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

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

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.

scholarly journals PO-0784: Pre-treatment IMRT quality assurance: sensibility and specificity analysis of gamma index method

2013 ◽  
Vol 106 ◽  
pp. S299
Author(s):  
S. Bresciani ◽  
A. Maggio ◽  
A. Miranti ◽  
A. Di Dia ◽  
C. Cutaia ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Index Method ◽  
Gamma Index ◽  
Pre Treatment

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 Interpretation of Gamma Index for Quality Assurance of Simultaneously Integrated Boost (SIB) IMRT Plans for Head and Neck Carcinoma

2017 ◽  
Vol 23 (4) ◽  
pp. 93-97 ◽  
Author(s):  
Maria Atiq ◽  
Atia Atiq ◽  
Khalid Iqbal ◽  
Quratul ain Shamsi ◽  
Farah Andleeb ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Head And Neck ◽  
Dose Distribution ◽  
Confidence Limit ◽  
Passing Rate ◽  
Gamma Analysis ◽  
Gamma Index ◽  
Integrated Boost ◽  
Calculated Dose ◽  
Dose Difference

Abstract Objective: The Gamma Index is prerequisite to estimate point-by-point difference between measured and calculated dose distribution in terms of both Distance to Agreement (DTA) and Dose Difference (DD). This study aims to inquire what percentage of pixels passing a certain criteria assure a good quality plan and suggest gamma index as efficient mechanism for dose verification of Simultaneous Integrated Boost Intensity Modulated Radiotherapy plans. Method: In this study, dose was calculated for 14 head and neck patients and IMRT Quality Assurance was performed with portal dosimetry using the Eclipse treatment planning system. Eclipse software has a Gamma analysis function to compare measured and calculated dose distribution. Plans of this study were deemed acceptable when passing rate was 95% using tolerance for Distance to agreement (DTA) as 3mm and Dose Difference (DD) as 5%. Result and Conclusion: Thirteen cases pass tolerance criteria of 95% set by our institution. Confidence Limit for DD is 9.3% and for gamma criteria our local CL came out to be 2.0% (i.e., 98.0% passing). Lack of correlation was found between DD and γ passing rate with R2 of 0.0509. Our findings underline the importance of gamma analysis method to predict the quality of dose calculation. Passing rate of 95% is achieved in 93% of cases which is adequate level of accuracy for analyzed plans thus assuring the robustness of SIB IMRT treatment technique. This study can be extended to investigate gamma criteria of 5%/3mm for different tumor localities and to explore confidence limit on target volumes of small extent and simple geometry.

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

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.

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