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Goddu SM, Hao Y, Ji Z, Setianegara J, Liu F, Green W, Sobotka LG, Zhao T, Perkins S, Darafsheh A. High spatiotemporal resolution scintillation imaging of pulsed pencil beam scanning proton beams produced by a gantry-mounted synchrocyclotron. Med Phys 2024; 51:4996-5006. [PMID: 38748998 DOI: 10.1002/mp.17116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/23/2024] [Accepted: 04/18/2024] [Indexed: 07/10/2024] Open
Abstract
BACKGROUND A dosimeter with high spatial and temporal resolution would be of significant interest for pencil beam scanning (PBS) proton beams' characterization, especially when facing small fields and beams with high temporal dynamics. Optical imaging of scintillators has potential in providing sub-millimeter spatial resolution with pulse-by-pulse basis temporal resolution when the imaging system is capable of operating in synchrony with the beam-producing accelerator. PURPOSE We demonstrate the feasibility of imaging PBS proton beams as they pass through a plastic scintillator detector to simultaneously obtain multiple beam parameters, including proton range, pencil beam's widths at different depths, spot's size, and spot's position on a pulse-by-pulse basis with sub-millimeter resolution. MATERIALS AND METHODS A PBS synchrocyclotron was used for proton irradiation. A BC-408 plastic scintillator block with 30 × 30 × 5 cm3 size, and another block with 30 × 30 × 0.5 cm3 size, positioned in an optically sealed housing, were used sequentially to measure the proton range, and spot size/location, respectively. A high-speed complementary metal-oxide-semiconductor (CMOS) camera system synchronized with the accelerator's pulses through a gating module was used for imaging. Scintillation images, captured with the camera directly facing the 5-cm-thick scintillator, were corrected for background (BG), and ionization quenching of the scintillator to obtain the proton range. Spots' position and size were obtained from scintillation images of the 0.5-cm-thick scintillator when a 45° mirror was used to reflect the scintillation light toward the camera. RESULTS Scintillation images with 0.16 mm/pixel resolution corresponding to all proton pulses were captured. Pulse-by-pulse analysis showed that variations of the range, spots' position, and size were within ± 0.2% standard deviation of their average values. The absolute ranges were within ± 1 mm of their expected values. The average spot-positions were mostly within ± 0.8 mm and spots' sigma agreed within 0.2 mm of the expected values. CONCLUSION Scintillation-imaging PBS beams with high-spatiotemporal resolution is feasible and may help in efficient and cost-effective acceptance testing and commissioning of existing and even emerging technologies such as FLASH, grid, mini-beams, and so forth.
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Affiliation(s)
- S Murty Goddu
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Yao Hao
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Zhen Ji
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Jufri Setianegara
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Fengwei Liu
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Winter Green
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Lee G Sobotka
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Tianyu Zhao
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Stephanie Perkins
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Arash Darafsheh
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
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Yamamoto S, Yamashita T, Yoshino M, Kamada K, Yoshikawa A, Nishio T, Kataoka J. Scintillation of polyester fabric and clothing via proton irradiation and its utilization in surface imaging of proton pencil beams. Sci Rep 2024; 14:13494. [PMID: 38866842 PMCID: PMC11169216 DOI: 10.1038/s41598-024-62456-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Accepted: 05/16/2024] [Indexed: 06/14/2024] Open
Abstract
In the realm of radiation therapy, a conspicuous obstacle lies in the dearth of external observation concerning radiation beams aimed at the patient. While real-time monitoring of such beams on the patient's surface during therapy holds promise, the imaging of particle beams has thus far proven to be a formidable task. Here, we show our discovery of polyester fabrics and cloths as auspicious scintillating materials, ideally suited for the visualization of radiation beams upon the patient's surface. The light output of polyester fabrics ranged from 10 to 20% of that observed in plastic scintillators. When exposed to spot scanning proton beams, clear beam spots emerged on the surface of the polyester cloths. The movement of these scanning beams was effectively captured using a CMOS camera in a light-shield-free with lights-off environment. The resulting images provided a means for evaluating spills of the proton beams. The inherent flexibility of polyester fabrics and clothing enhances their appeal for applications in the intricate landscape of radiation therapy, promising a bright future for surface beam imaging endeavors.
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Affiliation(s)
- Seiichi Yamamoto
- Faculty of Science and Engineering, Waseda University, Tokyo, Japan.
| | | | - Masao Yoshino
- New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, Japan
| | - Kei Kamada
- New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, Japan
| | - Akira Yoshikawa
- New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, Japan
| | - Teiji Nishio
- Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Jun Kataoka
- Faculty of Science and Engineering, Waseda University, Tokyo, Japan
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Bjegovic K, Sun L, Pandey P, Grilj V, Ballesteros-Zebadua P, Paisley R, Gonzalez G, Wang S, Vozenin MC, Limoli CL, Xiang SL. 4D in vivodosimetry for a FLASH electron beam using radiation-induced acoustic imaging. Phys Med Biol 2024; 69:115053. [PMID: 38722574 DOI: 10.1088/1361-6560/ad4950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 05/09/2024] [Indexed: 06/01/2024]
Abstract
Objective. The primary goal of this research is to demonstrate the feasibility of radiation-induced acoustic imaging (RAI) as a volumetric dosimetry tool for ultra-high dose rate FLASH electron radiotherapy (FLASH-RT) in real time. This technology aims to improve patient outcomes by accurate measurements ofin vivodose delivery to target tumor volumes.Approach. The study utilized the FLASH-capable eRT6 LINAC to deliver electron beams under various doses (1.2 Gy pulse-1to 4.95 Gy pulse-1) and instantaneous dose rates (1.55 × 105Gy s-1to 2.75 × 106Gy s-1), for imaging the beam in water and in a rabbit cadaver with RAI. A custom 256-element matrix ultrasound array was employed for real-time, volumetric (4D) imaging of individual pulses. This allowed for the exploration of dose linearity by varying the dose per pulse and analyzing the results through signal processing and image reconstruction in RAI.Main Results. By varying the dose per pulse through changes in source-to-surface distance, a direct correlation was established between the peak-to-peak amplitudes of pressure waves captured by the RAI system and the radiochromic film dose measurements. This correlation demonstrated dose rate linearity, including in the FLASH regime, without any saturation even at an instantaneous dose rate up to 2.75 × 106Gy s-1. Further, the use of the 2D matrix array enabled 4D tracking of FLASH electron beam dose distributions on animal tissue for the first time.Significance. This research successfully shows that 4Din vivodosimetry is feasible during FLASH-RT using a RAI system. It allows for precise spatial (∼mm) and temporal (25 frames s-1) monitoring of individual FLASH beamlets during delivery. This advancement is crucial for the clinical translation of FLASH-RT as enhancing the accuracy of dose delivery to the target volume the safety and efficacy of radiotherapeutic procedures will be improved.
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Affiliation(s)
- Kristina Bjegovic
- The Department of Biomedical Engineering, University of California, Irvine, CA 92617, United States of America
| | - Leshan Sun
- The Department of Biomedical Engineering, University of California, Irvine, CA 92617, United States of America
| | - Prabodh Pandey
- Department of Radiological Sciences, University of California, Irvine, Irvine, CA 92697, United States of Americaica
| | - Veljko Grilj
- Laboratory of Radiation Oncology, Radiation Oncology Service and Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Paola Ballesteros-Zebadua
- Laboratory of Radiation Oncology, Radiation Oncology Service and Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- Laboratory of Medical Physics, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - Ryan Paisley
- Laboratory of Radiation Oncology, Radiation Oncology Service and Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Gilberto Gonzalez
- Department of Radiation Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, United States of America
| | - Siqi Wang
- The Department of Biomedical Engineering, University of California, Irvine, CA 92617, United States of America
| | - Marie Catherine Vozenin
- Laboratory of Radiation Oncology, Radiation Oncology Service and Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- Sector of Radiobiology applied to Radiation Oncology, Radiation Oncology Service, Geneva University Hospital and University of Geneva, Geneva, Switzerland
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA 92697-2695, United States of America
| | - Shawn Liangzhong Xiang
- The Department of Biomedical Engineering, University of California, Irvine, CA 92617, United States of America
- Department of Radiological Sciences, University of California, Irvine, Irvine, CA 92697, United States of Americaica
- Beckman Laser Institute & Medical Clinic, University of California, Irvine, Irvine, CA 92612, United States of America
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4
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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] [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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5
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Goddu SM, Westphal GT, Sun B, Wu Y, Bloch CD, Bradley JD, Darafsheh A. Synchronized high-speed scintillation imaging of proton beams, generated by a gantry-mounted synchrocyclotron, on a pulse-by-pulse basis. Med Phys 2022; 49:6209-6220. [PMID: 35760763 DOI: 10.1002/mp.15826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/09/2022] [Accepted: 06/09/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND With the emergence of more complex and novel proton delivery techniques, there is a need for quality assurance (QA) tools with high spatiotemporal resolution to conveniently measure the spatial and temporal properties of the beam. In this context, scintillation-based dosimeters, if synchronized with the radiation beam and corrected for ionization quenching, are appealing. PURPOSE To develop a synchronized high-speed scintillation imaging system for characterization and verification of the proton therapy beams on a pulse-by-pulse basis. MATERIALS AND METHODS A 30 cm × 30 cm × 5 cm block of BC-408 plastic scintillator placed in a light-tight housing was irradiated by proton beams generated by a Mevion S250TM proton therapy synchrocyclotron. A high-speed camera system, placed perpendicular to the beam direction and facing the scintillator, was synchronized to the accelerator's pulses to capture images. Opening and closing of the camera's shutter was controlled by setting a proper time delay and exposure time, respectively. The scintillation signal was recorded as a set of two-dimensional (2D) images. Empirical correction factors were applied to the images to correct for the non-uniformity of the pixel sensitivity and quenching of the scintillator. Proton range and modulation were obtained from the corrected images. RESULTS The camera system was able to capture all data on a pulse-by-pulse basis at a rate of ∼504 frames per second. The applied empirical correction method for ionization quenching was effective and the corrected composite image provided a 2D map of dose distribution. The measured range (depth of distal 90%) through scintillation imaging agreed within 1.2 mm with that obtained from ionization chamber measurement. CONCLUSION A high-speed camera system capable of capturing scintillation signals from individual proton pulses was developed. The scintillation imaging system is promising for rapid proton beam characterization and verification. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- S Murty Goddu
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | | | - Baozhou Sun
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Yu Wu
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Charles D Bloch
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, WA, 98133, USA
| | - Jeffrey D Bradley
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA, 30308, USA
| | - Arash Darafsheh
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
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6
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Cloutier É, Beaulieu L, Archambault L. Direct in-water radiation dose measurements using Cherenkov emission corrected signals from polarization imaging for a clinical radiotherapy application. Sci Rep 2022; 12:9608. [PMID: 35688843 PMCID: PMC9187683 DOI: 10.1038/s41598-022-12672-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 05/12/2022] [Indexed: 11/08/2022] Open
Abstract
Cherenkov emission (CE) is a visible blueish light emitted in water mediums irradiated by most radiotherapy treatment beams. However, CE is produced anisotropically which currently imposes a geometrical constraint uncertainty for dose measurements. In this work, polarization imaging is proposed and described as a method enabling precise 2D dose measurements using CE. CE produced in a water tank is imaged from four polarization angles using a camera coupled to a rotating polarizer. Using Malus' law, the polarized component of CE is isolated and corrected with Monte Carlo calculated CE polar and azimuthal angular distributions. Projected dose measurements resulting from polarization-corrected CE are compared to equivalent radiochromic film measurements. Overall, agreement between polarized corrected CE signal and films measurements is found to be within 3%, for projected percent depth dose (PPDD) and profiles at the different tested energies ([Formula: see text]: 6 and [Formula: see text], e[Formula: see text]: 6 and 18[Formula: see text]). In comparison, raw Cherenkov emission presented deviations up 60% for electron beam PPDDs and 20% for photon beams PPDDs. Finally, a degree of linear polarization between 29% and 47% was measured for CE in comparison to [Formula: see text]% for scintillation. Hence, polarization imaging is found to be a promising and powerful method for improved radio-luminescent dose measurements with possible extensions to signal separation.
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Affiliation(s)
- Émily Cloutier
- Centre Intégré de cancérologie and Axe Oncologie du CRCHU de Québec - Université Laval, CHU de Québec - Université Laval, Québec, G1R 2J6, Canada.
- Département de physique, de génie physique et d'optique, et Centre de recherche sur le cancer, Université Laval, Québec, G1V 0A6, Canada.
| | - Luc Beaulieu
- Centre Intégré de cancérologie and Axe Oncologie du CRCHU de Québec - Université Laval, CHU de Québec - Université Laval, Québec, G1R 2J6, Canada
- Département de physique, de génie physique et d'optique, et Centre de recherche sur le cancer, Université Laval, Québec, G1V 0A6, Canada
| | - Louis Archambault
- Centre Intégré de cancérologie and Axe Oncologie du CRCHU de Québec - Université Laval, CHU de Québec - Université Laval, Québec, G1R 2J6, Canada.
- Département de physique, de génie physique et d'optique, et Centre de recherche sur le cancer, Université Laval, Québec, G1V 0A6, Canada.
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Abstract
Malignant tumors rank as a leading cause of death worldwide. Accurate diagnosis and advanced treatment options are crucial to win battle against tumors. In recent years, Cherenkov luminescence (CL) has shown its technical advantages and clinical transformation potential in many important fields, particularly in tumor diagnosis and treatment, such as tumor detection in vivo, surgical navigation, radiotherapy, photodynamic therapy, and the evaluation of therapeutic effect. In this review, we summarize the advances in CL for tumor diagnosis and treatment. We first describe the physical principles of CL and discuss the imaging techniques used in tumor diagnosis, including CL imaging, CL endoscope, and CL tomography. Then we present a broad overview of the current status of surgical resection, radiotherapy, photodynamic therapy, and tumor microenvironment monitoring using CL. Finally, we shed light on the challenges and possible solutions for tumor diagnosis and therapy using CL.
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8
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Cloutier E, Archambault L, Beaulieu L. Accurate dose measurements using cherenkov emission polarization imaging. Med Phys 2022; 49:5417-5422. [PMID: 35502867 DOI: 10.1002/mp.15693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 02/21/2022] [Accepted: 05/02/2022] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Cherenkov radiation carries the potential of direct in-water dose measurements, but its precision is currently limited by a strong anisotropy. Taking advantage of polarization imaging, this work proposes a new approach for high accuracy Cherenkov emission dose measurements. METHODS Cherenkov radiation produced in a 15 × 15 × 20 cm3 water tank is imaged with a cooled CCD camera from four polarizer transmission axes [0°, 45°, 90°, 135°]. The water tank is positioned at the isocenter of a 5 × 5 cm2 , 6 MV and 18 MV photon beam. Using Malus' law, the polarized portion of the signal is extracted. Corrections are applied to the polarized signal following azimuthal and polar Cherenkov emission angular distributions extracted from Monte Carlo simulations. Projected percent depth dose and beam profiles are measured and compared with the prediction from a treatment planning system (TPS). RESULTS Corrected polarized signals on the central axis reduced deviations at depth (mean ± std) from 8±5% to 0.8 ±1% at 6 MV and 8±7% to 1±3% at 18 MV. For the profile measurement, differences between the corrected polarized signal and the TPS calculations are 1±3% and 2±3% on the central axis at 6 MV and 18 MV respectively. In these conditions, Cherenkov emission is shown to be partly polarized. CONCLUSIONS This work proposes a novel polarization imaging approach enabling high precision water-based dose measurements using Cherenkov radiation. The method allows correction of the Cherenkov emission anisotropy within 4% on the beam central axis and in depth. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Emily Cloutier
- Physics, physical engineering and optics department and Cancer Research Center, Universite Laval, Quebec, Canada.,CHU de Quebec - Universite Laval, CHU de Quebec, Quebec, Canada
| | - Louis Archambault
- Physics, physical engineering and optics department and Cancer Research Center, Universite Laval, Quebec, Canada.,CHU de Quebec - Universite Laval, CHU de Quebec, Quebec, Canada
| | - Luc Beaulieu
- Physics, physical engineering and optics department and Cancer Research Center, Universite Laval, Quebec, Canada.,CHU de Quebec - Universite Laval, CHU de Quebec, Quebec, Canada
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Yamamoto S, Yabe T, Hu N, Kanai Y, Tanaka H, Ono K. Optical imaging of lithium-containing zinc sulfate plate in water during irradiation of neutrons from boron neutron capture therapy (BNCT) system. Med Phys 2021; 49:1822-1830. [PMID: 34958515 DOI: 10.1002/mp.15424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 11/29/2021] [Accepted: 12/06/2021] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Optical imaging of ionizing radiation is a possible method for dose distribution measurements. However, it is not clear whether the imaging method is also applicable to neutrons. To clarify this, we performed the imaging of neutrons in water from boron neutron capture therapy (BNCT) systems. Such systems require efficient distribution measurements of neutrons for quality assessment (QA) of the beams. METHOD A water-filled phantom was irradiated from the side with an epithermal neutron beam, in which a lithium-containing zinc sulfate (Li-ZnS(Ag)) plate was set in the beam direction, and during this irradiation the scintillation of the plate was imaged using a cooled CCD camera. In the imaging, Li-6 in the Li-ZnS(Ag) plate captures neutrons and converts them to alpha particles (He-4) and tritium (H-3), while ZnS(Ag) in the Li-ZnS(Ag) plate produces scintillation light in the plate. We also conducted Monte Carlo simulation and compared its results with the experimental results. RESULTS The image of the emitted light from the Li-ZnS(Ag) plate was clearly obtained with an imaging time of 0.5 s. The depth and lateral profiles of the measured image using the Li-ZnS(Ag) plate showed the same shapes as the neutron distributions measured with gold foil, within a difference of 8%. The destructive effect of neutrons on the CCD camera increased ∼3 times, but the unit was still working after the measurement. CONCLUSION The optical imaging of neutrons in water is possible, and it has the potential to be a new method for efficient QA as well as for research on neutrons. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Seiichi Yamamoto
- Department of Integrated Health Science, Nagoya University Graduate School of Medicine
| | - Takuya Yabe
- Department of Integrated Health Science, Nagoya University Graduate School of Medicine.,Department of Radiation Technology, Nagoya University Hospital
| | - Naonori Hu
- Kansai BNCT Medical Center, Osaka Medical College
| | - Yasukazu Kanai
- Kansai BNCT Medical Center, Osaka Medical College.,Department of Biofunctional Analysis, Osaka University of Pharmaceutical Science
| | - Hiroki Tanaka
- Institute for Integrated Radiation and Nuclear Science, Kyoto University
| | - Koji Ono
- Kansai BNCT Medical Center, Osaka Medical College
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10
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Yamamoto S, Yabe T, Akagi T. Increase in the intensity of an optical signal with fluorescein during proton and carbon-ion irradiation. J Appl Clin Med Phys 2021; 22:188-197. [PMID: 34124832 PMCID: PMC8292686 DOI: 10.1002/acm2.13309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/05/2021] [Accepted: 05/10/2021] [Indexed: 11/25/2022] Open
Abstract
Purpose Although the imaging of luminescence emitted in water during irradiation of protons and carbon ions is a useful method for range and dose estimations, the intensity of the images is relatively low due to the low photon production of the luminescence phenomenon. Therefore, a relatively long time is required for the imaging. Since a fluorescent dye, fluorescein, may increase the intensity of the optical signal, we measured the luminescence images of water with different concentrations of fluorescein during irradiation of protons and carbon ions and compared the results with those by measurements with water. Methods A cooled charge‐coupled device (CCD) camera was used for imaging a water phantom with different concentrations of fluorescein from 0.0063 to 0.025 mg/cm3, in addition to a water phantom without fluorescein during irradiation of 150‐MeV protons and 241.5‐MeV/n carbon ions. Results For both protons and carbon ions, the intensity of the luminescence images increased as the concentration of fluorescein increased. With a fluorescein concentration of 0.025 mg/cm3, the intensities increased to more than 10 times those of water for both protons and carbon ions. Although the shape of the depth profiles of luminescence images of water with fluorescein appeared similar to that of water for protons, those for carbon ions were different from those of water due to the increase in the Cherenkov light component at shallow depths by the decrease in the angular dependencies of the Cherenkov light. Conclusion We confirmed the increase in intensity of the luminescence of water by adding fluorescein for particle ions. With a small amount of Cherenkov light contamination in the images, such as protons, the relative distributions of the luminescence images with fluorescein were similar to that of water and will be used for range or dose determination in a short time.
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Affiliation(s)
- Seiichi Yamamoto
- Department of Integrated Health Science, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takuya Yabe
- Department of Integrated Health Science, Nagoya University Graduate School of Medicine, Nagoya, Japan.,Department of Medical Technology, Nagoya University Hospital, Nagoya, Japan
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11
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Yamamoto S, Yabe T, Akagi T. Possibility evaluation of the optical imaging of proton mini-beams. Phys Med Biol 2021; 66. [PMID: 34010817 DOI: 10.1088/1361-6560/ac02d7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 05/19/2021] [Indexed: 11/11/2022]
Abstract
Proton therapy using mini-beams is a promising method to reduce radiation damage to normal tissue. However, distribution measurements of mini-beams are difficult due to their small structures. Since optical imaging is a possible method to measure high-resolution two-dimensional dose distribution, we conducted optical imaging of an acrylic block during the irradiation of mini-beams of protons. Mini-beams were made from a proton pencil beam irradiated to 1 mm slits made of tungsten plate. During irradiation of the mini-beams to the acrylic block, we measured the luminescence of the acrylic block using a charge-coupled device camera. With the measurements, we could obtain slit beam images that have slit shapes in the shallow area while they were uniform in their Bragg peaks, which was similar to the case of simulated optical images by Monte Carlo simulations. We confirmed that high-resolution optical imaging of mini-beams is possible and provides a promising method for efficient quality assessment of mini-beams as well as research on mini-beam therapy.
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Affiliation(s)
- Seiichi Yamamoto
- Department of Integrated Health Science, Nagoya University Graduate School of Medicine, Japan
| | - Takuya Yabe
- Department of Integrated Health Science, Nagoya University Graduate School of Medicine, Japan.,Department of Medical Technology, Nagoya University Hospital, Japan
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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] [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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Li Y, Liu H, Huang N, Wang Z, Zhang C. Analysis of corrected Cerenkov emission during electron radiotherapy by Monte Carlo method. Appl Radiat Isot 2021; 168:109481. [PMID: 33658131 DOI: 10.1016/j.apradiso.2020.109481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 10/09/2020] [Accepted: 10/15/2020] [Indexed: 10/23/2022]
Abstract
Cerenkov emission during electron radiotherapy had been emerging as a new dose assessment approach for clinical radiotherapy and could be imaged through a standard commercial camera. The purpose of this work aimed to study the accuracy of corrected Cerenkov emission method during electron radiotherapy by Monte Carlo (MC) method. GAMOS MC software was used to model the physics of electron therapy and calculated dose and Cerenkov photon distribution in water phantom. Compared to ionization chamber and diode measurement, MC simulated dose discrepancy was less than 1% in percentage depth dose (PDD) curves and less than. 2% in crossline profile curves, which was acceptable for clinical criterion. Compared to ionization chamber dose measurement, MC simulated Cerenkov discrepancy was less than 2% in crossline profile distribution, which was acceptable for clinical criterion. However, the Cerenkov PDD curves tended to overestimate the dose at the build-up region and underestimate the dose at the remaining attenuation region. After increasing the Cerenkov distribution depth to 2-3 mm, the discrepancy became well within 1% at the remaining attenuation region, which was acceptable for clinical criterion. Therefore, corrected Cerenkov emission could be used to assess PDD accuracy and crossline profile accuracy during electron radiotherapy.
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Affiliation(s)
- Yi Li
- State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710119, China; School of Physics, Xi'an Jiaotong University, Xi'an, 710049, China; University of Chinese Academy of Science, Beijing, 100084, China
| | - Hongjun Liu
- State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710119, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China.
| | - Nan Huang
- State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710119, China
| | - Zhaolu Wang
- State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710119, China
| | - Chunmin Zhang
- School of Physics, Xi'an Jiaotong University, Xi'an, 710049, China.
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14
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Simiele E, Viscariello N, DeWerd L. Monte Carlo modeling of the influence of strong magnetic fields on the stem-effect in plastic scintillation detectors used in radiotherapy dosimetry. Med Phys 2021; 48:1381-1394. [PMID: 33283279 DOI: 10.1002/mp.14637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/03/2020] [Accepted: 11/23/2020] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To investigate the impact of strong magnetic fields on the stem-effect in plastic scintillation detectors (PSDs) using Monte Carlo methods. METHODS Prior to building the light guide model, the properties of the Čerenkov process in GEANT4 were investigated by simulating depth-dose and depth-Čerenkov emission profiles in water as functions of Čerenkov process input parameters. In addition, profile simulations were performed for magnetic field strengths ranging from 0 T to 1.5 T. A PMMA light guide was constructed in GEANT4 using data from the manufacturer and literature. Simulations were performed with the model as functions of depth and fiber-beam angle where the simulated stem-effect spectrum and the Čerenkov light ratio (CLR) were scored and compared to measured data in the literature. The light guide optical properties were iteratively adjusted until agreement between the simulated and measured data was achieved. Simulations were performed with the validated model as functions of depth and magnetic field strength and the simulated data were compared to measured data in the literature. The model was also used to evaluate the sensitivity of the CLR to the various optical properties of the light guide in different irradiation conditions. RESULTS No significant changes in the depth-dose or depth-Čerenkov emission profiles were observed with step-size restrictions imposed by the Čerenkov process input parameters, which was attributed to the condensed history algorithm and transport parameters used in this work. Similar changes in the depth-dose and depth-Čerenkov emission profiles were observed with increasing magnetic field strength, which indicates the Čerenkov process is not adversely impacted by the presence of the magnetic field. Following optimization of the light guide optical properties, agreement within two standard deviations was observed between the simulated and measured optical data for all validation geometries considered. Agreement within one standard deviation was observed between the simulated and measured data for all depths and field strengths ≥0 T whereas discrepancies were observed for magnetic field strengths <-0.35 T. These significant differences were attributed to insufficient measurement data for this irradiation configuration during model validation. Of the light guide optical properties investigated, the fluorescence signal had the greatest impact on the CLR sensitivity to the magnetic field. CONCLUSIONS No significant change in the Čerenkov emission per dose in water was observed for magnetic field strengths up to 1.5 T. The nominal fiber fluorescence signal was found to have a significant impact on the CLR sensitivity to varying irradiation conditions where changes up to 11.7% were observed whereas the mirror reflectivity and fiber attenuation had a modest impact with maximum CLR changes of 2.6% and 1.2% relative to 0 T, respectively. The results of this work suggest light guides with low fiber fluorescence should be used with PSDs for dosimetry measurements in magnetic fields to minimize the impact of the magnetic field on the CLR correction.
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Affiliation(s)
- E Simiele
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - N Viscariello
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - L DeWerd
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
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15
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Pratt EC, Tamura R, Grimm J. Cerenkov Imaging. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00028-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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16
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Yamamoto S, Ninomiya K, Kawamura N, Hirano Y. Optical imaging of muons. Sci Rep 2020; 10:20790. [PMID: 33244067 PMCID: PMC7691342 DOI: 10.1038/s41598-020-76652-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/30/2020] [Indexed: 12/04/2022] Open
Abstract
Optical imaging of particle beams is a promising method for range and width estimations. However it was not clear that optical imaging was possible for muons. To clarify this, we conducted optical imaging of muons, since high-intensity muons are now available at J-PARC. We irradiated positive muons with different momenta to water or plastic scintillator block, and imaged using a charge-coupled device (CCD) camera during irradiation. The water and plastic scintillator block produced quite different images. The images of water during irradiation of muons produced elliptical shape light distribution at the end of the ranges due to Cherenkov-light from the positrons produced by positive muon decay, while, for the plastic scintillator block, we measured images similar to the dose distributions. We were able to estimate the ranges of muons as well as the measurement of the asymmetry of the direction of the positron emission by the muon decays from the optical images of the water, although the measured ranges were 4 mm to 5 mm larger than the calculated values. The ranges and widths of the beams could also be estimated from the optical images of the plastic scintillator block. We confirmed that optical imaging of muons was possible and is a promising method for the quality assessment, research of muons, and the future muon radiotherapy.
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Affiliation(s)
- Seiichi Yamamoto
- Department of Integrated Health Science, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Kazuhiko Ninomiya
- Department of Chemistry, Osaka University Graduate School of Science, Osaka, Japan
| | | | - Yoshiyuki Hirano
- Department of Integrated Health Science, Nagoya University Graduate School of Medicine, Nagoya, Japan
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17
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Step-size effect on calculated photon and electron beam Cherenkov-to-dose conversion factors. Phys Med 2020; 78:32-37. [PMID: 32916557 DOI: 10.1016/j.ejmp.2020.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 08/10/2020] [Accepted: 08/13/2020] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Previous work presented and validated in-water Cherenkov emission (CE)-based radiotherapy dosimetry. Condensed history Monte Carlo (MC)-calculated electron beam CE-to-dose conversion with <4π CE detection, however, could exhibit step-size dependence. This work presents a physics update and numerical study of this step-size dependence in photon and electron beams, elucidates the CE generation physics, and guides further research. METHODS The CE-to-dose conversion, kCθ±δθ, is calculated for photons (6X, 15X) and electrons (6E, 20E) on-axis in-water with: θ±δθ∈{90°±90°(4π),90°±5°,45°±45°,90°±45°}, 10 cm equivalent square, 100 cm SSD, 1cm voxel radius and beam-dependent length. Relative deviation from single-scattering (SS) simulation is evaluated on maximum fractional electron step energy loss ESTEPE∈0.01-0.25. Standard uncertainties (k=1, 108histories) are reported. A simplified method considering only the straight step direction is also implemented. RESULTS No significant step-size effect (>0.1%) was observed for dose and all kCθ±δθ, except for surface dosimetry at 90°±5° (-1.6%±0.5%, 20E), which is not recommended. Electron SS deviation uncertainties (k=1), otherwise, varied from <0.2% overall to <0.1% with large apertures. Photon uncertainties varied from <1.1% overall to <0.2% non-superficially with large apertures. The simplified straight-step method exhibited overall greater deviation from SS, most notably -2.8%±0.1% (6E) and -2.5%±0.4% (20E) superficially with 90°±45°, and -1.4%±0.3% (6X) and -0.6%±0.2% (15X) non-superficially with 90°±5° for ESTEPE∈[0.10,0.25]. CONCLUSIONS We demonstrate step-size independence of newly-implemented correction in EGSnrc directional Cherenkov calculations. This advances clinical CE-based dosimetry and is useful for the general Monte Carlo community.
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18
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Yogo K, Matsushita A, Tatsuno Y, Shimo T, Hirota S, Nozawa M, Ozawa S, Ishiyama H, Yasuda H, Nagata Y, Hayakawa K. Imaging Cherenkov emission for quality assurance of high-dose-rate brachytherapy. Sci Rep 2020; 10:3572. [PMID: 32108157 PMCID: PMC7046619 DOI: 10.1038/s41598-020-60519-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 02/12/2020] [Indexed: 11/26/2022] Open
Abstract
With advances in high-dose-rate (HDR) brachytherapy, the importance of quality assurance (QA) is increasing to ensure safe delivery of the treatment by measuring dose distribution and positioning the source with much closer intervals for highly active sources. However, conventional QA is time-consuming, involving the use of several different measurement tools. Here, we developed simple QA method for HDR brachytherapy based on the imaging of Cherenkov emission and evaluated its performance. Light emission from pure water irradiated by an 192Ir γ-ray source was captured using a charge-coupled device camera. Monte Carlo calculations showed that the observed light was primarily Cherenkov emissions produced by Compton-scattered electrons from the γ-rays. The uncorrected Cherenkov light distribution, which was 5% on average except near the source (within 7 mm from the centre), agreed with the dose distribution calculated using the treatment planning system. The accuracy was attributed to isotropic radiation and short-range Compton electrons. The source positional interval, as measured from the light images, was comparable to the expected intervals, yielding spatial resolution similar to that permitted by conventional film measurements. The method should be highly suitable for quick and easy QA investigations of HDR brachytherapy as it allows simultaneous measurements of dose distribution, source strength, and source position using a single image.
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Affiliation(s)
- Katsunori Yogo
- Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-minami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan.
- Graduate School of Medical Science, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa, 252-0373, Japan.
| | - Akihiro Matsushita
- Graduate School of Medical Science, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa, 252-0373, Japan
| | - Yuya Tatsuno
- Graduate School of Medical Science, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa, 252-0373, Japan
| | - Takahiro Shimo
- Department of Radiology, Tokyo Nishi Tokushukai Hospital, 3-1-1 Matsubara-cho, Akishima, Tokyo, 196-0003, Japan
| | - Seiko Hirota
- Department of Radiation Biophysics, Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8553, Japan
| | - Marika Nozawa
- School of Medicine, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa, 252-0373, Japan
| | - Shuichi Ozawa
- Hiroshima High Precision Radiotherapy Cancer Center, 3-2-2 Futabanosato, Higashi-ku, Hiroshima, 732-0057, Japan
- Department of Radiation Oncology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
| | - Hiromichi Ishiyama
- Graduate School of Medical Science, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa, 252-0373, Japan
- School of Medicine, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa, 252-0373, Japan
| | - Hiroshi Yasuda
- Department of Radiation Biophysics, Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8553, Japan
| | - Yasushi Nagata
- Hiroshima High Precision Radiotherapy Cancer Center, 3-2-2 Futabanosato, Higashi-ku, Hiroshima, 732-0057, Japan
- Department of Radiation Oncology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
| | - Kazushige Hayakawa
- Graduate School of Medical Science, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa, 252-0373, Japan
- School of Medicine, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa, 252-0373, Japan
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Xie Y, Petroccia H, Maity A, Miao T, Zhu Y, Bruza P, Pogue BW, Plastaras JP, Dong L, Zhu TC. Cherenkov imaging for total skin electron therapy (TSET). Med Phys 2020; 47:201-212. [PMID: 31665544 PMCID: PMC7050296 DOI: 10.1002/mp.13881] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 10/16/2019] [Accepted: 10/16/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Total skin electron therapy (TSET) utilizes high-energy electrons to treat malignancies on the entire body surface. The otherwise invisible radiation beam can be observed via the optical Cherenkov photons emitted from interactions between the high-energy electron beam and tissue. METHODS AND MATERIALS With a time-gated intensified camera system, the Cherenkov emission can be used to evaluate the dose uniformity on the surface of the patient in real time. Fifteen patients undergoing TSET in various conditions (whole body and half body) were imaged and analyzed. Each patient was monitored during TSET via in vivo detectors (IVD) in nine locations. For accurate Cherenkov imaging, a comparison between IVD and Cherenkov profiles was conducted using a polyvinyl chloride board to establish the perspective corrections. RESULTS AND DISCUSSION With proper corrections developed in this study including the perspective and inverse square corrections, the Cherenkov imaging provided two-dimensional maps proportional to dose and projected on patient skin. The results of ratio between chest and umbilicus points were in good agreement with in vivo point dose measurements, with a standard deviation of 2.4% compared to OSLD measurements. CONCLUSIONS Cherenkov imaging is a viable tool for validating patient-specific dose distributions during TSET.
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Affiliation(s)
- Yunhe Xie
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Heather Petroccia
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Amit Maity
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tianshun Miao
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
| | - Yihua Zhu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - 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
- DoseOptics LLC, Lebanon, NH 03756, USA
| | - John P. Plastaras
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lei Dong
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Timothy C. Zhu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA
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Oraiqat I, DeBruin S, Pearce R, Como C, Mikell J, Taylor C, Way J, Suarez M, Rehemtulla A, Clarke R, El Naqa I. Silicon Photomultipliers for Deep Tissue Cerenkov Emission Detection During External Beam Radiotherapy. IEEE PHOTONICS JOURNAL 2019; 11:6802316. [PMID: 33747354 PMCID: PMC7971172 DOI: 10.1109/jphot.2019.2931845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Cerenkov Emission (CE) during external beam radiation therapy (EBRT) from a linear accelerator (Linac) has been demonstrated as a useful tool for radiotherapy quality assurance and potentially other applications for online tracking of tumors during treatment delivery. However, some of the current challenges that are impacting the potential of CE are related to the limited detection sensitivity and the lack of flexible tools to fit into an already complex treatment delivery environment. Silicon photomultiplier (SiPM) solid-state devices are new promising tools for low light detection due to their extreme sensitivity that mirrors photomultiplier tubes and yet have a form factor that is similar to silicon photodiodes, allowing for improved flexibility in device design that may help in the process of wider clinical applicability. In this work, we assess the feasibility of using SiPMs to detect CE during EBRT from a Linac and contrast their performance with commercially available silicon photodiodes (PDs). We demonstrate the feasibility of the SiPM based probes for standard dosimetry measurements. We also demonstrate that CE optical signals can be detected from tissue depths about five times greater than that for standard probes based on PDs, making our SiPM probe an enabling technology of CE measurements, particularly for deep tissue applications.
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Affiliation(s)
- Ibrahim Oraiqat
- Radiation Oncology Department, University of Michigan, Ann Arbor, MI 48109 USA
| | | | - Robin Pearce
- Biomedical Engineering Department, University of Michigan, Ann Arbor, MI 48108 USA
| | - Christopher Como
- Biomedical Engineering Department, University of Michigan, Ann Arbor, MI 48108 USA
| | - Justin Mikell
- Radiation Oncology Department, University of Michigan, Ann Arbor, MI 48109 USA
| | - Charles Taylor
- Biomedical Engineering Department, University of Michigan, Ann Arbor, MI 48108 USA
| | - John Way
- Biomedical Engineering Department, University of Michigan, Ann Arbor, MI 48108 USA
| | - Manuel Suarez
- Biomedical Engineering Department, University of Michigan, Ann Arbor, MI 48108 USA
| | - Alnawaz Rehemtulla
- Radiation Oncology Department, University of Michigan, Ann Arbor, MI 48109 USA
| | - Roy Clarke
- Endectra, LLC, Ann Arbor, MI 48109 USA
- Physics Department, University of Michigan, Ann Arbor, MI 48109 USA
| | - Issam El Naqa
- Radiation Oncology Department, University of Michigan, Ann Arbor, MI 48109 USA
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Brost E, Watanabe Y. Space-variant deconvolution of Cerenkov light images acquired from a curved surface. Med Phys 2019; 46:4021-4036. [PMID: 31274192 DOI: 10.1002/mp.13698] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/22/2019] [Accepted: 06/26/2019] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Cerenkov photons are generated by high-energy radiation used in external beam radiation therapy (EBRT). This study expands upon the Cerenkov light dosimetry formula previously developed to relate an image of Cerenkov photons to the primary beam fluence. Extension of this formulation allows for deconvolution to be performed on images acquired from curved geometries. METHODS The integral equation, which represented the formation of Cerenkov photon image from an incident high-energy photon beam, was expanded to allow for space-variance of the convolution kernel called as the Cerenkov scatter function (CSF). The GAMOS (Geant4-based Architecture for Medicine-Oriented Simulations) Monte Carlo (MC) particle simulation software was used to obtain the CSF for different incident beam angles. The image of a curved surface was first projected to a flat plane by using a perspective correction method. Then, the planar image was partitioned into small segments (or blocks), where a CSF corresponding to a specific beam incident angle was applied for deconvolution. The block size and the margin around the block were optimized by studying the effects of those parameters on the deconvolution accuracy for a test image. We evaluated three deconvolution techniques: Richardson-Lucy, Blind, and Total Variation minimization (TV/L2) algorithms, to select the most accurate method for the current applications. RESULTS Analysis of deconvolution algorithms showed that the TV/L2 method provided the most accurate solution to the deconvolution problem for Cerenkov imaging. Optimization of space-variant deconvolution parameters showed that including a margin that is at least 42.9% of the image width provided the most accurate product image. There was no optimal size for the deconvolution area and should be chosen based on the presence of unique CSF kernels within an image. Space-variant deconvolution improved measured field size in Cerenkov photon images by 7.37%, as compared with 1.74% by space-invariant deconvolution. Space-variant deconvolution improved measured penumbra by 99.3%, as compared with 76.7% by space-invariant deconvolution. Space-variant deconvolution introduced artifacts in flat regions of the beam. Artifacts were avoided through selective space-variant deconvolution in only the penumbra region. CONCLUSIONS Primary photon fluence distributions of a curved surface can be obtained by using space-variant deconvolution methods in Cerenkov light dosimetry. The TV/L2 algorithm is the best method for deconvolution of Cerenkov photon images from an open-field beam derived from either a flat or curved surface. The partition size chosen for space-variant deconvolution should be at least six times the full width at half maximum (FWHM) of the corresponding scatter kernel used in deconvolution. Space-variant deconvolution is necessary if the incident beam angle difference is larger than 6 ∘ between regions of an image.
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Affiliation(s)
- Eric Brost
- Department of Radiation Oncology, University of Minnesota, 420 Delaware St. SE, Minneapolis, MN, MMC-494, USA
| | - Yoichi Watanabe
- Department of Radiation Oncology, University of Minnesota, 420 Delaware St. SE, Minneapolis, MN, MMC-494, USA
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22
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Hirano Y, Yamamoto S. Estimation of the fractions of luminescence of water at higher energy than Cerenkov-light threshold for various types of radiation. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-9. [PMID: 31218874 PMCID: PMC6977019 DOI: 10.1117/1.jbo.24.6.066005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 05/21/2019] [Indexed: 06/09/2023]
Abstract
Although the luminescence of water at a lower energy than the Cerenkov-light (CL) threshold has been found for various types of radiation, the fractions of the luminescence of water to the total produced light have not been obvious for radiations at a higher energy than the CL threshold because it is difficult to separate these two types of light. Thus, we used a Monte Carlo simulation to estimate the fractions of the luminescence of water for various types of radiation at a higher energy than the CL threshold to confirm the major component of the produced light. After we confirmed that the estimated light production of the luminescence of water could adequately simulate the experimental results, we calculated the produced light photons of this luminescence and the CL from water for protons (170 MeV), carbon ions (330 MeV/n), high-energy x-ray (6 MV) from a linear accelerator (LINAC), high-energy electrons (9 MeV) from LINAC, positrons (F-18, C-11, O-15, and N-13), and high-energy gamma photon radionuclides (Co-60). For protons, the major fraction of the produced light was the luminescence of water in addition to the CL from the prompt gamma photons produced by the nuclear interactions. For carbon ions, the major fraction of the produced light was the luminescence of water and the CL produced by the secondary electrons in addition to the prompt gamma photons produced by the nuclear interactions. For high-energy x-ray and electrons from LINAC, the fractions of luminescence of water were ∼0.1 % to 0.2%. The fractions of luminescence of water for positrons were 0.2% to 1.5% and that for Co-60 was 0.4%. We conclude that the major fractions of light produced from x-ray and electrons from LINAC, positron radionuclides, and the Co-60 source are CL, with fractions of the luminescence of water from <0.1 % to 1.5%.
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Affiliation(s)
- Yoshiyuki Hirano
- Nagoya University Graduate School of Medicine, Department of Radiological and Medical Laboratory Sciences, Nagoya, Japan
| | - Seiichi Yamamoto
- Nagoya University Graduate School of Medicine, Department of Radiological and Medical Laboratory Sciences, Nagoya, Japan
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Zlateva Y, Muir BR, Seuntjens JP, El Naqa I. Cherenkov emission-based external radiotherapy dosimetry: II. Electron beam quality specification and uncertainties. Med Phys 2019; 46:2383-2393. [PMID: 30706493 DOI: 10.1002/mp.13413] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 01/06/2019] [Accepted: 01/15/2019] [Indexed: 11/05/2022] Open
Abstract
PURPOSE Cherenkov emission (CE) is ubiquitous in external radiotherapy. It is also unique in that it carries the promise of 3D, micrometer-resolution, perturbation-free, in-water dosimetry with a beam quality-independent detector response calibration. Our aim is to bring CE-based dosimetry into the clinic and we motivate this here with electron beams. We Monte Carlo (MC) calculate and characterize broad-beam CE-to-dose conversion factors in water for a clinically representative library of electron beam qualities, address beam quality specification and reference depth selection, and develop a preliminary uncertainty budget based on our MC results and relative experimental work of a companion study (Paper I). METHODS Broad electron beam CE-to-dose conversion factors k C θ ± δ θ include CE generated at polar angles θ ± δθ on beam axis in water. With modifications to the EGSnrc code SPRRZnrc, k C θ ± δ θ factors are calculated for a total of 20 electron beam qualities from four BEAMnrc models (Varian Clinac 2100C/D, Clinac 21EX, TrueBeam, and Elekta Precise). We examine beam quality, depth, and detection angle dependence for θ ± δ θ = 90 ∘ ± 90 ∘ (4π detection), 90 ∘ ± 5 ∘ , 45 ∘ ± 45 ∘ , and 90 ∘ ± 45 ∘ . As discussed in Paper I, 4π detection offers the strongest CE-dose correlation and θ = 90 ∘ with small δθ is most practical. The two additional configurations are considered as a compromise between these two extremes. We address beam quality specification and reference depth selection in terms of the electron beam quality specifier R 50 , obtained from the depth of 50% CE C 50 , and derive a best-case uncertainty budget for the CE-based dosimetry formalism proposed in Paper I at each detection configuration. RESULTS The k C θ ± δ θ factor was demonstrated to capture variations in the beam spectrum, angle, photon contamination, and electron fluence below the CE threshold (∼260 keV in the visible) in accordance with theory. The root-mean-square deviation and maximum deviation of a second-order polynomial fit of simulated R 50 values in terms of C 50 were 0.05 and 0.11 mm at 4π and 0.20 and 0.33 mm at 90 ∘ ± 5 ∘ detection, respectively. The fit performance on experimental data in Paper I was in agreement with these values within experimental uncertainties (±1.5 mm, 95% CI). A two-term power function fit of k C θ ± δ θ in terms of R 50 at a reference depth d ref = a R 50 + b resulted in total d ref -dependent dose uncertainty contribution estimate of 0.8% and 1.1% and preliminary best-case estimate of the combined standard dose uncertainty of 1.1% and 1.3% at 4π and 90 ∘ ± 5 ∘ detection, respectively. The results and corresponding uncertainties with the two intermediate apertures were generally of the same order as the 4π case. In addition, a theoretically consistent downstream shift of the percent-depth CE (PDC) by the difference between R 50 and C 50 improved the depth dependence of the 4π conversion by an order of magnitude (±2.8%). Therefore, a large aperture centered on a θ value between 45 ∘ and 90 ∘ combined with a downstream PDC shift may be recommended for beam-axis CE-based electron beam dosimetry in water. CONCLUSIONS By delivering R 50 -based CE-to-dose conversion data and demonstrating the potential for dosimetric uncertainty on the order of 1%, we bring CE-based electron beam dosimetry closer to clinical realization.
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Affiliation(s)
- Yana Zlateva
- Medical Physics Unit, McGill University, Montreal, QC, H4A 3J1, Canada
| | - Bryan R Muir
- Metrology Research Centre, National Research Council Canada, Ottawa, ON, K1A 0R6, Canada
| | - Jan P Seuntjens
- Medical Physics Unit, McGill University, Montreal, QC, H4A 3J1, Canada
| | - Issam El Naqa
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, 48103-4943, USA
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Zlateva Y, Muir BR, El Naqa I, Seuntjens JP. Cherenkov emission-based external radiotherapy dosimetry: I. Formalism and feasibility. Med Phys 2019; 46:2370-2382. [PMID: 31034637 DOI: 10.1002/mp.13414] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 01/06/2019] [Accepted: 01/07/2019] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Cherenkov emission (CE)-based external beam dosimetry is envisioned to involve the detection of CE directly in water with placement of a high-resolution detector out of the field, avoiding perturbations encountered with traditional dosimeters. In this work, we lay out the groundwork for its implementation in the clinic and motivate CE-based dosimeter design efforts. To that end, we examine a formalism for broad-beam in-water CE-based dosimetry of external radiotherapy beams, design and test a Monte Carlo (MC) simulation framework for the calculation of CE-to-dose conversion factors used by the formalism, and demonstrate the experimental feasibility of this method. METHODS The formalism is conceptually analogous to ionization-based dosimetry and employs CE-to-dose conversion factors, k C θ ± δ θ , including only and all CE generated within polar angles θ ± δθ on beam axis. The EGSnrc user code SPRRZnrc is modified to calculate k C θ ± δ θ , as well as CE spectral and angular distributions. The modified code is tested with monoenergetic parallel electrons on a thin water slab. Detector configurations are examined for broad 6-22 MeV electron beams from a BEAMnrc TrueBeam model, with a focus on θ ± δ θ = 90 ∘ ± 90 ∘ (4π detection), 90 ∘ ± 5 ∘ , and 42 ∘ ± 5 ∘ ( θ = 42 ∘ is the CE angle of relativistic electrons in water). We perform a relative experimental validation at 90 ∘ with electron beams, using a simple detector design with spherical optics and geometrical optics approximation of the sensitive volume, which spans the water tank. Due to transient charged particle equilibrium, broad photon beams are generally less sensitive to beam quality, depth, and angle. RESULTS For 0.1-50 MeV electrons on a thin water slab, the code outputs CE photon spectral density per unit mass (calculated from dose and k C θ ± δ θ ) and angle in agreement with theory within ±0.03% and ± 0 . 01 ∘ , respectively, corresponding to the output precision. The 42 ∘ configuration was found impractical due to detection considerations. Detection at 90 ∘ ± δ θ for small δθ exhibited beam quality dependence of the same order as well as strong superficial depth dependence. A 4π configuration ameliorates these effects. A more practical approach may employ a large numerical aperture. In comparing with literature, we find that these effects are less pronounced for broad photon beams in water, as expected. Measured relative k C 90 ∘ ± δ θ at small δθ were within 1% of simulated factors (relative to their local average) for percent-depth CE (PDC) >50%. At other depths, deviations were in accordance with signal-to-noise, known detector limitations, and approximations. It was found that the CE spectrum is beam quality and depth invariant, while for electron beams the CE angular distribution is strongly dependent on beam quality and depth. However, the uncertainty of CE and PDC measurement at 90 ∘ ± δ θ detection for small δθ due to ± 0 . 1 ∘ deviations around δθ was shown to be ≤1% and <0.1% (k = 1), respectively. The robustness to expected detector setup variations was found to result in ≤1% (k = 1) local uncertainty contribution for PDC >50%. CONCLUSIONS Based on our MC and experimental studies, we conclude that the CE-based method is promising for high-resolution, perturbation-free, three-dimensional dosimetry in water, with specific applications contingent on comprehensive detector development and characterization.
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Affiliation(s)
- Yana Zlateva
- Medical Physics Unit, McGill University, Montreal, QC, H4A 3J1, Canada
| | - Bryan R Muir
- Metrology Research Centre, National Research Council Canada, Ottawa, ON, K1A 0R6, Canada
| | - Issam El Naqa
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, 48103-4943, USA
| | - Jan P Seuntjens
- Medical Physics Unit, McGill University, Montreal, QC, H4A 3J1, Canada
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Hirano Y, Yamamoto S. Angular dependencies of Cerenkov-light in water for carbon-ion, high energy x-ray and electron. Biomed Phys Eng Express 2019. [DOI: 10.1088/2057-1976/ab05b0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Miao T, Bruza P, Pogue BW, Jermyn M, Krishnaswamy V, Ware W, Rafie F, Gladstone DJ, Williams BB. Cherenkov imaging for linac beam shape analysis as a remote electronic quality assessment verification tool. Med Phys 2018; 46:811-821. [PMID: 30471126 DOI: 10.1002/mp.13303] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 11/11/2018] [Accepted: 11/12/2018] [Indexed: 11/10/2022] Open
Abstract
PURPOSE A remote imaging system tracking Cherenkov emission was analyzed to verify that the linear accelerator (linac) beam shape could be quantitatively measured at the irradiation surface for Quality Audit (QA). METHODS The Cherenkov camera recorded 2D dose images delivered on a solid acrylonitrile butadiene styrene (ABS) plastic phantom surface for a range of square beam sizes, and 6 MV photons. Imaging was done at source to surface distance (SSD) of 100 cm and compared to GaF film images and linac light fields of the same beam sizes, ranging over 5 × 5 cm2 up to 20 × 20 cm2 . Line profiles of each field were compared in both X and Y jaw directions. Each measurement was repeated on two different Clinac2100 machines. An interreader comparison of the beam width interpretation was completed using procedures commonly employed for beam to light field coincidence verification. Cherenkov measurements are also done for beams of complex treatment plan and isocenter QA. RESULTS The Cherenkov image widths matched with the measured GaF images and light field images, with accuracy in the range of ±1 mm standard deviation. The differences between the measurements were minor and within tolerance of geometrical requirement of standard linac QA procedures conducted by human setup verification, which had a similar error range. The measurement made by the remote imaging system allowed for beam shape extraction of radiation fields at the SSD location of the beam. CONCLUSIONS The proposed Cherenkov image acquisition system provides a valid way to remotely confirm radiation field sizes and provides similar information to that obtained from the linac light field or GaF film estimates of the beam size. The major benefit of this approach is that with a fixed installation of the camera, testing could be done completely under software control with automated image analysis, potentially simplifying conventional QA procedures with appropriate calibration of boundary definitions, and the natural extension to capturing dynamic treatment beamlets at SSD could have future value, such as verification of beam plans with complex beam shapes, like IMRT or "star-shot" QA for the isocenter.
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Affiliation(s)
- Tianshun Miao
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - 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.,DoseOptics LLC, Lebanon, NH, 03766, USA
| | - Michael Jermyn
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.,DoseOptics LLC, Lebanon, NH, 03766, USA
| | | | | | - Frank Rafie
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.,Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA.,Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.,Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA.,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, USA.,Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA.,Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
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Black PJ, Velten C, Wang YF, Na YH, Wuu CS. An investigation of clinical treatment field delivery verification using cherenkov imaging: IMRT positioning shifts and field matching. Med Phys 2018; 46:302-317. [PMID: 30346639 DOI: 10.1002/mp.13250] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 10/01/2018] [Accepted: 10/10/2018] [Indexed: 11/12/2022] Open
Abstract
PURPOSE Cherenkov light emission has been shown to correlate with ionizing radiation dose delivery in solid tissue. An important clinical application of Cherenkov light is the real-time verification of radiation treatment delivery in vivo. To test the feasibility of treatment field verification, Cherenkov light images were acquired concurrent with radiation beam delivery to standard and anthropomorphic phantoms. Specifically, we tested two clinical treatment scenarios: (a) Observation of field overlaps or gaps in matched 3D fields and (b) Patient positioning shifts during intensity modulated radiation therapy (IMRT) field delivery. Further development of this technique would allow real-time detection of treatment delivery errors on the order of millimeters so that patient safety and treatment quality can be improved. METHODS Cherenkov light emission was captured using a PI-MAX4 intensified charge coupled device (ICCD) system (Princeton Instruments). All radiation delivery was performed using a Varian Trilogy linear accelerator (linac) operated at 6 MV or 18 MV for photon and 6 MeV or 16 MeV for electron studies. Field matching studies were conducted with photon and electron beams at gantry angles of 0°, 15°, and 45°. For each modality and gantry angle, a total of three data sets were acquired. Overlap and gap distances of 0, 2, 5, and 10 mm were tested and delivered to solid phantom material of 30 × 30 × 5 cm3 . Phantom materials used were white plastic water and brown solid water. Tests were additionally performed on an anthropomorphic phantom with an irregular surface. Positioning shift studies were performed using IMRT fields delivered to a thoracic anthropomorphic phantom. For thoracic phantom measurements, the camera was placed laterally to observe the entire right side of the phantom. Fields were delivered with known translational patient positioning shifts in four directions. Changes in the Cherenkov fluence were evaluated through the generation of difference maps from unshifted Cherenkov images. All images were evaluated using ImageJ, Python, and MATLAB software packages. RESULTS For matched fields, Cherenkov images were able to quantitate matched field separations with discrepancies between 2 and 4 mm, depending on gantry angle and beam energy or modality. For all photon and electron beams delivered at a gantry angle of 0°, image analysis indicated average discrepancies of less than 2 mm for all field gaps and overlaps, with 83% of matched fields exhibiting discrepancies less than 1 mm. Beams delivered obliquely to the phantom surface exhibited average discrepancies as high as 4 mm for electron beams delivered at large oblique angles. Finally, for IMRT field delivery, vertical and lateral patient positioning shifts of 2 mm were detected in some cases, indicating the potential detectability threshold of using this technique alone. CONCLUSIONS Our study indicates that Cherenkov imaging can be used to support and bolster current treatment delivery verification techniques, improving our ability to recognize and rectify millimeter-scale delivery and positioning errors.
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Affiliation(s)
- Paul J Black
- Department of Radiation Oncology, Columbia University, New York, NY, 10032, USA.,Department of Radiation Oncology, Novant Health, Winston-Salem, NC, 27103, USA
| | - Christian Velten
- Department of Radiation Oncology, Columbia University, New York, NY, 10032, USA
| | - Yi-Fang Wang
- Department of Radiation Oncology, Columbia University, New York, NY, 10032, USA
| | - Yong Hum Na
- Department of Radiation Oncology, Columbia University, New York, NY, 10032, USA
| | - Cheng-Shie Wuu
- Department of Radiation Oncology, Columbia University, New York, NY, 10032, USA.,Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA
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Brost E, Watanabe Y. Characterization of the Cerenkov scatter function: a convolution kernel for Cerenkov light dosimetry. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-12. [PMID: 30378350 DOI: 10.1117/1.jbo.23.10.105007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 10/01/2018] [Indexed: 05/20/2023]
Abstract
Cerenkov light is created in clinical applications involving high-energy radiation such as in radiation therapy. There is considerable interest in using Cerenkov light as a means to perform in vivo dosimetry during radiation therapy; however, a better understanding of the light-to-dose relationship is needed. One such method to solve this relationship is that of a deconvolution formulation, which relies on the Cerenkov scatter function (CSF). The CSF describes the creation of Cerenkov photons by a pencil beam of high-energy radiation, and the subsequent scattering that occurs before emission from the irradiated medium surface. This study investigated the dependence of the CSF on common radiation beam parameters (beam energy and incident angle) and the type of irradiated medium. An analytical equation with fitting coefficients of the CSF was obtained for common beam energies in a stratified skin model and optical phantom. Perturbation analysis was performed to investigate the dependence of the deconvolved Cerenkov images on the full-width at half-maximum and amplitude of the CSF. The irradiated material and beam angle had a large impact on the deconvolution process, whereas the beam energy had little effect.
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Affiliation(s)
- Eric Brost
- University of Minnesota, Department of Radiation Oncology, Minneapolis, Minnesota, United States
| | - Yoichi Watanabe
- University of Minnesota, Department of Radiation Oncology, Minneapolis, Minnesota, United States
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Yabe T, Sasano M, Hirano Y, Toshito T, Akagi T, Yamashita T, Hayashi M, Azuma T, Sakamoto Y, Komori M, Yamamoto S. Addition of luminescence process in Monte Carlo simulation to precisely estimate the light emitted from water during proton and carbon-ion irradiation. Phys Med Biol 2018; 63:125019. [PMID: 29923503 DOI: 10.1088/1361-6560/aac74b] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Although luminescence of water lower in energy than the Cerenkov-light threshold during proton and carbon-ion irradiation has been found, the phenomenon has not yet been implemented for Monte Carlo simulations. The results provided by the simulations lead to misunderstandings of the physical phenomenon in optical imaging of water during proton and carbon-ion irradiation. To solve the problems, as well as to clarify the light production of the luminescence of water, we modified a Monte Carlo simulation code to include the light production from the luminescence of water and compared them with the experimental results of luminescence imaging of water. We used GEANT4 for the simulation of emitted light from water during proton and carbon-ion irradiation. We used the light production from the luminescence of water using the scintillation process in GEANT4 while those of Cerenkov light from the secondary electrons and prompt gamma photons in water were also included in the simulation. The modified simulation results showed similar depth profiles to those of the measured data for both proton and carbon-ion. When the light production of 0.1 photons/MeV was used for the luminescence of water in the simulation, the simulated depth profiles showed the best match to those of the measured results for both the proton and carbon-ion compared with those used for smaller and larger numbers of photons/MeV. We could successively obtain the simulated depth profiles that were basically the same as the experimental data by using GEANT4 when we assumed the light production by the luminescence of water. Our results confirmed that the inclusion of the luminescence of water in Monte Carlo simulation is indispensable to calculate the precise light distribution in water during irradiation of proton and carbon-ion.
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Affiliation(s)
- Takuya Yabe
- Department of Radiological Sciences, Nagoya University Graduate School of Medicine, Nagoya-shi, Aichi, Japan. These two authors contributed equally to this paper
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Andreozzi JM, Mooney KE, Brůža P, Curcuru A, Gladstone DJ, Pogue BW, Green O. Remote Cherenkov imaging-based quality assurance of a magnetic resonance image-guided radiotherapy system. Med Phys 2018; 45:2647-2659. [PMID: 29663429 DOI: 10.1002/mp.12919] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 02/09/2018] [Accepted: 04/04/2018] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Tools to perform regular quality assurance of magnetic resonance image-guided radiotherapy (MRIgRT) systems should ideally be independent of interference from the magnetic fields. Remotely acquired optical Cherenkov imaging-based dosimetry measurements in water were investigated for this purpose, comparing measures of dose accuracy, temporal dynamics, and overall integrated IMRT delivery. METHODS A 40 × 30.5 × 37.5 cm3 water tank doped with 1 g/L of quinine sulfate was imaged using an intensified charge-coupled device (ICCD) to capture the Cherenkov emission while being irradiated by a commercial MRIgRT system (ViewRay™). The ICCD was placed down-bore at the end of the couch, 4 m from treatment isocenter and behind the 5-Gauss line of the 0.35-T MRI. After establishing optimal camera acquisition settings, square beams of increasing size (4.2 × 4.2 cm2 , 10.5 × 10.5 cm2 , and 14.7 × 14.7 cm2 ) were imaged at 0.93 frames per second, from an individual cobalt-60 treatment head, to develop projection measures related to percent depth dose (PDD) curves and cross beam profiles (CPB). These Cherenkov-derived measurements were compared to ionization chamber (IC) and radiographic film dosimetry data, as well as simulation data from the treatment planning system (TPS). An intensity-modulated radiotherapy (IMRT) commissioning plan from AAPM TG-119 (C4:C-Shape) was also imaged at 2.1 frames per second, and the single linear sum image from 509 s of plan delivery was compared to the dose volume prediction generated by the TPS using gamma index analysis. RESULTS Analysis of standardized test target images (1024 × 1024 pixels) yielded a pixel resolution of 0.37 mm/pixel. The beam width measured from the Cherenkov image-generated projection CBPs was within 1 mm accuracy when compared to film measurements for all beams. The 502 point measurements (i.e., pixels) of the Cherenkov image-based projection percent depth dose curves (pPDDs) were compared to pPDDs simulated by the treatment planning system (TPS), with an overall average error of 0.60%, 0.56%, and 0.65% for the 4.2, 10.5, and 14.7 cm square beams, respectively. The relationships between pPDDs and central axis PDDs derived from the TPS were used to apply a weighting factor to the Cherenkov pPDD, so that the Cherenkov data could be directly compared to IC PDDs (average error of -0.07%, 0.10%, and -0.01% for the same sized beams, respectively). Finally, the composite image of the TG-119 C4 treatment plan achieved a 95.1% passing rate using 4%/4 mm gamma index agreement criteria between Cherenkov intensity and TPS dose volume data. CONCLUSIONS This is the first examination of Cherenkov-generated pPDDs and pCBPs in an MR-IGRT system. Cherenkov imaging measurements were fast to acquire, and minimal error was observed overall. Cherenkov imaging also provided novel real-time data for IMRT QA. The strengths of this imaging are the rapid data capture ability providing real-time, high spatial resolution data, combined with the remote, noncontact nature of imaging. The biggest limitation of this method is the two-dimensional (2D) projection-based imaging of three-dimensional (3D) dose distributions through the transparent water tank.
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Affiliation(s)
| | - Karen E Mooney
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Petr Brůža
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Austen Curcuru
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - David J Gladstone
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03766, USA
- Geisel School of Medicine and Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Brian W Pogue
- Thayer School of Engineering and Department of Physics and Astronomy, Dartmouth College, Hanover, NH, 03755, USA
| | - Olga Green
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
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Brost EE, Watanabe Y. A mathematical deconvolution formulation for superficial dose distribution measurement by Cerenkov light dosimetry. Med Phys 2018; 45:3880-3892. [PMID: 29856473 DOI: 10.1002/mp.13021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 05/15/2018] [Accepted: 05/15/2018] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Cerenkov photons are created by high-energy radiation beams used for radiation therapy. In this study, we developed a Cerenkov light dosimetry technique to obtain a two-dimensional dose distribution in a superficial region of medium from the images of Cerenkov photons by using a deconvolution method. METHODS An integral equation was derived to represent the Cerenkov photon image acquired by a camera for a given incident high-energy photon beam by using convolution kernels. Subsequently, an equation relating the planar dose at a depth to a Cerenkov photon image using the well-known relationship between the incident beam fluence and the dose distribution in a medium was obtained. The final equation contained a convolution kernel called the Cerenkov dose scatter function (CDSF). The CDSF function was obtained by deconvolving the Cerenkov scatter function (CSF) with the dose scatter function (DSF). The GAMOS (Geant4-based Architecture for Medicine-Oriented Simulations) Monte Carlo particle simulation software was used to obtain the CSF and DSF. The dose distribution was calculated from the Cerenkov photon intensity data using an iterative deconvolution method with the CDSF. The theoretical formulation was experimentally evaluated by using an optical phantom irradiated by high-energy photon beams. RESULTS The intensity of the deconvolved Cerenkov photon image showed linear dependence on the dose rate and the photon beam energy. The relative intensity showed a field size dependence similar to the beam output factor. Deconvolved Cerenkov images showed improvement in dose profiles compared with the raw image data. In particular, the deconvolution significantly improved the agreement in the high dose gradient region, such as in the penumbra. Deconvolution with a single iteration was found to provide the most accurate solution of the dose. Two-dimensional dose distributions of the deconvolved Cerenkov images agreed well with the reference distributions for both square fields and a multileaf collimator (MLC) defined, irregularly shaped field. CONCLUSIONS The proposed technique improved the accuracy of the Cerenkov photon dosimetry in the penumbra region. The results of this study showed initial validation of the deconvolution method for beam profile measurements in a homogeneous media. The new formulation accounted for the physical processes of Cerenkov photon transport in the medium more accurately than previously published methods.
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Affiliation(s)
- Eric Edward Brost
- Department of Radiation Oncology, University of Minnesota, 420 Delaware St. SE, MMC-494, Minneapolis, MN, USA
| | - Yoichi Watanabe
- Department of Radiation Oncology, University of Minnesota, 420 Delaware St. SE, MMC-494, Minneapolis, MN, USA
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Komori M, Sekihara E, Yabe T, Horita R, Toshito T, Yamamoto S. Luminescence imaging of water during uniform-field irradiation by spot scanning proton beams. Phys Med Biol 2018; 63:11NT01. [PMID: 29722295 DOI: 10.1088/1361-6560/aac223] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Luminescence was found during pencil-beam proton irradiation to water phantom and range could be estimated from the luminescence images. However, it is not yet clear whether the luminescence imaging is applied to the uniform fields made of spot-scanning proton-beam irradiations. For this purpose, imaging was conducted for the uniform fields having spread out Bragg peak (SOBP) made by spot scanning proton beams. We designed six types of the uniform fields with different ranges, SOBP widths and irradiation fields. One of the designed fields was irradiated to water phantom and a cooled charge coupled device camera was used to measure the luminescence image during irradiations. We estimated the ranges, field widths, and luminescence intensities from the luminescence images and compared those with the dose distribution calculated by a treatment planning system. For all types of uniform fields, we could obtain clear images of the luminescence showing the SOBPs. The ranges and field widths evaluated from the luminescence were consistent with those of the dose distribution calculated by a treatment planning system within the differences of -4 mm and -11 mm, respectively. Luminescence intensities were almost proportional to the SOBP widths perpendicular to the beam direction. The luminescence imaging could be applied to uniform fields made of spot scanning proton beam irradiations. Ranges and widths of the uniform fields with SOBP could be estimated from the images. The luminescence imaging is promising for the range and field width estimations in proton therapy.
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Affiliation(s)
- Masataka Komori
- Department of Radiological Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya 461-8673, Japan
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Bruza P, Andreozzi JM, Gladstone DJ, Jarvis LA, Rottmann J, Pogue BW. Online Combination of EPID & Cherenkov Imaging for 3-D Dosimetry in a Liquid Phantom. IEEE TRANSACTIONS ON MEDICAL IMAGING 2017; 36:2099-2103. [PMID: 28644800 PMCID: PMC5659346 DOI: 10.1109/tmi.2017.2717800] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Online acquisition of Cherenkov and portal imaging data was combined with a reconstruction scheme called EC3-D, providing a full 3-D dosimetry of megavoltage X-ray beams in a water tank. The methodology was demonstrated and quantified in a single static beam. Furthermore, the dynamics and visualization of the 3-D dose reconstruction were demonstrated with a volumetric modulated arc therapy plan for TG-119 C-Shape geometry. The developed algorithm combines depth dose information, provided by Cherenkov images, with the lateral dose distribution, provided by the electronic portal imaging device. The strength of our approach lies in the acquisition of both imaging data streams with sub-millimeter theoretical resolution at 5-Hz frame-rate, which can be concurrently processed by the fast Fourier transform-based analysis, thus providing means for an efficient real-time 3-D dosimetry.
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Ai Y, Tang X, Shu D, Shao W, Gong C, Geng C, Zhang X, Yu H. Measurement of dose in radionuclide therapy by using Cerenkov radiation. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2017; 40:695-705. [PMID: 28808904 DOI: 10.1007/s13246-017-0579-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 08/06/2017] [Indexed: 12/23/2022]
Abstract
This work aims to determine the relationship between Cerenkov photon emission and radiation dose from internal radionuclide irradiation. Water and thyroid phantoms were used to simulate the distribution of Cerenkov photon emission and dose deposition through Monte Carlo method. The relationship between Cerenkov photon emission and dose deposition was quantitatively analyzed. A neck phantom was also used to verify Cerenkov photon detection for thyroid radionuclide therapy. Results show that Cerenkov photon emission and dose deposition exhibit the same distribution pattern in water phantom, and this relative distribution relationship also existed in the thyroid phantom. Moreover, Cerenkov photon emission exhibits a specific quantitative relation to dose deposition. For thyroid radionuclide therapy, only a part of Cerenkov photon produced by thyroid could penetrate the body for detection; therefore, the use of Cerenkov radiation for measurement of radionuclide therapy dose may be more suitable for superficial tumors. This study demonstrated that Cerenkov radiation has the potential to be used for measuring radiation dose for radionuclide therapy.
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Affiliation(s)
- Yao Ai
- Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao St., Nanjing, 210016, China
| | - Xiaobin Tang
- Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao St., Nanjing, 210016, China.
- Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 29 Yudao St., Nanjing, 210016, China.
| | - Diyun Shu
- Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao St., Nanjing, 210016, China
| | - Wencheng Shao
- Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao St., Nanjing, 210016, China
| | - Chunhui Gong
- Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao St., Nanjing, 210016, China
| | - Changran Geng
- Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao St., Nanjing, 210016, China
- Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 29 Yudao St., Nanjing, 210016, China
| | - Xudong Zhang
- Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao St., Nanjing, 210016, China
| | - Haiyan Yu
- Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao St., Nanjing, 210016, China
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Bruza P, Andreozzi JM, Gladstone DJ, Jarvis LA, Rottmann J, Pogue BW. Real-time 3D dose imaging in water phantoms: reconstruction from simultaneous EPID-Cherenkov 3D imaging (EC3D). ACTA ACUST UNITED AC 2017. [DOI: 10.1088/1742-6596/847/1/012034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Pogue BW, Zhang R, Glaser A, Andreozzi JM, Bruza P, Gladstone DJ, Jarvis LA. Cherenkov imaging in the potential roles of radiotherapy QA and delivery. ACTA ACUST UNITED AC 2017. [DOI: 10.1088/1742-6596/847/1/012046] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ciarrocchi E, Belcari N. Cerenkov luminescence imaging: physics principles and potential applications in biomedical sciences. EJNMMI Phys 2017; 4:14. [PMID: 28283990 PMCID: PMC5346099 DOI: 10.1186/s40658-017-0181-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 02/27/2017] [Indexed: 12/24/2022] Open
Abstract
Cerenkov luminescence imaging (CLI) is a novel imaging modality to study charged particles with optical methods by detecting the Cerenkov luminescence produced in tissue. This paper first describes the physical processes that govern the production and transport in tissue of Cerenkov luminescence. The detectors used for CLI and their most relevant specifications to optimize the acquisition of the Cerenkov signal are then presented, and CLI is compared with the other optical imaging modalities sharing the same data acquisition and processing methods. Finally, the scientific work related to CLI and the applications for which CLI has been proposed are reviewed. The paper ends with some considerations about further perspectives for this novel imaging modality.
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Affiliation(s)
- Esther Ciarrocchi
- Department of Physics "E. Fermi", University of Pisa, Pisa, Italy. .,INFN, section of Pisa, Pisa, Italy.
| | - Nicola Belcari
- Department of Physics "E. Fermi", University of Pisa, Pisa, Italy.,INFN, section of Pisa, Pisa, Italy
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Darafsheh A, Taleei R, Kassaee A, Finlay JC. Proton therapy dosimetry using the scintillation of the silica fibers. OPTICS LETTERS 2017; 42:847-850. [PMID: 28198880 DOI: 10.1364/ol.42.000847] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate the feasibility of proton therapy dose measurement by using scintillation of a bare silica glass fiber. The emission spectra of the optical fiber at various depths in tissue-mimicking phantoms, irradiated with proton beams of energies 100-225 MeV show two distinct peaks at 460 and 650 nm whose nature is connected with the silica point defects. Our experimental results and Monte Carlo simulation showed that the Čerenkov radiation cannot be responsible for such a phenomenon. We showed that the intensity of the peak at 650 nm correlates with the proton dose with a minimal effect of ionization quenching, while the intensity peak at 460 nm under-reports the radiation dose.
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Shaffer TM, Pratt EC, Grimm J. Utilizing the power of Cerenkov light with nanotechnology. NATURE NANOTECHNOLOGY 2017; 12:106-117. [PMID: 28167827 PMCID: PMC5540309 DOI: 10.1038/nnano.2016.301] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 12/22/2016] [Indexed: 05/12/2023]
Abstract
The characteristic blue glow of Cerenkov luminescence (CL) arises from the interaction between a charged particle travelling faster than the phase velocity of light and a dielectric medium, such as water or tissue. As CL emanates from a variety of sources, such as cosmic events, particle accelerators, nuclear reactors and clinical radionuclides, it has been used in applications such as particle detection, dosimetry, and medical imaging and therapy. The combination of CL and nanoparticles for biomedicine has improved diagnosis and therapy, especially in oncological research. Although radioactive decay itself cannot be easily modulated, the associated CL can be through the use of nanoparticles, thus offering new applications in biomedical research. Advances in nanoparticles, metamaterials and photonic crystals have also yielded new behaviours of CL. Here, we review the physics behind Cerenkov luminescence and associated applications in biomedicine. We also show that by combining advances in nanotechnology and materials science with CL, new avenues for basic and applied sciences have opened.
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Affiliation(s)
- Travis M. Shaffer
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Department of Chemistry, Hunter College and Graduate Center of the City University of New York, New York, New York 10065, USA
| | - Edwin C. Pratt
- Department of Pharmacology, Weill Cornell Medical College, New York, New York 10021, USA
| | - Jan Grimm
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Department of Pharmacology, Weill Cornell Medical College, New York, New York 10021, USA
- Department of Radiology, Weill Cornell Medical College, New York, New York 10021, USA
- Correspondence should be addressed to J.G.
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40
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Glaser AK, Andreozzi JM, Zhang R, Pogue BW, Gladstone DJ. Optical cone beam tomography of Cherenkov-mediated signals for fast 3D dosimetry of x-ray photon beams in water. Med Phys 2016; 42:4127-36. [PMID: 26133613 DOI: 10.1118/1.4922135] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To test the use of a three-dimensional (3D) optical cone beam computed tomography reconstruction algorithm, for estimation of the imparted 3D dose distribution from megavoltage photon beams in a water tank for quality assurance, by imaging the induced Cherenkov-excited fluorescence (CEF). METHODS An intensified charge-coupled device coupled to a standard nontelecentric camera lens was used to tomographically acquire two-dimensional (2D) projection images of CEF from a complex multileaf collimator (MLC) shaped 6 MV linear accelerator x-ray photon beam operating at a dose rate of 600 MU/min. The resulting projections were used to reconstruct the 3D CEF light distribution, a potential surrogate of imparted dose, using a Feldkamp-Davis-Kress cone beam back reconstruction algorithm. Finally, the reconstructed light distributions were compared to the expected dose values from one-dimensional diode scans, 2D film measurements, and the 3D distribution generated from the clinical Varian ECLIPSE treatment planning system using a gamma index analysis. A Monte Carlo derived correction was applied to the Cherenkov reconstructions to account for beam hardening artifacts. RESULTS 3D light volumes were successfully reconstructed over a 400 × 400 × 350 mm(3) volume at a resolution of 1 mm. The Cherenkov reconstructions showed agreement with all comparative methods and were also able to recover both inter- and intra-MLC leaf leakage. Based upon a 3%/3 mm criterion, the experimental Cherenkov light measurements showed an 83%-99% pass fraction depending on the chosen threshold dose. CONCLUSIONS The results from this study demonstrate the use of optical cone beam computed tomography using CEF for the profiling of the imparted dose distribution from large area megavoltage photon beams in water.
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Affiliation(s)
- Adam K Glaser
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
| | | | - Rongxiao Zhang
- Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755
| | - Brian W Pogue
- Thayer School of Engineering and Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755
| | - David J Gladstone
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766
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Roussakis Y, Zhang R, Heyes G, Webster G, Mason S, Green S, Pogue B, Dehghani H. Real-time Cherenkov emission portal imaging during CyberKnife® radiotherapy. Phys Med Biol 2015; 60:N419-25. [PMID: 26513015 DOI: 10.1088/0031-9155/60/22/n419] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The feasibility of real-time portal imaging during radiation therapy, through the Cherenkov emission (CE) effect is investigated via a medical linear accelerator (CyberKnife(®)) irradiating a partially-filled water tank with a 60 mm circular beam. A graticule of lead/plywood and a number of tissue equivalent materials were alternatively placed at the beam entrance face while the induced CE at the exit face was imaged using a gated electron-multiplying-intensified-charged-coupled device (emICCD) for both stationary and dynamic scenarios. This was replicated on an Elekta Synergy(®) linear accelerator with portal images acquired using the iViewGT(™) system. Profiles across the acquired portal images were analysed to reveal the potential resolution and contrast limits of this novel CE based portal imaging technique and compared against the current standard. The CE resolution study revealed that using the lead/plywood graticule, separations down to 3.4 ± 0.5 mm can be resolved. A 28 mm thick tissue-equivalent rod with electron density of 1.69 relative to water demonstrated a CE contrast of 15% through air and 14% through water sections, as compared to a corresponding contrast of 19% and 12% using the iViewGT(™) system. For dynamic scenarios, video rate imaging with 30 frames per second was achieved. It is demonstrated that CE-based portal imaging is feasible to identify both stationary and dynamic objects within a CyberKnife(®) radiotherapy treatment field.
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Affiliation(s)
- Yiannis Roussakis
- Physical Sciences of Imaging in the Biomedical Science, University of Birmingham, Birmingham, West Midlands B15 2TT, UK
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Andreozzi JM, Zhang R, Glaser AK, Jarvis LA, Pogue BW, Gladstone DJ. Camera selection for real-time in vivo radiation treatment verification systems using Cherenkov imaging. Med Phys 2015; 42:994-1004. [PMID: 25652512 DOI: 10.1118/1.4906249] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
PURPOSE To identify achievable camera performance and hardware needs in a clinical Cherenkov imaging system for real-time, in vivo monitoring of the surface beam profile on patients, as novel visual information, documentation, and possible treatment verification for clinicians. METHODS Complementary metal-oxide-semiconductor (CMOS), charge-coupled device (CCD), intensified charge-coupled device (ICCD), and electron multiplying-intensified charge coupled device (EM-ICCD) cameras were investigated to determine Cherenkov imaging performance in a clinical radiotherapy setting, with one emphasis on the maximum supportable frame rate. Where possible, the image intensifier was synchronized using a pulse signal from the Linac in order to image with room lighting conditions comparable to patient treatment scenarios. A solid water phantom irradiated with a 6 MV photon beam was imaged by the cameras to evaluate the maximum frame rate for adequate Cherenkov detection. Adequate detection was defined as an average electron count in the background-subtracted Cherenkov image region of interest in excess of 0.5% (327 counts) of the 16-bit maximum electron count value. Additionally, an ICCD and an EM-ICCD were each used clinically to image two patients undergoing whole-breast radiotherapy to compare clinical advantages and limitations of each system. RESULTS Intensifier-coupled cameras were required for imaging Cherenkov emission on the phantom surface with ambient room lighting; standalone CMOS and CCD cameras were not viable. The EM-ICCD was able to collect images from a single Linac pulse delivering less than 0.05 cGy of dose at 30 frames/s (fps) and pixel resolution of 512 × 512, compared to an ICCD which was limited to 4.7 fps at 1024 × 1024 resolution. An intensifier with higher quantum efficiency at the entrance photocathode in the red wavelengths [30% quantum efficiency (QE) vs previous 19%] promises at least 8.6 fps at a resolution of 1024 × 1024 and lower monetary cost than the EM-ICCD. CONCLUSIONS The ICCD with an intensifier better optimized for red wavelengths was found to provide the best potential for real-time display (at least 8.6 fps) of radiation dose on the skin during treatment at a resolution of 1024 × 1024.
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Affiliation(s)
| | - Rongxiao Zhang
- Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755
| | - Adam K Glaser
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
| | - Lesley A Jarvis
- Department of Medicine, Geisel School of Medicine and Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766
| | - Brian W Pogue
- Thayer School of Engineering and Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755
| | - David J Gladstone
- Department of Medicine, Geisel School of Medicine and Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766
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Glaser AK, Zhang R, Andreozzi JM, Gladstone DJ, Pogue BW. Cherenkov radiation fluence estimates in tissue for molecular imaging and therapy applications. Phys Med Biol 2015; 60:6701-18. [PMID: 26270125 PMCID: PMC5145313 DOI: 10.1088/0031-9155/60/17/6701] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cherenkov radiation has recently emerged as an interesting phenomenon for a number of applications in the biomedical sciences. Its unique properties, including broadband emission spectrum, spectral weight in the ultraviolet and blue wavebands, and local generation of light within a given tissue, have made it an attractive new source of light within tissue for molecular imaging and phototherapy applications. While several studies have investigated the total Cherenkov light yield from radionuclides in units of [photons/decay], further consideration of the light propagation in tissue is necessary to fully consider the utility of this signal in vivo. Therefore, to help further guide the development of this novel field, quantitative estimates of the light fluence rate of Cherenkov radiation from both radionuclides and radiotherapy beams in a biological tissue are presented for the first time. Using Monte Carlo simulations, these values were found to be on the order of 0.01-1 nW cm(-2) per MBq g(-1) for radionuclides, and 1-100 μW cm(-2) per Gy s(-1) for external radiotherapy beams, dependent on the given waveband, optical properties, and radiation source. For phototherapy applications, the total light fluence was found to be on the order of nJ cm(-2) for radionuclides, and mJ cm(-2) for radiotherapy beams. The results indicate that diagnostic potential is reasonable for Cherenkov excitation of molecular probes, but phototherapy may remain elusive at such exceedingly low fluence values. The results of this study are publicly available for distribution online at www.dartmouth.edu/optmed/.
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Affiliation(s)
- Adam K. Glaser
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
| | - Rongxiao Zhang
- Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755
| | | | - David J. Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
- Norris Cotton Cancer Center, Lebanon, New Hampshire 03756
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire 03755
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
- Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755
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Darafsheh A, Zhang R, Kanick SC, Pogue BW, Finlay JC. Spectroscopic separation of Čerenkov radiation in high-resolution radiation fiber dosimeters. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:095001. [PMID: 26334972 DOI: 10.1117/1.jbo.20.9.095001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 07/31/2015] [Indexed: 06/05/2023]
Abstract
We have investigated Čerenkov radiation generated in phosphor-based optical fiber dosimeters irradiated with clinical electron beams. We fabricated two high-spatial resolution fiber-optic probes, with 200 and 400 μm core diameters, composed of terbium-based phosphor tips. A generalizable spectroscopic method was used to separate Čerenkov radiation from the transmitted signal by the fiber based on the assumption that the recorded signal is a linear superposition of two basis spectra: characteristic luminescence of the phosphor medium and Čerenkov radiation. We performed Monte Carlo simulations of the Čerenkov radiation generated in the fiber and found a strong dependence of the recorded Čerenkov radiation on the numerical aperture of the fiber at shallow phantom depths; however, beyond the depth of maximum dose that dependency is minimal. The simulation results agree with the experimental results for Čerenkov radiation generated in fibers. The spectroscopic technique used in this work can be used for development of high-spatial resolution fiber micro dosimeters and for optical characterization of various scintillating materials, such as phosphor nanoparticles, in ionizing radiation fields of high energy.
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Affiliation(s)
- Arash Darafsheh
- University of Pennsylvania, Department of Radiation Oncology, 3400 Civic Center Boulevard, Philadelphia, Pennsylvania 19104, United States
| | - Rongxiao Zhang
- Dartmouth College, Department of Physics and Astronomy, Hanover, New Hampshire 03755, United States
| | - Stephen Chad Kanick
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire 03755, United States
| | - Brian W Pogue
- Dartmouth College, Department of Physics and Astronomy, Hanover, New Hampshire 03755, United StatescDartmouth College, Thayer School of Engineering, Hanover, New Hampshire 03755, United States
| | - Jarod C Finlay
- University of Pennsylvania, Department of Radiation Oncology, 3400 Civic Center Boulevard, Philadelphia, Pennsylvania 19104, United States
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Tanha K, Pashazadeh AM, Pogue BW. Review of biomedical Čerenkov luminescence imaging applications. BIOMEDICAL OPTICS EXPRESS 2015; 6:3053-65. [PMID: 26309766 PMCID: PMC4541530 DOI: 10.1364/boe.6.003053] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/15/2015] [Accepted: 07/16/2015] [Indexed: 05/04/2023]
Abstract
Čerenkov radiation is a fascinating optical signal, which has been exploited for unique diagnostic biological sensing and imaging, with significantly expanded use just in the last half decade. Čerenkov Luminescence Imaging (CLI) has desirable capabilities for niche applications, using specially designed measurement systems that report on radiation distributions, radiotracer and nanoparticle concentrations, and are directly applied to procedures such as medicine assessment, endoscopy, surgery, quality assurance and dosimetry. When compared to the other imaging tools such as PET and SPECT, CLI can have the key advantage of lower cost, higher throughput and lower imaging time. CLI can also provide imaging and dosimetry information from both radioisotopes and linear accelerator irradiation. The relatively short range of optical photon transport in tissue means that direct Čerenkov luminescence imaging is restricted to small animals or near surface human use. Use of Čerenkov-excitation for additional molecular probes, is now emerging as a key tool for biosensing or radiosensitization. This review evaluates these new improvements in CLI for both medical value and biological insight.
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Affiliation(s)
- Kaveh Tanha
- Persian Gulf Nuclear Medicine Research Center, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Ali Mahmoud Pashazadeh
- Persian Gulf Nuclear Medicine Research Center, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Brian W Pogue
- Thayer School of Engineering, Department of Surgery in the Geisel School of Medicine, Dartmouth College, Hanover NH 03755 USA
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Glaser AK, Andreozzi JM, Davis SC, Zhang R, Pogue BW, Fox CJ, Gladstone DJ. Video-rate optical dosimetry and dynamic visualization of IMRT and VMAT treatment plans in water using Cherenkov radiation. Med Phys 2015; 41:062102. [PMID: 24877829 DOI: 10.1118/1.4875704] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE A novel technique for optical dosimetry of dynamic intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans was investigated for the first time by capturing images of the induced Cherenkov radiation in water. METHODS A high-sensitivity, intensified CCD camera (ICCD) was configured to acquire a two-dimensional (2D) projection image of the Cherenkov radiation induced by IMRT and VMAT plans, based on the Task Group 119 (TG-119) C-Shape geometry. Plans were generated using the Varian Eclipse treatment planning system (TPS) and delivered using 6 MV x-rays from a Varian TrueBeam Linear Accelerator (Linac) incident on a water tank doped with the fluorophore quinine sulfate. The ICCD acquisition was gated to the Linac target trigger pulse to reduce background light artifacts, read out for a single radiation pulse, and binned to a resolution of 512 × 512 pixels. The resulting videos were analyzed temporally for various regions of interest (ROI) covering the planning target volume (PTV) and organ at risk (OAR), and summed to obtain an overall light intensity distribution, which was compared to the expected dose distribution from the TPS using a gamma-index analysis. RESULTS The chosen camera settings resulted in 23.5 frames per second dosimetry videos. Temporal intensity plots of the PTV and OAR ROIs confirmed the preferential delivery of dose to the PTV versus the OAR, and the gamma analysis yielded 95.9% and 96.2% agreement between the experimentally captured Cherenkov light distribution and expected TPS dose distribution based upon a 3%/3 mm dose difference and distance-to-agreement criterion for the IMRT and VMAT plans, respectively. CONCLUSIONS The results from this initial study demonstrate the first documented use of Cherenkov radiation for video-rate optical dosimetry of dynamic IMRT and VMAT treatment plans. The proposed modality has several potential advantages over alternative methods including the real-time nature of the acquisition, and upon future refinement may prove to be a robust and novel dosimetry method with both research and clinical applications.
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Affiliation(s)
- Adam K Glaser
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
| | | | - Scott C Davis
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
| | - Rongxiao Zhang
- Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755
| | - Brian W Pogue
- Department of Physics and Astronomy and Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
| | - Colleen J Fox
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766
| | - David J Gladstone
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766
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Pogue BW, Glaser AK, Zhang R, Gladstone DJ. Cherenkov radiation dosimetry in water tanks – video rate imaging, tomography and IMRT & VMAT plan verification. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/1742-6596/573/1/012013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Helo Y, Kacperek A, Rosenberg I, Royle G, Gibson AP. The physics of Cerenkov light production during proton therapy. Phys Med Biol 2014; 59:7107-23. [DOI: 10.1088/0031-9155/59/23/7107] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Holt RW, Zhang R, Esipova TV, Vinogradov SA, Glaser AK, Gladstone DJ, Pogue BW. Cherenkov excited phosphorescence-based pO2 estimation during multi-beam radiation therapy: phantom and simulation studies. Phys Med Biol 2014; 59:5317-5328. [PMID: 25146556 DOI: 10.1088/0031-9155/59/18/5317] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Megavoltage radiation beams used in External Beam Radiotherapy (EBRT) generate Cherenkov light emission in tissues and equivalent phantoms. This optical emission was utilized to excite an oxygen-sensitive phosphorescent probe, PtG4, which has been developed specifically for NIR lifetime-based sensing of the partial pressure of oxygen (pO2). Phosphorescence emission, at different time points with respect to the excitation pulse, was acquired by an intensifier-gated CCD camera synchronized with radiation pulses delivered by a medical linear accelerator. The pO2 distribution was tomographically recovered in a tissue-equivalent phantom during EBRT with multiple beams targeted from different angles at a tumor-like anomaly. The reconstructions were tested in two different phantoms that have fully oxygenated background, to compare a fully oxygenated and a fully deoxygenated inclusion. To simulate a realistic situation of EBRT, where the size and location of the tumor is well known, spatial information of a prescribed region was utilized in the recovery estimation. The phantom results show that region-averaged pO2 values were recovered successfully, differentiating aerated and deoxygenated inclusions. Finally, a simulation study was performed showing that pO2 in human brain tumors can be measured to within 15 mmHg for edge depths less than 10-20 mm using the Cherenkov Excited Phosphorescence Oxygen imaging (CEPhOx) method and PtG4 as a probe. This technique could allow non-invasive monitoring of pO2 in tumors during the normal process of EBRT, where beams are generally delivered from multiple angles or arcs during each treatment fraction.
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Affiliation(s)
- Robert W Holt
- Department of Physics & Astronomy, Dartmouth College Hanover NH 03755
| | - Rongxiao Zhang
- Department of Physics & Astronomy, Dartmouth College Hanover NH 03755
| | - Tatiana V Esipova
- Department of Biophysics & Biochemistry, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104
| | - Sergei A Vinogradov
- Department of Biophysics & Biochemistry, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104
| | - Adam K Glaser
- Thayer School of Engineering, Dartmouth College Hanover NH 03755
| | - David J Gladstone
- Department of Medicine, Geisel School of Medicine, Lebanon NH 03756.,Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon NH 03756
| | - Brian W Pogue
- Department of Physics & Astronomy, Dartmouth College Hanover NH 03755.,Thayer School of Engineering, Dartmouth College Hanover NH 03755
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Glaser AK, Zhang R, Gladstone DJ, Pogue BW. Optical dosimetry of radiotherapy beams using Cherenkov radiation: the relationship between light emission and dose. Phys Med Biol 2014; 59:3789-811. [PMID: 24938928 DOI: 10.1088/0031-9155/59/14/3789] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recent studies have proposed that light emitted by the Cherenkov effect may be used for a number of radiation therapy dosimetry applications. There is a correlation between the captured light and expected dose under certain conditions, yet discrepancies have also been observed and a complete examination of the theoretical differences has not been done. In this study, a fundamental comparison between the Cherenkov emission and absorbed dose was explored for x-ray photons, electrons, and protons using both a theoretical and Monte Carlo-based analysis. Based on the findings of where dose correlates with Cherenkov emission, it was concluded that for x-ray photons the light emission would be optimally suited for narrow beam stereotactic radiation therapy and surgery validation studies, for verification of dynamic intensity-modulated and volumetric modulated arc therapy treatment plans in water tanks, near monoenergetic sources (e.g., Co-60 and brachy therapy sources) and also for entrance and exit surface imaging dosimetry of both narrow and broad beams. For electron use, Cherenkov emission was found to be only suitable for surface dosimetry applications. Finally, for proton dosimetry, there exists a fundamental lack of Cherenkov emission at the Bragg peak, making the technique of little use, although post-irradiation detection of light emission from radioisotopes could prove to be useful.
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Affiliation(s)
- Adam K Glaser
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
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