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Guo J, Zhou L, Zeng H. Research on the correction method for radiotherapy verification plans based on displaced electronic portal imaging device. J Appl Clin Med Phys 2024:e14401. [PMID: 38778555 DOI: 10.1002/acm2.14401] [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: 01/03/2024] [Revised: 04/21/2024] [Accepted: 04/25/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND It has been observed that under the single isocenter conditions, the potential shifts of the electronic portal imaging devices (EPID) may be introduced when executing portal dosimetry (PD) plans for bilateral breast cancer, pleural mesothelioma, and lymphoma. These shifts are relative to the calibration positions of EPID and result in significant discrepancies in the plan verification results. PURPOSE To explore methods including correction model and specific correction matrices to revise the data obtained from displaced EPID. METHODS Two methods, the correction model and the specific correction matrices, were applied to correct the data. Five experiments were designed and conducted to build correction model and to validate the effectiveness of these two methods. Gamma passing rates were calculated and data profiles along X-axis and Y-axis were captured. RESULTS The gamma passing rates for the EPID-displaced IMRT validation plans after applying correction model, along with the application of specific correction matrices to VMAT and IMRT validation plans, exhibit results that are comparable to the cases with non-displaced EPID. Except for the VMAT plans applied correction model which showed larger discrepancies (0.041 ± 0.028, 0.049 ± 0.030), the other three exhibit minimal differences in discrepancy values. In all profiles, the corrected data from displaced EPID exhibit a high level of agreement with data obtained from non-displaced EPID. Good consistency is observed in actual application of the correction model and the specific correction matrices between gamma passing rates of data corrected and those of non-displaced data. CONCLUSIONS The proposed methods involving correction model and specific correction matrices can correct the data collected from the displaced EPID, and the gamma passing rates of the corrected data show results that are comparable to some extent with those of non-displaced data. Particularly, the results corrected by specific correction matrices closely resemble the data from non-displaced EPID.
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Affiliation(s)
- Jian Guo
- Department of Radiation Oncology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Leyuan Zhou
- Department of Radiation Oncology, The Fourth Affiliated Hospital of Soochow University, Suzhou, China
| | - Haibin Zeng
- Department of Radiation Oncology, The Fourth Affiliated Hospital of Soochow University, Suzhou, China
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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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A C Fiagan Y, Bossuyt E, Nevens D, Machiels M, Chiairi I, Joye I, Paul M, Gevaert T, Verellen D. The use of in-vivo dosimetry to identify head and neck cancer patients needing adaptive radiotherapy. Radiother Oncol 2023; 184:109676. [PMID: 37084887 DOI: 10.1016/j.radonc.2023.109676] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 04/12/2023] [Accepted: 04/12/2023] [Indexed: 04/23/2023]
Abstract
BACKGROUND AND PURPOSE Head and neck cancer (HNC) patients experiencing anatomical changes during their radiotherapy (RT) course may benefit from adaptive RT (ART). We investigated the sensitivity of an electronic portal imaging device (EPID)-based in-vivo dosimetry (EIVD) systemto detect patients that require ART and identified its limitations. MATERIALS AND METHODS A retrospective study was conducted for 182 HNC patients: laryngeal cancer without elective lymph nodes (group A), postoperative RT (group B) and primary RT including elective lymph nodes (group C). The effect of anatomical changes on the dose distribution and volumetric changes was quantified. The receiver operating characteristic curve was used to obtain the optimal cut-off value for the gamma passing rate (%GP) with a dose difference of 3% and a distance to agreement of 3mm. RESULTS Fifty HNC patients receiving ART were analyzed: 1 in group A, 10 in group B and 39 in group C. Failed fractions (FFs) occurred in 1/1, 6/10 and 23/39 cases before ART in group A, B and C respectively. In the four cases in group B without FFs, only minor dosimetric changes were observed. One of the cases in group C without FFs had significant dosimetric changes (false negative). Three cases received ART because of clinical reasons that cannot be detected by EIVD. The optimal cut-off value for the %GP was 95%/95.2% for old/new generation machines respectively. CONCLUSION EIVD in combined with 3D imaging techniques can be synergistic in the detection of anatomical changes in HNC patients who benefit from ART.
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Affiliation(s)
- Yawo A C Fiagan
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium.
| | - Evy Bossuyt
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium
| | - Daan Nevens
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
| | - Melanie Machiels
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
| | - Ibrahim Chiairi
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
| | - Ines Joye
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
| | - Meijnders Paul
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
| | - Thierry Gevaert
- Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium; Department of Radiation Oncology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium
| | - Dirk Verellen
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
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Chen L, Zhang Z, Yu L, Peng J, Feng B, Zhao J, Liu Y, Xia F, Zhang Z, Hu W, Wang J. A clinically relevant online patient QA solution with daily CT scans and EPID-based in vivo dosimetry: a feasibility study on rectal cancer. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac9950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 10/11/2022] [Indexed: 11/06/2022]
Abstract
Abstract
Objective. Adaptive radiation therapy (ART) could protect organs at risk (OARs) while maintain high dose coverage to targets. However, there is still a lack of efficient online patient quality assurance (QA) methods, which is an obstacle to large-scale adoption of ART. We aim to develop a clinically relevant online patient QA solution for ART using daily CT scans and EPID-based in vivo dosimetry. Approach. Ten patients with rectal cancer at our center were included. Patients’ daily CT scans and portal images were collected to generate reconstructed 3D dose distributions. Contours of targets and OARs were recontoured on these daily CT scans by a clinician or an auto-segmentation algorithm, then dose-volume indices were calculated, and the percent deviation of these indices to their original plans were determined. This deviation was regarded as the metric for clinically relevant patient QA. The tolerance level was obtained using a 95% confidence interval of the QA metric distribution. These deviations could be further divided into anatomically relevant or delivery relevant indicators for error source analysis. Finally, our QA solution was validated on an additional six clinical patients. Main results. In rectal cancer, the 95% confidence intervals of the QA metric for PTV ΔD
95 (%) were [−3.11%, 2.35%], and for PTV ΔD
2 (%) were [−0.78%, 3.23%]. In validation, 68% for PTV ΔD
95 (%), and 79% for PTV ΔD
2 (%) of the 28 fractions are within tolerances of the QA metrics. one patient’s dosimetric impact of anatomical variations during treatment were observed through the source of error analysis. Significance. The online patient QA solution using daily CT scans and EPID-based in vivo dosimetry is clinically feasible. Source of error analysis has the potential for distinguishing sources of error and guiding ART for future treatments.
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Bedford JL, Hanson IM. Optimisation of a composite difference metric for prompt error detection in real-time portal dosimetry of simulated volumetric modulated arc therapy. Br J Radiol 2021; 94:20201014. [PMID: 33733813 PMCID: PMC8010558 DOI: 10.1259/bjr.20201014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/15/2020] [Accepted: 10/28/2020] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES In real-time portal dosimetry, thresholds are set for several measures of difference between predicted and measured images, and signals larger than those thresholds signify an error. The aim of this work is to investigate the use of an additional composite difference metric (CDM) for earlier detection of errors. METHODS Portal images were predicted for the volumetric modulated arc therapy plans of six prostate patients. Errors in monitor units, aperture opening, aperture position and path length were deliberately introduced into all 180 segments of the treatment plans, and these plans were delivered to a water-equivalent phantom. Four different metrics, consisting of central axis signal, mean image value and two image difference measures, were used to identify errors, and a CDM was added, consisting of a weighted power sum of the individual metrics. To optimise the weights of the CDM and to evaluate the resulting timeliness of error detection, a leave-pair-out strategy was used. For each combination of four patients, the weights of the CDM were determined by an exhaustive search, and the result was evaluated on the remaining two patients. RESULTS The median segment index at which the errors were identified was 87 (range 40-130) when using all of the individual metrics separately. Using a CDM as well as multiple separate metrics reduced this to 73 (35-95). The median weighting factors of the four metrics constituting the composite were (0.15, 0.10, 0.15, 0.00). Due to selection of suitable threshold levels, there was only one false positive result in the six patients. CONCLUSION This study shows that, in conjunction with appropriate error thresholds, use of a CDM is able to identify increased image differences around 20% earlier than the separate measures. ADVANCES IN KNOWLEDGE This study shows the value of combining difference metrics to allow earlier detection of errors during real-time portal dosimetry for volumetric modulated arc therapy treatment.
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Affiliation(s)
- James L Bedford
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, UK
| | - Ian M Hanson
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, UK
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Iramina H, Nakamura M, Mizowaki T. Actual delivered dose calculation on intra-irradiation cone-beam computed tomography images: a phantom study. Phys Med Biol 2021; 66:015007. [PMID: 33238248 DOI: 10.1088/1361-6560/abcdeb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Cone-beam computed tomography (CBCT) images acquired during volumetric modulated arc therapy (VMAT; ii-CBCT) can be used to calculate actual delivered doses (ADDs). However, such ii-CBCT images are degraded by scattered megavoltage x-rays (MV-scatters). We aimed to evaluate the dose calculation accuracy of the MV-scatter uncorrected or corrected ii-CBCT images acquired during VMAT deliveries. For MV-scatter correction on concurrent kilovoltage projections (P MVkV), projections consisting only of MV-scatters (P MVS) were acquired under the same MV beam parameters and gantry angles and subtracted from P MVkV (P MVScorr). In addition, the projections by kilovoltage beams were acquired for reference (P kV). The corresponding CBCT images were reconstructed using the Feldkamp-Davis-Kress algorithm (CBCTMVkV, CBCTMVScorr, and CBCTkV as reference). A multi-energy phantom with rods of various relative electron densities (REDs) was used to generate a CBCT-number-to-RED conversion table. First, CBCTkV was reconstructed. Then, the mean CBCT-numbers within each rod were extracted, and a reference table was generated. Concurrent kilovoltage imaging with various field sizes was also demonstrated, and CBCTMVkV and CBCTMVScorr were reconstructed. The extracted CBCT-numbers of each ii-CBCT image were converted into REDs using the reference table. Next, the absolute differences of RED between the ii-CBCT image and CBCTkV were calculated. Ten VMAT plans using a 10 MV flattening-filter-free beam were used for concurrent imaging of an anthropomorphic torso phantom. Moreover, an iterative reconstruction algorithm (IRA) was used for CBCTMVScorr. The plans were recalculated for the corresponding CBCTMVkV, CBCTMVScorr, CBCTMVScorr+IRA, and CBCTkV with the reference table. Finally, the doses were evaluated using 3D gamma analysis (1%/1 mm). The median difference ranges between CBCTMVkV/CBCTMVScorr and the reference values were -0.58 to -0.10/-0.03 to 0.00. The median gamma pass rates of the doses on CBCTMVkV, CBCTMVScorr, and CBCTMVScorr+IRA to the rate on CBCTkV were 70.4, 99.5, and 98.2%, respectively. CBCTMVScorr were comparable with CBCTkV for calculating the ADD from VMAT.
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Affiliation(s)
- Hiraku Iramina
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
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