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Han H, Geng C, Deng X, Li J, Shu D, Tang X. A preliminary study of multispectral Cherenkov imaging and a Fricke-xylenol orange gel film (MCIFF) for online, absolute dose measurement. Med Phys 2024; 51:3734-3745. [PMID: 38224326 DOI: 10.1002/mp.16942] [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: 07/03/2023] [Revised: 12/17/2023] [Accepted: 01/03/2024] [Indexed: 01/16/2024] Open
Abstract
BACKGROUND Cherenkov luminescence imaging has shown potential for relative dose distribution and field verification in radiation therapy. However, to date, limited research utilizing Cherenkov luminescence for absolute dose calibration has been conducted owing to uncertainties arising from camera positioning and tissue surface optical properties. PURPOSE This paper introduces a novel approach to multispectral Cherenkov luminescence imaging combined with Fricke-xylenol orange gel (FXG) film, termed MCIFF, which can enable online full-field absolute dose measurement. By integrating these two approaches, MCIFF allows for calibration of the ratio between two spectral intensities with absorbed dose, thereby enabling absolute dose measurement. METHODS All experiments are conducted on a Varian Clinac 23EX, utilizing an electron multiplying charge-coupled device (EMCCD) camera and a two-way image splitter for simultaneous capture of two-spectral Cherenkov imaging. In the first part of this study, the absorbance curves of the prepared FXG film, which receives different doses, are measured using a fluorescence spectrophotometer to verify the correlation between absorbance and dose. In the second part, the FXG film is positioned directly under the radiation beam to corroborate the dose measurement capacity of MCIFF across various beams. In the third part, the feasibility of MCIFF is tested in actual radiotherapy settings via a humanoid model, demonstrating its versatility with various radiotherapy materials. RESULTS The results of this study indicate that the logarithmic ratios of spectral intensities at wavelengths of 550 ± 50 and 700 ± 100 nm accurately reflect variations in radiation dose (R2 > 0.96) across different radiation beams, particle energies, and dose rates. The slopes of the fitting lines remain consistent under varying beam conditions, with discrepancies of less than 8%. The optical profiles obtained using the MCIFF exhibit a satisfactory level of agreement with the measured results derived from the treatment planning system (TPS) and EBT3 films. Specifically, for photon beams, the lateral distances between the 80% and 20% isodose lines, referred to as the penumbra (P80-20) values, obtained through TPS, EBT3 films, and MCIFF, are determined as 0.537, 0.664, and 0.848 cm, respectively. Similarly, for electron beams, the P80-20 values obtained through TPS, EBT3 films, and MCIFF are found to be 0.432, 0.561, and 0.634 cm, respectively. Furthermore, imaging of the anthropomorphic phantom demonstrates the practical application of MCIFF in real radiotherapy environments. CONCLUSION By combining an FXG film with Cherenkov luminescence imaging, MCIFF can calibrate Cherenkov luminescence to absorbed dose, filling the gap in online 2D absolute dose measurement methods in clinical practice, and providing a new direction for the clinical application of optical imaging to radiation therapy.
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Affiliation(s)
- Haonan Han
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Changran Geng
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
- Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautic, Nanjing University of Aeronautics and Astronautics, Ministry of Industry and Information Technology, Nanjing, People's Republic of China
- Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Xinping Deng
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Jun Li
- Radiotherapy Center, Subei People's Hospital of Jiangsu Province, Yangzhou, People's Republic of China
| | - Diyun Shu
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
- Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Xiaobin Tang
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
- Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautic, Nanjing University of Aeronautics and Astronautics, Ministry of Industry and Information Technology, Nanjing, People's Republic of China
- Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
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Di X, Geng C, Guo C, Shang Y, Fu H, Han H, Tang X. Enhanced Cherenkov imaging for real-time beam visualization by applying a novel carbon quantum dot sheeting in radiotherapy. Med Phys 2023; 50:1215-1227. [PMID: 36433734 DOI: 10.1002/mp.16121] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 11/10/2022] [Accepted: 11/10/2022] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Cherenkov imaging can be used to visualize the placement of the beam directly on the patient's surface tissue and evaluate the accuracy of treatment planning. However, Cherenkov emission intensity is lower than ambient light. At present, time gating is the only way to realize Cherenkov imaging with ambient light. PURPOSE This study proposes preparing a novel carbon quantum dot (cQD) sheeting to adjust the wavelength of Cherenkov emission to obtain the optimal wavelength meeting the sensitive detection region of the camera, meanwhile the total optical signal is also increased. By combining a specific filter, this approach might help in using lower-cost camera systems without intensifier-coupled to accomplish in vivo monitoring of the surface beam profile on patients with ambient light. METHODS The cQD sheetings were prepared by spin coating and UV curing with different concentrations. All experiments were performed on the Varian VitalBeam system and optical emission was captured using an electron multiplying charge-coupled device (EMCCD) camera. To quantify the optical characteristics and certify the improvement of light intensity as well as signal-to-noise ratio (SNR) of cQD sheeting, the first part of the study was carried out on solid water with 6 and 10 MV photon beams. The second part was carried out on an anthropomorphic phantom to explore the applicability of sheeting when using different radiotherapy materials and the imaging effect of sheeting with the impact of ambient light sources. Additionally, thanks to the narrow emission spectrum of the cQD, a band-pass filter was tested to reduce the effect from environmental lights. RESULTS The experimental results show that the optical intensity collected with sheeting has an excellent linear relationship (R2 > 0.99) with the dose for 6 and 10 MV photons. The full-width half maximum (FWHM) in x and y axis matched with the measured EBT film image, with accuracy in the range of ±1.2 and ±2.7 mm standard deviation, respectively. CQD sheeting can significantly improve the light intensity and SNR of optical images. Using 0.1 mg/ml sheeting as an example, the signal intensity is increased by 209%, and the SNR is increased by 147.71% at 6 MV photons. The imaging on the anthropomorphic phantom verified that cQD sheeting could be applied to different radiotherapy materials. The average optical intensity increased by about 69.25%, 63.72%, and 61.78%, respectively, after adding cQD sheeting to bolus, mask sample and the combination of bolus and mask. Corresponding SNR is improved by about 62.78%, 56.77%, and 68.80%, respectively. Through the sheeting, optical images with SNR > 5 can be obtained in the presence of ambient light and it can be improved through combining with a band-pass filter. When red ambient lights are on, the SNR is increased by about 98.85% after adding a specific filter. CONCLUSION Through a combination of cQD sheeting and corresponding filter, light intensity and SNR of optical images can be increased significantly, and it shed new light on the promotion of the clinical application of optical imaging to visualize the beam in radiotherapy.
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Affiliation(s)
- Xing Di
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Changran Geng
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China.,Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Chang Guo
- Department of Radiation Oncology, Jiangsu Cancer Hospital, Nanjing, People's Republic of China
| | - Yufen Shang
- Department of Radiation Physics, Dezhou Second People's Hospital, Dezhou, People's Republic of China
| | - Hongtao Fu
- Department of Radiation Physics, Dezhou Second People's Hospital, Dezhou, People's Republic of China
| | - Haonan Han
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Xiaobin Tang
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China.,Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
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Mc Larney BE, Zhang Q, Pratt EC, Skubal M, Isaac E, Hsu HT, Ogirala A, Grimm J. Detection of Shortwave-Infrared Cerenkov Luminescence from Medical Isotopes. J Nucl Med 2023; 64:177-182. [PMID: 35738902 PMCID: PMC9841262 DOI: 10.2967/jnumed.122.264079] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/11/2022] [Accepted: 06/11/2022] [Indexed: 01/28/2023] Open
Abstract
Medical radioisotopes produce Cerenkov luminescence (CL) from charged subatomic particles (β+/-) traveling faster than light in dielectric media (e.g., tissue). CL is a blue-weighted and continuous emission, decreasing proportionally to increasing wavelength. CL imaging (CLI) provides an economic PET alternative with the advantage of also being able to image β- and α emitters. Like any optical modality, CLI is limited by the optical properties of tissue (scattering, absorption, and ambient photon removal). Shortwave-infrared (SWIR, 900-1700 nm) CL has been detected from MeV linear accelerators but not yet from keV medical radioisotopes. Methods: Indium-gallium-arsenide sensors and SWIR lenses were mounted onto an ambient light-excluding preclinical enclosure. An exposure and processing pipeline was developed for SWIR CLI and then performed across 6 radioisotopes at in vitro and in vivo conditions. Results: SWIR CL was detected from the clinical radioisotopes 90Y, 68Ga, 18F, 89Zr, 131I, and 32P (biomedical research). SWIR CLI's advantage over visible-wavelength (VIS) CLI (400-900 nm) was shown via increased light penetration and decreased scattering at depth. The SWIR CLI radioisotope sensitivity limit (8.51 kBq/μL for 68Ga), emission spectrum, and ex vivo and in vivo examples are reported. Conclusion: This work shows that radioisotope SWIR CLI can be performed with unmodified commercially available components. SWIR CLI has significant advantages over VIS CLI, with preserved VIS CLI features such as radioisotope radiance levels and dose response linearity. Further improvements in SWIR optics and technology are required to enable widespread adoption.
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Affiliation(s)
- Benedict E Mc Larney
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Molecular Imaging Therapy Service, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Qize Zhang
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Molecular Imaging Therapy Service, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Edwin C Pratt
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Molecular Imaging Therapy Service, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Magdalena Skubal
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Molecular Imaging Therapy Service, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Elizabeth Isaac
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Molecular Imaging Therapy Service, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Hsiao-Ting Hsu
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Molecular Imaging Therapy Service, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Anuja Ogirala
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Molecular Imaging Therapy Service, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Jan Grimm
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York;
- Molecular Imaging Therapy Service, Memorial Sloan Kettering Cancer Center, New York, New York
- Pharmacology Program, Weill Cornell Medical College, New York, New York
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York; and
- Department of Radiology, Weill Cornell Medical Center, New York, New York
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Bianfei S, Fang L, Zhongzheng X, Yuanyuan Z, Tian Y, Tao H, Jiachun M, Xiran W, Siting Y, Lei L. Application of Cherenkov radiation in tumor imaging and treatment. Future Oncol 2022; 18:3101-3118. [PMID: 36065976 DOI: 10.2217/fon-2022-0022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cherenkov radiation (CR) is the characteristic blue glow that is generated during radiotherapy or radioisotope decay. Its distribution and intensity naturally reflect the actual dose and field of radiotherapy and the location of radioisotope imaging agents in vivo. Therefore, CR can represent a potential in situ light source for radiotherapy monitoring and radioisotope-based tumor imaging. When used in combination with new imaging techniques, molecular probes or nanomedicine, CR imaging exhibits unique advantages (accuracy, low cost, convenience and fast) in tumor radiotherapy monitoring and imaging. Furthermore, photosensitive nanomaterials can be used for CR photodynamic therapy, providing new approaches for integrating tumor imaging and treatment. Here the authors review the latest developments in the use of CR in tumor research and discuss current challenges and new directions for future studies.
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Affiliation(s)
- Shao Bianfei
- Department of Head and Neck Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Liu Fang
- Department of Head and Neck Oncology, West China Hospital, Sichuan University, Chengdu, China.,Department of Radiation Oncology, Henan Cancer Hospital, Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Xiang Zhongzheng
- Department of Head and Neck Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Zeng Yuanyuan
- Department of Head and Neck Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Yang Tian
- Department of Head and Neck Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - He Tao
- Department of Head and Neck Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Ma Jiachun
- Department of Head and Neck Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Wang Xiran
- Department of Head and Neck Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Yu Siting
- Department of Head and Neck Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Liu Lei
- Department of Head and Neck Oncology, West China Hospital, Sichuan University, Chengdu, China
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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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Hachadorian RL, Bruza P, Jermyn M, Gladstone DJ, Zhang R, Jarvis LA, Pogue BW. Remote dose imaging from cherenkov light using spatially-resolved CT calibration in breast radiotherapy. Med Phys 2022; 49:4018-4025. [PMID: 35304768 DOI: 10.1002/mp.15614] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/16/2022] [Accepted: 03/10/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Imaging Cherenkov light during radiotherapy allows the visualization and recording of frame-by-frame relative maps of the dose being delivered to the tissue at each control point used throughout treatment, providing one of the most complete real-time means of treatment quality assurance. In non-turbid media, the intensity of Cherenkov light is linear with surface dose deposited, however the emission from patient tissue is well-known to be reduced by absorbing tissue components such as hemoglobin, fat, water and melanin, and diffused by the scattering components of tissue. Earlier studies have shown that bulk correction could be achieved by using the patient planning CT scan for attenuation correction. METHODS In this study, CT maps were used for correction of spatial variations in emissivity. Testing was completed on Cherenkov images from radiotherapy treatments of post-lumpectomy breast cancer patients (n = 13), combined with spatial renderings of the patient radiodensity (CT number) from their planning CT scan. RESULTS The correction technique was shown to provide a pixel-by-pixel correction that suppressed many of the inter- and intra-patient differences in the Cherenkov light emitted per unit dose. This correction was established from a calibration curve that correlated Cherenkov light intensity to surface-rendered CT number (R6MV 2 = 0.70 and R10MV 2 = 0.72). The corrected Cherenkov intensity per unit dose standard error was reduced by nearly half (from ∼30% to ∼17%). CONCLUSIONS This approach provides evidence that the planning CT scan can mitigate some of the tissue-specific attenuation in Cherenkov images, allowing them to be translated into near surface dose images. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Petr Bruza
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,DoseOptics LLC, NH, Lebanon
| | - Michael Jermyn
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,DoseOptics LLC, NH, Lebanon
| | - David J Gladstone
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH
| | - Rongxiao Zhang
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH
| | - Lesley A Jarvis
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH
| | - Brian W Pogue
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,DoseOptics LLC, NH, Lebanon
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Li Y, Liu H, Huang N, Wang Z, Zhang C. The Measurement of the Surface Dose in Regular and Small Radiation Therapy Fields Using Cherenkov Imaging. Technol Cancer Res Treat 2022; 21:15330338211073432. [PMID: 35119327 PMCID: PMC8819764 DOI: 10.1177/15330338211073432] [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] [Indexed: 12/02/2022] Open
Abstract
Purpose: The aim of this study is to measure the output factor (OF)
and profile of surface dose in regular and small radiation therapy fields using
Cherenkov imaging (CI). Methods: A medical linear accelerator
(linac) was employed to generate radiation fields, including regular open photon
field (ROPF), regular wedge photon field (RWPF), regular electron field (REF)
and small photon field (SPF). The photon beams consisted of two filter modes
including flattening filter (FF) and flattening filter free (FFF). All fields
were delivered to a solid water phantom. Cherenkov light was captured using a
charge-coupled device system during phantom irradiation. The OF and profile of
surface dose measured by CI were compared with those determined by film
measurement, ionization chamber measurement and treatment planning system
calculation in order to examine the feasibility of measuring surface dose OF and
profile using CI. Results: The discrepancy between surface dose OF
measured by CI and that determined by other methods is less than 6% in ROPFs
with size less than 10 × 10 cm2, REFs with size less than 10 × 10
cm2, and SPFs except for 1 × 1 cm2 field. In the flat
profile region, the discrepancy between surface dose profile measured by CI and
that determined by other methods is less than 4% in REFs and less than 3% in
ROPFs, RWPFs, and SPFs except for 1 × 1 cm2 field. The discrepancy of the
surface dose profile is in compliance with the recommendation by IAEA TRS 430
reports. The discrepancy between field width measured by CI and that determined
by film measurement is equal to or less than 2 mm, which is within the tolerance
recommend by the guidelines of linac quality assurance in regular open FF photon
fields, SPFs, and REFs with cone size of 10 × 10 cm2 in area.
Conclusion: CI can be used to quantitatively measure the OF and
profile of surface dose. It is feasible to use CI to measure the surface dose
profile and field width in regular open FF photon fields and SPFs except for
1 × 1 cm2 field.
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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 Sciences, Beijing 100049,
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
- Hongjun Liu, PhD, 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, PhD, School of Physics,
Xi’an Jiaotong University, Xi’an 710049, 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
- Hongjun Liu, PhD, 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, PhD, School of Physics,
Xi’an Jiaotong University, Xi’an 710049, China.
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Decker SM, Alexander DA, Hachadorian RL, Zhang R, Gladstone DJ, Bruza P, Pogue BW. Estimation of diffuse Cherenkov optical emission from external beam radiation build-up in tissue. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210129RR. [PMID: 34545714 PMCID: PMC8451315 DOI: 10.1117/1.jbo.26.9.098003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 08/27/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE Optical imaging of Cherenkov emission during radiation therapy could be used to verify dose delivery in real-time if a more comprehensive quantitative understanding of the factors affecting emission intensity could be developed. AIM This study aims to explore the change in diffuse Cherenkov emission intensity with x-ray beam energy from irradiated tissue, both theoretically and experimentally. APPROACH Derivation of the emitted Cherenkov signal was achieved using diffusion theory, and experimental studies with 6 to 18 MV energy x-rays were performed in tissue phantoms to confirm the model predictions as related to the radiation build-up factor with depth into tissue. RESULTS Irradiation at lower x-ray energies results in a greater surface dose and higher build-up slope, which results in a ∼46 % greater diffusely emitted Cherenkov signal per unit dose at 6 MV relative to 18 MV x-rays. However, this phenomenon competes with a decrease in signal from less Cherenkov photons being generated at lower energies, a ∼44 % reduction at 6 versus 18 MV. The result is an emitted Cherenkov signal that is nearly constant with beam energy. CONCLUSIONS This study explains why the observed Cherenkov emission from tissue is not a strong function of beam energy, despite the known strong correlation between Cherenkov intensity and particle energy in the absence of build-up and scattering effects.
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Affiliation(s)
- Savannah M. Decker
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Daniel A. Alexander
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | | | - Rongxiao Zhang
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth–Hitchcock Medical Center, Lebanon, New Hampshire, United States
| | - David J. Gladstone
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth–Hitchcock Medical Center, Lebanon, New Hampshire, United States
| | - Petr Bruza
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- DoseOptics LLC, Lebanon, New Hampshire, United States
| | - Brian W. Pogue
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- DoseOptics LLC, Lebanon, New Hampshire, United States
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9
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Andreozzi JM, Brůža P, Cammin J, Alexander DA, Pogue BW, Green O, Gladstone DJ. Optical emission-based phantom to verify coincidence of radiotherapy and imaging isocenters on an MR-linac. J Appl Clin Med Phys 2021; 22:252-261. [PMID: 34409766 PMCID: PMC8425893 DOI: 10.1002/acm2.13377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 05/03/2021] [Accepted: 07/09/2021] [Indexed: 11/15/2022] Open
Abstract
Purpose Demonstrate a novel phantom design using a remote camera imaging method capable of concurrently measuring the position of the x‐ray isocenter and the magnetic resonance imaging (MRI) isocenter on an MR‐linac. Methods A conical frustum with distinct geometric features was machined out of plastic. The phantom was submerged in a small water tank, and aligned using room lasers on a MRIdian MR‐linac (ViewRay Inc., Cleveland, OH). The phantom physical isocenter was visualized in the MR images and related to the DICOM coordinate isocenter. To view the x‐ray isocenter, an intensified CMOS camera system (DoseOptics LLC., Hanover, NH) was placed at the foot of the treatment couch, and centered such that the optical axis of the camera was coincident with the central axis of the treatment bore. Two or four 8.3mm x 24.1cm beams irradiated the phantom from cardinal directions, producing an optical ring on the conical surface of the phantom. The diameter of the ring, measured at the peak intensity, was compared to the known diameter at the position of irradiation to determine the Z‐direction offset of the beam. A star‐shot method was employed on the front face of the frustum to determine X‐Y alignment of the MV beam. Known shifts were applied to the phantom to establish the sensitivity of the method. Results Couch translations, demonstrative of possible isocenter misalignments, on the order of 1mm were detectable for both the radiotherapy and MRI isocenters. Data acquired on the MR‐linac demonstrated an average error of 0.28mm(N=10, R2=0.997, σ=0.37mm) in established Z displacement, and 0.10mm(N=5, σ=0.34mm) in XY directions of the radiotherapy isocenter. Conclusions The phantom was capable of measuring both the MRI and radiotherapy treatment isocenters. This method has the potential to be of use in MR‐linac commissioning, and could be streamlined to be valuable in daily constancy checks of isocenter coincidence.
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Affiliation(s)
- Jacqueline M Andreozzi
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA.,Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Petr Brůža
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Jochen Cammin
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Daniel A Alexander
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Brian W Pogue
- Thayer School of Engineering and Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire, USA
| | - Olga Green
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - David J Gladstone
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA.,Geisel School of Medicine, Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
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Tsuneda M, Nishio T, Ezura T, Karasawa K. Plastic scintillation dosimeter with a conical mirror for measuring 3D dose distribution. Med Phys 2021; 48:5639-5650. [PMID: 34389992 DOI: 10.1002/mp.15164] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 03/22/2021] [Accepted: 08/01/2021] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To test the measurement technique of the three-dimensional (3D) dose distribution measured image by capturing the scintillation light generated using a plastic scintillator and a scintillating screen. METHODS Our imaging system constituted a column shaped plastic scintillator covered by a Gd2 O2 S:Tb scintillating screen, a conical mirror and a cooled CCD camera. The scintillator was irradiated with 6 MV photon beams. Meanwhile, the irradiated plan was prepared for the static field plans, two-field plan (2F plan) and the conformal arc plan (CA plan). The 2F plan contained 16 mm2 and 10 mm2 fields irradiated from gantry angles of 0° and 25°, respectively. The gantry was rotated counterclockwise from 45° to 315° for the CA plan. The field size was then obtained as 10 mm2 . A Monte Carlo simulation was performed in the experimental geometry to obtain the calculated 3D dose distribution as the reference data. Dose response was acquired by comparing between the reference and the measurement. The dose rate dependence was verified by irradiating the same MU value at different dose rates ranging from 100 to 600 MU/min. Deconvolution processing was applied to the measured images for the correction of light blurring. The measured 3D dose distribution was reconstructed from each measured image. Gamma analysis was performed to these 3D dose distributions. The gamma criteria were 3% for the dose difference, 2 mm for the distance-to-agreement and 10% for the threshold. RESULTS Dose response for the scintillation light was linear. The variation in the light intensity for the dose rate ranging from 100 to 600 MU/min was less than 0.5%, while our system presents dose rate independence. For the 3D dose measurement, blurring of light through deconvolution processing worked well. The 3D gamma passing rate (3D GPR) for the 10 × 10 mm2 , 16 × 16 mm2 , and 20 × 20 mm2 fields were observed to be 99.3%, 98.8%, and 97.8%, respectively. Reproducibility of measurement was verified. The 3D GPR results for the 2F plan and the CA plan were 99.7% and 100%, respectively. CONCLUSIONS We developed a plastic scintillation dosimeter and demonstrated that our system concept can act as a suitable technique for measuring the 3D dose distribution from the gamma results. In the future, we will attempt to measure the 4D dose distribution for clinical volumetric modulated arc radiation therapy (VMAT)-SBRTplans.
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Affiliation(s)
- Masato Tsuneda
- Department of Radiation Oncology, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
| | - Teiji Nishio
- Department of Medical Physics, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
| | - Takatomo Ezura
- Division of Radiation Medical Physics, Kanagawa Cancer Center, Yokohama, Kanagawa, Japan
| | - Kumiko Karasawa
- Department of Radiation Oncology, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
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11
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Alexander DA, Bruza P, Rassias AG, Andreozzi JM, Pogue BW, Zhang R, Gladstone DJ. Visual Isocenter Position Enhanced Review (VIPER): a Cherenkov imaging-based solution for MR-linac daily QA. Med Phys 2021; 48:2750-2759. [PMID: 33887796 DOI: 10.1002/mp.14892] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/28/2021] [Accepted: 04/05/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE This study demonstrates a robust Cherenkov imaging-based solution to MR-Linac daily QA, including mechanical-imaging-radiation isocenter coincidence verification. METHODS A fully enclosed acrylic cylindrical phantom was designed to be mountable to the existing jig, indexable to the treatment couch. An ABS plastic conical structure was fixed inside the phantom, held in place with 3D-printed spacers, and filled with water allowing for high edge contrast on MR imaging scans. Both a star shot plan and a four-angle sheet beam plan were delivered to the phantom; the former allowed for radiation isocenter localization in the x-z plane (A/P and L/R directions) relative to physical landmarks on the phantom, and the latter allowed for the longitudinal position of the sheet beam to be encoded as a ring of Cherenkov radiation emitted from the phantom, allowing for isocenter localization on the y-axis (S/I directions). A custom software application was developed to perform near-real-time analysis of the data by any clinical user. RESULTS Calibration procedures show that linearity between longitudinal position and optical ring diameter is high (R2 > 0.99), and that RMSE is low (0.184 mm). The star shot analysis showed a minimum circle radius of 0.34 mm. The final isocenter coincidence measurements in the lateral, longitudinal, and vertical directions were -0.61 mm, 0.55 mm, and -0.14 mm, respectively, and the total 3D distance coincidence was 0.83 mm, with each of these being below 2 mm tolerance. CONCLUSION This novel system provided an efficient, MR safe, all-in-one method for acquisition and near-real-time analysis of isocenter coincidence data. This represents a direct measurement of the 3D isocentricity. The combination of this phantom and the custom analysis application makes this solution readily clinically deployable after the longitudinal analysis of performance consistency.
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Affiliation(s)
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Aris G Rassias
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | | | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
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12
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Hachadorian R, Farwell JC, Bruza P, Jermyn M, Gladstone DJ, Pogue BW, Jarvis LA. Verification of field match lines in whole breast radiation therapy using Cherenkov imaging. Radiother Oncol 2021; 160:90-96. [PMID: 33892022 DOI: 10.1016/j.radonc.2021.04.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 03/17/2021] [Accepted: 04/09/2021] [Indexed: 01/05/2023]
Abstract
PURPOSE In mono-isocentric radiation therapy treatment plans designed to treat the whole breast and supraclavicular lymph nodes, the fields meet at isocenter, forming the match line. Insufficient coverage at the match line can lead to recurrence, and overlap over weeks of treatment can lead to increased risk of healthy tissue toxicity. Cherenkov imaging was used to assess the accuracy of delivery at the match line and identify potential incidents during patient treatments. METHODS AND MATERIALS A controlled calibration was constructed from the deconvolved Cherenkov images from the delivery of a modified patient treatment plan to an anthropomorphic phantom with introduced separation and overlap. The trend from this calibration was then used to evaluate the field match line for accuracy and inter-fraction consistency for two patients. RESULTS The intersection point between matching field profiles was directly correlated to the distance (gap/overlap) between the fields (anthropomorphic phantom R2 = 0.994 "breath hold" and R2 = 0.990 "free breathing"). The profile intersection points from two patients' imaging sessions yielded an average of +1.40 mm offset (overlap) and -1.32 mm offset (gap), thereby introducing roughly a 25.0% over-dose and a -23.6% under-dose (R2 = 0.994). CONCLUSIONS This study shows that field match regions can be detected and quantified by taking deconvolved Cherenkov images and using their product image to create steep intensity gradients, causing match lines to stand out. These regions can then be quantitatively translated into a dose consequence. This approach offers a high sensitivity detection method which can quantify match line variability and errors in vivo.
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Affiliation(s)
| | | | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, United States
| | - Michael Jermyn
- Thayer School of Engineering, Dartmouth College, Hanover, United States; DoseOptics LLC, Lebanon, United States
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, United States; Norris Cotton Cancer Center at Dartmouth Hitchcock Medical Center, Lebanon, United States; Geisel School of Medicine, Dartmouth College, Hanover, United States
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, United States; DoseOptics LLC, Lebanon, United States; Norris Cotton Cancer Center at Dartmouth Hitchcock Medical Center, Lebanon, United States; Geisel School of Medicine, Dartmouth College, Hanover, United States
| | - Lesley A Jarvis
- Norris Cotton Cancer Center at Dartmouth Hitchcock Medical Center, Lebanon, United States; Geisel School of Medicine, Dartmouth College, Hanover, United States.
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13
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Jarvis LA, Hachadorian RL, Jermyn M, Bruza P, Alexander DA, Tendler II, Williams BB, Gladstone DJ, Schaner PE, Zaki BI, Pogue BW. Initial Clinical Experience of Cherenkov Imaging in External Beam Radiation Therapy Identifies Opportunities to Improve Treatment Delivery. Int J Radiat Oncol Biol Phys 2021; 109:1627-1637. [PMID: 33227443 PMCID: PMC10544920 DOI: 10.1016/j.ijrobp.2020.11.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 10/05/2020] [Accepted: 11/05/2020] [Indexed: 12/18/2022]
Abstract
PURPOSE The value of Cherenkov imaging as an on-patient, real-time, treatment delivery verification system was examined in a 64-patient cohort during routine radiation treatments in a single-center study. METHODS AND MATERIALS Cherenkov cameras were mounted in treatment rooms and used to image patients during their standard radiation therapy regimen for various sites, predominantly for whole breast and total skin electron therapy. For most patients, multiple fractions were imaged, with some involving bolus or scintillators on the skin. Measures of repeatability were calculated with a mean distance to conformity (MDC) for breast irradiation images. RESULTS In breast treatments, Cherenkov images identified fractions when treatment delivery resulted in dose on the contralateral breast, the arm, or the chin and found nonideal bolus positioning. In sarcoma treatments, safe positioning of the contralateral leg was monitored. For all 199 imaged breast treatment fields, the interfraction MDC was within 7 mm compared with the first day of treatment (with only 7.5% of treatments exceeding 3 mm), and all but 1 fell within 7 mm relative to the treatment plan. The value of imaging dose through clear bolus or quantifying surface dose with scintillator dots was examined. Cherenkov imaging also was able to assess field match lines in cerebral-spinal and breast irradiation with nodes. Treatment imaging of other anatomic sites confirmed the value of surface dose imaging more broadly. CONCLUSIONS Daily radiation therapy can be imaged routinely via Cherenkov emissions. Both the real-time images and the posttreatment, cumulative images provide surrogate maps of surface dose delivery that can be used for incident discovery and/or continuous improvement in many delivery techniques. In this initial 64-patient cohort, we discovered 6 minor incidents using Cherenkov imaging; these otherwise would have gone undetected. In addition, imaging provides automated, quantitative metrics useful for determining the quality of radiation therapy delivery.
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Affiliation(s)
- Lesley A Jarvis
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.
| | | | - Michael Jermyn
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - Petr Bruza
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | | | - Irwin I Tendler
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - Benjamin B Williams
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire; Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - David J Gladstone
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire; Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - Philip E Schaner
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Bassem I Zaki
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Brian W Pogue
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
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14
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Alexander DA, Zhang R, Brůža P, Pogue BW, Gladstone DJ. Scintillation imaging as a high‐resolution, remote, versatile 2D detection system for MR‐linac quality assurance. Med Phys 2020; 47:3861-3869. [PMID: 32583484 PMCID: PMC10363284 DOI: 10.1002/mp.14353] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/31/2020] [Accepted: 06/11/2020] [Indexed: 02/04/2023] Open
Abstract
PURPOSE To demonstrate the potential benefits of remote camera-based scintillation imaging for routine quality assurance (QA) measurements for magnetic resonance guided radiotherapy (MRgRT) linear accelerators. METHODS A wall-mounted CMOS camera with a time-synchronized intensifier was used to image photons produced from a scintillation screen in response to dose deposition from a 6 MV FFF x-ray beam produced by a 0.35 T MR-linac. The oblique angle of the field of view was corrected using a projective transform from a checkerboard calibration target. Output sensitivity and constancy was measured using the scintillator and benchmarked against an A28 ion chamber. Field cross-plane and in-plane profiles were measured for field sizes ranging from 1.68 × 1.66 cm2 to 20.02 × 19.92 cm2 with both scintillation imaging and using an IC profiler. Multileaf collimator (MLC) shifts were introduced to test sensitivity of the scintillation imaging system to small spatial deviations. A picket fence test and star-shot were delivered to both the scintillator and EBT3 film to compare accuracy in measuring MLC positions and isocenter size. RESULTS The scintillation imaging system showed comparable sensitivity and linearity to the ion chamber in response to changes in machine output down to 0.5 MU (R2 = 0.99). Cross-plane profiles show strong agreement with defined field sizes using full width half maximum (FWHM) measurement of <2 mm for field sizes below 15 cm, but the oblique viewing angle was the limiting factor in accuracy of in-plane profile widths. However, the system provided high-resolution profiles in both directions for constancy measurements. Small shifts in the field position down to 0.5 mm were detectable with <0.1 mm accuracy. Multileaf collimator positions as measured with both scintillation imaging and EBT3 film were measured within ± 1 mm tolerance and both detection systems produced similar isocenter sizes from the star-shot analysis (0.81 and 0.83 mm radii). CONCLUSIONS Remote scintillation imaging of a two-dimensional screen provided a rapid, versatile, MR-compatible solution to many routine quality assurance procedures including output constancy, profile flatness and symmetry constancy, MLC position verification and isocenter size. This method is high-resolution, does not require post-irradiation readout, and provides simple, instantaneous data acquisition. Full automation of the readout and processing could make this a very simple but effective QA tool, and is adaptable to all medical accelerators.
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Affiliation(s)
| | - Rongxiao Zhang
- Thayer School of Engineering and Geisel School of Medicine Dartmouth College Hanover NH03755USA
- Norris Cotton Cancer Center Dartmouth‐Hitchcock Medical Center Lebanon NH03756USA
| | - Petr Brůža
- Thayer School of Engineering Dartmouth College Hanover NH03755USA
| | - Brian W. Pogue
- Thayer School of Engineering and Geisel School of Medicine Dartmouth College Hanover NH03755USA
- Norris Cotton Cancer Center Dartmouth‐Hitchcock Medical Center Lebanon NH03756USA
| | - David J. Gladstone
- Thayer School of Engineering and Geisel School of Medicine Dartmouth College Hanover NH03755USA
- Norris Cotton Cancer Center Dartmouth‐Hitchcock Medical Center Lebanon NH03756USA
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15
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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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Tendler II, Bruza P, Jermyn M, Fleury A, Williams BB, Jarvis LA, Pogue BW, Gladstone DJ. Improvements to an optical scintillator imaging-based tissue dosimetry system. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-6. [PMID: 31313537 PMCID: PMC6630097 DOI: 10.1117/1.jbo.24.7.075001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 06/24/2019] [Indexed: 05/15/2023]
Abstract
Previous work has shown that capturing optical emission from plastic discs attached directly to the skin can be a viable means to accurately measure surface dose during total skin electron therapy. This method can provide accurate dosimetric information rapidly and remotely without the need for postprocessing. The objective of this study was to: (1) improve the robustness and usability of the scintillators and (2) enhance sensitivity of the optical imaging system to improve scintillator emission detection as related to tissue surface dose. Baseline measurements of scintillator optical output were obtained by attaching the plastic discs to a flat tissue phantom and simultaneously irradiating and imaging them. Impact on underlying surface dose was evaluated by placing the discs on-top of the active element of an ionization chamber. A protective coating and adhesive backing were added to allow easier logistical use, and they were also subjected to disinfection procedures, while verifying that these changes did not affect the linearity of response with dose. The camera was modified such that the peak of detector quantum efficiency better overlapped with the emission spectra of the scintillating discs. Patient imaging was carried out and surface dose measurements were captured by the updated camera and compared to those produced by optically stimulated luminescence detectors (OSLD). The updated camera was able to measure surface dose with < 3 % difference compared to OSLD–Cherenkov emission from the patient was suppressed and scintillation detection was enhanced by 25 × and 7 × , respectively. Improved scintillators increase underlying surface dose on average by 5.2 ± 0.1 % and light output decreased by 2.6 ± 0.3 % . Disinfection had < 0.02 % change on scintillator light output. The enhanced sensitivity of the imaging system to scintillator optical emission spectrum can now enable a reduction in physical dimensions of the dosimeters without loss in ability to detect light output.
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Affiliation(s)
- Irwin I. Tendler
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Address all correspondence to Irwin I. Tendler, E-mail:
| | - Petr Bruza
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Michael Jermyn
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- DoseOptics LLC, Lebanon, New Hampshire, United States
| | - Antoine Fleury
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Université de Strasbourg, Télécom Physique Strasbourg, Illkirch-Graffenstaden, France
| | - Benjamin B. Williams
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States
| | - Lesley A. Jarvis
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States
| | - Brian W. Pogue
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- DoseOptics LLC, Lebanon, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States
| | - David J. Gladstone
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States
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Damulira E, Yusoff MNS, Omar AF, Mohd Taib NH. A Review: Photonic Devices Used for Dosimetry in Medical Radiation. SENSORS 2019; 19:s19102226. [PMID: 31091779 PMCID: PMC6567371 DOI: 10.3390/s19102226] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 11/28/2022]
Abstract
Numerous instruments such as ionization chambers, hand-held and pocket dosimeters of various types, film badges, thermoluminescent dosimeters (TLDs) and optically stimulated luminescence dosimeters (OSLDs) are used to measure and monitor radiation in medical applications. Of recent, photonic devices have also been adopted. This article evaluates recent research and advancements in the applications of photonic devices in medical radiation detection primarily focusing on four types; photodiodes – including light-emitting diodes (LEDs), phototransistors—including metal oxide semiconductor field effect transistors (MOSFETs), photovoltaic sensors/solar cells, and charge coupled devices/charge metal oxide semiconductors (CCD/CMOS) cameras. A comprehensive analysis of the operating principles and recent technologies of these devices is performed. Further, critical evaluation and comparison of their benefits and limitations as dosimeters is done based on the available studies. Common factors barring photonic devices from being used as radiation detectors are also discussed; with suggestions on possible solutions to overcome these barriers. Finally, the potentials of these devices and the challenges of realizing their applications as quintessential dosimeters are highlighted for future research and improvements.
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Affiliation(s)
- Edrine Damulira
- Medical Radiation Programme, School of Health Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Malaysia.
| | - Muhammad Nur Salihin Yusoff
- Medical Radiation Programme, School of Health Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Malaysia.
| | - Ahmad Fairuz Omar
- Engineering Physics Laboratory, School of Physics, Universiti Sains Malaysia, Penang 11800, Malaysia.
| | - Nur Hartini Mohd Taib
- Department of Radiology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Malaysia.
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