Analyses of integrated EPID images for on‐treatment quality assurance to account for interfractional variations in volumetric modulated arc therapy

Matsushita, Norimasa; Nakamura, Mitsuhiro; Sasaki, Makoto; Yano, Shinsuke; Yoshimura, Masataka; Mizowaki, Takashi

doi:10.1002/acm2.12805

Cited by 6 publications

(9 citation statements)

References 25 publications

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“…Based on the assessment of body weight for each subject, it was found that body weight correlated with GPR. This is consistent with a study conducted by Matsushita, Nakamura [16], in which, for the nasopharynx, the correlation values between GPR and changes in body weight or neck volume were −0.77 and −0.74, respectively.…”

Section: Discussionsupporting

confidence: 92%

“…The nasopharyngeal case exhibited a decrease in the GPR value faster than the cervical and breast cases as explained in figure 1. This is in line with research conducted by Matsushita, Nakamura [16], who showed that the GPR value of the nasopharynx has a steeper curve than that of the cervix. In the case of breasts, almost all fractions had a GPR value of < 95%.…”

Section: Discussionsupporting

confidence: 92%

“…IVD research conducted by Matsushita, Nakamura [16] found a decrease in the gamma passing rate (GPR) value in nasopharyngeal cases. This decrease indicates a change in the dose distribution in patients when compared to the first fraction [17].…”

Section: Introductionmentioning

confidence: 99%

“…In vivo dosimetry evaluation using the EPID was carried out by Matsushita, Nakamura [16] and Kang, Li [3]. Matsushita, Nakamura [16] used TrueBeam STx and PerFRACTION software for the evaluation of the nasopharynx, and then a weight correlation test was carried out. Kang, Li [3] used the EPID on Halcyon 2.0 for pelvic cases.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of dose distribution reproducibility based on a fluence map of in vivo transit dose using an electronic portal imaging device

Tardi,

Fitriandini,

Fauziah

et al. 2023

Biomed. Phys. Eng. Express

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Morphological changes can affect distribution of dose in patients. Determination of the dose distribution changes for each fraction radiotherapy can be done by relative in vivo dosimetry (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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Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analysis of dose distribution reproducibility based on a fluence map of in vivo transit dose using an electronic portal imaging device

Tardi,

Fitriandini,

Fauziah

et al. 2023

Biomed. Phys. Eng. Express

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“…Inputting mechanical errors that occur in every VMAT delivery to perform dose recalculation on intrairradiation CBCT images lead to more precise ADDs in clinical situations, and recalculation can be performed using dedicated software (Matsushita et al 2020). The dose calculation algorithm implemented in this software is equivalent to a superposition/convolution algorithm.…”

Section: Discussionmentioning

confidence: 99%

Actual delivered dose calculation on intra-irradiation cone-beam computed tomography images: a phantom study

Iramina¹,

Nakamura²,

Mizowaki³

2021

Phys. Med. Biol.

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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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Research on the correction method for radiotherapy verification plans based on displaced electronic portal imaging device

Guo,

Zhou,

Zeng

2024

J Applied Clin Med Phys

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BackgroundIt 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.PurposeTo explore methods including correction model and specific correction matrices to revise the data obtained from displaced EPID.MethodsTwo 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.ResultsThe 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.ConclusionsThe 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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Analyses of integrated EPID images for on‐treatment quality assurance to account for interfractional variations in volumetric modulated arc therapy

Cited by 6 publications

References 25 publications

Analysis of dose distribution reproducibility based on a fluence map of in vivo transit dose using an electronic portal imaging device

Analysis of dose distribution reproducibility based on a fluence map of in vivo transit dose using an electronic portal imaging device

Actual delivered dose calculation on intra-irradiation cone-beam computed tomography images: a phantom study

Research on the correction method for radiotherapy verification plans based on displaced electronic portal imaging device

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