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Seo J, Lee H, Hwan Ahn S, Yoon M. Feasibility study of a scintillation sheet-based detector for fluence monitoring during external photon beam radiotherapy. Phys Med 2023; 112:102628. [PMID: 37354806 DOI: 10.1016/j.ejmp.2023.102628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 03/24/2023] [Accepted: 06/13/2023] [Indexed: 06/26/2023] Open
Abstract
PURPOSE This study evaluated the properties of a scintillation sheet-based dosimetry system for beam monitoring with high spatial resolution, including the effects of this system on the treatment beam. The dosimetric characteristics and feasibility of this system for clinical use were also evaluated. METHODS The effects of the dosimetry system on the beam were evaluated by measuring the percentage depth doses, dose profiles, and transmission factors. Fifteen treatment plans were created, and the influence of the dosimetry system on these clinical treatment plans was evaluated. The performance of the system was assessed by determining signal linearity, dose rate dependence, and reproducibility. The feasibility of the system for clinical use was evaluated by comparing intensity distributions with reference intensity distributions verified by quality assurance. RESULTS The spatial resolution of the dosimetry system was found to be 0.43 mm/pixel when projected to the isocenter plane. The dosimetry system attenuated the intensity of 6 MV beams by about 1.1%, without affecting the percentage depth doses and dose profiles. The response of the dosimetry system was linear, independent of the dose rate used in the clinic, and reproducible. Comparison of intensity distributions of evaluation treatment fields with reference intensity distributions showed that the 1%/1 mm average gamma passing rate was 99.6%. CONCLUSIONS The dosimetry system did not significantly alter the beam characteristics, indicating that the system could be implemented by using only a transmission factor. The dosimetry system is clinically suitable for monitoring treatment beam delivery with higher spatial resolution than other transmission detectors.
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Affiliation(s)
- Jaehyeon Seo
- Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea; Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon, Republic of Korea
| | - Hyunho Lee
- Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea; Department of Radiation Oncology, Samsung Medical Center, Seoul, Republic of Korea
| | - Sung Hwan Ahn
- Department of Radiation Oncology, Samsung Medical Center, Seoul, Republic of Korea.
| | - Myonggeun Yoon
- Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea; FieldCure Ltd, Seoul, Republic of Korea.
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2
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Zhao X, Stanley DN, Cardenas CE, Harms J, Popple RA. Do we need patient-specific QA for adaptively generated plans? Retrospective evaluation of delivered online adaptive treatment plans on Varian Ethos. J Appl Clin Med Phys 2022; 24:e13876. [PMID: 36560887 PMCID: PMC9924122 DOI: 10.1002/acm2.13876] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/09/2022] [Accepted: 11/15/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The clinical introduction of dedicated treatment units for online adaptive radiation therapy (OART) has led to widespread adoption of daily adaptive radiotherapy. OART allows for rapid generation of treatment plans using daily patient anatomy, potentially leading to reduction of treatment margins and increased normal tissue sparing. However, the OART workflow does not allow for measurement of patient-specific quality assurance (PSQA) during treatment delivery sessions and instead relies on secondary dose calculations for verification of adapted plans. It remains unknown if independent dose verification is a sufficient surrogate for PSQA measurements. PURPOSE To evaluate the plan quality of previously treated adaptive plans through multiple standard PSQA measurements. METHODS This IRB-approved retrospective study included sixteen patients previously treated with OART at our institution. PSQA measurements were performed for each patient's scheduled and adaptive plans: five adaptive plans were randomly selected to perform ion chamber measurements and two adaptive plans were randomly selected for ArcCHECK measurements. The same ArcCHECK 3D dose distribution was also sent to Mobius3D to evaluate the second-check dosimetry system. RESULTS All (n = 96) ion chamber measurements agreed with the planned dose within 3% with a mean of 1.4% (± 0.7%). All (n = 48) plans passed ArcCHECK measurements using a 95% gamma passing threshold and 3%/2 mm criteria with a mean of 99.1% (± 0.7%). All (n = 48) plans passed Mobius3D second-check performed with 95% gamma passing threshold and 5%/3 mm criteria with a mean of 99.0% (± 0.2%). CONCLUSION Plan measurement for PSQA may not be necessary for every online-adaptive treatment verification. We recommend the establishment of a periodic PSQA check to better understand trends in passing rates for delivered adaptive treatments.
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Affiliation(s)
- Xiaodong Zhao
- Department of Radiation OncologyWashington University in St. LouisSt. LouisMissouriUSA
| | - Dennis N. Stanley
- Department of Radiation OncologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Carlos E. Cardenas
- Department of Radiation OncologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Joseph Harms
- Department of Radiation OncologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Richard A. Popple
- Department of Radiation OncologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
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Yoosuf AM, Ahmad MB, AlShehri S, Alhadab A, Alqathami M. Investigation of optimum minimum segment width on VMAT plan quality and deliverability: A comprehensive dosimetric and clinical evaluation using DVH analysis. J Appl Clin Med Phys 2021; 22:29-40. [PMID: 34592787 PMCID: PMC8598144 DOI: 10.1002/acm2.13417] [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: 04/19/2021] [Revised: 06/23/2021] [Accepted: 08/24/2021] [Indexed: 12/15/2022] Open
Abstract
Purpose Minimum segment width (MSW) plays a fundamental role in the shaping of optimized apertures and creation of segments of varying sizes and shapes in complex radiotherapy treatment plans. The purpose of this work was to study the effect of MSW on dose distribution in patients planned with VMAT for various treatment sites using dose volume histogram (DVH) analysis. Materials and methods For the validation of optimum MSW, 125 clinical treatment plans were evaluated. Five groups were identified (brain, head and neck, thorax, pelvis, and extremity), and five cases were chosen from each group. For each case, five plans were created with different MSW (0.5, 0.8, 1.0, 1.25, and 1.5 cm). The quality of treatment plans created using different MSW were compared using dosimetric indicators such as target coverage (D98—dose to 98% of the planning target volume (PTV), maximum dose (D2—maximum dose to 2% of the PTV), monitor units (MU), and DVH parameters related to organs at risk (OAR). The effect of the MSW on delivery accuracy was quantitatively analyzed using the measured fluence utilizing ionization chamber‐based transmission detector and model‐based dose verification system. Traditional global gamma analysis (2%, 2 mm) and dose volume information was gathered for the PTV and organs at risk and compared for different MSWs. Results A total of 125 plans were created and compared across five groups. In terms of treatment plan quality, the plans using MSW of 0.5 cm was found to be superior in all groups. PTV coverage (D98) decreased significantly (p < 0.05) as the MSW increased. Similarly, the maximum dose (D2) was found to be increased significantly (p < 0.05) as the MSW increased from 0.5 cm, with MSW of 1.5 cm being the least in terms of plan quality for both PTVs and OARs. In terms of plan deliverability using DVH analysis, treatment planning system (TPS) compared to measured fluence, VMAT plans produced with MSW of 0.5 cm showed a better dosimetric index and a smaller deviation for both PTVs and OARs. The deliverability of the plans deteriorated as the MSW increased. Conclusion Dose volume histogram (DVH) analysis demonstrated that treatment plans with minimal MSW showed better plan quality and deliverability and provided clinical relevance as compared to gamma index analysis.
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Affiliation(s)
- Ab Mohamed Yoosuf
- Department of Radiation Oncology, Ministry of National Guard-Health Affairs, Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Muhammad Bilal Ahmad
- Department of Radiation Oncology, Ministry of National Guard-Health Affairs, Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Salem AlShehri
- Department of Radiation Oncology, Ministry of National Guard-Health Affairs, Riyadh, Saudi Arabia.,King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Abdulrahman Alhadab
- Department of Radiation Oncology, Ministry of National Guard-Health Affairs, Riyadh, Saudi Arabia
| | - Mamdouh Alqathami
- Department of Radiation Oncology, Ministry of National Guard-Health Affairs, Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center, Riyadh, Saudi Arabia.,King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
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Alharthi T, George A, Arumugam S, Holloway L, Thwaites D, Vial P. An investigation of the IQM signal variation and error detection sensitivity for patient specific pre-treatment QA. Phys Med 2021; 86:6-18. [PMID: 34049118 DOI: 10.1016/j.ejmp.2021.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/11/2021] [Accepted: 05/03/2021] [Indexed: 11/19/2022] Open
Abstract
PURPOSE To evaluate the Integral Quality Monitor (IQM) as a clinical dosimetry device for detecting photon beam delivery errors in clinically relevant conditions. MATERIALS AND METHODS The IQM's ability to detect delivery errors introduced into clinical VMAT plans for two different treatment sites was assessed. This included measuring 103 nasopharynx VMAT plans and 78 lung SBRT VMAT plans with introduced errors in gantry angle (1-5°) and in MLC-defined field size and field shift (1-5 mm). The IQM sensitivity was compared to ArcCheck detector performance. Signal dependence on field position for on-axis and asymmetrically offset square field sizes from 1 × 1 cm2 to 30 × 30 cm2 was also investigated. RESULTS The IQM detected almost all introduced clinically-significant MLC field size errors, but not some small gantry angle errors or most MLC field shift errors. The IQM sensitivity was comparable to the ArcCheck for lung SBRT, but worse for the nasopharynx plans. Differences between IQM calculated/predicted and measured signals were within ± 2% for all on-axis square fields, but up to 60% for the smallest asymmetrically offset fields at large offsets. CONCLUSION The IQM performance was consistent and reproducible. It showed highest sensitivity to the field size errors for these plans, but did not detect some clinically-significant introduced gantry angle errors or most MLC field shift errors. The IQM calculation model is still being developed, which should improve small offset-field performance. Care is required in IQM use for plan verification or online monitoring, especially for small fields that are off-axis in the detector gradient direction.
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Affiliation(s)
- Thahabah Alharthi
- Institute of Medical Physics, School of Physics, The University of Sydney, Sydney, New South Wales, Australia; School of Medicine, Taif University, Taif, Saudi Arabia; Liverpool and Macarthur Cancer Therapy Centers, Liverpool, NSW, Australia; Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.
| | - Armia George
- Liverpool and Macarthur Cancer Therapy Centers, Liverpool, NSW, Australia.
| | - Sankar Arumugam
- Liverpool and Macarthur Cancer Therapy Centers, Liverpool, NSW, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia.
| | - Lois Holloway
- Institute of Medical Physics, School of Physics, The University of Sydney, Sydney, New South Wales, Australia; Liverpool and Macarthur Cancer Therapy Centers, Liverpool, NSW, Australia; Ingham Institute for Applied Medical Research, Sydney, NSW, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia.
| | - David Thwaites
- Institute of Medical Physics, School of Physics, The University of Sydney, Sydney, New South Wales, Australia.
| | - Phil Vial
- Liverpool and Macarthur Cancer Therapy Centers, Liverpool, NSW, Australia; Ingham Institute for Applied Medical Research, Sydney, NSW, Australia; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia.
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Dudas D, Semmler M, Průša P, Neue G, Koniarova I, Peterkova K, Gallus P, Koncek O, Vrba V. The use of Pantherpix pixel detector in radiotherapy QA. Phys Med 2021; 82:332-340. [PMID: 33721792 DOI: 10.1016/j.ejmp.2021.01.072] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 12/23/2020] [Accepted: 01/16/2021] [Indexed: 11/17/2022] Open
Abstract
There are various different detectors, which can be used for radiotherapy measurements, and more are about to be adopted. Hybrid pixel detectors (HPD) have been originally developed for the high energy physics. However, over the last few years they also expanded in the medical physics. Novel 2D detector Pantherpix is a HPD designed specifically for the radiotherapy. In this article, its properties are characterised and an assessment of its use in radiotherapy photon beams is provided. Properties such as response stability, response linearity, angular dependence and energy dependence were studied. In order to prove sufficient clinical quality for relative dosimetry, further measurements were undertaken (i.e. dose profiles and collimator scatter factors). Acquired results were compared with ion chamber and gafchromic film results. Namely the applicability of PhPix for cobalt beam therapy, which is still widely used (and will be used in near future) in economically less developed countries, is considered.
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Affiliation(s)
- Denis Dudas
- CTU - Faculty of Nuclear Sciences and Physical Engineering, Prague, Czech Republic; UJP PRAHA a.s., Prague, Czech Republic.
| | | | - Petr Průša
- CTU - Faculty of Nuclear Sciences and Physical Engineering, Prague, Czech Republic.
| | - Gordon Neue
- CTU - Faculty of Nuclear Sciences and Physical Engineering, Prague, Czech Republic
| | - Irena Koniarova
- National Radiation Protection Institute v.v.i., Prague, Czech Republic
| | | | | | | | - Vaclav Vrba
- CTU - Faculty of Nuclear Sciences and Physical Engineering, Prague, Czech Republic
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6
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Shin D, Yoon M, Moon S, Jo Y, Seo J. Inter-fractional entrance dose monitoring as quality assurance using Gafchromic EBT3 film. J Cancer Res Ther 2021; 18:1152-1158. [DOI: 10.4103/jcrt.jcrt_8_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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7
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Paxton AB, Sarkar V, Kunz JN, Szegedi M, Zhao H, Huang YJ, Nelson G, Rassiah P, Su FCF, Salter BJ. Evaluation of the effects of implementing a diode transmission device into the clinical workflow. Phys Med 2020; 80:335-341. [DOI: 10.1016/j.ejmp.2020.11.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 11/06/2020] [Accepted: 11/11/2020] [Indexed: 12/22/2022] Open
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8
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Jeong S, Yoon M, Chung K, Ahn SH, Lee B, Seo J. Clinical application of a gantry-attachable plastic scintillating plate dosimetry system in pencil beam scanning proton therapy beam monitoring. Phys Med 2020; 77:181-186. [DOI: 10.1016/j.ejmp.2020.08.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/24/2020] [Accepted: 08/19/2020] [Indexed: 12/14/2022] Open
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9
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C M, F C P DP. X-Ray Beam Segment Size and Entrance Location Effects on the Integral Quality Monitor (IQM®) Signal and Usefulness in Predicting Complex Segment Output Signals. J Biomed Phys Eng 2020; 10:395-410. [PMID: 32802788 PMCID: PMC7416101 DOI: 10.31661/jbpe.v0i0.1162] [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: 04/15/2019] [Accepted: 06/12/2019] [Indexed: 11/16/2022]
Abstract
Background: The Integral Quality Monitor (IQM®) is an independent online dosimetry device attached to the treatment machine to monitor the accuracy of radiation delivery. Objective: This study investigates the influence of beam segment size and displacement as projected onto the IQM chamber on the signals and determine how individual signals can be added to get a combined segment signal made up of smaller segments. Material and Methods: This is an experimental original research type of study. IQM response maps were generated by irradiating the IQM sensitive area with small elementary segments and measuring their corresponding signals per monitor unit (MU). The output signal/MU was measured for regular and irregular fields and compared with the predicted signal/MU obtained from decomposing the open segment into a set of smaller regular segments and summing their signals from their respective response maps. The dependence of signals on segment size, shape, location and combination was investigated. Results: Predicted signals were calculated within 95-98 % accuracy for regular fields and 90-98% for irregular fields. More uniform fluence contain distribution for larger segments was observed. Response maps were consistent with the geometrical symmetry in the chamber’s wedge shape and the symmetry in the linac fluence. Conclusion: The field decomposition method allows the pre-calculation of known segment output signals per MU within 2% error, although the accuracy drops significantly for smaller, irregular fields. A method of correcting predicted signals in smaller segments needs to be laid down to get a better match with measured signals.
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Affiliation(s)
- Mahuvava C
- PhD, Department of Medical Physics, Faculty of Health Sciences, University of the Free State, P.O. Box 339, Bloemfontein, 9300 South Africa
| | - Du Plessis F C P
- PhD, Department of Medical Physics, Faculty of Health Sciences, University of the Free State, P.O. Box 339, Bloemfontein, 9300 South Africa
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Esposito M, Villaggi E, Bresciani S, Cilla S, Falco MD, Garibaldi C, Russo S, Talamonti C, Stasi M, Mancosu P. Clarifications on our review on estimating dose delivery accuracy in stereotactic body radiation therapy: A review of in-vivo measurement methods: In response to the letter of Kos. Radiother Oncol 2020; 153:320-321. [PMID: 32663534 DOI: 10.1016/j.radonc.2020.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/01/2020] [Accepted: 07/01/2020] [Indexed: 11/17/2022]
Affiliation(s)
- Marco Esposito
- S.C. Fisica Sanitaria Firenze-Empoli, Azienda Sanitaria USL Toscana Centro, Italy
| | | | - Sara Bresciani
- Medical Physics, Candiolo Cancer Institute - FPO IRCCS, Turin, Italy
| | - Savino Cilla
- Medical Physics Unit, Gemelli Molise Hospital, Campobasso, Italy
| | - Maria Daniela Falco
- Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Cristina Garibaldi
- Radiation Research Unit, European Institute of Oncology IRCCS, Milan, Italy
| | - Serenella Russo
- S.C. Fisica Sanitaria Firenze-Empoli, Azienda Sanitaria USL Toscana Centro, Italy
| | - Cinzia Talamonti
- University of Florence, Dept Biomedical Experimental and Clinical Science, "Mario Serio", Medical Physics Unit, AOU Careggi, Florence, Italy
| | - Michele Stasi
- Medical Physics, Candiolo Cancer Institute - FPO IRCCS, Turin, Italy.
| | - Pietro Mancosu
- Medical Physics Unit of Radiotherapy Dept., Humanitas Clinical and Research Hospital - IRCCS, Rozzano, Italy
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11
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Mahuvava C, Du Plessis FCP. Integral quality monitor (IQM
®
) signal correction factors for small fields to predict larger irregular segment output signals. Med Phys 2019; 46:5848-5860. [DOI: 10.1002/mp.13831] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/07/2019] [Accepted: 09/09/2019] [Indexed: 11/09/2022] Open
Affiliation(s)
- Courage Mahuvava
- Medical Physics Department Faculty of Health Sciences University of the Free State P.O. Box 339 Bloemfontein 9300South Africa
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12
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Mohamed Yoosuf AB, AlShehri S, Alhadab A, Alqathami M. DVH analysis using a transmission detector and model-based dose verification system as a comprehensive pretreatment QA tool for VMAT plans: Clinical experience and results. J Appl Clin Med Phys 2019; 20:80-87. [PMID: 31605456 PMCID: PMC6839390 DOI: 10.1002/acm2.12743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/31/2019] [Accepted: 09/15/2019] [Indexed: 11/22/2022] Open
Abstract
Purpose Dose volume histogram (DVH)‐based analysis is utilized as a pretreatment quality assurance tool to determine clinical relevance from measured dose which is difficult in conventional gamma‐based analysis. In this study, we report our clinical experience with an ionization‐based transmission detector and model‐based verification system, using DVH analysis, as a comprehensive pretreatment QA tool for complex volumetric modulated arc therapy plans. Methods and Materials Seventy‐three subsequent treatment plans categorized into four clinical sites (Head and Neck, Thorax, Abdomen, and Pelvis) were evaluated. The average dose (Dmean) and dose received by 1% (D1) of the planning target volumes (PTVs) and organs at risks (OARs) calculated using the treatment planning system (TPS) were compared to a computed (model‐based) and reconstructed dose, from the measured fluence, using DVH analysis. The correlation between gamma (3% 3 mm) and DVH‐based analysis for targets was evaluated. Furthermore, confidence and action limits for detector and verification systems were established. Results Linear regression confirmed an excellent correlation between TPS planned and computed dose using a model‐based verification system (r2 = 1). The average percentage difference between TPS calculated and reconstructed dose for PTVs achieved using DVH analysis for each site is as follows: Head and Neck — 0.57 ± 2.8% (Dmean) and 2.6 ± 2.7% (D1), Abdomen — 0.19 ± 2.8% and 1.64 ± 2.2%, Thorax — 0.24 ± 2.1% and 3.12 ± 2.8%, Pelvis 0.37 ± 2.4% and 1.16 ± 2.3%, respectively. The average percentage of passed gamma values achieved was above 95% for all cases. However, no correlation was observed between gamma passing rates and DVH difference (%) for PTVs (r2 = 0.11). The results demonstrate a confidence limit of 5% (Dmean and D1) for PTVs using DVH analysis for both computed and reconstructed dose distribution. Conclusion DVH analysis of treatment plan using a model‐based verification system and transmission detector provided useful information on clinical relevance for all cases and could be used as a comprehensive pretreatment patient‐specific QA tool.
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Affiliation(s)
- Ahamed B Mohamed Yoosuf
- Department of Oncology, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Salem AlShehri
- Department of Oncology, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia.,King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Abdulrahman Alhadab
- Department of Oncology, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia.,King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Mamdooh Alqathami
- Department of Oncology, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center, Riyadh, Saudi Arabia.,King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
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Strauss L, Shaw W. Considerations for the verification of volumetric modulated arc therapy-planned dose distributions. SOUTH AFRICAN JOURNAL OF ONCOLOGY 2019. [DOI: 10.4102/sajo.v3i0.86] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Background: Volumetric modulated arc therapy (VMAT) is the standard of care for many clinical indications, but should only be considered with proper technical support and quality assurance (QA) in place. Despite the high accuracy of VMAT systems, errors can be present and adequate verification is required. Dosimetric VMAT verification systems have a broadly similar analysis philosophy. However, many factors influence the analyses and the subsequent QA outcome, based on which the plan will pass or fail.Aim: This study investigated various factors that influence the dosimetric impact and detectability of known linac component deviations on VMAT QA, including geometries, tissue densities, gamma criteria and dose–volume differences.Setting: Universitas Hospital (Annex), Bloemfontein, South Africa.Methods: Deliberate multi-leaf collimator (MLC)-bank offsets were introduced on four different VMAT plans of the prostate, nasopharynx and brain. Measured reference dose sets were compared to measured QA results, using the IBA Dolphin© detector and Compass© software for three dosimetric scenarios. Gamma pass rates over a range of criteria from 1%/2-mm to 4%/4-mm in the total volumes and per structure, as well as dose–volume differences were studied.Results: Gamma tests in the total patient/phantom did not sufficiently detect errors. The calculation media did not influence the QA outcome greatly. However, the detection geometry affected the results. Per structure gamma analyses provided superior error detection, although still missed some clinically relevant differences. The addition of dose–volume analyses highlighted several important errors.Conclusion: Volumetric modulated arc therapy using only total volume gamma analyses can easily overlook clinically relevant errors. The choice of gamma criterion is crucial. Verification with at least a per structure gamma test in combination with dose–volume checks is recommended, especially in small target volume cases.
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Giglioli FR, Gallio E, Franco P, Badellino S, Ricardi U, Fiandra C. Clinical evaluation of a transmission detector system and comparison with a homogeneous 3D phantom dosimeter. Phys Med 2019; 58:159-164. [DOI: 10.1016/j.ejmp.2019.01.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 01/23/2019] [Accepted: 01/26/2019] [Indexed: 11/16/2022] Open
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Razinskas G, Wegener S, Greber J, Sauer OA. Sensitivity of the IQM transmission detector to errors of VMAT plans. Med Phys 2018; 45:5622-5630. [DOI: 10.1002/mp.13228] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 09/28/2018] [Accepted: 09/28/2018] [Indexed: 11/09/2022] Open
Affiliation(s)
- Gary Razinskas
- Radiation Oncology University of Wuerzburg Josef‐Schneider‐Str. 11 97080 Wuerzburg Germany
| | - Sonja Wegener
- Radiation Oncology University of Wuerzburg Josef‐Schneider‐Str. 11 97080 Wuerzburg Germany
| | - Johannes Greber
- Radiation Oncology University of Wuerzburg Josef‐Schneider‐Str. 11 97080 Wuerzburg Germany
| | - Otto A. Sauer
- Radiation Oncology University of Wuerzburg Josef‐Schneider‐Str. 11 97080 Wuerzburg Germany
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16
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Characterization of EPID software for VMAT transit dosimetry. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2018; 41:1021-1027. [DOI: 10.1007/s13246-018-0693-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 10/08/2018] [Indexed: 10/28/2022]
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17
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Rangaraj D, Yaddanapudi S, Cai J. Transmission detectors are safe and the future for patient-specific QA in radiation therapy. Med Phys 2018; 46:1-4. [PMID: 30230548 DOI: 10.1002/mp.13201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 09/11/2018] [Accepted: 09/13/2018] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Sridhar Yaddanapudi
- Department of Radiation Oncology; University of Iowa Health Care; Iowa City IA 52242 USA
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Park SY, Park JM, Kim JI, Lee S, Choi CH. Validation of new transmission detector transmission factors for online dosimetry: an experimental study. Radiat Oncol 2018; 13:156. [PMID: 30143012 PMCID: PMC6109263 DOI: 10.1186/s13014-018-1106-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 08/20/2018] [Indexed: 01/14/2023] Open
Abstract
Background The demand for dose verification during treatment has risen with the increasing use of intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) in modern radiation therapy. This study aims to validate the transmission factors of a new transmission detector, the Dolphin online monitoring system (IBA Dosimetry, Schwarzenbruck, Germany), for clinical use. Methods The transmission factors of the Dolphin detector were evaluated using 6 MV, 6 flattening filter free (FFF), 10 MV, and 10 FFF clinical beams from a TrueBeam STx linear accelerator system. Two-dimensional (2D) dose distributions were measured through portal dosimetry with and without Dolphin to derive the transmission factors. The measurements were performed using 10 IMRT and 10 VMAT treatment plans. The transmission factors were calculated using a non-negative least squares problem solver for the 2D dose matrix. Normalized plans were generated using the derived transmission factors. Patient-specific quality assurance with normalized plans was performed using portal dosimetry and an ArcCheck detector to verify the transmission factors. The gamma passing rates were calculated for the 2%/2 mm and 1%/1 mm criteria. Results The transmission factors for the 6 MV, 6 FFF, 10 MV, and 10 FFF beams, were 0.878, 0.824, 0.913, and 0.883, respectively. The average dose difference between the original plan without Dolphin and the normalized plan with Dolphin was less than 1.8% for all measurements. The mean passing rates of the gamma evaluation were 98.1 ± 2.1 and 82.9 ± 12.6 for the 2%/2 mm and 1%/1 mm criteria, respectively, for portal dosimetry of the original plan. In the case of the portal dosimetry of the normalized plan, the mean passing rates of the gamma evaluation were 97.2 ± 2.8 and 79.1 ± 14.8 for the 2%/2 mm and 1%/1 mm criteria, respectively. Conclusions The Dolphin detector can be used for online dosimetry when valid transmission factors are applied to the clinical plan.
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Affiliation(s)
- So-Yeon Park
- Department of Radiation Oncology, Veterans Health Service Medical Center, Seoul, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Jong Min Park
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jung-In Kim
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Sungyoung Lee
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Chang Heon Choi
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea. .,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea. .,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea.
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Development of Optical Fiber Based Measurement System for the Verification of Entrance Dose Map in Pencil Beam Scanning Proton Beam. SENSORS 2018; 18:s18010227. [PMID: 29342941 PMCID: PMC5796397 DOI: 10.3390/s18010227] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 01/11/2018] [Accepted: 01/13/2018] [Indexed: 11/28/2022]
Abstract
This study describes the development of a beam monitoring system for the verification of entrance dose map in pencil beam scanning (PBS) proton therapy based on fiber optic radiation sensors (FORS) and the validation of this system through a feasibility study. The beam monitoring system consisted of 128 optical fibers optically coupled to photo-multiplier tubes. The performance of the beam monitoring system based on FORS was verified by comparing 2D dose maps of square-shaped fields of various sizes, which were obtained using conventional dosimeters such as MatriXX and EBT3 film, with those measured using FORS. The resulting full-width at half maximum and penumbra were compared for PBS proton beams, with a ≤2% difference between each value, indicating that measurements using the conventional dosimetric tool corresponded to measurements based on FORS. For irregularly-shaped fields, a comparison based on the gamma index between 2D dose maps obtained using MatriXX and EBT3 film and the 2D dose map measured by the FORS showed passing rates of 96.9 ± 1.3% and 96.2 ± 1.9%, respectively, confirming that FORS-based measurements for PBS proton therapy agreed well with those measured using the conventional dosimetric tools. These results demonstrate that the developed beam monitoring system based on FORS is good candidate for monitoring the entrance dose map in PBS proton therapy.
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20
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Pasler M, Hernandez V, Jornet N, Clark CH. Novel methodologies for dosimetry audits: Adapting to advanced radiotherapy techniques. Phys Imaging Radiat Oncol 2018; 5:76-84. [PMID: 33458373 PMCID: PMC7807589 DOI: 10.1016/j.phro.2018.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 03/08/2018] [Accepted: 03/08/2018] [Indexed: 11/25/2022] Open
Abstract
With new radiotherapy techniques, treatment delivery is becoming more complex and accordingly, these treatment techniques require dosimetry audits to test advanced aspects of the delivery to ensure best practice and safe patient treatment. This review of novel methodologies for dosimetry audits for advanced radiotherapy techniques includes recent developments and future techniques to be applied in dosimetry audits. Phantom-based methods (i.e. phantom-detector combinations) including independent audit equipment and local measurement equipment as well as phantom-less methods (i.e. portal dosimetry, transmission detectors and log files) are presented and discussed. Methodologies for both conventional linear accelerator (linacs) and new types of delivery units, i.e. Tomotherapy, stereotactic devices and MR-linacs, are reviewed. Novel dosimetry audit techniques such as portal dosimetry or log file evaluation have the potential to allow parallel auditing (i.e. performing an audit at multiple institutions at the same time), automation of data analysis and evaluation of multiple steps of the radiotherapy treatment chain. These methods could also significantly reduce the time needed for audit and increase the information gained. However, to maximise the potential, further development and harmonisation of dosimetry audit techniques are required before these novel methodologies can be applied.
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Affiliation(s)
- Marlies Pasler
- Lake Constance Radiation Oncology Center Singen-Friedrichshafen, Germany
| | - Victor Hernandez
- Department of Medical Physics, Hospital Sant Joan de Reus, IISPV, Tarragona, Spain
| | - Núria Jornet
- Servei de RadiofísicaiRadioprotecció, Hospital de la Santa CreuiSant Pau, Spain
| | - Catharine H. Clark
- Department of Medical Physics, Royal Surrey County Hospital, Guildford, Surrey, UK
- Metrology for Medical Physics (MEMPHYS), National Physical Laboratory, Teddington, Middlesex, UK
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21
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Marrazzo L, Arilli C, Pasler M, Kusters M, Canters R, Fedeli L, Calusi S, Casati M, Talamonti C, Simontacchi G, Livi L, Pallotta S. Real-time beam monitoring for error detection in IMRT plans and impact on dose-volume histograms : A multi-center study. Strahlenther Onkol 2017; 194:243-254. [PMID: 29255923 DOI: 10.1007/s00066-017-1245-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 11/25/2017] [Indexed: 11/26/2022]
Abstract
PURPOSE This study aimed to test the sensitivity of a transmission detector for online dose monitoring of intensity-modulated radiation therapy (IMRT) for detecting small delivery errors. Furthermore, the correlation of changes in detector output induced by small delivery errors with other metrics commonly employed to quantify the deviations between calculated and delivered dose distributions was investigated. METHODS Transmission detector measurements were performed at three institutions. Seven types of errors were induced in nine clinical step-and-shoot (S&S) IMRT plans by modifying the number of monitor units (MU) and introducing small deviations in leaf positions. Signal reproducibility was investigated for short- and long-term stability. Calculated dose distributions were compared in terms of γ passing rates and dose-volume histogram (DVH) metrics (e.g., Dmean, Dx%, Vx%). The correlation between detector signal variations, γ passing rates, and DVH parameters was investigated. RESULTS Both short- and long-term reproducibility was within 1%. Dose variations down to 1 MU (∆signal 1.1 ± 0.4%) as well as changes in field size and positions down to 1 mm (∆signal 2.6 ± 1.0%) were detected, thus indicating high error-detection sensitivity. A moderate correlation of detector signal was observed with γ passing rates (R2 = 0.57-0.70), while a good correlation was observed with DVH metrics (R2 = 0.75-0.98). CONCLUSION The detector is capable of detecting small delivery errors in MU and leaf positions, and is thus a highly sensitive dose monitoring device for S&S IMRT for clinical practice. The results of this study indicate a good correlation of detector signal with DVH metrics; therefore, clinical action levels can be defined based on the presented data.
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Affiliation(s)
- Livia Marrazzo
- Medical Physic Unit, Careggi University Hospital, Largo Brambilla 3, 50134, Florence, Italy.
| | - Chiara Arilli
- Medical Physic Unit, Careggi University Hospital, Largo Brambilla 3, 50134, Florence, Italy
| | - Marlies Pasler
- Lake Constance Radiation Oncology Center, Singen-Friedrichshafen, Germany
| | - Martijn Kusters
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Richard Canters
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Luca Fedeli
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Silvia Calusi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Marta Casati
- Medical Physic Unit, Careggi University Hospital, Largo Brambilla 3, 50134, Florence, Italy
| | - Cinzia Talamonti
- Medical Physic Unit, Careggi University Hospital, Largo Brambilla 3, 50134, Florence, Italy
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | | | - Lorenzo Livi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
- Radiation Oncology Unit, Careggi University Hospital, Florence, Italy
| | - Stefania Pallotta
- Medical Physic Unit, Careggi University Hospital, Largo Brambilla 3, 50134, Florence, Italy
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
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Medical physics in radiation Oncology: New challenges, needs and roles. Radiother Oncol 2017; 125:375-378. [PMID: 29150160 DOI: 10.1016/j.radonc.2017.10.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 10/30/2017] [Indexed: 12/21/2022]
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Comparison of gamma- and DVH-based in vivo dosimetric plan evaluation for pelvic VMAT treatments. Radiother Oncol 2017; 125:405-410. [PMID: 29017719 DOI: 10.1016/j.radonc.2017.09.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/25/2017] [Accepted: 09/15/2017] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND PURPOSE To compare DVH-based quality assurance to a multi-parametric γ-based methodology for in vivo EPID dosimetry for VMAT to the pelvis. MATERIALS AND METHODS For 47 rectum, 37 prostate, and 44 bladder VMAT treatments we reconstructed the 3D dose distributions of 387 fractions from in vivo EPID dosimetry. The difference between planned and measured dose was evaluated using γ analysis (3%/3mm) in the 50% isodose volume (IDV) and DVH differences (ΔD2, ΔD50 and ΔD98) of targets and organs at risk. The γ-indicators mean γ, γ pass rate and γ1% were compared to DVH-differences and their correlations were studied. DVH-based alerts on PTV and IDV were compared to γ-based alerts. RESULTS Average PTV D50 and D98 dose differences were 0.0±2.2% (1SD) and -1.4±2.9% (1SD). Alert criteria of |ΔD50|<3.5-4.5% corresponded to an alert rate of about 10%. Strong correlations between mean γ and γ pass rate and difference in PTV ΔD50 were observed for all sites. DVH- and γ-based alerts agreed on >80% of the fractions for the majority of compared alert thresholds and methods. This agreement is >90% for the larger deviations. CONCLUSIONS Strong correlations between some γ- and DVH indicators were found. Our comparison of multi-parametric alert strategies showed clinical equivalence for γ- and DVH-based methods.
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Pasler M, Michel K, Marrazzo L, Obenland M, Pallotta S, Björnsgard M, Lutterbach J. Error detection capability of a novel transmission detector: a validation study for online VMAT monitoring. ACTA ACUST UNITED AC 2017; 62:7440-7450. [DOI: 10.1088/1361-6560/aa7dc7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Nakaguchi Y, Ono T, Maruyama M, Shimohigashi Y, Kai Y. Validation of a method for in vivo 3D dose reconstruction in SBRT using a new transmission detector. J Appl Clin Med Phys 2017; 18:69-75. [PMID: 28574221 PMCID: PMC5874859 DOI: 10.1002/acm2.12103] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 02/09/2017] [Accepted: 03/27/2017] [Indexed: 11/30/2022] Open
Abstract
Stereotactic body radiation therapy (SBRT) involves the delivery of substantially larger doses over fewer fractions than conventional therapy. Therefore, SBRT treatments will strongly benefit patients using vivo patient dose verification, because the impact of the fraction is large. For in vivo measurements, a commercially available quality assurance (QA) system is the COMPASS system (IBA Dosimetry, Germany). For measurements, the system uses a new transmission detector (Dolphin, IBA Dosimetry). In this study, we evaluated the method for in vivo 3D dose reconstruction for SBRT using this new transmission detector. We confirmed the accuracy of COMPASS with Dolphin for SBRT using multi leaf collimator (MLC) test patterns and clinical SBRT cases. We compared the results between the COMPASS, the treatment planning system, the Kodak EDR2 film, and the Monte Carlo (MC) calculations. MLC test patterns were set up to investigate various aspects of dose reconstruction for SBRT: (a) simple open fields (2 × 2–10 × 10 cm2), (b) a square wave chart pattern, and (c) the MLC position detectability test in which the MLCs were changed slightly. In clinical cases, we carried out 6 and 8 static IMRT beams for SBRT in the lung and liver. For MLC test patterns, the differences between COMPASS and MC were around 3%. The COMPASS with the dolphin system showed sufficient resolution in SBRT. For clinical cases, COMPASS can detect small changes for the dose profile and dose–volume histogram. COMPASS also showed good agreement with MC. We can confirm the feasibility of SBRT QA using the COMPASS system with Dolphin. This method was successfully operated using the new transmission detector and verified by measurements and MC.
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Affiliation(s)
- Yuji Nakaguchi
- Department of Radiological Technology, Kumamoto University Hospital, Kumamoto, Japan
| | - Takeshi Ono
- Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Masato Maruyama
- Department of Radiological Technology, Kumamoto University Hospital, Kumamoto, Japan
| | | | - Yudai Kai
- Department of Radiological Technology, Kumamoto University Hospital, Kumamoto, Japan
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