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Gao J, Anand D. Off-iso Winston-Lutz test on seven linear accelerators. J Appl Clin Med Phys 2024:e14470. [PMID: 39042435 DOI: 10.1002/acm2.14470] [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: 04/15/2024] [Revised: 05/31/2024] [Accepted: 06/26/2024] [Indexed: 07/24/2024] Open
Abstract
PURPOSE The aim of this study is to find optimal gantry, collimator, and couch angles for performing single isocenter, multiple target stereotactic radiosurgery (SIMT-SRS). Nineteen angle sets were tested across seven linear accelerators for radiation-isocenter coincidence and off-isocenter coincidence. The off-isocenter Winston-Lutz test was performed to evaluate the accuracy of isocenter alignment for each angle set, and optimal angle sets as well as maximum off-isocenter distance to target for each angle set was determined. The influence of simulated patient weight on off-iso Winston-Lutz test accuracy was also inspected. METHOD The SNC MultiMet-WL phantom and MultiMet-WL QA Software v2.1 were used for the direct measurement and analysis of the off-iso Winston-Lutz test (also referred to as Winston-Lutz-Gao test). A two-step method was developed to ensure precise initial placement of the target. Nineteen beams were delivered at 6X energy and 2 × 2 cm field size to each of six targets on the MultiMet Cube with couch kicks at five cardinal angles (90°, 45°, 0°, 315°, and 270°). To reduce imaging uncertainty, only EPID was used in target alignment and test image acquisition. A total of 200 Ibs (90.7 kg) of weight was also used to mimic patient weight. All tests were performed on both the free table and the weighted table. RESULTS For two new TrueBeam machines, the maximum offset was within the 1 mm tolerance when the off-iso distance is less than 7 cm. Two older VitalBeam machines exhibited unfavorable gantry, couch, and collimator (GCC) angle sets: Linac No. 3 at (0,90,0), (0,270,0) and Linac No. 4 at (0,45,45) and (0,90,0). The C-Series Linacs failed in the majority of GCC angle sets, with Linac No. 5 exhibiting a maximum offset of 1.53 mm. Four of seven machines show a clear trend that offset increases with off-isocenter distance. Additionally, the IGRT table was less susceptible to the addition of simulated patient weight than the ExactCouch. CONCLUSION Among the seven linear accelerators addressed, newer model machines such as the Varian TrueBeam were more precise than older models, especially in comparison to the C-Series Linacs. The newer machines are more suitable for delivering SIMT-SRS procedures in all GCC angle sets, and the results indicate that newer TrueBeams are capable of performing SIMT-SRS procedures at all angle sets for targets of off-iso distances up to 7 cm. The trend that offset between the target center and radiation field center increases with off-iso distance, however, does not always hold true across machines. This may be comprised by the EPID's severe off-axis horn effect. Lastly, the IGRT couch was less susceptible to patient weight compared to ExactCouch in the off-isocenter Winston-Lutz test.
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Affiliation(s)
- Junfang Gao
- Radiotherapy Clinics of Georgia, Decatur, Georgia, USA
- Radiation oncology department, Texas Oncology, Houston, Texas, USA
| | - David Anand
- Radiation oncology department, Texas Oncology, Houston, Texas, USA
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Sait AA, Yoganathan SA, Jones GW, Patel T, Rastogi N, Pandey SP, Mani S, Boopathy R. Small field measurements using electronic portal imaging device. Biomed Phys Eng Express 2024; 10:055001. [PMID: 38906125 DOI: 10.1088/2057-1976/ad5a9e] [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: 03/06/2024] [Accepted: 06/21/2024] [Indexed: 06/23/2024]
Abstract
Purpose/Objective. Small-field measurement poses challenges. Although many high-resolution detectors are commercially available, the EPID for small-field dosimetry remains underexplored. This study aimed to evaluate the performance of EPID for small-field measurements and to derive tailored correction factors for precise small-field dosimetry verification.Material/Methods. Six high-resolution radiation detectors, including W2 and W1 plastic scintillators, Edge-detector, microSilicon, microDiamond and EPID were utilized. The output factors, depth doses and profiles, were measured for various beam energies (6 MV-FF, 6 MV-FFF, 10 MV-FF, and 10 MV-FFF) and field sizes (10 × 10 cm2, 5 × 5 cm2, 4 × 4 cm2, 3 × 3 cm2, 2 × 2 cm2, 1 × 1 cm2, 0.5 × 0.5 cm2) using a Varian Truebeam linear accelerator. During measurements, acrylic plates of appropriate depth were placed on the EPID, while a 3D water tank was used with five-point detectors. EPID measured data were compared with W2 plastic scintillator and measurements from other high-resolution detectors. The analysis included percentage deviations in output factors, differences in percentage for PDD and for the profiles, FWHM, maximum difference in the flat region, penumbra, and 1D gamma were analyzed. The output factor and depth dose ratios were fitted using exponential functions and fractional polynomial fitting in STATA 16.2, with W2 scintillator as reference, and corresponding formulae were obtained. The established correction factors were validated using two Truebeam machines.Results. When comparing EPID and W2-PSD across all field-sizes and energies, the deviation for output factors ranged from 1% to 15%. Depth doses, the percentage difference beyond dmax ranged from 1% to 19%. For profiles, maximum of 4% was observed in the 100%-80% region. The correction factor formulae were validated with two independent EPIDs and closely matched within 3%.Conclusion. EPID can effectively serve as small-field dosimetry verification tool with appropriate correction factors.
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Affiliation(s)
- A Aziz Sait
- Department of Physics, Faculty of Engineering, Teerthanker Mahaveer University, Moradabad, India
| | - S A Yoganathan
- Radiation Oncology, NCCCR, Hamad Medical Corporation Doha, Qatar
| | - Glenn W Jones
- University of West Indies, School of Clinical Medicine and Research, Nassau, The Bahamas
| | - Tusar Patel
- Department of Medical Physics, Advanced Medical Physics, Houston, TX, United States of America
| | - Nikhil Rastogi
- Department of Physics, Faculty of Engineering, Teerthanker Mahaveer University, Moradabad, India
| | - S P Pandey
- Department of Physics, Faculty of Engineering, Teerthanker Mahaveer University, Moradabad, India
- Delhi Technical Campus, Knowledge Park-III, Greater Noida (UP), India
| | - Sunil Mani
- Department of Medical Physics, Advanced Medical Physics, Houston, TX, United States of America
| | - Raghavendiran Boopathy
- Department of Radiation Oncology, The University of Oklahoma College of Medicine, OK, United States of America
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Hajare R, K K S, Kumar A, Kalita R, Kaginelli S, Mahantshetty U. Commissioning and dosimetric verification of volumetric modulated arc therapy for multiple modalities using electronic portal imaging device-based 3D dosimetry system: a novel approach. Radiol Phys Technol 2024; 17:412-424. [PMID: 38492203 DOI: 10.1007/s12194-024-00792-z] [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: 12/04/2023] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 03/18/2024]
Abstract
The purpose of this study was to validate an electronic portal imaging device (EPID) based 3-dimensional (3D) dosimetry system for the commissioning of volumetric modulated arc therapy (VMAT) delivery for flattening filter (FF) and flattening filter free (FFF) modalities based on test suites developed according to American Association of Physicists in Medicine Task Group 119 (AAPM TG 119) and pre-treatment patient specific quality assurance (PSQA).With ionisation chamber, multiple-point measurement in various planes becomes extremely difficult and time-consuming, necessitating repeated exposure of the plan. The average agreement between measured and planned doses for TG plans is recommended to be within 3%, and both the ionisation chamber and PerFRACTION™ measurement were well within this prescribed limit. Both point dose differences with the planned dose and gamma passing rates are comparable with TG reported multi-institution results. From our study, we found that no significant differences were found between FF and FFF beams for measurements using PerFRACTION™ and ion chamber. Overall, PerFRACTION™ produces acceptable results to be used for commissioning and validating VMAT and for performing PSQA. The findings support the feasibility of integrating PerFRACTION™ into routine quality assurance procedures for VMAT delivery. Further multi-institutional studies are recommended to establish global baseline values and enhance the understanding of PerFRACTION™'s capabilities in diverse clinical settings.
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Affiliation(s)
- Raghavendra Hajare
- Department of Radiation Oncology, Homi Bhabha Cancer Hospital & Research Centre, Visakhapatnam, India.
- Division of Medical Physics, JSS Academy of Higher Education and Research, Mysuru, India.
| | - Sreelakshmi K K
- Department of Radiation Oncology, Homi Bhabha Cancer Hospital & Research Centre, Visakhapatnam, India
| | - Anil Kumar
- Department of Radiation Oncology, Homi Bhabha Cancer Hospital & Research Centre, Visakhapatnam, India
| | - Rituraj Kalita
- Department of Radiation Oncology, Tezpur Cancer Centre, Bihuguri, India
| | - Shanmukhappa Kaginelli
- Division of Medical Physics, JSS Academy of Higher Education and Research, Mysuru, India
| | - Umesh Mahantshetty
- Department of Radiation Oncology, Homi Bhabha Cancer Hospital & Research Centre, Visakhapatnam, India
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Kirby J, Chester K. Automation to facilitate optimisation of breast radiotherapy treatments using EPID-based in vivodosimetry. Phys Med Biol 2024; 69:095018. [PMID: 38537296 DOI: 10.1088/1361-6560/ad387e] [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: 11/24/2023] [Accepted: 03/26/2024] [Indexed: 04/25/2024]
Abstract
Objective. To use automation to facilitate the monitoring of each treatment fraction using an electronic portal imaging device (EPID) basedin vivodosimetry (IVD) system, allowing optimisation of breast radiotherapy delivery for individual patients and cohorts.Approach. A suite of in-house software was developed to reduce the number of manual interactions with the commercial IVD system, dosimetry check. An EPID specific pixel sensitivity map facilitated use of the EPID panel away from the central axis. Point dose difference and the change in standard deviation in dose were identified as useful dose metrics, with standard deviation used in preference to gamma in the presence of a systematic dose offset. Automated IVD was completed for 3261 fractions across 704 patients receiving breast radiotherapy.Main results. Multiple opportunities for treatment optimisation were identified for individual patients and across patient cohorts as a result of successful implementation of automated IVD. 5.1% of analysed fractions were out of tolerance with 27.1% of these considered true positives. True positive results were obtained on any fraction of treatment and if IVD had only been completed on the first fraction, 84.4% of true positive results would have been missed. This was made possible due to the automation that saved over 800 h of manual intervention and stored data in an accessible database.Significance. An improved EPID calibration to allow off-axis measurement maximises the number of patients eligible for IVD (36.8% of patients in this study). We also demonstrate the importance in selecting context-specific assessment metrics and how these can lead to a managable false positive rate. We have shown that the use of fully automated IVD facilitates use on every fraction of treatment. This leads to identification of areas for treatment improvement for both individuals and across a patient cohort, expanding the uses of IVD from simply gross error detection towards treatment optimisation.
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Affiliation(s)
- Joshua Kirby
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Freeman Hospital, United Kingdom
| | - Katherine Chester
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Cumberland Infirmary, United Kingdom
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Zeng Y, Li H, Chang Y, Han Y, Liu H, Pang B, Han J, Hu B, Cheng J, Zhang S, Yang K, Quan H, Yang Z. In vivo EPID-based daily treatment error identification for volumetric-modulated arc therapy in head and neck cancers with a hierarchical convolutional neural network: a feasibility study. Phys Eng Sci Med 2024:10.1007/s13246-024-01414-z. [PMID: 38647634 DOI: 10.1007/s13246-024-01414-z] [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: 05/07/2023] [Accepted: 03/06/2024] [Indexed: 04/25/2024]
Abstract
We proposed a deep learning approach to classify various error types in daily VMAT treatment of head and neck cancer patients based on EPID dosimetry, which could provide additional information to support clinical decisions for adaptive planning. 146 arcs from 42 head and neck patients were analyzed. Anatomical changes and setup errors were simulated in 17,820 EPID images of 99 arcs obtained from 30 patients using in-house software for model training, validation, and testing. Subsequently, 141 clinical EPID images from 47 arcs belonging to the remaining 12 patients were utilized for clinical testing. The hierarchical convolutional neural network (HCNN) model was trained to classify error types and magnitudes using EPID dose difference maps. Gamma analysis with 3%/2 mm (dose difference/distance to agreement) criteria was also performed. The F1 score, a combination of precision and recall, was utilized to evaluate the performance of the HCNN model and gamma analysis. The adaptive fractioned doses were calculated to verify the HCNN classification results. For error type identification, the overall F1 score of the HCNN model was 0.99 and 0.91 for primary type and subtype identification, respectively. For error magnitude identification, the overall F1 score in the simulation dataset was 0.96 and 0.70 for the HCNN model and gamma analysis, respectively; while the overall F1 score in the clinical dataset was 0.79 and 0.20 for the HCNN model and gamma analysis, respectively. The HCNN model-based EPID dosimetry can identify changes in patient transmission doses and distinguish the treatment error category, which could potentially provide information for head and neck cancer treatment adaption.
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Affiliation(s)
- Yiling Zeng
- Department of Medical Physics, School of Physics and Technology, Wuhan University, Wuhan, 430072, China
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Heng Li
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Yu Chang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yang Han
- College of Electrical Engineering, Sichuan University, Chengdu, 610065, China
| | - Hongyuan Liu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Bo Pang
- Department of Medical Physics, School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Jun Han
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Bin Hu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Junping Cheng
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Sheng Zhang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Kunyu Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Hong Quan
- Department of Medical Physics, School of Physics and Technology, Wuhan University, Wuhan, 430072, China.
| | - Zhiyong Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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Zhou Y, Liu Y, Chen M, Fang J, Xiao L, Huang S, Qi Z, Deng X, Zhang J, Peng Y. Commissioning and clinical evaluation of a novel high-resolution quality assurance digital detector array for SRS and SBRT. J Appl Clin Med Phys 2024; 25:e14258. [PMID: 38175960 PMCID: PMC11005972 DOI: 10.1002/acm2.14258] [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: 07/08/2023] [Revised: 12/03/2023] [Accepted: 12/18/2023] [Indexed: 01/06/2024] Open
Abstract
PURPOSE We aimed to perform the commissioning and clinical evaluation of myQA SRS detector array for patient-specific quality assurance (PSQA) of stereotactic radiosurgery (SRS)/ stereotactic body radiotherapy (SBRT) plans. METHODS To perform the commissioning of myQA SRS, its dose linearity, dose-rate dependence, angular dependence, and field-size dependence were investigated. Ten SBRT plans were selected for clinical evaluation: 1) Common clinical deviations based on the original SBRT plan (Plan0), including multileaf collimator (MLC) positioning deviation and treatment positioning deviation were introduced. 2) Compared the performance of the myQA SRS and a high-resolution EPID dosimetry system in PSQA measurement for the SBRT plans. Evaluation parameters include gamma passing rate (GPR) and distance-to-agreement (DTA) pass rate (DPR). RESULTS The dose linearity, angle dependence, and field-size dependence of myQA SRS system exhibit excellent performance. The myQA SRS is highly sensitive in the detection of MLC deviations. The GPR of (3%/1 mm) decreases from 90.4% of the original plan to 72.7%/62.9% with an MLC outward/inward deviation of 3 mm. Additionally, when the setup error deviates by 1 mm in the X, Y, and Z directions with the GPR of (3%/1 mm) decreasing by an average of -20.9%, -25.7%, and -24.7%, respectively, and DPR (1 mm) decreasing by an average of -33.7%, -32.9%, and -29.8%. Additionally, the myQA SRS has a slightly higher GPR than EPID for PSQA, However, the difference is not statistically significant with the GPR of (3%/1 mm) of (average 90.4%% vs. 90.1%, p = 0.414). CONCLUSION Dosimetry characteristics of the myQA SRS device meets the accuracy and sensitivity requirement of PSQA for SRS/SBRT treatment. The dose rate dependence should be adequately calibrated before its application and a more stringent GPR (3%/1 mm) evaluation criterion is suggested when it is used for SRS/SBRT QA.
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Affiliation(s)
- Yang Zhou
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
- Department of Radiation Oncology, Zhuzhou Hospital Affiliated to Xiangya School of MedicineCentral South UniversityZhuzhouP. R. China
| | - Yimei Liu
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Meining Chen
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Jianlan Fang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Liangjie Xiao
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Shaomin Huang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Zhenyu Qi
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Xiaowu Deng
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Jun Zhang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Yinglin Peng
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
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Fog LS, Webb LK, Barber J, Jennings M, Towns S, Olivera S, Shakeshaft J. ACPSEM position paper: pre-treatment patient specific plan checks and quality assurance in radiation oncology. Phys Eng Sci Med 2024; 47:7-15. [PMID: 38315415 DOI: 10.1007/s13246-023-01367-9] [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: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 02/07/2024]
Abstract
The Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM) has not previously made recommendations outlining the requirements for physics plan checks in Australia and New Zealand. A recent workforce modelling exercise, undertaken by the ACPSEM, revealed that the workload of a clinical radiation oncology medical physicist can comprise of up to 50% patient specific quality assurance activities. Therefore, in 2022 the ACPSEM Radiation Oncology Specialty Group (ROSG) set up a working group to address this issue. This position paper authored by ROSG endorses the recommendations of the American Association of Physicists in Medicine (AAPM) Task Group 218, 219 and 275 reports with some contextualisation for the Australia and New Zealand settings. A few recommendations from other sources are also endorsed to complete the position.
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Affiliation(s)
- Lotte S Fog
- Alfred Health Radiation Oncology, Melbourne, VIC, Australia.
| | | | - Jeffrey Barber
- Sydney West Radiation Oncology Network, Blacktown Hospital, Blacktown, NSW, 2148, Australia
| | - Matthew Jennings
- ICON Cancer Care, Cordelia St, South Brisbane, QLD, 4101, Australia
| | - Sam Towns
- Alfred Health Radiation Oncology, Melbourne, VIC, Australia
| | - Susana Olivera
- ICON Cancer Care, Liz Plummer Cancer Centre, Cairns, QLD, 4870, Australia
| | - John Shakeshaft
- ICON Cancer Care, Gold Coast University Hospital, 1 Hospital Blvd, Southport, QLD, 4215, Australia
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Abdelmajeed M, Attalla EM, Elshemey WM, Elfiky AA, Awadly ME, Eldesoky AR. In vivo dose measurements for tangential field-in-field ultra-hypofractionated breast radiotherapy. J Med Imaging Radiat Sci 2024; 55:37-44. [PMID: 38042641 DOI: 10.1016/j.jmir.2023.11.001] [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: 06/28/2023] [Revised: 10/08/2023] [Accepted: 11/02/2023] [Indexed: 12/04/2023]
Abstract
INTRODUCTION Ultra-hypofractionated radiotherapy (UHF-RT) mandates more accuracy in each part of the treatment cycle to maximize cure rates and minimize toxicities. In vivo dosimetry is a direct method for verifying overall treatment accuracy. This study evaluated uncertainties in the delivered dose of Hypofractionated (HF) and UHF Whole Breast Irradiation (WBI) and to analyze the accuracy of the workflow to pave the way for a wide-scale use of UHF-RT. METHODS Thirty-three breast cancer cases, including 16 HF-WBI and 17 UHF-WBI were treated with 3D conformal Radiotherapy (3D-CRT), where 79 fields were analyzed for dose verification. The measurement point was set at the beam entrance (1.5 cm depth). The expected dose at Dmax was calculated via TPS. Before in vivo measurements, diode detectors were tested and calibrated. We developed initial validation measurements for UHF-RT on an anthropomorphic breast phantom for the first time. RESULTS For RANDO phantom, the percentage difference between measured and calculated doses showed an average of -0.52 ± 5.4%, in addition to an excellent dose reproducibility within 0.6%. The overall in vivo measurements for studied cases showed that 83.5% of the measured doses were within ±5% and only 1.8% of the measured doses were greater than ±10% of the calculated doses. The percentage accuracy was slightly larger for UHF cohort (84.2%) compared to HF cohort (83.2%). The maximum percentage difference between them was less than 1%. CONCLUSION Breast in vivo dosimetry is an adequate tool for treatment verification that improves the accuracy of the treatment cycle. UHF-RT may contribute in reducing the long waiting lists, increasing patient convenience, and saving the available resources for breast cancer patients.
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Affiliation(s)
- Mohamed Abdelmajeed
- Department of Radiotherapy and Nuclear Medicine, National Cancer Institute, Cairo University, Giza, Egypt.
| | - Ehab M Attalla
- Department of Radiotherapy and Nuclear Medicine, National Cancer Institute, Cairo University, Giza, Egypt
| | - Wael M Elshemey
- Physics Department, Faculty of Science, Islamic University of Madinah, Madinah, KSA.
| | - Abdo A Elfiky
- Department of Biophysics, Faculty of Science, Cairo University, Giza, Egypt
| | - Marwa El Awadly
- Department of Radiotherapy and Nuclear Medicine, National Cancer Institute, Cairo University, Giza, Egypt
| | - Ahmed R Eldesoky
- Department of Clinical Oncology and Nuclear Medicine, Mansoura University, Mansoura, Egypt
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Sánchez‐Artuñedo D, Pié‐Padró S, Hermida‐López M, Duch‐Guillén MA, Beltran‐Vilagrasa M. Validation of an in vivo transit dosimetry algorithm using Monte Carlo simulations and ionization chamber measurements. J Appl Clin Med Phys 2024; 25:e14187. [PMID: 37890864 PMCID: PMC10860462 DOI: 10.1002/acm2.14187] [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: 07/11/2023] [Revised: 09/14/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
PURPOSE Transit dosimetry is a safety tool based on the transit images acquired during treatment. Forward-projection transit dosimetry software, as PerFRACTION, compares the transit images acquired with an expected image calculated from the DICOM plan, the CT, and the structure set. This work aims to validate PerFRACTION expected transit dose using PRIMO Monte Carlo simulations and ionization chamber measurements, and propose a methodology based on MPPG5a report. METHODS The validation process was divided into three groups of tests according to MPPG5a: basic dose validation, IMRT dose validation, and heterogeneity correction validation. For the basic dose validation, the fields used were the nine fields needed to calibrate PerFRACTION and three jaws-defined. For the IMRT dose validation, seven sweeping gaps fields, the MLC transmission and 29 IMRT fields from 10 breast treatment plans were measured. For the heterogeneity validation, the transit dose of these fields was studied using three phantoms: 10 , 30 , and a 3 cm cork slab placed between 10 cm of solid water. The PerFRACTION expected doses were compared with PRIMO Monte Carlo simulation results and ionization chamber measurements. RESULTS Using the 10 cm solid water phantom, for the basic validation fields, the root mean square (RMS) of the difference between PerFRACTION and PRIMO simulations was 0.6%. In the IMRT fields, the RMS of the difference was 1.2%. When comparing respect ionization chamber measurements, the RMS of the difference was 1.0% both for the basic and the IMRT validation. The average passing rate with a γ(2%/2 mm, TH = 20%) criterion between PRIMO dose distribution and PerFRACTION expected dose was 96.0% ± 5.8%. CONCLUSION We validated PerFRACTION calculated transit dose with PRIMO Monte Carlo and ionization chamber measurements adapting the methodology of the MMPG5a report. The methodology presented can be applied to validate other forward-projection transit dosimetry software.
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Affiliation(s)
- David Sánchez‐Artuñedo
- Servei de Física i Protecció RadiològicaHospital Universitari Vall d'HebronBarcelonaSpain
| | - Savannah Pié‐Padró
- Servei de Física i Protecció RadiològicaHospital Universitari Vall d'HebronBarcelonaSpain
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Tzomakas MK, Peppa V, Alexiou A, Karakatsanis G, Episkopakis A, Michail C, Valais I, Fountos G, Kalyvas N, Kandarakis IS. A phantom based evaluation of the clinical imaging performance of electronic portal imaging devices. Heliyon 2023; 9:e21116. [PMID: 37916082 PMCID: PMC10616349 DOI: 10.1016/j.heliyon.2023.e21116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 10/14/2023] [Accepted: 10/16/2023] [Indexed: 11/03/2023] Open
Abstract
Purpose In this study an evaluation of the imaging performance of an electronic portal imaging device (EPID) is presented. The evaluation performed employing the QC-3V image quality phantom. Methods An EPID system of a 6 MV LINAC, was used to obtain images of a QC-3V EPID phantom. The X-ray source to phantom distance was 100 cm and the field size was 15x15 cm2. The irradiation conditions comprised Dose Rates (DR) of 200, 400 and 600 for a 2 MU-100 MU range. The Contrast Transfer Function (CTF), the Noise Power Spectrum (NPS), the Normalized Noise Power Spectrum (NNPS) and the Contrast-to-Noise Ratio (CNR) were studied. In addition, an alternative factor showing a frequency related output signal-to-noise ratio (SNR), the Signal-to-Noise-Frequency Response (SNFR), has been introduced. SNFR is a comprehensive quality index, easily determined in clinical environment. Results The CTF curves were found comparable to each other. The lowest values were measured at 2 MU and 200 MU/min. Concerning the NPS and NNPS graphs it was found that the values decrease up to approximately 0.3 lp/mm and demonstrate a white noise shape afterwards. SNFR values were found reducing with spatial frequency. Highest CNR were found between the region 7 and 11 of the phantom. Conclusions The influence of MU and DR on EPID performance were investigated. Image quality was assessed using the QC-3V phantom. The presented results can lead to image quality amelioration and act supportively to current image quality control routine protocols.
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Affiliation(s)
- Marios K. Tzomakas
- Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Egaleo, 12210 Athens, Greece
| | - Vasiliki Peppa
- General Hospital of Athens Alexandra, Department of Radiotherapy, 11528 Athens, Greece
| | - Antigoni Alexiou
- General Hospital of Athens Alexandra, Department of Radiotherapy, 11528 Athens, Greece
| | - Georgios Karakatsanis
- General Hospital of Athens Alexandra, Department of Radiotherapy, 11528 Athens, Greece
| | - Anastasios Episkopakis
- Elekta, 15124 Athens, Greece
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 115 27 Athens, Greece
| | - Christos Michail
- Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Egaleo, 12210 Athens, Greece
| | - Ioannis Valais
- Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Egaleo, 12210 Athens, Greece
| | - George Fountos
- Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Egaleo, 12210 Athens, Greece
| | - Nektarios Kalyvas
- Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Egaleo, 12210 Athens, Greece
| | - Ioannis S. Kandarakis
- Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Egaleo, 12210 Athens, Greece
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