open access

Vol 25, No 5 (2020)
Original research articles
Published online: 2020-09-01
Submitted: 2020-03-16
Get Citation

Monte Carlo commissioning of radiotherapy LINAC—Introducing an improved methodology

Saqib Bajwa, Attia Gul, Shahbaz Ahmed, Muhammad B. Kakakhel
DOI: 10.1016/j.rpor.2020.06.009
·
Rep Pract Oncol Radiother 2020;25(5):720-724.

open access

Vol 25, No 5 (2020)
Original research articles
Published online: 2020-09-01
Submitted: 2020-03-16

Abstract

Purpose

Monte Carlo (MC) commissioning of medical linear accelerator (LINAC) is a time-consuming process involving a comparison between measured and simulated cross beam/lateral profiles and percentage depth doses (PDDs) for various field sizes. An agreement between these two data sets is sought by trial and error method while varying the incident electron beam parameters, such as electron beam energy or width, etc. This study aims to improve the efficiency of MC commissioning of a LINAC by assessing the feasibility of using a limited number of simulated PDDs.

Materials and methods

Using EGSnrc codes, a Varian Clinac 2100 unit has been commissioned for 6 MV photon beam, and a methodology has been proposed to identify the incident electron beam parameters in a speedier fashion. Impact of voxel size in 3-dimensions and cost functions used for comparison of the measured and simulated data have been investigated along with the role of interpolation.

Results

A voxel size of 1 × 1×0.5 cm3 has been identified as suitable for accurate and fast commissioning of the LIANC. The optimum number of simulated PDDs (required for further interpolation) has been found to be five.

Conclusion

The present study suggests that PDDs alone at times can be insufficient for an unambiguous commissioning process and should be supported by including the lateral beam profiles in the process.

Abstract

Purpose

Monte Carlo (MC) commissioning of medical linear accelerator (LINAC) is a time-consuming process involving a comparison between measured and simulated cross beam/lateral profiles and percentage depth doses (PDDs) for various field sizes. An agreement between these two data sets is sought by trial and error method while varying the incident electron beam parameters, such as electron beam energy or width, etc. This study aims to improve the efficiency of MC commissioning of a LINAC by assessing the feasibility of using a limited number of simulated PDDs.

Materials and methods

Using EGSnrc codes, a Varian Clinac 2100 unit has been commissioned for 6 MV photon beam, and a methodology has been proposed to identify the incident electron beam parameters in a speedier fashion. Impact of voxel size in 3-dimensions and cost functions used for comparison of the measured and simulated data have been investigated along with the role of interpolation.

Results

A voxel size of 1 × 1×0.5 cm3 has been identified as suitable for accurate and fast commissioning of the LIANC. The optimum number of simulated PDDs (required for further interpolation) has been found to be five.

Conclusion

The present study suggests that PDDs alone at times can be insufficient for an unambiguous commissioning process and should be supported by including the lateral beam profiles in the process.

Get Citation

Keywords

Monte Carlo; Commissioning; EGSnrc; PDDs; Lateral profiles

About this article
Title

Monte Carlo commissioning of radiotherapy LINAC—Introducing an improved methodology

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 25, No 5 (2020)

Pages

720-724

Published online

2020-09-01

DOI

10.1016/j.rpor.2020.06.009

Bibliographic record

Rep Pract Oncol Radiother 2020;25(5):720-724.

Keywords

Monte Carlo
Commissioning
EGSnrc
PDDs
Lateral profiles

Authors

Saqib Bajwa
Attia Gul
Shahbaz Ahmed
Muhammad B. Kakakhel

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