scholarly journals Predictive gamma passing rate for three‐dimensional dose verification with finite detector elements via improved dose uncertainty potential accumulation model

2020 ◽  
Vol 47 (3) ◽  
pp. 1349-1356
Author(s):  
Eiji Shiba ◽  
Akito Saito ◽  
Makoto Furumi ◽  
Daisuke Kawahara ◽  
Kentaro Miki ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dose Verification ◽  
Accumulation Model ◽  
Passing Rate ◽  
Dose Uncertainty ◽  
Gamma Passing Rate

scholarly journals Predictive gamma passing rate by dose uncertainty potential accumulation model

2018 ◽  
Vol 46 (2) ◽  
pp. 999-1005 ◽  
Author(s):  
Eiji Shiba ◽  
Akito Saito ◽  
Makoto Furumi ◽  
Yuji Murakami ◽  
Takayuki Ohguri ◽  
...  
Keyword(s):  
Accumulation Model ◽  
Passing Rate ◽  
Dose Uncertainty ◽  
Gamma Passing Rate

scholarly journals A Beam Projection-Based Modified Gamma Analysis Scheme for Clinically Interpretable Pre-Treatment Dose Verification

Dose-Response ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 155932582110016
Author(s):  
Yiling Wang ◽  
Gang Yin ◽  
Jie Wang ◽  
Yue Zhao ◽  
Min Liu ◽  
...  
Keyword(s):  
Clinical Significance ◽  
Conventional Method ◽  
Hot Spots ◽  
Dose Verification ◽  
Modified Method ◽  
Passing Rate ◽  
Gamma Analysis ◽  
Analysis Scheme ◽  
Cold Spots ◽  
Gamma Passing Rate

Purpose: To investigate a novel gamma analysis system for dose verification results in terms of clinical significance. Methods and Materials: The modified scheme redefined the computational domain of the conventional gamma analysis with the projections of beams and the regions of interest (ROI). We retrospectively studied 6 patients with the conventional and the modified gamma analysis schemes while compared their performances. The cold spots ratio of the planning target volume (PTV) and the hot spots ratio of the organs at risk (OAR) were also computed by the modified scheme to assess the clinical significance. Results: The result of the gamma passing rate in the modified method was conformable to that in the conventional method with a cut-off threshold of 5%. The cold spots ratio of PTV and hot spots ratio of OAR were able to be evaluated by the modified scheme. For an introduced 7.1% dose error, the discrimination ratio in gamma passing rate of the conventional method was lower than 2%, while it was improved to 5% by the modified method. Conclusions: The modified gamma analysis scheme had a comparable quality as the conventional scheme in terms of dose inspection. Besides, it could improve the clinical significance of the QA result and provide the assessment for ROI-specific discrepancy. The modified scheme could also be conveniently integrated into the conventional dose verification process, benefiting the less developed regions where high-end 3D dose verification devices are not affordable.

scholarly journals Erratum to: Effect of Minimum Segment Width on Gamma Passing Rate Considering MLC Position Error for Volumetric Modulated Arc Therapy

2019 ◽  
Vol 74 (9) ◽  
pp. 912-912
Author(s):  
Young Min Moon ◽  
Sang Il Bae ◽  
Chul Won Choi ◽  
Wan Jeon ◽  
Jin Young Kim ◽  
...  
Keyword(s):  
Volumetric Modulated Arc Therapy ◽  
Position Error ◽  
Passing Rate ◽  
Arc Therapy ◽  
Gamma Passing Rate

SU-E-T-361: Three Dimensional Dose Verification in Proton Therapy Using EBT2 Film Array

2011 ◽  
Vol 38 (6Part16) ◽  
pp. 3570-3570
Author(s):  
M Yoon ◽  
S Kim ◽  
S Choi ◽  
J Han ◽  
D Hwang ◽  
...  
Keyword(s):  
Proton Therapy ◽  
Three Dimensional ◽  
Dose Verification ◽  
Ebt2 Film

Effect of Minimum Segment Width on Gamma Passing Rate Considering MLC Position Error for Volumetric Modulated Arc Therapy

2019 ◽  
Vol 74 (7) ◽  
pp. 724-730
Author(s):  
Young Min Moon ◽  
Sang Il Bae ◽  
Chul Won Choi ◽  
Wan Wan Jeon ◽  
Jin Young Kim ◽  
...  
Keyword(s):  
Volumetric Modulated Arc Therapy ◽  
Position Error ◽  
Passing Rate ◽  
Arc Therapy ◽  
Gamma Passing Rate

scholarly journals Verification of an optimizer algorithm by the beam delivery evaluation of intensity-modulated arc therapy plans

2021 ◽  
Vol 55 (4) ◽  
pp. 508-515
Author(s):  
Tamas Pocza ◽  
Domonkos Szegedi ◽  
Tibor Major ◽  
Csilla Pesznyak
Keyword(s):  
Dose Rate ◽  
Early Stage ◽  
Plan Quality ◽  
Imaging Device ◽  
Passing Rate ◽  
Treatment Plans ◽  
Beam Delivery ◽  
Fraction Dose ◽  
Delivery Accuracy ◽  
Gamma Passing Rate

Abstract Background In the case of dynamic radiotherapy plans, the fractionation schemes can have dosimetric effects. Our goal was to define the effect of the fraction dose on the plan quality and the beam delivery. Materials and methods Treatment plans were created for 5 early-stage lung cancer patients with different dose schedules. The planned total dose was 60 Gy, fraction dose was 2 Gy, 3 Gy, 5 Gy, 12 Gy and 20 Gy. Additionally renormalized plans were created by changing the prescribed fraction dose after optimization. The dosimetric parameters and the beam delivery parameters were collected to define the plan quality and the complexity of the treatment plans. The accuracy of dose delivery was verified with dose measurements using electronic portal imaging device (EPID). Results The plan quality was independent from the used fractionation scheme. The fraction dose could be changed safely after the optimization, the delivery accuracy of the treatment plans with changed prescribed dose was not lower. According to EPID based measurements, the high fraction dose and dose rate caused the saturation of the detector, which lowered the gamma passing rate. The aperture complexity score, the gantry speed and the dose rate changes were not predicting factors for the gamma passing rate values. Conclusions The plan quality and the delivery accuracy are independent from the fraction dose, moreover the fraction dose can be changed safely after the dose optimization. The saturation effect of the EPID has to be considered when the action limits of the quality assurance system are defined.

scholarly journals Dosimetric study of the interplay effect using three-dimensional motion phantom in proton pencil beam scanning treatment of moving thoracic tumours

2021 ◽  
pp. 1-10
Author(s):  
Hardev S. Grewal ◽  
Salahuddin Ahmad ◽  
Hosang Jin
Keyword(s):  
Treatment Planning ◽  
Three Dimensional ◽  
Spot Size ◽  
Passing Rate ◽  
Treatment Plans ◽  
Motion Phantom ◽  
Interplay Effect ◽  
The Impact ◽  
Motion Amplitude ◽  
Dose Difference

Abstract Aim: The dosimetric and clinical advantages offered by implementation of pencil beam scanning (PBS) proton therapy for moving thoracic tumours is hindered by interplay effect. The purpose of this study is to evaluate the impact of large proton beam spot size along with adaptive aperture (AA) and various motion mitigation techniques on the interplay effect for a range of motion amplitudes in a three-dimensional (3D) respiratory motion phantom. Materials and Methods: Point doses using ionisation chamber (IC) and planner dose distributions with radiochromic film were compared against the corresponding treatment planning system (TPS) information. A 3D respiratory motion phantom was scanned either for static or 4D computed tomographic (CT) technique for 6-, 10- and 14-mm motion amplitudes in SI direction. For free breathing (FB) treatment, a tumour was contoured on maximum intensity projection scan and an average scan was used for treatment planning. Each FB treatment was delivered with one, three and five volumetric repaintings (VRs). Three phases (CT40–60%) were extracted from the 4D-CT scans of each motion amplitude for the respiratory-gated treatment and were used for the treatment planning and delivery. All treatment plans were made using AA and robustly optimised with 5-mm set-up and 3·5% density uncertainty. A total of 26 treatment plans were delivered to IC and film using static, dynamic and respiratory-gated treatments combinations. A percent dose difference between IC and TPS for the point dose and gamma indices for film–TPS planner dose comparison was used. Results: The dose profile of film and TPS for the static phantom matched well, and percent dose difference between IC and TPS was 0·4%. The percent dose difference for all the gated treatments were below 3·0% except 14-mm motion amplitude-gated treatment. The gamma passing rate was more than 95% for film–TPS comparison for all gated treatment for the investigated gamma acceptance criteria. For FB treatments, the percent dose difference for 6-, 10- and 14-mm motion amplitude was 1·4%, −2·7% and −4·1%, respectively. As the number of VR increased, the percent difference between measured and calculated values decreased. The gamma passing rate met the required tolerance for different acceptance criteria except for the 14-mm motion amplitude FB treatment. Conclusion: The PBS technique for the FB thoracic treatments up to 10-mm motion amplitude can be implemented with an acceptable accuracy using large proton beam spot size, AA and robust optimisation. The impact of the interplay effect can be reduced with VR and respiratory-gated treatment and extend the treatable tumour motion amplitude.

scholarly journals Assessment of Delivery Quality Assurance for Stereotactic Radiosurgery With Cyberknife

2021 ◽  
Vol 11 ◽  
Author(s):  
Jun Li ◽  
Xile Zhang ◽  
Yuxi Pan ◽  
Hongqing Zhuang ◽  
Junjie Wang ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Stereotactic Radiosurgery ◽  
Dose Distribution ◽  
Ionization Chamber ◽  
Treatment Time ◽  
Target Volume ◽  
Sensitive Volume ◽  
Passing Rates ◽  
Passing Rate ◽  
Gamma Passing Rate

PurposeThe purpose of this study is to establish and assess a practical delivery quality assurance method for stereotactic radiosurgery with Cyberknife by analyzing the geometric and dosimetric accuracies obtained using a PTW31016 PinPoint ionization chamber and EBT3 films. Moreover, this study also explores the relationship between the parameters of plan complexity, target volume, and deliverability parameters and provides a valuable reference for improving plan optimization and validation.MethodsOne hundred fifty cases of delivery quality assurance plans were performed on Cyberknife to assess point dose and planar dose distribution, respectively, using a PTW31016 PinPoint ionization chamber and Gafchromic EBT3 films. The measured chamber doses were compared with the planned mean doses in the sensitive volume of the chamber, and the measured planar doses were compared with the calculated dose distribution using gamma index analysis. The gamma passing rates were evaluated using the criteria of 3%/1 mm and 2%/2 mm. The statistical significance of the correlations between the complexity metrics, target volume, and the gamma passing rate were analyzed using Spearman’s rank correlation coefficient.ResultsFor point dose comparison, the averaged dose differences (± standard deviations) were 1.6 ± 0.73% for all the cases. For planar dose distribution, the mean gamma passing rate for 3%/1 mm, and 2%/2 mm evaluation criteria were 94.26% ± 1.89%, and 93.86% ± 2.16%, respectively. The gamma passing rates were higher than 90% for all the delivery quality assurance plans with the criteria of 3%/1 mm and 2%/2 mm. The difference in point dose was lowly correlated with volume of PTV, number of beams, and treatment time for 150 DQA plans, and highly correlated with volume of PTV for 18 DQA plans of small target. DQA gamma passing rate (2%/2 mm) was a moderate significant correlation for the number of nodes, number of beams and treatment time, and a low correlation with MU.ConclusionPTW31016 PinPoint ionization chamber and EBT3 film can be used for routine Cyberknife delivery quality assurance. The point dose difference should be within 3%. The gamma passing rate should be higher than 90% for the criteria of 3%/1 mm and 2%/2 mm. In addition, the plan complexity and PTV volume were found to have some influence on the plan deliverability.

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