Gamma Index Analysis as a Patient-Specific Quality Assurance Tool for High-Precision Radiotherapy: A Clinical Perspective of Single Institute Experience

S, Das; Kharade, Vipin; Pandey, Vivek; KV, Anju; Pasricha, Rajesh; Gupta, Manish

doi:10.7759/cureus.30885

Cited by 7 publications

(3 citation statements)

References 18 publications

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“…The measured and MC Calculated data for FF mode are shown in figure 2. The estimated gamma index (<1) with acceptance criteria of 3%/3 mm [32] shows that the measured data and the MC calculated are in good agreement in all points. The maximum relative dose differences between MC and measurement data were 1.8% and 2.7% in the build-up and semi-equilibrium region, respectively.…”

Section: Benchmark the 2100 C/d Varian Linac's Head Modelmentioning

confidence: 56%

Dosimetric parameters calculation for 18 MV photon beam in flattening filter (FF) and flattening filter free (FFF) linear accelerators with and without magnetic deflector and lead filter

Hashemizadeh,

Zabihzadeh,

Shahbazian

et al. 2024

Biomed. Phys. Eng. Express

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Dosimetric characteristics of the flattening filter (FF) and flattening filter free (FFF) modes of 18 MV therapeutic photon beam were investigated with and without the magnetic deflector (MD) and lead filter. MCNP version 6.1.0 Monte Carlo (MC) code was used to simulate the 18 MV photon beam of 2100 C/D-Varian linear accelerator (LINAC) for the FF and FFF modes. The MD (uniform magnetic flux density of 1 Tesla) and lead filter (thickness of 1 mm) were modeled to remove contaminant electrons. The dosimetric parameters for different scenarios of LINAC’s head were calculated. Removing the flattening filter in the FFF mode increased the dose rate, electron contamination, skin dose, out-of-field dose and un-flatness compared to the FF mode. While the lead filter decreased the contaminant electrons significantly, using the MD removed all secondary electrons from the beam line. The surface dose was decreased by 8.3 % and 11.2 % for the magnetic deflector (MD) and lead filter in the FF mode, respectively. The surface dose was decreased by 16.8 % and 20.3 % for the MD and lead filter scenarios in the FFF mode, respectively. The MD and lead filter decreased surface penumbra by 15.5 % and 11.5 % compared to the FFF mode. Removing the flattening filter from the LINAC’s head improves most of the dosimetric characteristics of the 18MV therapeutic beam. The use of a lead filter and magnetic deflector preserves the skin-sparing property of megavoltage beams that deteriorate in FFF mode. However, using a magnetic deflector does not reduce photon fluence and dose rate.

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Section: Benchmark the 2100 C/d Varian Linac's Head Modelmentioning

confidence: 56%

Dosimetric parameters calculation for 18 MV photon beam in flattening filter (FF) and flattening filter free (FFF) linear accelerators with and without magnetic deflector and lead filter

Hashemizadeh,

Zabihzadeh,

Shahbazian

et al. 2024

Biomed. Phys. Eng. Express

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“…However, the detector resolution and computation algorithm significantly affected the gamma passing rate. However, a large amount of acquired data in RapidArc delivery with rotational arc acquisition allows better estimation of the dose distribution by the software [12]. In the current study, no action limits were chosen.…”

Section: Disscussionmentioning

confidence: 99%

Evaluation of Patient-Specific Quality Assurance for RapidArc Treatment Delivery Using Dose Volume Histogram

Manna

2023

JOPC

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This study aims to evaluate the application of dose volume histogram (DVH) metrics within the patient-specific quality assurance (PSQA) protocol in various sites for RapidArc treatment delivery. Forty patients were included in this study, of which twenty each Head and Neck (H&N) and Pelvis Rapid Arc plans were evaluated. Octavius 4D 1500 detector array with vented parallel plate ion chambers was used for this study, which reconstruct the pre-treatment measured doses into threedimensional (3D) during pre-treatment quality assurance. The verisoft DVH application was utilized to estimate the dose administered to the patient's volume, explicitly focusing on the errors associated in the DVH. The measured data were compared with the treatment planning system created verification plan. Three-dimensional local and global gamma were evaluated using different gamma criteria of 3 mm/3%, 3 mm/2%, 2 mm/3% and 2 mm/2%, respectively. In addition, the agreement score was analysed for axial, coronal, and sagittal planes in addition to the volumetric analysis. All plans meet the action level requirement of >95% with 3%/3 mm gamma acceptance criteria. In addition, the DVH demonstrated that the doses administered to the target volumes and organs at risk remained within the specified dose tolerances for all cases. The DVH analysis will be applied to identify the instances where patient dose errors surpass the predetermined established action threshold. The gamma index did not initially identify these and may have utility in determining the reason for failed plans. Further, it enables identifying and managing dose errors associated with the patient's anatomy. Finally, this study has showcased the incorporation of DVH metrics into RapidArc PSQA protocol may deliver clinically meaningful outcomes in close proximity to the gamma index.

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“…In the Varian treatment workstation, accept the treatment plan from the R&V system, and remove the interlock for QA mode treatment delivery. 8) Once the delivery is finished, perform the gamma index analysis [11] with a specified (e.g. 2 mm/3%) passing criteria on the PTW Octavius workstation, and export the PSQA report.…”

Section: )mentioning

confidence: 99%

Implementation of Level-3 Autonomous Patient-Specific Quality Assurance with Automated Human Interactive Devices

Zhang,

Zhao,

Baker

et al. 2023

IJMPCERO

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Purpose: Patient-specific quality assurance (PSQA) requires manual operation of different workstations, which is time-consuming and error-prone. Therefore, developing automated solutions to improve efficiency and accuracy is a priority. The purpose of this study was to develop a general software interface with scripting on a human interactive device (HID) for improving the efficiency and accuracy of manual quality assurance (QA) procedures. Methods: As an initial application, we aimed to automate our PSQA workflow that involves Varian Eclipse treatment planning system, Elekta MOSAIQ oncology information system and PTW Verisoft application. A general platform, the AutoFrame interface with two imbedded subsystems-the AutoFlow and the PyFlow, was developed with a scripting language for automating human operations of aforementioned systems. The interface included three functional modules: GUI module, UDF script interpreter and TCP/IP communication module. All workstations in the PSQA process were connected, and most manual operations were automated by AutoFrame sequentially or in parallel. Results: More than 20 PSQA tasks were performed both manually and using the developed AutoFrame interface. On average, 175 (±12) manual operations of the PSQA procedure were eliminated and performed by the automated process. The time to complete a PSQA task was 8.23 (±0.78) minutes for the automated workflow, in comparison to 13.91 (±3.01) minutes needed for manual operations. Conclusion: We have developed the AutoFrame interface framework that successfully automated our PSQA procedure, and significantly reduced the time, human (control/clicking/typing) errors, and operators' stress. Future work will focus on improving the system's flexibility and stability and extending its operations to other QA procedures.

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Gamma Index Analysis as a Patient-Specific Quality Assurance Tool for High-Precision Radiotherapy: A Clinical Perspective of Single Institute Experience

Cited by 7 publications

References 18 publications

Dosimetric parameters calculation for 18 MV photon beam in flattening filter (FF) and flattening filter free (FFF) linear accelerators with and without magnetic deflector and lead filter

Dosimetric parameters calculation for 18 MV photon beam in flattening filter (FF) and flattening filter free (FFF) linear accelerators with and without magnetic deflector and lead filter

Evaluation of Patient-Specific Quality Assurance for RapidArc Treatment Delivery Using Dose Volume Histogram

Implementation of Level-3 Autonomous Patient-Specific Quality Assurance with Automated Human Interactive Devices

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