenkov imaging system that could achieve fully automated incident detection is outlined. RESULTS Cherenkov imaging has shown direct visualization of many instances of beam delivery to patients that were sub-optimal. These are seen mostly in isolated cases of normal tissue in the beam where it was not expected, such as limbs, chin, contralateral breast or axilla. Incorrect placement of bolus is also readily visualized. Comparisons can be made on a day-to-day basis, but also on a delivery to plan basis if the plan was incorporated into the treatment delivery process. Analysis of the incidents seen indicates that there are automatable metrics of image quality that could have detected them. Overall, if the system detection of variations were fully automated, these could be detected without human intervention. CONCLUSION The capabilities for reducing nearly all human error in setup and delivery are available or emerging, and Cherenkov imaging is perhaps one of the most direct ways to capture and computationally analyze the treatment in real time. These tools require further integration with automated analysis and plan integration, but the initial steps are well underway and individual parts are now possible with advances in R&D of the system integration.
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Affiliation(s)
- B W Pogue
- University of Wisconsin-Madison, Madison, WI
| | - S M Decker
- Thayer School of Engineering, Dartmouth College, Hanover, NH
| | - R Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, NH
| | - P Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, NH
| | - D J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, NH
| | - L A Jarvis
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH
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Rahman M, Kozelka J, Hildreth J, Schönfeld A, Sloop AM, Ashraf MR, Bruza P, Gladstone DJ, Pogue BW, Simon WE, Zhang R. Characterization of a diode dosimeter for UHDR FLASH radiotherapy. Med Phys 2023; 50:5875-5883. [PMID: 37249058 DOI: 10.1002/mp.16474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 05/31/2023] Open
Abstract
BACKGROUND Ultra-high dose rate (UHDR) FLASH beams typically deliver dose at rates of >40 Gy/sec. Characterization of these beams with respect to dose, mean dose rate, and dose per pulse requires dosimeters which exhibit high temporal resolution and fast readout capabilities. PURPOSE A diode EDGE Detector with a newly designed electrometer has been characterized for use in an UHDR electron beam and demonstrated appropriateness for UHDR FLASH radiotherapy dosimetry. METHODS Dose linearity, mean dose rate, and dose per pulse dependencies of the EDGE Detector were quantified and compared with dosimeters including a W1 scintillator detector, radiochromic film, and ionization chamber that were irradiated with a 10 MeV UHDR beam. The dose, dose rate, and dose per pulse were controlled via an in-house developed scintillation-based feedback mechanism, repetition rate of the linear accelerator, and source-to-surface distance, respectively. Depth-dose profiles and temporal profiles at individual pulse resolution were compared to the film and scintillation measurements, respectively. The radiation-induced change in response sensitivity was quantified via irradiation of ∼5kGy. RESULTS The EDGE Detector agreed with film measurements in the measured range with varying dose (up to 70 Gy), dose rate (nearly 200 Gy/s), and dose per pulse (up to 0.63 Gy/pulse) on average to within 2%, 5%, and 1%, respectively. The detector also agreed with W1 scintillation detector on average to within 2% for dose per pulse (up to 0.78 Gy/pulse). The EDGE Detector signal was proportional to ion chamber (IC) measured dose, and mean dose rate in the bremsstrahlung tail to within 0.4% and 0.2% respectively. The EDGE Detector measured percent depth dose (PDD) agreed with film to within 3% and per pulse output agreed with W1 scintillator to within -6% to +5%. The radiation-induced response decrease was 0.4% per kGy. CONCLUSIONS The EDGE Detector demonstrated dose linearity, mean dose rate independence, and dose per pulse independence for UHDR electron beams. It can quantify the beam spatially, and temporally at sub millisecond resolution. It's robustness and individual pulse detectability of treatment deliveries can potentially lead to its implementation for in vivo FLASH dosimetry, and dose monitoring.
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Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- UT Southwestern Medical Center, Dallas, Texas, USA
| | | | | | | | - Austin M Sloop
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - M Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Stanford University, Stanford, California, USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin, USA
| | | | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Department of Radiation Medicine, Westchester Medical Center, New York Medical College,Valhalla, New York, USA
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Duval KEA, Aulwes E, Zhang R, Rahman M, Ashraf MR, Sloop A, Sunnerberg J, Williams BB, Cao X, Bruza P, Kheirollah A, Tavakkoli A, Jarvis LA, Schaner PE, Swartz HM, Gladstone DJ, Pogue BW, Hoopes PJ. Comparison of Tumor Control and Skin Damage in a Mouse Model after Ultra-High Dose Rate Irradiation and Conventional Irradiation. Radiat Res 2023; 200:223-231. [PMID: 37590482 PMCID: PMC10551764 DOI: 10.1667/rade-23-00057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 07/07/2023] [Indexed: 08/19/2023]
Abstract
Recent studies suggest ultra-high dose rate radiation treatment (UHDR-RT) reduces normal tissue damage compared to conventional radiation treatment (CONV-RT) at the same dose. In this study, we compared first, the kinetics and degree of skin damage in wild-type C57BL/6 mice, and second, tumor treatment efficacy in GL261 and B16F10 dermal tumor models, at the same UHDR-RT and CONV-RT doses. Flank skin of wild-type mice received UHDR-RT or CONV-RT at 25 Gy and 30 Gy. Normal skin damage was tracked by clinical observation to determine the time to moist desquamation, an endpoint which was verified by histopathology. Tumors were inoculated on the right flank of the mice, then received UHDR-RT or CONV-RT at 1 × 11 Gy, 1 × 15, 1 × 25, 3 × 6 and 3 × 8 Gy, and time to tumor tripling volume was determined. Tumors also received 1 × 11, 1 × 15, 3 × 6 and 3 × 8 Gy doses for assessment of CD8+/CD4+ tumor infiltrate and genetic expression 96 h postirradiation. All irradiations of the mouse tumor or flank skin were performed with megavoltage electron beams (10 MeV, 270 Gy/s for UHDR-RT and 9 MeV, 0.12 Gy/s for CONV-RT) delivered via a clinical linear accelerator. Tumor control was statistically equal for similar doses of UHDR-RT and CONV-RT in B16F10 and GL261 murine tumors. There were variable qualitative differences in genetic expression of immune and cell damage-associated pathways between UHDR and CONV irradiated B16F10 tumors. Compared to CONV-RT, UHDR-RT resulted in an increased latent period to skin desquamation after a single 25 Gy dose (7 days longer). Time to moist skin desquamation did not significantly differ between UHDR-RT and CONV-RT after a 30 Gy dose. The histomorphological characteristics of skin damage were similar for UHDR-RT and CONV-RT. These studies demonstrated similar tumor control responses for equivalent single and fractionated radiation doses, with variable difference in expression of tumor progression and immune related gene pathways. There was a modest UHDR-RT skin sparing effect after a 1 × 25 Gy dose but not after a 1 × 30 Gy dose.
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Affiliation(s)
- Kayla E. A. Duval
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Ethan Aulwes
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Rongxiao Zhang
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - M. Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Austin Sloop
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Jacob Sunnerberg
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Benjamin B. Williams
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | | | - Armin Tavakkoli
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Lesley A. Jarvis
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Philip E. Schaner
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Harold M. Swartz
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - David J. Gladstone
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Brian W. Pogue
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin
| | - P. Jack Hoopes
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
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10
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Rahman M, Zhang R, Gladstone DJ, Williams BB, Chen E, Dexter CA, Thompson L, Bruza P, Pogue BW. Failure Mode and Effects Analysis for Experimental Use of FLASH on a Clinical Accelerator. Pract Radiat Oncol 2023; 13:153-165. [PMID: 36375771 PMCID: PMC10373055 DOI: 10.1016/j.prro.2022.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 08/21/2022] [Accepted: 10/07/2022] [Indexed: 11/13/2022]
Abstract
PURPOSE The use of a linear accelerator (LINAC) in ultrahigh-dose-rate (UHDR) mode can provide a conduit for wider access to UHDR FLASH effects, sparing normal tissue, but care needs to be taken in the use of such systems to ensure errors are minimized. The failure mode and effects analysis was carried out in a team that has been involved in converting a LINAC between clinical use and UHDR experimental mode for more than 1 year after the proposed methods of TG100. METHODS AND MATERIALS A team of 9 professionals with extensive experience were polled to outline the process map and workflow for analysis, and developed fault trees for potential errors, as well as failure modes that would result. The team scored the categories of severity magnitude, occurrence likelihood, and detectability potential in a scale of 1 to 10, so that a risk priority number (RPN = severity×occurrence×detectability) could be assessed for each. RESULTS A total of 46 potential failure modes were identified, including 5 with an RPN >100. These failure modes involved (1) patient set up, (2) gating mechanisms in delivery, and (3) detector in the beam stop mechanism. The identified methods to mitigate errors included the (1) use of a checklist post conversion, (2) use of robust radiation detectors, (3) automation of quality assurance and beam consistency checks, and (4) implementation of surface guidance during beam delivery. CONCLUSIONS The failure mode and effects analysis process was considered critically important in this setting of a new use of a LINAC, and the expert team developed a higher level of confidence in the ability to safely move UHDR LINAC use toward expanded research access.
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Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; University of Texas Southwestern Medical Center, Dallas, Texas.
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Benjamin B Williams
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Erli Chen
- Cheshire Medical Center, Keene, New Hampshire
| | - Chad A Dexter
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Lawrence Thompson
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin
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11
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Wickramasinghe VA, Decker SM, Streeter SS, Sloop AM, Petusseau AF, Alexander DA, Bruza P, Gladstone DJ, Zhang R, Pogue BW. Color-resolved Cherenkov imaging allows for differential signal detection in blood and melanin content. J Biomed Opt 2023; 28:036005. [PMID: 36923987 PMCID: PMC10008915 DOI: 10.1117/1.jbo.28.3.036005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
Significance High-energy x-ray delivery from a linear accelerator results in the production of spectrally continuous broadband Cherenkov light inside tissue. In the absence of attenuation, there is a linear relationship between Cherenkov emission and deposited dose; however, scattering and absorption result in the distortion of this linear relationship. As Cherenkov emission exits the absorption by tissue dominates the observed Cherenkov emission spectrum. Spectroscopic interpretation of this effects may help to better relate Cherenkov emission to ionizing radiation dose delivered during radiotherapy. Aim In this study, we examined how color Cherenkov imaging intensity variations are caused by absorption from both melanin and hemoglobin level variations, so that future Cherenkov emission imaging might be corrected for linearity to delivered dose. Approach A custom, time-gated, three-channel intensified camera was used to image the red, green, and blue wavelengths of Cherenkov emission from tissue phantoms with synthetic melanin layers and varying blood concentrations. Our hypothesis was that spectroscopic separation of Cherenkov emission would allow for the identification of attenuated signals that varied in response to changes in blood content versus melanin content, because of their different characteristic absorption spectra. Results Cherenkov emission scaled with dose linearly in all channels. Absorption in the blue and green channels increased with increasing oxy-hemoglobin in the blood to a greater extent than in the red channel. Melanin was found to absorb with only slight differences between all channels. These spectral differences can be used to derive dose from measured Cherenkov emission. Conclusions Color Cherenkov emission imaging may be used to improve the optical measurement and determination of dose delivered in tissues. Calibration for these factors to minimize the influence of the tissue types and skin tones may be possible using color camera system information based upon the linearity of the observed signals.
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Affiliation(s)
| | - Savannah M. Decker
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Samuel S. Streeter
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Austin M. Sloop
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Arthur F. Petusseau
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Daniel A. Alexander
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Petr Bruza
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - David J. Gladstone
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
| | - Rongxiao Zhang
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
| | - Brian W. Pogue
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- University of Wisconsin–Madison, Department of Medical Physics, Madison, Wisconsin, United States
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12
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Clark M, Ding X, Zhao L, Pogue B, Gladstone D, Rahman M, Zhang R, Bruza P. Ultra-fast, high spatial resolution single-pulse scintillation imaging of synchrocyclotron pencil beam scanning proton delivery. Phys Med Biol 2023; 68:045016. [PMID: 36716492 PMCID: PMC9935801 DOI: 10.1088/1361-6560/acb753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 01/12/2023] [Accepted: 01/30/2023] [Indexed: 02/01/2023]
Abstract
Objective.To demonstrates the ability of an ultra-fast imaging system to measure high resolution spatial and temporal beam characteristics of a synchrocyclotron proton pencil beam scanning (PBS) system.Approach.An ultra-fast (1 kHz frame rate), intensified CMOS camera was triggered by a scintillation sheet coupled to a remote trigger unit for beam on detection. The camera was calibrated using the linear (R2> 0.9922) dose response of a single spot beam to varying currents. Film taken for the single spot beam was used to produce a scintillation intensity to absolute dose calibration.Main results. Spatial alignment was confirmed with the film, where thexandy-profiles of the single spot cumulative image agreed within 1 mm. A sample brain patient plan was analyzed to demonstrate dose and temporal accuracy for a clinically-relevant plan, through agreement within 1 mm to the planned and delivered spot locations. The cumulative dose agreed with the planned dose with a gamma passing rate of 97.5% (2 mm/3%, 10% dose threshold).Significance. This is the first system able to capture single-pulse spatial and temporal information for the unique pulse structure of a synchrocyclotron PBS systems at conventional dose rates, enabled by the ultra-fast sampling frame rate of this camera. This study indicates that, with continued camera development and testing, target applications in clinical and FLASH proton beam characterization and validation are possible.
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Affiliation(s)
| | - Xuanfeng Ding
- Beaumont Proton Therapy Center, Detroit, MI, United States of America
| | - Lewei Zhao
- Beaumont Proton Therapy Center, Detroit, MI, United States of America
| | - Brian Pogue
- University of Wisconsin-Madison, Madison, WI, United States of America
| | - David Gladstone
- Dartmouth College, NH, Lebanon
- Dartmouth Cancer Center, NH, Lebanon
| | | | - Rongxiao Zhang
- Dartmouth College, NH, Lebanon
- Dartmouth Cancer Center, NH, Lebanon
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13
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Alexander DA, Decker SM, Jermyn M, Bruza P, Zhang R, Chen E, McGlynn TL, Rosselot RA, Lee J, Rose ML, Williams BB, Pogue BW, Gladstone DJ, Jarvis LA. One Year of Clinic-Wide Cherenkov Imaging for Discovery of Quality Improvement Opportunities in Radiation Therapy. Pract Radiat Oncol 2023; 13:71-81. [PMID: 35777728 PMCID: PMC10984217 DOI: 10.1016/j.prro.2022.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/20/2022] [Accepted: 06/07/2022] [Indexed: 01/10/2023]
Abstract
PURPOSE Cherenkov imaging is clinically available as a radiation therapy treatment verification tool. The aim of this work was to discover the benefits of always-on Cherenkov imaging as a novel incident detection and quality improvement system through review of all imaging at our center. METHODS AND MATERIALS Multicamera Cherenkov imaging systems were permanently installed in 3 treatment bunkers, imaging continuously over a year. Images were acquired as part of normal treatment procedures and reviewed for potential treatment delivery anomalies. RESULTS In total, 622 unique patients were evaluated for this study. We identified 9 patients with treatment anomalies occurring over their course of treatment, which were only detected with Cherenkov imaging. Categorizing each event indicated issues arising in simulation, planning, pretreatment review, and treatment delivery, and none of the incidents were detected before this review by conventional measures. The incidents identified in this study included dose to unintended areas in planning, dose to unintended areas due to positioning at treatment, and nonideal bolus placement during setup. CONCLUSIONS Cherenkov imaging was shown to provide a unique method of detecting radiation therapy incidents that would have otherwise gone undetected. Although none of the events detected in this study reached the threshold of reporting, they identified opportunities for practice improvement and demonstrated added value of Cherenkov imaging in quality assurance programs.
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Affiliation(s)
- Daniel A Alexander
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire.
| | - Savannah M Decker
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Dose Optics LLC, Lebanon, New Hampshire
| | - Michael Jermyn
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Dose Optics LLC, Lebanon, New Hampshire
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Dose Optics LLC, Lebanon, New Hampshire
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Dartmouth Cancer Center, Lebanon, New Hampshire
| | - Erli Chen
- Cheshire Medical Center, Keene, New Hampshire
| | | | | | - Jae Lee
- Dartmouth Cancer Center, Lebanon, New Hampshire
| | | | - Benjamin B Williams
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Dartmouth Cancer Center, Lebanon, New Hampshire
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Dose Optics LLC, Lebanon, New Hampshire; Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Lesley A Jarvis
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Dartmouth Cancer Center, Lebanon, New Hampshire
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14
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Miao T, Zhang R, Jermyn M, Bruza P, Zhu T, Pogue BW, Gladstone DJ, Williams BB. Computational dose visualization & comparison in total skin electron treatment suggests superior coverage by the rotational versus the Stanford technique. J Med Imaging Radiat Sci 2022; 53:612-622. [PMID: 36045017 PMCID: PMC10152509 DOI: 10.1016/j.jmir.2022.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/16/2022] [Accepted: 08/11/2022] [Indexed: 12/24/2022]
Abstract
INTRODUCTION/BACKGROUND The goal of Total Skin Electron Therapy (TSET) is to achieve a uniform surface dose, although assessment of this is never really done and typically limited points are sampled. A computational treatment simulation approach was developed to estimate dose distributions over the body surface, to compare uniformity of (i) the 6 pose Stanford technique and (ii) the rotational technique. METHODS The relative angular dose distributions from electron beam irradiation was calculated by Monte Carlo simulation for cylinders with a range of diameters, approximating body part curvatures. These were used to project dose onto a 3D body model of the TSET patient's skin surfaces. Computer animation methods were used to accumulate the dose values, for display and analysis of the homogeneity of coverage. RESULTS The rotational technique provided more uniform coverage than the Stanford technique. Anomalies of under dose were observed in lateral abdominal regions, above the shoulders and in the perineum. The Stanford technique had larger areas of low dose laterally. In the rotational technique, 90% of the patient's skin was within ±10% of the prescribed dose, while this percentage decreased to 60% or 85% for the Stanford technique, varying with patient body mass. Interestingly, the highest discrepancy was most apparent in high body mass patients, which can be attributed to the loss of tangent dose at low angles of curvature. DISCUSSION/CONCLUSION This simulation and visualization approach is a practical means to analyze TSET dose, requiring only optical surface body topography scans. Under- and over-exposed body regions can be found, and irradiation could be customized to each patient. Dose Area Histogram (DAH) distribution analysis showed the rotational technique to have better uniformity, with most areas within 10% of the umbilicus value. Future use of this approach to analyze dose coverage is possible as a routine planning tool.
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Affiliation(s)
- Tianshun Miao
- Thayer School of Engineering, Dartmouth College, Hanover NH, 03755, USA
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover NH, 03755, USA; Department of Medicine, Radiation Oncology, Norris Cotton Cancer Center, Dartmouth Hitchcock Medical Center, Lebanon, NH 03766, USA
| | - Michael Jermyn
- Thayer School of Engineering, Dartmouth College, Hanover NH, 03755, USA; DoseOptics, LLC, Lebanon NH 03755 USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover NH, 03755, USA; DoseOptics, LLC, Lebanon NH 03755 USA
| | - Timothy Zhu
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA, 19104 USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover NH, 03755, USA; DoseOptics, LLC, Lebanon NH 03755 USA; Department of Medical Physics, University of Wisconsin-Madison, Wisconsin WI 53705 USA.
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover NH, 03755, USA; Department of Medicine, Radiation Oncology, Norris Cotton Cancer Center, Dartmouth Hitchcock Medical Center, Lebanon, NH 03766, USA
| | - Benjamin B Williams
- Thayer School of Engineering, Dartmouth College, Hanover NH, 03755, USA; Department of Medicine, Radiation Oncology, Norris Cotton Cancer Center, Dartmouth Hitchcock Medical Center, Lebanon, NH 03766, USA
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15
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Rahman M, Ashraf R, Zhang R, Cao X, Gladstone D, Jarvis L, Hoopes P, Pogue B, Bruza P. In Vivo Cherenkov Imaging-Guided FLASH Radiotherapy. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Rahman M, Erhart K, Gladstone D, Bruza P, Thomas C, Jarvis L, Hoopes P, Pogue B, Zhang R. Intensity Modulation in Electron FLASH Radiotherapy. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.2248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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17
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Sloop A, Sunnerberg J, Bruza P, Gladstone D, Jarvis L, Jr CT, Pogue B, Zhang R, Rahman M. Comparison of Two Modified Linear Accelerators for Use in FLASH Clinical Trials. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.2153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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18
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Petusseau AF, Bruza P, Pogue BW. Protoporphyrin IX delayed fluorescence imaging: a modality for hypoxia-based surgical guidance. J Biomed Opt 2022; 27:106005. [PMID: 36217225 PMCID: PMC9549807 DOI: 10.1117/1.jbo.27.10.106005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
SIGNIFICANCE Hypoxia imaging for surgical guidance has never been possible, yet it is well known that most tumors have microregional chronic and/or cycling hypoxia present as well as chaotic blood flow. The ability to image oxygen partial pressure (pO2) is therefore a unique control of tissue metabolism and can be used in a range of disease applications to understand the complex biochemistry of oxygen supply and consumption. AIM Delayed fluorescence (DF) from the endogenous molecule protoporphyrin IX (PpIX) has been shown to be a truly unique reporter of the local oxygen partial pressure in tissue. PpIX is endogenously synthesized by mitochondria in most tissues, and the particular property of DF emission is directly related to low microenvironmental oxygen concentration. Here, it is shown that PpIX has a unique emission in hypoxic tumor tissue regions, which is measured as a DF signal in the red to near-infrared spectrum. APPROACH A time-gated imaging system was used for PpIX DF for wide field direct mapping of pO2 changes. Acquiring both prompt and DF in a rapid sequential cycle allowed for imaging oxygenation in a way that was insensitive to the PpIX concentration. By choosing adequate parameters, the video rate acquisition of pO2 images could be achieved, providing real-time tissue metabolic information. RESULTS In this report, we show the first demonstration of imaging hypoxia signals from PpIX in a pancreatic cancer model, exhibiting >5X contrast relative to surrounding normal oxygenated tissues. Additionally, tissue palpation amplifies the signal and provides intuitive temporal contrast based upon neoangiogenic blood flow differences. CONCLUSIONS PpIX DF provides a mechanism for tumor contrast that could easily be translated to human use as an intrinsic contrast mechanism for oncologic surgical guidance.
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Affiliation(s)
- Arthur F. Petusseau
- Dartmouth College, Thayer School of Engineering and Dartmouth Cancer Center, Hanover, New Hampshire, United States
| | - Petr Bruza
- Dartmouth College, Thayer School of Engineering and Dartmouth Cancer Center, Hanover, New Hampshire, United States
| | - Brian W. Pogue
- University of Wisconsin–Madison, Department of Medical Physics, Madison, Wisconsin, United States
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19
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Decker SM, Alexander DA, Bruza P, Zhang R, Chen E, Jarvis LA, Gladstone DJ, Pogue BW. Performance comparison of quantitative metrics for analysis of in vivo Cherenkov imaging incident detection during radiotherapy. Br J Radiol 2022; 95:20211346. [PMID: 35834415 PMCID: PMC10996952 DOI: 10.1259/bjr.20211346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 06/06/2022] [Accepted: 06/10/2022] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Examine the responses of multiple image similarity metrics to detect patient positioning errors in radiotherapy observed through Cherenkov imaging, which may be used to optimize automated incident detection. METHODS An anthropomorphic phantom mimicking patient vasculature, a biological marker seen in Cherenkov images, was simulated for a breast radiotherapy treatment. The phantom was systematically shifted in each translational direction, and Cherenkov images were captured during treatment delivery at each step. The responses of mutual information (MI) and the γ passing rate (%GP) were compared to that of existing field-shape matching image metrics, the Dice coefficient, and mean distance to conformity (MDC). Patient images containing other incidents were analyzed to verify the best detection algorithm for different incident types. RESULTS Positional shifts in all directions were registered by both MI and %GP, degrading monotonically as the shifts increased. Shifts in intensity, which may result from erythema or bolus-tissue air gaps, were detected most by %GP. However, neither metric detected beam-shape misalignment, such as that caused by dose to unintended areas, as well as currently employed metrics (Dice and MDC). CONCLUSIONS This study indicates that different radiotherapy incidents may be detected by comparing both inter- and intrafractional Cherenkov images with a corresponding image similarity metric, varying with the type of incident. Future work will involve determining appropriate thresholds per metric for automatic flagging. ADVANCES IN KNOWLEDGE Classifying different algorithms for the detection of various radiotherapy incidents allows for the development of an automatic flagging system, eliminating the burden of manual review of Cherenkov images.
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Affiliation(s)
- Savannah M Decker
- Thayer School of Engineering, Dartmouth College,
Hanover, New Hampshire, United
States
| | - Daniel A Alexander
- Thayer School of Engineering, Dartmouth College,
Hanover, New Hampshire, United
States
- DoseOptics LLC, Lebanon, New
Hampshire, United States
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College,
Hanover, New Hampshire, United
States
- DoseOptics LLC, Lebanon, New
Hampshire, United States
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College,
Hanover, New Hampshire, United
States
- Geisel School of Medicine, Dartmouth College,
Hanover, New Hampshire, United
States
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical
Center, Lebanon, New Hampshire,
United States
| | - Erli Chen
- Cheshire Medical Center, Keene
NH, United States
| | - Lesley A Jarvis
- Geisel School of Medicine, Dartmouth College,
Hanover, New Hampshire, United
States
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical
Center, Lebanon, New Hampshire,
United States
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College,
Hanover, New Hampshire, United
States
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College,
Hanover, New Hampshire, United
States
- DoseOptics LLC, Lebanon, New
Hampshire, United States
- Department of Medical Physics, University of
Wisconsin-Madison, Madison,
Wisconsin, United States
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20
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Zhang R, Rahman M, Bruza P, Thomas CR, Jarvis LA, Hoopes PJ, Gladstone DJ, Pogue BW. Electron flash-RT program in clinical setting for human translation. J Clin Oncol 2022. [DOI: 10.1200/jco.2022.40.16_suppl.e13596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e13596 Background: A FLASH-RT program was established at Dartmouth-Hitchcock Medical Center in minimally-modified clinical setting by joint efforts of biomedical engineering, radiation oncology, radiation biology and medical physics teams. Various projects on dosimetry, chemical sensing, molecular profiling, software/hardware development, and translational studies have been conducted. The aim is to share logistical considerations and experience on running a FLASH-RT program to support institution-wide academic activities with an ultimate goal of treating human patients with FLASH-RT in 2022. Methods: A linac was converted in the clinical setting by qualified engineers to deliver an ultra-high dose rate (UHDR) electron beam. Routine safety and dosimetry checks were done by physicists for every reversible conversion. Long-term record-keeping and retrospective surveys were carried out to demonstrate the feasibility, safety, stability and accuracy of this dual-purpose (FLASH and conventional RT) approach. Comprehensive failure mode and effects analysis (FMEA) has been completed to systematically evaluate safety related considerations. A treatment planning system (TPS) has been developed in Varian Eclipse to facilitated comparative studies. The FLASH-capable linac has been utilized as shared resource to support institution-wide academic activities as well as normal clinical treatments. Results: With its safety (no accident or FLASH-related malfunction), flexibility (> 100 conversions in 2 years), reliability (̃6000 hours in flash mode and ̃5x105 Gy accumulative dose delivered at isocenter) and accuracy (̃5% conversion-to-conversion variations) demonstrated by commissioning, long-term user experience and comprehensive FMEA analysis, the FLASH-RT platform has been actively utilized for researches in six major categories 1) FLASH beam dosimetry; 2) real-time beam delivery monitoring and control; 3) oximetry and chemical sensing; 4) preclinical/translational small/large animal treatment with tumor control and normal tissue complication endpoints, 5) treatment plan and delivery optimization; 6) the design of phase I/II trials. Key findings in each category will be reported. Conclusions: A FLASH-RT program in clinical setting is established at Dartmouth with joint efforts, promoting collaborative projects to advance FLASH-RT to clinical treatment. The system has been reliably utilized for over two years for mechanistic as well as translational studies and support a phase I/II trial treating cutaneous lymphoma with eFLASH-RT.
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Affiliation(s)
| | | | | | - Charles R. Thomas
- Geisel School of Medicine at Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH
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21
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Ashraf MR, Rahman M, Cao X, Duval K, Williams BB, Hoopes PJ, Gladstone DJ, Pogue BW, Zhang R, Bruza P. Individual pulse monitoring and dose control system for pre-clinical implementation of FLASH-RT. Phys Med Biol 2022; 67:10.1088/1361-6560/ac5f6f. [PMID: 35313290 PMCID: PMC10305796 DOI: 10.1088/1361-6560/ac5f6f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 03/21/2022] [Indexed: 11/11/2022]
Abstract
Objective.Existing ultra-high dose rate (UHDR) electron sources lack dose rate independent dosimeters and a calibrated dose control system for accurate delivery. In this study, we aim to develop a custom single-pulse dose monitoring and a real-time dose-based control system for a FLASH enabled clinical linear accelerator (Linac).Approach.A commercially available point scintillator detector was coupled to a gated integrating amplifier and a real-time controller for dose monitoring and feedback control loop. The controller was programmed to integrate dose for each radiation pulse and stop the radiation beam when the prescribed dose was delivered. Additionally, the scintillator was mounted in a solid water phantom and placed underneath mice skin forin vivodose monitoring. The scintillator was characterized in terms of its radiation stability, mean dose-rate (Ḋm), and dose per pulse (Dp) dependence.Main results.TheDpexhibited a consistent ramp-up period across ∼4-5 pulse. The plastic scintillator was shown to be linear withḊm(40-380 Gy s-1) andDp(0.3-1.3 Gy Pulse-1) to within +/- 3%. However, the plastic scintillator was subject to significant radiation damage (16%/kGy) for the initial 1 kGy and would need to be calibrated frequently. Pulse-counting control was accurately implemented with one-to-one correspondence between the intended and the actual delivered pulses. The dose-based control was sufficient to gate on any pulse of the Linac.In vivodosimetry monitoring with a 1 cm circular cut-out revealed that during the ramp-up period, the averageDpwas ∼0.045 ± 0.004 Gy Pulse-1, whereas after the ramp-up it stabilized at 0.65 ± 0.01 Gy Pulse-1.Significance.The tools presented in this study can be used to determine the beam parameter space pertinent to the FLASH effect. Additionally, this study is the first instance of real-time dose-based control for a modified Linac at ultra-high dose rates, which provides insight into the tool required for future clinical translation of FLASH-RT.
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Affiliation(s)
- M. Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Kayla Duval
- Department of Medicine, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
| | - Benjamin B. Williams
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - P. Jack Hoopes
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 03755 USA
| | - David J. Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 03755 USA
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
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22
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Hachadorian RL, Bruza P, Jermyn M, Gladstone DJ, Zhang R, Jarvis LA, Pogue BW. Remote dose imaging from cherenkov light using spatially-resolved CT calibration in breast radiotherapy. Med Phys 2022; 49:4018-4025. [PMID: 35304768 DOI: 10.1002/mp.15614] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/16/2022] [Accepted: 03/10/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Imaging Cherenkov light during radiotherapy allows the visualization and recording of frame-by-frame relative maps of the dose being delivered to the tissue at each control point used throughout treatment, providing one of the most complete real-time means of treatment quality assurance. In non-turbid media, the intensity of Cherenkov light is linear with surface dose deposited, however the emission from patient tissue is well-known to be reduced by absorbing tissue components such as hemoglobin, fat, water and melanin, and diffused by the scattering components of tissue. Earlier studies have shown that bulk correction could be achieved by using the patient planning CT scan for attenuation correction. METHODS In this study, CT maps were used for correction of spatial variations in emissivity. Testing was completed on Cherenkov images from radiotherapy treatments of post-lumpectomy breast cancer patients (n = 13), combined with spatial renderings of the patient radiodensity (CT number) from their planning CT scan. RESULTS The correction technique was shown to provide a pixel-by-pixel correction that suppressed many of the inter- and intra-patient differences in the Cherenkov light emitted per unit dose. This correction was established from a calibration curve that correlated Cherenkov light intensity to surface-rendered CT number (R6MV 2 = 0.70 and R10MV 2 = 0.72). The corrected Cherenkov intensity per unit dose standard error was reduced by nearly half (from ∼30% to ∼17%). CONCLUSIONS This approach provides evidence that the planning CT scan can mitigate some of the tissue-specific attenuation in Cherenkov images, allowing them to be translated into near surface dose images. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Petr Bruza
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,DoseOptics LLC, NH, Lebanon
| | - Michael Jermyn
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,DoseOptics LLC, NH, Lebanon
| | - David J Gladstone
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH
| | - Rongxiao Zhang
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH
| | - Lesley A Jarvis
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH
| | - Brian W Pogue
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,DoseOptics LLC, NH, Lebanon
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23
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Ashraf R, Rahman M, Zhang R, Hoopes C, Gladstone D, Williams B, Pogue B, Bruza P. FLASH Modalities Track (Oral Presentations) INDIVIDUAL PULSE MONITORING AND FEEDBACK SYSTEM FOR FLASH-RT BEAM CONTROL USING FIBER-COUPLED SCINTILLATING DETECTORS. Phys Med 2022. [DOI: 10.1016/s1120-1797(22)01458-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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24
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Cao X, Zhang R, Ashraf R, Rahman M, Gunn J, Bruza P, Gladstone D, Williams B, Swartz H, Hoopes C, Pogue B. A COMPUTATINAL ANALYSIS OF IN VIVO OXYGEN KINETICS DURING ELECTRON FLASH IRRADIATION. Phys Med 2022. [DOI: 10.1016/s1120-1797(22)01604-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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25
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Rahman M, Ashraf R, Gladstone D, Bruza P, Jarvis L, Schaner P, Gill G, Cao X, Pogue B, Hoopes C, Zhang R. FLASH in the Clinic Track (Oral Presentations) ELECTRON FLASH FOR THE CLINIC: LINAC CONVERSION, COMMISSIONING AND TREATMENT PLANNING. Phys Med 2022. [DOI: 10.1016/s1120-1797(22)01468-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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26
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Zhang R, Bruza P, Duval K, Cao X, Ashraf R, Rahman M, Gill G, Hartford A, Zaki B, Schaner P, Jarvis L, Hoopes P, Pogue B, Gladstone D. LOGISTICS OF A FLASH-RT PROGRAM IN CLINICAL SETTING. Phys Med 2022. [DOI: 10.1016/s1120-1797(22)01673-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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27
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Rahman M, Ashraf MR, Gladstone DJ, Bruza P, Jarvis LA, Schaner PE, Cao X, Pogue BW, Hoopes PJ, Zhang R. Treatment Planning System for Electron FLASH Radiotherapy: Open-source for Clinical Implementation. Int J Radiat Oncol Biol Phys 2021; 112:1023-1032. [PMID: 34762969 PMCID: PMC10386889 DOI: 10.1016/j.ijrobp.2021.10.148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 08/31/2021] [Accepted: 10/22/2021] [Indexed: 10/19/2022]
Abstract
PURPOSE A Monte Carlo (MC) beam model and its implementation in a clinical treatment planning system (TPS, Varian Eclipse) are presented for a modified ultra-high dose-rate electron FLASH radiotherapy LINAC (eFLASH-RT) utilizing clinical accessories and geometry. METHODS The gantry head without scattering foils or targets, representative of the LINAC modifications, was modelled in Geant4-based GAMOS MC toolkit. The energy spectrum (σE) and beam source emittance cone angle (θcone) were varied to match the calculated open field central-axis percent depth dose (PDD) and lateral profiles with Gafchromic film measurements. The beam model and its Eclipse configuration were validated with measured profiles of the open field and nominal fields for clinical applicators. A MC forward dose calculation was conducted for a mouse whole brain treatment and an eFLASH-RT plan was compared to a conventional (Conv-RT) electron plan in Eclipse for a human patient with metastatic renal cell carcinoma. RESULTS The eFLASH beam model agreed best with measurements at σE=0.5 MeV and θcone=3.9±0.2 degrees. The model and its Eclipse configuration were validated to clinically acceptable accuracy (the absolute average error was within 1.5% for in-water lateral, 3% for in-air lateral, and 2% for PDD's). The forward calculation showed adequate dose delivery to the entire mouse brain, while sparing the organ-at-risk (lung). The human patient case demonstrated the planning capability with routine accessories to achieve an acceptable plan (90% of the tumor volume receiving 95% and 90% of the prescribed dose for eFLASH and conventional, respectively). CONCLUSION To the best of our knowledge, this is the first functional beam model commissioned in a clinical TPS for eFLASH-RT, enabling planning and evaluation with minimal deviation from Conv-RT workflow. It facilitates the clinical translation as eFLASH-RT and Conv-RT plan quality were comparable for a human patient involving complex geometries and tissue heterogeneity. The methods can be expanded to model other eFLASH irradiators with different beam characteristics.
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Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US.
| | - M Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US; Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Lesley A Jarvis
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Philip E Schaner
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 03755 USA
| | - P Jack Hoopes
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US; Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 03755 USA
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US; Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
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28
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Alexander DA, Nomezine A, Jarvis LA, Gladstone DJ, Pogue BW, Bruza P. Color Cherenkov imaging of clinical radiation therapy. Light Sci Appl 2021; 10:226. [PMID: 34737264 PMCID: PMC8569159 DOI: 10.1038/s41377-021-00660-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 10/01/2021] [Accepted: 10/08/2021] [Indexed: 05/08/2023]
Abstract
Color vision is used throughout medicine to interpret the health and status of tissue. Ionizing radiation used in radiation therapy produces broadband white light inside tissue through the Cherenkov effect, and this light is attenuated by tissue features as it leaves the body. In this study, a novel time-gated three-channel camera was developed for the first time and was used to image color Cherenkov emission coming from patients during treatment. The spectral content was interpreted by comparison with imaging calibrated tissue phantoms. Color shades of Cherenkov emission in radiotherapy can be used to interpret tissue blood volume, oxygen saturation and major vessels within the body.
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Affiliation(s)
- Daniel A Alexander
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- DoseOptics LLC, Lebanon, NH, USA
| | - Anthony Nomezine
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Lesley A Jarvis
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- DoseOptics LLC, Lebanon, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA.
- DoseOptics LLC, Lebanon, NH, USA.
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29
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Rahman M, Ashraf M, Gladstone D, Bruza P, Jarvis L, Schaner P, Cao X, Pogue B, Hoopes P, Zhang R. Treatment Planning System for Clinical Translation of Electron FLASH Radiotherapy. Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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30
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Alexander D, Bruza P, Nomezine A, Pogue B, Jarvis L, Gladstone D. Imaging Radiotherapy-Induced Cherenkov Emission in Color. Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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31
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Rahman M, Bruza P, Hachadorian R, Alexander D, Cao X, Zhang R, Gladstone DJ, Pogue BW. Optimization of in vivo Cherenkov imaging dosimetry via spectral choices for ambient background lights and filtering. J Biomed Opt 2021; 26:JBO-210195RR. [PMID: 34643072 PMCID: PMC8510878 DOI: 10.1117/1.jbo.26.10.106003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE The Cherenkov emission spectrum overlaps with that of ambient room light sources. Choice of room lighting devices dramatically affects the efficient detection of Cherenkov emission during patient treatment. AIM To determine optimal room light sources allowing Cherenkov emission imaging in normally lit radiotherapy treatment delivery rooms. APPROACH A variety of commercial light sources and long-pass (LP) filters were surveyed for spectral band separation from the red to near-infrared Cherenkov light emitted by tissue. Their effects on signal-to-noise ratio (SNR), Cherenkov to background signal ratio, and image artifacts were quantified by imaging irradiated tissue equivalent phantoms with an intensified time-gated CMOS camera. RESULTS Because Cherenkov emission from tissue lies largely in the near-infrared spectrum, a controlled choice of ambient light that avoids this spectral band is ideal, along with a camera that is maximally sensitive to it. An RGB LED light source produced the best SNR out of all sources that mimic room light temperature. A 675-nm LP filter on the camera input further reduced ambient light detected (optical density > 3), achieving maximal SNR for Cherenkov emission near 40. Reduction of the room light signal reduced artifacts from specular reflection on the tissue surface and also minimized spurious Cherenkov signals from non-tissue features such as bolus. CONCLUSIONS LP filtering during image acquisition for near-infrared light in tandem with narrow band LED illuminated rooms improves image quality, trading off the loss of red wavelengths for better removal of room light in the image. This spectral filtering is also critically important to remove specular reflection in the images and allow for imaging of Cherenkov emission through clear bolus. Beyond time-gated external beam therapy systems, the spectral separation methods can be utilized for background removal for continuous treatment delivery methods including proton pencil beam scanning systems and brachytherapy.
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Affiliation(s)
- Mahbubur Rahman
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Petr Bruza
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Rachael Hachadorian
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Daniel Alexander
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Xu Cao
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Rongxiao Zhang
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Radiation Oncology, Hanover, New Hampshire, United States
- Dartmouth-Hitchcock Medical Center, Norris Cotton Cancer Center, Lebanon, New Hampshire, United States
| | - David J. Gladstone
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Radiation Oncology, Hanover, New Hampshire, United States
- Dartmouth-Hitchcock Medical Center, Norris Cotton Cancer Center, Lebanon, New Hampshire, United States
| | - Brian W. Pogue
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth-Hitchcock Medical Center, Norris Cotton Cancer Center, Lebanon, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Surgery, Hanover, New Hampshire, United States
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Pétusseau AF, Bruza P, Pogue BW. Survey of X-ray induced Cherenkov excited fluorophores with potential for human use. J Radiat Res 2021; 62:833-840. [PMID: 34247250 PMCID: PMC8438248 DOI: 10.1093/jrr/rrab055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/13/2021] [Indexed: 06/13/2023]
Abstract
X-ray induced molecular luminescence (XML) is a phenomenon that can be utilized for clinical, deep-tissue functional imaging of tailored molecular probes. In this study, a survey of common or clinically approved fluorophores was carried out for their megavoltage X-ray induced excitation and emission characteristics. We find that direct scintillation effects and Cherenkov generation are two possible ways to cause these molecules' excitation. To distinguish the contributions of each excitation mechanism, we exploited the dependency of Cherenkov radiation yield on X-ray energy. The probes were irradiated by constant dose of 6 MV and 18 MV X-ray radiation, and their relative emission intensities and spectra were quantified for each X-ray energy pair. From the ratios of XML, yield for 6 MV and 18 MV irradiation we found that the Cherenkov radiation dominated as an excitation mechanism, except for aluminum phthalocyanine, which exhibited substantial scintillation. The highest emission yields were detected from fluorescein, proflavin and aluminum phthalocyanine, in that order. XML yield was found to be affected by the emission quantum yield, overlap of the fluorescence excitation and Cherenkov emission spectra, scintillation yield. Considering all these factors and XML emission spectrum respective to tissue optical window, aluminum phthalocyanine offers the best XML yield for deep tissue use, while fluorescein and proflavine are most useful for subcutaneous or superficial use.
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Affiliation(s)
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
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33
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Decker SM, Alexander DA, Hachadorian RL, Zhang R, Gladstone DJ, Bruza P, Pogue BW. Estimation of diffuse Cherenkov optical emission from external beam radiation build-up in tissue. J Biomed Opt 2021; 26:JBO-210129RR. [PMID: 34545714 PMCID: PMC8451315 DOI: 10.1117/1.jbo.26.9.098003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 08/27/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE Optical imaging of Cherenkov emission during radiation therapy could be used to verify dose delivery in real-time if a more comprehensive quantitative understanding of the factors affecting emission intensity could be developed. AIM This study aims to explore the change in diffuse Cherenkov emission intensity with x-ray beam energy from irradiated tissue, both theoretically and experimentally. APPROACH Derivation of the emitted Cherenkov signal was achieved using diffusion theory, and experimental studies with 6 to 18 MV energy x-rays were performed in tissue phantoms to confirm the model predictions as related to the radiation build-up factor with depth into tissue. RESULTS Irradiation at lower x-ray energies results in a greater surface dose and higher build-up slope, which results in a ∼46 % greater diffusely emitted Cherenkov signal per unit dose at 6 MV relative to 18 MV x-rays. However, this phenomenon competes with a decrease in signal from less Cherenkov photons being generated at lower energies, a ∼44 % reduction at 6 versus 18 MV. The result is an emitted Cherenkov signal that is nearly constant with beam energy. CONCLUSIONS This study explains why the observed Cherenkov emission from tissue is not a strong function of beam energy, despite the known strong correlation between Cherenkov intensity and particle energy in the absence of build-up and scattering effects.
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Affiliation(s)
- Savannah M. Decker
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Daniel A. Alexander
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | | | - Rongxiao Zhang
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth–Hitchcock Medical Center, Lebanon, New Hampshire, United States
| | - David J. Gladstone
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth–Hitchcock Medical Center, Lebanon, New Hampshire, United States
| | - Petr Bruza
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- DoseOptics LLC, Lebanon, New Hampshire, United States
| | - Brian W. Pogue
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- DoseOptics LLC, Lebanon, New Hampshire, United States
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Cao X, Zhang R, Esipova TV, Allu SR, Ashraf R, Rahman M, Gunn JR, Bruza P, Gladstone DJ, Williams BB, Swartz HM, Hoopes PJ, Vinogradov SA, Pogue BW. Quantification of Oxygen Depletion During FLASH Irradiation In Vitro and In Vivo. Int J Radiat Oncol Biol Phys 2021; 111:240-248. [PMID: 33845146 PMCID: PMC8338745 DOI: 10.1016/j.ijrobp.2021.03.056] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 03/28/2021] [Accepted: 03/31/2021] [Indexed: 01/01/2023]
Abstract
PURPOSE Delivery of radiation at ultrahigh dose rates (UHDRs), known as FLASH, has recently been shown to preferentially spare normal tissues from radiation damage compared with tumor tissues. However, the underlying mechanism of this phenomenon remains unknown, with one of the most widely considered hypotheses being that the effect is related to substantial oxygen depletion upon FLASH, thereby altering the radiochemical damage during irradiation, leading to different radiation responses of normal and tumor cells. Testing of this hypothesis would be advanced by direct measurement of tissue oxygen in vivo during and after FLASH irradiation. METHODS AND MATERIALS Oxygen measurements were performed in vitro and in vivo using the phosphorescence quenching method and a water-soluble molecular probe Oxyphor 2P. The changes in oxygen per unit dose (G-values) were quantified in response to irradiation by 10 MeV electron beam at either UHDR reaching 300 Gy/s or conventional radiation therapy dose rates of 0.1 Gy/s. RESULTS In vitro experiments with 5% bovine serum albumin solutions at 23°C resulted in G-values for oxygen consumption of 0.19 to 0.21 mm Hg/Gy (0.34-0.37 μM/Gy) for conventional irradiation and 0.16 to 0.17 mm Hg/Gy (0.28-0.30 μM/Gy) for UHDR irradiation. In vivo, the total decrease in oxygen after a single fraction of 20 Gy FLASH irradiation was 2.3 ± 0.3 mm Hg in normal tissue and 1.0 ± 0.2 mm Hg in tumor tissue (P < .00001), whereas no decrease in oxygen was observed from a single fraction of 20 Gy applied in conventional mode. CONCLUSIONS Our observations suggest that oxygen depletion to radiologically relevant levels of hypoxia is unlikely to occur in bulk tissue under FLASH irradiation. For the same dose, FLASH irradiation induces less oxygen consumption than conventional irradiation in vitro, which may be related to the FLASH sparing effect. However, the difference in oxygen depletion between FLASH and conventional irradiation could not be quantified in vivo because measurements of oxygen depletion under conventional irradiation are hampered by resupply of oxygen from the blood.
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Affiliation(s)
- Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education & School of Life Science and Technology, Xidian University, Xi'an, Shaanxi, China
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Tatiana V Esipova
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Chemistry, School or Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Srinivasa Rao Allu
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Chemistry, School or Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Jason R Gunn
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Benjamin B Williams
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Harold M Swartz
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - P Jack Hoopes
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Chemistry, School or Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania.
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire.
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Rahman M, Ashraf MR, Zhang R, Bruza P, Dexter CA, Thompson L, Cao X, Williams BB, Hoopes PJ, Pogue BW, Gladstone DJ. Electron FLASH Delivery at Treatment Room Isocenter for Efficient Reversible Conversion of a Clinical LINAC. Int J Radiat Oncol Biol Phys 2021; 110:872-882. [PMID: 33444695 PMCID: PMC10416223 DOI: 10.1016/j.ijrobp.2021.01.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/02/2020] [Accepted: 01/07/2021] [Indexed: 12/21/2022]
Abstract
PURPOSE In this study, procedures were developed to achieve efficient reversible conversion of a clinical linear accelerator (LINAC) and deliver ultrahigh-dose-rate (UHDR) electron or conventional beams to the treatment room isocenter for FLASH radiation therapy. METHODS AND MATERIALS The LINAC was converted to deliver UHDR beam within 20 minutes by retracting the x-ray target from the beam's path, positioning the carousel on an empty port, and selecting 10 MV photon beam energy in the treatment console. Dose rate surface and depth dose profiles were measured in solid water phantom at different field sizes with Gafchromic film and an optically stimulated luminescent dosimeter (OSLD). A pulse controller counted the pulses via scattered radiation signal and gated the delivery for a preset pulse count. A fast photomultiplier tube-based Cherenkov detector measured the per pulse beam output at a 2-ns sampling rate. After conversion back to clinical mode, conventional beam output, flatness, symmetry, field size, and energy were measured for all clinically commissioned energies. RESULTS The surface average dose rates at the isocenter for 1-cm diameter and 1.5-in diameter circular fields and for a jaws-wide-open field were 238 ± 5 Gy/s, 262 ± 5 Gy/s, and 290 ± 5 Gy/s, respectively. The radial symmetry of the beams was within 2.4%, 0.5%, and 0.2%, respectively. The doses from simultaneous irradiation of film and OSLD were within 1%. The photomultiplier tube showed the LINAC required ramp up time in the first 4 to 6 pulses before the output stabilized, after which its stability was within 3%. CONCLUSIONS At the isocenter of the treatment room, 10 MeV UHDR beams were achieved. The beam output was reproducible but requires further investigation of the ramp up time, equivalent to ∼1 Gy, requiring dose monitoring. The UHDR beam can irradiate both small and large subjects to investigate potential FLASH radiobiological effects in minimally modified clinical settings, and the dose rate can be further increased by reducing the source-to-surface distance.
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Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire.
| | - M Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Chad A Dexter
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Lawrence Thompson
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Benjamin B Williams
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - P Jack Hoopes
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
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Rahman M, Ashraf MR, Zhang R, Gladstone DJ, Cao X, Williams BB, Hoopes PJ, Pogue BW, Bruza P. Spatial and temporal dosimetry of individual electron FLASH beam pulses using radioluminescence imaging. Phys Med Biol 2021; 66:10.1088/1361-6560/ac0390. [PMID: 34015774 PMCID: PMC10468779 DOI: 10.1088/1361-6560/ac0390] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 05/20/2021] [Indexed: 11/11/2022]
Abstract
Purpose.In this study, spatio-temporal beam profiling for electron ultra-high dose rate (UHDR; >40 Gy s-1) radiation via Cherenkov emission and radioluminescence imaging was investigated using intensified complementary metal-oxide-semiconductor cameras.Methods.The cameras, gated to FLASH optimized linear accelerator pulses, imaged radioluminescence and Cherenkov emission incited by single pulses of a UHDR (>40 Gy s-1) 10 MeV electron beam delivered to the isocenter. Surface dosimetry was investigated via imaging Cherenkov emission or scintillation from a solid water phantom or Gd2O2S:Tb screen positioned on top of the phantom, respectively. Projected depth-dose profiles were imaged from a tank filled with water (Cherenkov emission) and a 1 g l-1quinine sulfate solution (scintillation). These optical results were compared with projected lateral dose profiles measured by Gafchromic film at different depths, including the surface.Results.The per-pulse beam output from Cherenkov imaging agreed with the photomultiplier tube Cherenkov output to within 3% after about the first five to seven ramp-up pulses. Cherenkov emission and scintillation were linear with dose (R2 = 0.987 and 0.995, respectively) and independent of dose rate from ∼50 to 300 Gy s-1(0.18-0.91 Gy/pulse). The surface dose distribution from film agreed better with scintillation than with Cherenkov emission imaging (3%/3 mm gamma pass rates of 98.9% and 88.8%, respectively). Using a 450 nm bandpass filter, the quinine sulfate-based water imaging of the projected depth optical profiles agreed with the projected film dose to within 5%.Conclusion.The agreement of surface dosimetry using scintillation screen imaging and Gafchromic film suggests it can verify the consistency of daily beam quality assurance parameters with an accuracy of around 2% or 2 mm. Cherenkov-based surface dosimetry was affected by the target's optical properties, prompting additional calibration. In projected depth-dose profiling, scintillation imaging via spectral suppression of Cherenkov emission provided the best match to film. Both camera-based imaging modalities resolved dose from single UHDR beam pulses of up to 60 Hz repetition rate and 1 mm spatial resolution.
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Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - M. Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - David J. Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Benjamin B. Williams
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - P. Jack Hoopes
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 03755 USA
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 03755 USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
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Alexander DA, Bruza P, Rassias AG, Andreozzi JM, Pogue BW, Zhang R, Gladstone DJ. Visual Isocenter Position Enhanced Review (VIPER): a Cherenkov imaging-based solution for MR-linac daily QA. Med Phys 2021; 48:2750-2759. [PMID: 33887796 DOI: 10.1002/mp.14892] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/28/2021] [Accepted: 04/05/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE This study demonstrates a robust Cherenkov imaging-based solution to MR-Linac daily QA, including mechanical-imaging-radiation isocenter coincidence verification. METHODS A fully enclosed acrylic cylindrical phantom was designed to be mountable to the existing jig, indexable to the treatment couch. An ABS plastic conical structure was fixed inside the phantom, held in place with 3D-printed spacers, and filled with water allowing for high edge contrast on MR imaging scans. Both a star shot plan and a four-angle sheet beam plan were delivered to the phantom; the former allowed for radiation isocenter localization in the x-z plane (A/P and L/R directions) relative to physical landmarks on the phantom, and the latter allowed for the longitudinal position of the sheet beam to be encoded as a ring of Cherenkov radiation emitted from the phantom, allowing for isocenter localization on the y-axis (S/I directions). A custom software application was developed to perform near-real-time analysis of the data by any clinical user. RESULTS Calibration procedures show that linearity between longitudinal position and optical ring diameter is high (R2 > 0.99), and that RMSE is low (0.184 mm). The star shot analysis showed a minimum circle radius of 0.34 mm. The final isocenter coincidence measurements in the lateral, longitudinal, and vertical directions were -0.61 mm, 0.55 mm, and -0.14 mm, respectively, and the total 3D distance coincidence was 0.83 mm, with each of these being below 2 mm tolerance. CONCLUSION This novel system provided an efficient, MR safe, all-in-one method for acquisition and near-real-time analysis of isocenter coincidence data. This represents a direct measurement of the 3D isocentricity. The combination of this phantom and the custom analysis application makes this solution readily clinically deployable after the longitudinal analysis of performance consistency.
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Affiliation(s)
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Aris G Rassias
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | | | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
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Ashraf M, Rahman M, Zhang R, Cao X, Williams BB, Hoopes PJ, Gladstone DJ, Pogue BW, Bruza P. Technical Note: Single-pulse beam characterization for FLASH-RT using optical imaging in a water tank. Med Phys 2021; 48:2673-2681. [PMID: 33730367 PMCID: PMC10771323 DOI: 10.1002/mp.14843] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE High dose rate conditions, coupled with problems related to small field dosimetry, make dose characterization for FLASH-RT challenging. Most conventional dosimeters show significant dependence on dose rate at ultra-high dose rate conditions or fail to provide sufficiently fast temporal data for pulse to pulse dosimetry. Here fast 2D imaging of radioluminescence from a water and quinine phantom was tested for dosimetry of individual 4 μs linac pulses. METHODS A modified clinical linac delivered an electron FLASH beam of >50 Gy/s to clinical isocenter. This modification removed the x-ray target and flattening filter, leading to a beam that was symmetric and gaussian, as verified with GafChromic EBT-XD film. Lateral projected 2D dose distributions for each linac pulse were imaged in a quinine-doped water tank using a gated intensified camera, and an inverse Abel transform reconstruction provided 3D images for on-axis depth dose values. A total of 20 pulses were delivered with a 10 MeV, 1.5 cm circular beam, and beam with jaws wide open (40 × 40 cm2 ), and a 3D dose distribution was recovered for each pulse. Beam output was analyzed on a pulse by pulse basis. RESULTS The Rp , Dmax , and the R50 measured with film and optical methods agreed to within 1 mm for the 1.5 cm circular beam and the beam with jaws wide open. Cross beam profiles for both beams agreed with film data with >95% passing rate (2%/2 mm gamma criteria). The optical central axis depth dose agreed with film data, except for near the surface. A temporal pulse analysis revealed a ramp-up period where the dose per pulse increased for the first few pulses and then stabilized. CONCLUSIONS Optical imaging of radioluminescence was presented as a valuable tool for establishing a baseline for the recently initiated electron FLASH beam at our institution.
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Affiliation(s)
- M.Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Benjamin B. Williams
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - P. Jack Hoopes
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 0375 USA
| | - David J. Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 0375 USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
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Hachadorian R, Farwell JC, Bruza P, Jermyn M, Gladstone DJ, Pogue BW, Jarvis LA. Verification of field match lines in whole breast radiation therapy using Cherenkov imaging. Radiother Oncol 2021; 160:90-96. [PMID: 33892022 DOI: 10.1016/j.radonc.2021.04.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 03/17/2021] [Accepted: 04/09/2021] [Indexed: 01/05/2023]
Abstract
PURPOSE In mono-isocentric radiation therapy treatment plans designed to treat the whole breast and supraclavicular lymph nodes, the fields meet at isocenter, forming the match line. Insufficient coverage at the match line can lead to recurrence, and overlap over weeks of treatment can lead to increased risk of healthy tissue toxicity. Cherenkov imaging was used to assess the accuracy of delivery at the match line and identify potential incidents during patient treatments. METHODS AND MATERIALS A controlled calibration was constructed from the deconvolved Cherenkov images from the delivery of a modified patient treatment plan to an anthropomorphic phantom with introduced separation and overlap. The trend from this calibration was then used to evaluate the field match line for accuracy and inter-fraction consistency for two patients. RESULTS The intersection point between matching field profiles was directly correlated to the distance (gap/overlap) between the fields (anthropomorphic phantom R2 = 0.994 "breath hold" and R2 = 0.990 "free breathing"). The profile intersection points from two patients' imaging sessions yielded an average of +1.40 mm offset (overlap) and -1.32 mm offset (gap), thereby introducing roughly a 25.0% over-dose and a -23.6% under-dose (R2 = 0.994). CONCLUSIONS This study shows that field match regions can be detected and quantified by taking deconvolved Cherenkov images and using their product image to create steep intensity gradients, causing match lines to stand out. These regions can then be quantitatively translated into a dose consequence. This approach offers a high sensitivity detection method which can quantify match line variability and errors in vivo.
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Affiliation(s)
| | | | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, United States
| | - Michael Jermyn
- Thayer School of Engineering, Dartmouth College, Hanover, United States; DoseOptics LLC, Lebanon, United States
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, United States; Norris Cotton Cancer Center at Dartmouth Hitchcock Medical Center, Lebanon, United States; Geisel School of Medicine, Dartmouth College, Hanover, United States
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, United States; DoseOptics LLC, Lebanon, United States; Norris Cotton Cancer Center at Dartmouth Hitchcock Medical Center, Lebanon, United States; Geisel School of Medicine, Dartmouth College, Hanover, United States
| | - Lesley A Jarvis
- Norris Cotton Cancer Center at Dartmouth Hitchcock Medical Center, Lebanon, United States; Geisel School of Medicine, Dartmouth College, Hanover, United States.
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Jarvis LA, Hachadorian RL, Jermyn M, Bruza P, Alexander DA, Tendler II, Williams BB, Gladstone DJ, Schaner PE, Zaki BI, Pogue BW. Initial Clinical Experience of Cherenkov Imaging in External Beam Radiation Therapy Identifies Opportunities to Improve Treatment Delivery. Int J Radiat Oncol Biol Phys 2021; 109:1627-1637. [PMID: 33227443 PMCID: PMC10544920 DOI: 10.1016/j.ijrobp.2020.11.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 10/05/2020] [Accepted: 11/05/2020] [Indexed: 12/18/2022]
Abstract
PURPOSE The value of Cherenkov imaging as an on-patient, real-time, treatment delivery verification system was examined in a 64-patient cohort during routine radiation treatments in a single-center study. METHODS AND MATERIALS Cherenkov cameras were mounted in treatment rooms and used to image patients during their standard radiation therapy regimen for various sites, predominantly for whole breast and total skin electron therapy. For most patients, multiple fractions were imaged, with some involving bolus or scintillators on the skin. Measures of repeatability were calculated with a mean distance to conformity (MDC) for breast irradiation images. RESULTS In breast treatments, Cherenkov images identified fractions when treatment delivery resulted in dose on the contralateral breast, the arm, or the chin and found nonideal bolus positioning. In sarcoma treatments, safe positioning of the contralateral leg was monitored. For all 199 imaged breast treatment fields, the interfraction MDC was within 7 mm compared with the first day of treatment (with only 7.5% of treatments exceeding 3 mm), and all but 1 fell within 7 mm relative to the treatment plan. The value of imaging dose through clear bolus or quantifying surface dose with scintillator dots was examined. Cherenkov imaging also was able to assess field match lines in cerebral-spinal and breast irradiation with nodes. Treatment imaging of other anatomic sites confirmed the value of surface dose imaging more broadly. CONCLUSIONS Daily radiation therapy can be imaged routinely via Cherenkov emissions. Both the real-time images and the posttreatment, cumulative images provide surrogate maps of surface dose delivery that can be used for incident discovery and/or continuous improvement in many delivery techniques. In this initial 64-patient cohort, we discovered 6 minor incidents using Cherenkov imaging; these otherwise would have gone undetected. In addition, imaging provides automated, quantitative metrics useful for determining the quality of radiation therapy delivery.
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Affiliation(s)
- Lesley A Jarvis
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.
| | | | - Michael Jermyn
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - Petr Bruza
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | | | - Irwin I Tendler
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - Benjamin B Williams
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire; Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - David J Gladstone
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire; Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - Philip E Schaner
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Bassem I Zaki
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Brian W Pogue
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
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Rahman M, Ramish Ashraf M, Zhang R, Bruza P, Dexter CA, Thompson L, Cao X, Williams BB, Jack Hoopes P, Pogue BW, Gladstone DJ. In Reply to Newell et al. Int J Radiat Oncol Biol Phys 2021; 110:909-910. [PMID: 33811977 DOI: 10.1016/j.ijrobp.2021.03.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 03/23/2021] [Indexed: 11/18/2022]
Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - M Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Chad A Dexter
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Lawrence Thompson
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Benjamin B Williams
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - P Jack Hoopes
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
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Zhu TC, Ong Y, Sun H, Zhong W, Miao T, Dimofte A, Bruza P, Maity A, Plastaras JP, Paydar I, Dong L, Pogue BW. Cherenkov imaging for Total Skin Electron Therapy - an evaluation of dose uniformity. Proc SPIE Int Soc Opt Eng 2021; 11628:116280R. [PMID: 34083857 PMCID: PMC8171222 DOI: 10.1117/12.2583939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Total Skin Electron Therapy (TSET) utilizes high-energy electrons to treat cancers on the entire body surface. The otherwise invisible radiation beam can be observed via the optical Cherenkov photons emitted from interaction between the high-energy electron beam and tissue. Cherenkov emission can be used to evaluate the dose uniformity on the surface of the patient in real-time using a time-gated intensified camera system. Each patient was monitored during TSET by in-vivo detectors (IVD) as well as Scintillators. Patients undergoing TSET in various conditions (whole body and half body) were imaged and analyzed. A rigorous methodology for converting Cherenkov intensity to surface dose as products of correction factors, including camera vignette correction factor, incident radiation correction factor, and tissue optical properties correction factor. A comprehensive study has been carried out by inspecting various positions on the patients such as vertex, chest, perineum, shins, and foot relative to the umbilicus point (the prescription point).
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Affiliation(s)
- Timothy C. Zhu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Yihong Ong
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Hongjin Sun
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Weili Zhong
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Tianshun Miao
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
| | - Andreea Dimofte
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
| | - Amit Maity
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - John P. Plastaras
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Ima Paydar
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Lei Dong
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
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Pogue BW, Zhang R, Cao X, Jia JM, Petusseau A, Bruza P, Vinogradov SA. Review of in vivo optical molecular imaging and sensing from x-ray excitation. J Biomed Opt 2021; 26:JBO-200308VR. [PMID: 33386709 PMCID: PMC7778455 DOI: 10.1117/1.jbo.26.1.010902] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/24/2020] [Indexed: 05/05/2023]
Abstract
SIGNIFICANCE Deep-tissue penetration by x-rays to induce optical responses of specific molecular reporters is a new way to sense and image features of tissue function in vivo. Advances in this field are emerging, as biocompatible probes are invented along with innovations in how to optimally utilize x-ray sources. AIM A comprehensive review is provided of the many tools and techniques developed for x-ray-induced optical molecular sensing, covering topics ranging from foundations of x-ray fluorescence imaging and x-ray tomography to the adaptation of these methods for sensing and imaging in vivo. APPROACH The ways in which x-rays can interact with molecules and lead to their optical luminescence are reviewed, including temporal methods based on gated acquisition and multipoint scanning for improved lateral or axial resolution. RESULTS While some known probes can generate light upon x-ray scintillation, there has been an emergent recognition that excitation of molecular probes by x-ray-induced Cherenkov light is also possible. Emission of Cherenkov radiation requires a threshold energy of x-rays in the high kV or MV range, but has the advantage of being able to excite a broad range of optical molecular probes. In comparison, most scintillating agents are more readily activated by lower keV x-ray energies but are composed of crystalline inorganic constituents, although some organic biocompatible agents have been designed as well. Methods to create high-resolution structured x-ray-optical images are now available, based upon unique scanning approaches and/or a priori knowledge of the scanned x-ray beam geometry. Further improvements in spatial resolution can be achieved by careful system design and algorithm optimization. Current applications of these hybrid x-ray-optical approaches include imaging of tissue oxygenation and pH as well as of certain fluorescent proteins. CONCLUSIONS Discovery of x-ray-excited reporters combined with optimized x-ray scan sequences can improve imaging resolution and sensitivity.
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Affiliation(s)
- Brian W. Pogue
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
- Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, United States
| | - Rongxiao Zhang
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
- Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, United States
| | - Xu Cao
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
| | - Jeremy Mengyu Jia
- Stanford University School of Medicine, Department of Radiation Oncology, Palo Alto, California, United States
| | - Arthur Petusseau
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
| | - Petr Bruza
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
| | - Sergei A. Vinogradov
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts of Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
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Vincent P, Bruza P, Palisoul SM, Gunn JR, Samkoe KS, Hoopes PJ, Hasan T, Pogue BW. Visualization and quantification of pancreatic tumor stroma in fresh tissue via ultraviolet surface excitation. J Biomed Opt 2021; 26:JBO-200312R. [PMID: 33423407 PMCID: PMC7850982 DOI: 10.1117/1.jbo.26.1.016002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/11/2020] [Indexed: 05/11/2023]
Abstract
SIGNIFICANCE The study has confirmed the feasibility of using ultraviolet (UV) excitation to visualize and quantify desmoplasia in fresh tumor tissue of pancreatic adenocarcinoma (PDAC) in an orthotopic xenograft mouse model, which provides a useful imaging platform to evaluate acute therapeutic responses. AIM Stromal network of collagen prominent in PDAC tumors is examined by imaging fresh tissue samples stained with histological dyes. Fluorescence signals are color-transferred to mimic Masson's trichrome staining. APPROACH Murine tumor samples were stained with Hoechst, eosin, and rhodamine B and excited at 275-nm. Fluorescence signals in the visible spectrum were captured by a CMOS color camera with high contrast and resolution at whole-tumor slice field of view. RESULTS Fluorescence imaging using UV excitation is capable of visualizing collagen deposition in PDAC tumors. Both fluorescence and histology data showed collagen content of up to 30%. The collagen modulation effect due to photodynamic priming treatment was observed showing 13% of collagen reduction. Necrosis area is visible and perfusion imaging using Texas Red dextran is feasible. CONCLUSIONS The study demonstrates collagen visualization in fresh PDAC tumor samples using UV excitation. This imaging platform also provides quantitative stromal information from fiber analysis and visibility of necrosis and perfusion, suitable for therapeutic response assessment of photodynamic therapy.
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Affiliation(s)
- Phuong Vincent
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Address all correspondence to Phuong Vincent,
| | - Petr Bruza
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Scott M. Palisoul
- Dartmouth-Hitchock Pathology Shared Resource Lab, Lebanon, New Hampshire, United States
| | - Jason R. Gunn
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Kimberley S. Samkoe
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - P. Jack Hoopes
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Geisel School of Medicine, Department of Surgery, Hanover, New Hampshire, United States
| | - Tayyaba Hasan
- Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
| | - Brian W. Pogue
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Geisel School of Medicine, Department of Surgery, Hanover, New Hampshire, United States
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Rahman M, Bruza P, Lin Y, Gladstone DJ, Pogue BW, Zhang R. Producing a Beam Model of the Varian ProBeam Proton Therapy System using TOPAS Monte Carlo Toolkit. Med Phys 2020; 47:6500-6508. [PMID: 33030241 PMCID: PMC10760485 DOI: 10.1002/mp.14532] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/31/2020] [Accepted: 09/16/2020] [Indexed: 11/08/2022] Open
Abstract
PURPOSE A Geant4-based TOPAS Monte Carlo toolkit was utilized to model a Varian ProBeam proton therapy system, with the aim of providing an independent computational platform for validating advanced dosimetric methods. MATERIALS AND METHODS The model was tested for accuracy of dose and linear energy transfer (LET) prediction relative to the commissioning data, which included integral depth dose (IDD) in water and spot profiles in air measured at varying depths (for energies of 70 to 240 MeV in increments of 10 MeV, and 242 MeV), and absolute dose calibration. Emittance was defined based on depth-dependent spot profiles and Courant-Snyder's particle transport theory, which provided spot size and angular divergence along the inline and crossline plane. Energy spectra were defined as Gaussian distributions that best matched the range and maximum dose of the IDD. The validity of the model was assessed based on measurements of range, dose to peak difference, mean point to point difference, spot sizes at different depths, and spread-out Bragg peak (SOBP) IDD and was compared to the current treatment planning software (TPS). RESULTS Simulated and commissioned spot sizes agreed within 2.5%. The single spot IDD range, maximum dose, and mean point to point difference of each commissioned energy agreed with the simulated profiles generally within 0.07 mm, 0.4%, and 0.6%, respectively. A simulated SOBP plan agreed with the measured dose within 2% for the plateau region. The protons/MU and absolute dose agreed with the current TPS to within 1.6% and exhibited the greatest discrepancy at higher energies. CONCLUSIONS The TOPAS model agreed well with the commissioning data and included inline and crossline asymmetry of the beam profiles. The discrepancy between the measured and TOPAS-simulated SOBP plan may be due to beam modeling simplifications of the current TPS and the nuclear halo effect. The model can compute LET, and motivates future studies in understanding equivalent dose prediction in treatment planning, and investigating scintillation quenching.
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Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
| | - Yuting Lin
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA 30322
| | - David J. Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
- Department of Medicine, Geisel School of Medicine at Dartmouth, Hanover NH 03755
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
- Department of Medicine, Geisel School of Medicine at Dartmouth, Hanover NH 03755
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Cao X, Jiang S, Gunn JR, Bruza P, Pogue BW. Single pixel hyperspectral Cherenkov-excited fluorescence imaging with LINAC X-ray sheet scanning and spectral unmixing. Opt Lett 2020; 45:6130-6133. [PMID: 33186932 DOI: 10.1364/ol.401286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
Cherenkov light induced from megavolt (MV) X-rays during external beam radiotherapy serves as an internal light source to excite phosphors or fluorophores within biological tissues for molecular imaging. The broad spectrum of Cherenkov light leads to significant spectral overlap with any luminescence emission and, to overcome this problem, a single pixel hyperspectral imaging methodology was demonstrated here by coupling the detection with light sheet scanning and filtered back projection reconstruction of hyperspectral images. Thin scanned sheets of MV X-rays produce Cherenkov light to illuminate the planes deep within the tissue-simulating media. A fluorescence probe was excited by Cherenkov light, and a complete hyperspectral sinogram of the data was obtained through translation and rotation of the beam. Hyperspectral 2D images finally were reconstructed. Through this approach of spectral unmixing, it was possible to resolve hyperspectral images of both the Cherenkov and resulting fluorescence intensity from molecular sensors.
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Alexander DA, Bruza P, Farwell JCM, Krishnaswamy V, Zhang R, Gladstone DJ, Pogue BW. Detective quantum efficiency of intensified CMOS cameras for Cherenkov imaging in radiotherapy. Phys Med Biol 2020; 65:225013. [PMID: 33179612 PMCID: PMC10416224 DOI: 10.1088/1361-6560/abb0c5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In this study the metric of detective quantum efficiency (DQE) was applied to Cherenkov imaging systems for the first time, and results were compared for different detector hardware, gain levels and with imaging processing for noise suppression. Intensified complementary metal oxide semiconductor cameras using different image intensifier designs (Gen3 and Gen2+) were used to image Cherenkov emission from a tissue phantom in order to measure the modulation transfer function (MTF) and noise power spectrum (NPS) of the systems. These parameters were used to calculate the DQE for varying acquisition settings and image processing steps. MTF curves indicated that the Gen3 system had superior contrast transfer and spatial resolution than the Gen2+ system, with [Formula: see text] values of 0.52 mm-1 and 0.31 mm-1, respectively. With median filtering for noise suppression, these values decreased to 0.50 mm-1 and 0.26 mm-1. The maximum NPS values for the Gen3 and Gen2+ systems at high gain were 1.3 × 106 mm2 and 9.1 × 104 mm2 respectively, representing a 14x decrease in noise power for the Gen2+ system. Both systems exhibited increased NPS intensity with increasing gain, while median filtering lowered the NPS. The DQE of each system increased with increasing gain, and at the maximum gain levels the Gen3 system had a low-frequency DQE of 0.31%, while the Gen2+ system had a value of 1.44%. However, at a higher frequency of 0.4 mm-1, these values became 0.54% and 0.03%. Filtering improved DQE for the Gen3 system and reduced DQE for the Gen2+ system and had a mix of detrimental and beneficial qualitative effects by decreasing the spatial resolution and sharpness but also substantially lowering noise. This methodology for DQE measurement allowed for quantitative comparison between Cherenkov imaging cameras and improvements to their sensitivity, and yielded the first formal assessment of Cherenkov image formation efficiency.
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Affiliation(s)
- Daniel A Alexander
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, United States of America
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, United States of America
| | | | | | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, United States of America
- Gesiel School of Medicine, Dartmouth College, Hanover, NH 03755, United States of America
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, United States of America
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, United States of America
- Gesiel School of Medicine, Dartmouth College, Hanover, NH 03755, United States of America
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, United States of America
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, United States of America
- DoseOptics LLC, Lebanon, NH 03766, United States of America
- Gesiel School of Medicine, Dartmouth College, Hanover, NH 03755, United States of America
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, United States of America
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Hachadorian R, Farwell C, Gladstone D, Bruza P, Pogue B, Jarvis L. Using Cherenkov Imaging to Verify Anterior Field Match Lines between Supraclavicular and Tangent Whole Breast Irradiation Fields. Int J Radiat Oncol Biol Phys 2020. [DOI: 10.1016/j.ijrobp.2020.07.770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Cao X, Gunn JR, Allu SR, Bruza P, Jiang S, Vinogradov SA, Pogue BW. Implantable sensor for local Cherenkov-excited luminescence imaging of tumor pO2 during radiotherapy. J Biomed Opt 2020; 25:JBO-200229SSR. [PMID: 33236619 PMCID: PMC7685386 DOI: 10.1117/1.jbo.25.11.112704] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 11/04/2020] [Indexed: 05/16/2023]
Abstract
SIGNIFICANCE The necessity to use exogenous probes for optical oxygen measurements in radiotherapy poses challenges for clinical applications. Options for implantable probe biotechnology need to be improved to alleviate toxicity concerns in human use and facilitate translation to clinical trial use. AIM To develop an implantable oxygen sensor containing a phosphorescent oxygen probe such that the overall administered dose of the probe would be below the Federal Drug Administration (FDA)-prescribed microdose level, and the sensor would provide local high-intensity signal for longitudinal measurements of tissue pO2. APPROACH PtG4, an oxygen quenched dendritic molecule, was mixed into an agarose matrix at 100 μM concentration, allowing for local injection into tumors at the total dose of 10 nmol per animal, forming a gel at the site of injection. Cherenkov-excited luminescence imaging (CELI) was used to acquire the phosphorescence and provide intratumoral pO2. RESULTS Although PtG4 does not form covalent bonds with agarose and gradually leaches out into the surrounding tissue, its retention time within the gel was sufficiently long to demonstrate the capability to measure intratumoral pO2 with the implantable gel sensors. The sensor's performance was first evaluated in vitro in tissue simulation phantoms, and then the sensor was used to measure changes in oxygen in MDA-MB-231 tumors during hypofractionated radiotherapy. CONCLUSIONS Our study demonstrates that implantable oxygen sensors in combination with CELI present a promising approach for quantifying oxygen changes during the course of radiation therapy and thus for evaluating the tumor response to radiation. By improving the design of the gel-probe composition in order to prevent leaching of the probe into the tissue, biosensors can be created that should allow longitudinal oxygen measurements in tumors by means of CELI while using FDA-compliant microdose levels of the probe and thus lowering toxicity concerns.
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Affiliation(s)
- Xu Cao
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Ministry of Education, Xidian University, Engineering Research Center of Molecular and Neuroimaging, School of Life Science and Technology, Xi’an, Shaanxi, China
- Address all correspondence to Xu Cao, ; Brian W. Pogue,
| | - Jason R. Gunn
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Srinivasa Rao Allu
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School or Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Petr Bruza
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Shudong Jiang
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States
| | - Sergei A. Vinogradov
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School or Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Brian W. Pogue
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States
- Address all correspondence to Xu Cao, ; Brian W. Pogue,
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Cao X, Yao C, Jiang S, Gunn J, Van Namen AC, Bruza P, Pogue BW. Time-gated luminescence imaging for background free in vivo tracking of single circulating tumor cells. Opt Lett 2020; 45:3761-3764. [PMID: 32630948 DOI: 10.1364/ol.391350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/26/2020] [Indexed: 05/20/2023]
Abstract
Fluorescence imaging is severely limited by the background and autofluorescence of tissues for in vivo detection of circulating tumor cells (CTCs). Time-gated luminescence (TGL) imaging, in combination with luminescent probes that possess hundreds of microsecond emission lifetimes, can be used to effectively suppress this background, which has predominantly nanosecond lifetimes. This Letter demonstrates the feasibility of TGL imaging using luminescent probes for the in vivo real time imaging and tracking of single CTCs circulating freely in the blood vessels with higher accuracy given by substantially higher signal-to-noise ratio. The luminescent probe used in this Letter was a commercial Eu3+ chelate (EuC) nanosphere with a super-long lifetime of near 800 µs, which enabled TGL imaging to achieve background-free detection with ∼5 times higher SNR versus steady state. Phantom and in vivo mouse studies indicated that EuC labeled tumor cells moving in medium or bloodstream at the speed of 1-2 mm/s could be captured in real time.
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