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 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 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

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 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.

scholarly journals Evaluation of Delta4DVH Anatomy in 3D Patient-Specific IMRT Quality Assurance

2020 ◽  
Vol 19 ◽  
pp. 153303382094581
Author(s):  
Du Tang ◽  
Zhen Yang ◽  
Xunzhang Dai ◽  
Ying Cao
Keyword(s):  
Quality Assurance ◽  
Treatment Planning ◽  
Treatment Plan ◽  
Planning System ◽  
Treatment Planning System ◽  
Patient Specific ◽  
Pencil Beam ◽  
Ion Chamber ◽  
Passing Rate ◽  
Gamma Passing Rate

Purpose: To evaluate the performance of Delta4DVH Anatomy in patient-specific intensity-modulated radiotherapy quality assurance. Materials and Methods: Dose comparisons were performed between Anatomy doses calculated with treatment plan dose measured modification and pencil beam algorithms, treatment planning system doses, film doses, and ion chamber measured doses in homogeneous and inhomogeneous geometries. The sensitivity of Anatomy doses to machine errors and output calibration errors was also investigated. Results: For a Volumetric Modulated Arc Therapy (VMAT) plan evaluated on the Delta4 geometry, the conventional gamma passing rate was 99.6%. For a water-equivalent slab geometry, good agreements were found between dose profiles in film, treatment planning system, and Anatomy treatment plan dose measured modification and pencil beam calculations. Gamma passing rate for Anatomy treatment plan dose measured modification and pencil beam doses versus treatment planning system doses was 100%. However, gamma passing rate dropped to 97.2% and 96% for treatment plan dose measured modification and pencil beam calculations in inhomogeneous head & neck phantom, respectively. For the 10 patients’ quality assurance plans, good agreements were found between ion chamber measured doses and the planned ones (deviation: 0.09% ± 1.17%). The averaged gamma passing rate for conventional and Anatomy treatment plan dose measured modification and pencil beam gamma analyses in Delta4 geometry was 99.6% ± 0.89%, 98.54% ± 1.60%, and 98.95% ± 1.27%, respectively, higher than averaged gamma passing rate of 97.75% ± 1.23% and 93.04% ± 2.69% for treatment plan dose measured modification and pencil beam in patients’ geometries, respectively. Anatomy treatment plan dose measured modification dose profiles agreed well with those in treatment planning system for both Delta4 and patients’ geometries, while pencil beam doses demonstrated substantial disagreement in patients’ geometries when compared to treatment planning system doses. Both treatment planning system doses are sensitive to multileaf collimator and monitor unit (MU) errors for high and medium dose metrics but not sensitive to the gantry and collimator rotation error smaller than 3°. Conclusions: The new Delta4DVH Anatomy with treatment plan dose measured modification algorithm is a useful tool for the anatomy-based patient-specific quality assurance. Cautions should be taken when using pencil beam algorithm due to its limitations in handling heterogeneity and in high-dose gradient regions.

PO-0811: From gamma passing-rate to DVH: Validation and first clinic applications of a commercial software

2014 ◽  
Vol 111 ◽  
pp. S64-S65
Author(s):  
L. Marrazzo ◽  
S. Calusi ◽  
M. Casati ◽  
C. Arilli ◽  
M. Bucciolini
Keyword(s):  
Commercial Software ◽  
Passing Rate ◽  
Gamma Passing Rate

scholarly journals Correlation Between Average Segment Width and Gamma Passing Rate as a Function of MLC Position Error in Volumetric Modulated Arc Therapy

2021 ◽  
Vol 20 ◽  
pp. 153303382110599
Author(s):  
Young Min Moon ◽  
Sang Il Bae ◽  
Moo Jae Han ◽  
Wan Jeon ◽  
Tosol Yu ◽  
...  
Keyword(s):  
Least Squares Method ◽  
Linear Regression Analysis ◽  
Volumetric Modulated Arc Therapy ◽  
Position Error ◽  
Coefficient Of Determination ◽  
Position Errors ◽  
Visual Basic For Applications ◽  
Passing Rate ◽  
Arc Therapy ◽  
Gamma Passing Rate

Objective: This study analyzed the correlation between the average segment width (ASW) and gamma passing rate according to the multi-leaf collimator (MLC) position error. Method: To evaluate the changes in the gamma passing rate according to the MLC position error, 21 volumetric modulated arc therapy (VMAT) plans were generated using pelvic lymph node metastatic prostate cancer patient's data which is sensitive to MLC position errors as they involve several long, narrow, irregular fields. The ASW for each VMAT plan was calculated using our own code developed using Visual Basic for Applications (VBA). The gamma passing rate of the VMAT plan according to the MLC position error was evaluated using ArcCHECK (Sun Nuclear, Melbourne, FL, USA) while inducing symmetric MLC position errors in 0.25 mm intervals from −1 mm to +1 mm in the infinity medical linear accelerator (Elekta AB, Stockholm, Sweden). Finally, we examined the correlation between the change in the passing rate ([Formula: see text]) due to the MLC position error and the ASW in VMAT through linear regression analysis using the least squares method. Results: The ASW and [Formula: see text] were found to have a linear correlation according to the MLC position error, and the coefficient of determination was 0.88. For a 1 mm position error of MLC in VMAT, the gamma passing rate improved by approximately 11.9% as the ASW increased by 10 mm. Conclusion: These results are expected to be employed as guidelines to minimize the dose uncertainty due to MLC position error in VMAT.

Comparison between different Dosimetric Tools based on Intensity-modulated Radiotherapy (IMRT): A Phantom Study

2021 ◽  
Vol 19 (11) ◽  
pp. 141-150
Author(s):  
Ahmed H. Waheeb ◽  
Zeinab Eltaher ◽  
Mohamed N. Yassin ◽  
Magdy M. Khalil
Keyword(s):  
Dose Distribution ◽  
Low Dose ◽  
Planning System ◽  
Treatment Planning System ◽  
Patient Specific ◽  
Dose Threshold ◽  
Passing Rate ◽  
Gamma Analysis ◽  
Calculated Dose ◽  
Gamma Passing Rate

This study examined the gamma passing rate (GPR) consistency during applying different kinds of gamma analyses and dosimeters to IMRT. Methods: Import treatment protocols for QA phantom irradiation have been recalculated. A gamma analysis was used for comparing the measured and calculated dose distribution of IMRT for different gamma criteria (2%/2mm, 3%/3mm, 4%/4mm, 3%/5mm, 3%/5mm). These criteria are evaluated when 5%, 10%, or 15% of the dose distribution is suppressed. Measured and calculated dose distribution was evaluated with gamma analysis to dose difference (DD) with DTA criteria (distance to agreement). IMRT QA plans to 25 patients from various sites were formed with the Varian Eclipse treatment planning system. Results: Results indicate different diverse hardware and software combinations show varied levels of agreement with expected analysis for the same pass-rate criterion. For a dosimetry audit of the IMRT technique, an EPID detector is superior to conventional methods comparable to Gafchromic EPT3 film and 2D array due to cost, time-consuming, and set up error to get result analysis. The gamma passing rate (GPR) average is increased by increasing the low-dose threshold for different dosimetric tools. For EPID, regardless of the gamma criterion employed, the %GP does not appear to be dependent on the low-dose threshold values (5%-15%) because it indicates that fulfilment the low-dose threshold to global normalization has little effect on patient-specific QA outcomes. Conclusions: It is concluded that GPRs differ depending on gamma, dosimetric tools, and the suppressing dose ratio. To get the best results of quality assurance, each institution should thus carefully develop its procedure for gamma analysis by defining the gamma index analysis and gamma criterion using its dosimetric tools.

Sign in / Sign up

Export Citation Format

Share Document