PD-0323 TOMOTHERAPY TREATMENT PLAN QUALITY ASSURANCE (QA): THE IMPACT OF APPLIED CRITERIA ON GAMMA PASSING RATE (%GP)

2012 ◽  
Vol 103 ◽  
pp. S128
Author(s):  
A. Di Dia ◽  
C. Sini ◽  
S. Bresciani ◽  
A. Maggio ◽  
A. Miranti ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Treatment Plan ◽  
Plan Quality ◽  
Passing Rate ◽  
The Impact ◽  
Gamma Passing Rate

Tomotherapy treatment plan quality assurance: The impact of applied criteria on passing rate in gamma index method

2013 ◽  
Vol 40 (12) ◽  
pp. 121711 ◽  
Author(s):  
Sara Bresciani ◽  
Amalia Di Dia ◽  
Angelo Maggio ◽  
Claudia Cutaia ◽  
Anna Miranti ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Treatment Plan ◽  
Plan Quality ◽  
Index Method ◽  
Passing Rate ◽  
Gamma Index ◽  
The Impact

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.

scholarly journals The Impact of Standardized Treatment Planning Guidelines on Treatment Plan Quality

2017 ◽  
Vol 99 (2) ◽  
pp. E556
Author(s):  
J.R. Kelly ◽  
H.S.M. Park ◽  
D.J. Carlson ◽  
M.S. Moran ◽  
L.D. Wilson ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Treatment Plan ◽  
Plan Quality ◽  
Standardized Treatment ◽  
The Impact

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.

SU-E-T-234: An Automated Tool for Treatment Plan Quality Evaluation and Clinical Trial Quality Assurance

2013 ◽  
Vol 40 (6Part14) ◽  
pp. 258-258
Author(s):  
J Wang ◽  
W Chen ◽  
M Studenski ◽  
Y Cui ◽  
A Lee ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Quality Assurance ◽  
Quality Evaluation ◽  
Treatment Plan ◽  
Plan Quality ◽  
Trial Quality ◽  
Automated Tool

TU-AB-201-02: An Automated Treatment Plan Quality Assurance Program for Tandem and Ovoid High Dose-Rate Brachytherapy

2015 ◽  
Vol 42 (6Part31) ◽  
pp. 3594-3594
Author(s):  
J Tan ◽  
F Shi ◽  
B Hrycushko ◽  
P Medin ◽  
S Stojadinovic ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Dose Rate ◽  
Treatment Plan ◽  
High Dose Rate ◽  
Quality Assurance Program ◽  
High Dose ◽  
Plan Quality ◽  
High Dose Rate Brachytherapy

Patient-specific quality assurance measurements for VMAT treatments: Do we really catch errors?

2013 ◽  
Vol 31 (31_suppl) ◽  
pp. 81-81 ◽  
Author(s):  
Wolfram Laub ◽  
Charles R. Thomas
Keyword(s):  
Quality Assurance ◽  
Head And Neck ◽  
Treatment Plan ◽  
Patient Specific ◽  
Imrt Qa ◽  
Passing Rates ◽  
Passing Rate ◽  
Gamma Index ◽  
Clinically Significant ◽  
Alignment Errors

81 Background: Patient-specific quality assurance measurements are time consuming and Gamma pass/fail criteria are often picked based on typical criteria used for IMRT QA measurements in the past. The questions needs to be asked if with these criteria QA plans could still show clinically significant deviations from the treatment plan calculated and how we should be doing QA for treatment delivery of complex treatment plans. In our study DICOM files of clinical Rapidarc plans were modified with in-house developed software to mimic leaf alignment errors and gravitation shifts. The Octavius 2D-ARRAY (PTW-Freiburg) and the Delta4 device (Scandidos) were used to investigate the effect of the simulated errors on the passing rate of quality assurance results. The manipulated Rapidarc plans were recalculated on patient CT scans in Eclipse. Methods: Three different types of errors were simulated and applied to five prostate (two arcs), three 2-arc head and neck cases and three 3-arc head and neck cases. The MLC modifications were: (1) both MLC banks are opened by 0.25mm, 0.50mm and 1.00mm in opposing directions resulting in larger fields, (2) both MLC banks are closed by 0.10mm, 0.25mm and 0.50mm, (3) both MLC banks are shifted in the same direction for lateral gantry angles to simulate effects of gravitational forces onto the leaves by 1mm, 2mm and 3mm, (4) 25%, 50% 70% and 100% of all active leaves are shifted by 3mm as in (3). QA evaluations were performed according to a gamma-index criterion of 3mm and 3% as well as 2mm and 2%. Results: All unmodified plans and the majority of the plans with the smallest modification pass the gamma-index criterion of 2%/2mm with >90%. After that the passing rate drops below 90%. For the largest modifications passing rates were typically below 85%. The Delta4 is generally more sensitive and the passing rate for modified plans drops below 90% earlier and more drastically. With the standard criteria (3mm, 3%) even the largest modifications would satisfy a >90% passing rate. Conclusions: A stricter gamma-index (2mm, 2%) is necessary in order to detect MLC positional errors and a passing rate of >90% should be expected. Clinical pass/fail criteria need to be developed.

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