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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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Tardi D, Fitriandini A, Fauziah AR, Wibowo WE, Siswantining T, Pawiro SA. Analysis of dose distribution reproducibility based on a fluence map of in vivo transit dose using an electronic portal imaging device. Biomed Phys Eng Express 2023; 10:015013. [PMID: 38052064 DOI: 10.1088/2057-1976/ad124a] [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: 09/06/2023] [Accepted: 12/05/2023] [Indexed: 12/07/2023]
Abstract
Morphological changes can affect distribution of dose in patients. Determination of the dose distribution changes for each fraction radiotherapy can be done by relativein vivodosimetry (IVD). This study analysed the distribution of doses per fraction based on the fluence map recorded by the electronic portal imaging device (EPID) of the patient's transit dose. This research examined cases involving the cervix, breast, and nasopharynx. Transit dose analysis was performed by calculating the gamma index (GI) with composite and field-by-field methods. The gamma passing rate (GPR) value was assessed for its correlation with the subject's body weight. In the case of the nasopharynx, breast, and cervix, the GPR value decreased as the fraction increased. In the case of the nasopharynx, the correlation between the GPR and fraction radiotherapy showed no difference when using either composite or field-by-field methods. However, in cases involving the cervix and breast, there was a difference in the correlation values between the composite and field-by-field methods, where the subject had a significant correlation (p< 0.05) when it was done using a field-by-field method. In addition, the nasopharynx had the highest number of subjects with significant correlation (p< 0.05) between GPR and body weight, followed by the cervix and breast. In the nasopharynx, breast, and cervix, the reproducibility of the dose distribution decreased. This decreased reproducibility was associated with changes in body weight.
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Affiliation(s)
- Didin Tardi
- Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, West Java, 16424, Indonesia
| | - Aninda Fitriandini
- Department of Radiation Oncology, Faculty of Medicine, Universitas Indonesia, Dr Cipto Mangunkusumo General Hospital, Jakarta, 10430, Indonesia
| | - Annisa Rahma Fauziah
- Department of Radiation Oncology, Faculty of Medicine, Universitas Indonesia, Dr Cipto Mangunkusumo General Hospital, Jakarta, 10430, Indonesia
| | - Wahyu Edy Wibowo
- Department of Radiation Oncology, Faculty of Medicine, Universitas Indonesia, Dr Cipto Mangunkusumo General Hospital, Jakarta, 10430, Indonesia
| | - Titin Siswantining
- Department of Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, West Java, 16424, Indonesia
| | - Supriyanto Ardjo Pawiro
- Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, West Java, 16424, Indonesia
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Kang S, Jin H, Chang JH, Jang BS, Shin KH, Choi CH, Kim JI. Evaluation of initial patient setup methods for breast cancer between surface-guided radiation therapy and laser alignment based on skin marking in the Halcyon system. Radiat Oncol 2023; 18:60. [PMID: 37016351 PMCID: PMC10071653 DOI: 10.1186/s13014-023-02250-3] [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: 12/08/2022] [Accepted: 03/27/2023] [Indexed: 04/06/2023] Open
Abstract
BACKGROUND This study was conducted to evaluate the efficiency and accuracy of the daily patient setup for breast cancer patients by applying surface-guided radiation therapy (SGRT) using the Halcyon system instead of conventional laser alignment based on the skin marking method. METHODS AND MATERIALS We retrospectively investigated 228 treatment fractions using two different initial patient setup methods. The accuracy of the residual rotational error of the SGRT system was evaluated by using an in-house breast phantom. The residual translational error was analyzed using the couch position difference in the vertical, longitudinal, and lateral directions between the reference computed tomography and daily kilo-voltage cone beam computed tomography acquired from the record and verification system. The residual rotational error (pitch, yaw, and roll) was also calculated using an auto rigid registration between the two images based on Velocity. The total setup time, which combined the initial setup time and imaging time, was analyzed to evaluate the efficiency of the daily patient setup for SGRT. RESULTS The average residual rotational errors using the in-house fabricated breast phantom for pitch, roll, and yaw were 0.14°, 0.13°, and 0.29°, respectively. The average differences in the couch positions for laser alignment based on the skin marking method were 2.7 ± 1.6 mm, 2.0 ± 1.2 mm, and 2.1 ± 1.0 mm for the vertical, longitudinal, and lateral directions, respectively. For SGRT, the average differences in the couch positions were 1.9 ± 1.2 mm, 2.9 ± 2.1 mm, and 1.9 ± 0.7 mm for the vertical, longitudinal, and lateral directions, respectively. The rotational errors for pitch, yaw, and roll without the surface-guided radiation therapy approach were 0.32 ± 0.30°, 0.51 ± 0.24°, and 0.29 ± 0.22°, respectively. For SGRT, the rotational errors were 0.30 ± 0.22°, 0.51 ± 0.26°, and 0.19 ± 0.13°, respectively. The average total setup times considering both the initial setup time and imaging time were 314 s and 331 s, respectively, with and without SGRT. CONCLUSION We demonstrated that using SGRT improves the accuracy and efficiency of initial patient setups in breast cancer patients using the Halcyon system, which has limitations in correcting the rotational offset.
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Affiliation(s)
- Seonghee Kang
- Department of Radiation Oncology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, Republic of Korea
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
- Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Republic of Korea
| | - Hyeongmin Jin
- Department of Radiation Oncology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, Republic of Korea
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
- Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Republic of Korea
| | - Ji Hyun Chang
- Department of Radiation Oncology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, Republic of Korea
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Bum-Sup Jang
- Department of Radiation Oncology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, Republic of Korea
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Kyung Hwan Shin
- Department of Radiation Oncology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, Republic of Korea
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Chang Heon Choi
- Department of Radiation Oncology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, Republic of Korea.
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea.
- Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Republic of Korea.
| | - Jung-In Kim
- Department of Radiation Oncology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, Republic of Korea.
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea.
- Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Republic of Korea.
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Standardization of upper limb exercises to improve radiation therapy for breast cancer, a conceptual literature review. J Med Imaging Radiat Sci 2022; 53:720-727. [PMID: 35965195 DOI: 10.1016/j.jmir.2022.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 07/13/2022] [Accepted: 07/22/2022] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Many patients with breast cancer are left with upper arm mobility dysfunction following surgery. Despite the beneficial effects of upper limb exercises on shoulder dysfunction, radiation therapists still do not widely encourage patients to participate in arm exercises after surgery. This conceptual literature review synthesizes evidence on how patients with breast cancer that participate in upper limb exercises after surgery have improved arm mobility which could result in a more consistent arm position during radiation therapy. METHODS A literature search was performed in the PubMed, Athabasca University Library, and Google Scholar databases to identify articles that evaluated the effect of upper limb exercises on patients' arm mobility and range of motion after breast cancer surgery, and the impact of arm position on anatomy during radiation therapy. Sixteen studies were included in the conceptual review synthesis. RESULTS The studies were heterogeneous in terms of the utilized exercise methods and the upper limb related outcomes measured. Twelve studies demonstrated that upper arm exercises are an effective intervention in restoring arm mobility and decreasing pain in women with breast cancer. Additionally, four studies showed that differences in arm rotation affect the breast region's anatomy, which could result in set-up errors during radiation therapy. CONCLUSION The effectiveness of radiation therapy for breast cancer treatment relies on women to reproduce their shoulder position each day. Any inability to replicate the arm position due to mobility issues can affect the accuracy of the dose delivered and, ultimately, the treatment outcome. Therefore, upper limb exercises should be recommended by radiation therapists to their patients before or during radiation therapy to improve patient comfort and the accuracy of treatment. Additionally, upper limb exercise standards need to be developed for patients with breast cancer and implemented by radiation therapists.
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Fiagan YA, Bossuyt E, Machiels M, Nevens D, Billiet C, Poortmans P, Gevaert T, Verellen D. Comparing treatment uncertainty for ultra- vs. standard-hypofractionated breast radiation therapy based on in-vivo dosimetry. Phys Imaging Radiat Oncol 2022; 22:85-90. [PMID: 35602547 PMCID: PMC9117915 DOI: 10.1016/j.phro.2022.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 11/26/2022] Open
Abstract
Background and purpose Postoperative ultrahypofractionated radiation therapy (UHFRT) in 5 fractions (fx) for breast cancer patients is as effective and safe as conventionally hypofractionated RT (HFRT) in 15 fx, liberating time for higher-level daily online Image-Guided Radiation Therapy (IGRT) corrections. In this retrospective study, treatment uncertainties occurring in patients treated with 5fx (5fx-group) were evaluated using electronic portal imaging device (EPID)-based in-vivo dosimetry (EIVD) and compared with the results from patients treated with conventionally HFRT (15fx-group) to validate the new technique and to evaluate if the shorter treatment schedule could have a positive effect on the treatment uncertainties. Materials and methods EPID-based integrated transit dose images were acquired for each treatment fraction in the 5fx-group (203 patients) and on the first 3 days of treatment and weekly thereafter in the 15fx-group (203 patients). A total of 1015 EIVD measurements in the 5fx-group and 1144 in the 15fx-group were acquired. Of the latter group, 755 had been treated with online IGRT correction (i.e., Online-IGRT 15fx-group). Results In the 15fx-group 12.0% of fractions failed (FFs) compared to 3.8% in the 5fx-group and 6.9% in the online-IGRT 15fx-group. Causes for FFs in the 15fx-group compared with the 5fx-group were patient positioning (7.4% vs. 2.2%), technical issues (3.1% vs. 1.2%) and breast swelling (1.4% vs. 0.5%). In the online-IGRT 15fx-group, 2.5% were attributed to patient positioning, 3.8% to technical issues and 0.5% to breast swelling. Conclusions EIVD demonstrated that UHFRT for breast cancer results in less FFs compared to standard HFRT. A large proportion of this decrease could be explained by using daily online IGRT.
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Dai G, Zhang X, Liu W, Li Z, Wang G, Liu Y, Xiao Q, Duan L, Li J, Song X, Li G, Bai S. Analysis of EPID Transmission Fluence Maps Using Machine Learning Models and CNN for Identifying Position Errors in the Treatment of GO Patients. Front Oncol 2021; 11:721591. [PMID: 34595115 PMCID: PMC8476908 DOI: 10.3389/fonc.2021.721591] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/30/2021] [Indexed: 02/05/2023] Open
Abstract
Purpose To find a suitable method for analyzing electronic portal imaging device (EPID) transmission fluence maps for the identification of position errors in the in vivo dose monitoring of patients with Graves' ophthalmopathy (GO). Methods Position errors combining 0-, 2-, and 4-mm errors in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions in the delivery of 40 GO patient radiotherapy plans to a human head phantom were simulated and EPID transmission fluence maps were acquired. Dose difference (DD) and structural similarity (SSIM) maps were calculated to quantify changes in the fluence maps. Three types of machine learning (ML) models that utilize radiomics features of the DD maps (ML 1 models), features of the SSIM maps (ML 2 models), and features of both DD and SSIM maps (ML 3 models) as inputs were used to perform three types of position error classification, namely a binary classification of the isocenter error (type 1), three binary classifications of LR, SI, and AP direction errors (type 2), and an eight-element classification of the combined LR, SI, and AP direction errors (type 3). Convolutional neural network (CNN) was also used to classify position errors using the DD and SSIM maps as input. Results The best-performing ML 1 model was XGBoost, which achieved accuracies of 0.889, 0.755, 0.778, 0.833, and 0.532 in the type 1, type 2-LR, type 2-AP, type 2-SI, and type 3 classification, respectively. The best ML 2 model was XGBoost, which achieved accuracies of 0.856, 0.731, 0.736, 0.949, and 0.491, respectively. The best ML 3 model was linear discriminant classifier (LDC), which achieved accuracies of 0.903, 0.792, 0.870, 0.931, and 0.671, respectively. The CNN achieved classification accuracies of 0.925, 0.833, 0.875, 0.949, and 0.689, respectively. Conclusion ML models and CNN using combined DD and SSIM maps can analyze EPID transmission fluence maps to identify position errors in the treatment of GO patients. Further studies with large sample sizes are needed to improve the accuracy of CNN.
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Affiliation(s)
- Guyu Dai
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xiangbin Zhang
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Wenjie Liu
- Machine Intelligence Laboratory, College of Computer Science, Sichuan University, Chengdu, China
| | - Zhibin Li
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Guangyu Wang
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Yaxin Liu
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Qing Xiao
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Lian Duan
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Jing Li
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xinyu Song
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Guangjun Li
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Sen Bai
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
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Esposito M, Piermattei A, Bresciani S, Orlandini LC, Falco MD, Giancaterino S, Cilla S, Ianiro A, Nigro R, Botez L, Riccardi S, Fidanzio A, Greco F, Villaggi E, Russo S, Stasi M. Improving dose delivery accuracy with EPID in vivo dosimetry: results from a multicenter study. Strahlenther Onkol 2021; 197:633-643. [PMID: 33594471 DOI: 10.1007/s00066-021-01749-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 01/22/2021] [Indexed: 12/26/2022]
Abstract
PURPOSE To investigate critical aspects and effectiveness of in vivo dosimetry (IVD) tests obtained by an electronic portal imaging device (EPID) in a multicenter and multisystem context. MATERIALS AND METHODS Eight centers with three commercial systems-SoftDiso (SD, Best Medical Italy, Chianciano, Italy), Dosimetry Check (DC, Math Resolution, LCC), and PerFRACTION (PF, Sun Nuclear Corporation, SNC, Melbourne, FL)-collected IVD results for a total of 2002 patients and 32,276 tests. Data are summarized for IVD software, radiotherapy technique, and anatomical site. Every center reported the number of patients and tests analyzed, and the percentage of tests outside of the tolerance level (OTL%). OTL% was categorized as being due to incorrect patient setup, incorrect use of immobilization devices, incorrect dose computation, anatomical variations, and unknown causes. RESULTS The three systems use different approaches and customized alert indices, based on local protocols. For Volumetric Modulated Arc Therapy (VMAT) treatments OTL% mean values were up to 8.9% for SD, 18.0% for DC, and 16.0% for PF. Errors due to "anatomical variations" for head and neck were up to 9.0% for SD and DC and 8.0% for PF systems, while for abdomen and pelvis/prostate treatments were up to 9%, 17.0%, and 9.0% for SD, DC, and PF, respectively. The comparison among techniques gave 3% for Stereotactic Body Radiation Therapy, 7.0% (range 4.7-8.9%) for VMAT, 10.4% (range 7.0-12.2%) for Intensity Modulated Radiation Therapy, and 13.2% (range 8.8-21.0%) for 3D Conformal Radiation Therapy. CONCLUSION The results obtained with different IVD software and among centers were consistent and showed an acceptable homogeneity. EPID IVD was effective in intercepting important errors.
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Affiliation(s)
- M Esposito
- S. C. Fisica Sanitaria Firenze-Empoli, Medical Physics Unit of Radiation Oncology Dept., Azienda Sanitaria USL Toscana Centro Florence, Via dell'Antella 58, 50012, Bagno a Ripoli, Firenze, Italy.
| | - A Piermattei
- UOC di Fisica Sanitaria, Radioterapia Oncologica ed Ematologia, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - S Bresciani
- Medical Physics, Candiolo Cancer Institute-FPO IRCCS, Turin, Italy
| | - L C Orlandini
- Department of Radiation Oncology, Sichuan Cancer Hospital, Chengdu, China
| | - M D Falco
- Dipartimento di Radioterapia, Università di Chieti, Chieti, Italy
| | - S Giancaterino
- Dipartimento di Radioterapia, Università di Chieti, Chieti, Italy
| | - S Cilla
- Medical Physics Unit, Fondazione di ricerca e cura "Giovanni Paolo II", Campobasso, Italy
| | - A Ianiro
- Medical Physics Unit, Fondazione di ricerca e cura "Giovanni Paolo II", Campobasso, Italy
| | - R Nigro
- OGP S. Camillo de Lellis, Rieti, Italy
| | - L Botez
- Medical Physics, Candiolo Cancer Institute-FPO IRCCS, Turin, Italy
| | | | - A Fidanzio
- UOC di Fisica Sanitaria, Radioterapia Oncologica ed Ematologia, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - F Greco
- UOC di Fisica Sanitaria, Radioterapia Oncologica ed Ematologia, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | | | - S Russo
- S. C. Fisica Sanitaria Firenze-Empoli, Azienda Sanitaria USL Toscana Centro Florence, Florence, Italy
| | - M Stasi
- S.C. Fisica Sanitaria, A.O. Ordine Mauriziano di Torino, Torino, Italy
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Matsushita N, Nakamura M, Sasaki M, Yano S, Yoshimura M, Mizowaki T. Analyses of integrated EPID images for on-treatment quality assurance to account for interfractional variations in volumetric modulated arc therapy. J Appl Clin Med Phys 2020; 21:110-116. [PMID: 31909889 PMCID: PMC6964755 DOI: 10.1002/acm2.12805] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/30/2019] [Accepted: 12/05/2019] [Indexed: 01/03/2023] Open
Abstract
Purpose To investigate the effects of interfractional variation, such as anatomical changes and setup errors, on dose delivery during treatment for prostate cancer (PC) and head and neck cancer (HNC) by courses of volumetric modulated arc therapy (VMAT) aided by on‐treatment electronic portal imaging device (EPID) images. Methods Seven patients with PC and 20 patients with HNC who had received VMAT participated in this study. After obtaining photon fluence at the position of the EPID for each treatment arc from on‐treatment integrated EPID images, we calculated the differences between the fluence for the first fraction and each subsequent fraction for each arc. The passing rates were investigated based on a tolerance level of 3% of the maximum fluence during the treatment courses and the correlations between the passing rates and anatomical changes. Results In PC, the median and lowest passing rates were 99.8% and 95.2%, respectively. No correlations between passing rates and interfractional variation were found. In HNC, the median passing rate of all fractions was 93.0%, and the lowest passing rate was 79.6% during the 35th fraction. Spearman’s correlation coefficients between the passing rates and changes in weight or neck volume were − 0.77 and − 0.74, respectively. Conclusions Analyses of the on‐treatment EPID images facilitates estimates of the interfractional anatomical variation in HNC patients during VMAT and thus improves assessments of the need for re‐planning or adaptive strategies and the timing thereof.
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Affiliation(s)
- Norimasa Matsushita
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan
| | - Mitsuhiro Nakamura
- Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Makoto Sasaki
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan.,Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shinsuke Yano
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan
| | - Michio Yoshimura
- Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takashi Mizowaki
- Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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