open access

Vol 26, No 1 (2021)
Research paper
Published online: 2021-01-22
Submitted: 2021-01-11
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A comparison of symmetry and flatness measurements in small electron fields by different dosimeters in electron beam radiotherapy

Mohamad Reza Bayatiani, Fatemeh Fallahi, Akbar Aliasgharzadeh, Mahdi Ghorbani, Benyamin Khajetash, Fatemeh Seif
DOI: 10.5603/RPOR.a2021.0009
·
Rep Pract Oncol Radiother 2021;26(1):50-58.

open access

Vol 26, No 1 (2021)
Original research articles
Published online: 2021-01-22
Submitted: 2021-01-11

Abstract

Background: Symmetry and flatness are two quantities which should be evaluated in the commissioning and quality control of an electron beam in electron beam radiotherapy. The aim of this study is to compare symmetry and flatness obtained using three different dosimeters for various small and large fields in electron beam radiotherapy with linac.

Materials and methods: Beam profile measurements were performed in a PTW water phantom for 10, 15 and 18 MeV electron beams of an Elekta Precise linac for small and large beams (1.5 × 1.5 cm2 to 20 × 20 cm2 field sizes). A Diode E detector and Semiflex-3D and Advanced Markus ionization chambers were used for dosimetry.

Results: Based on the obtained results, there are minor differences between the responses from different dosimeters (Diode E detector and Semiflex-3D and Advanced Markus ionization chambers) in measurement of symmetry and flatness for the electron beams. The symmetry and flatness values increase with increasing field size and electron beam energy for small and large field sizes, while the increases are minor in some cases.

Conclusions: The results indicate that the differences between the symmetry and flatness values obtained from the three dosimeter types are not practically important.

Abstract

Background: Symmetry and flatness are two quantities which should be evaluated in the commissioning and quality control of an electron beam in electron beam radiotherapy. The aim of this study is to compare symmetry and flatness obtained using three different dosimeters for various small and large fields in electron beam radiotherapy with linac.

Materials and methods: Beam profile measurements were performed in a PTW water phantom for 10, 15 and 18 MeV electron beams of an Elekta Precise linac for small and large beams (1.5 × 1.5 cm2 to 20 × 20 cm2 field sizes). A Diode E detector and Semiflex-3D and Advanced Markus ionization chambers were used for dosimetry.

Results: Based on the obtained results, there are minor differences between the responses from different dosimeters (Diode E detector and Semiflex-3D and Advanced Markus ionization chambers) in measurement of symmetry and flatness for the electron beams. The symmetry and flatness values increase with increasing field size and electron beam energy for small and large field sizes, while the increases are minor in some cases.

Conclusions: The results indicate that the differences between the symmetry and flatness values obtained from the three dosimeter types are not practically important.

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Keywords

radiotherapy; small field dosimetry; electron beam; symmetry; flatness; Diode E; Semiflex-3D; Advanced Markus

About this article
Title

A comparison of symmetry and flatness measurements in small electron fields by different dosimeters in electron beam radiotherapy

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 26, No 1 (2021)

Article type

Research paper

Pages

50-58

Published online

2021-01-22

DOI

10.5603/RPOR.a2021.0009

Bibliographic record

Rep Pract Oncol Radiother 2021;26(1):50-58.

Keywords

radiotherapy
small field dosimetry
electron beam
symmetry
flatness
Diode E
Semiflex-3D
Advanced Markus

Authors

Mohamad Reza Bayatiani
Fatemeh Fallahi
Akbar Aliasgharzadeh
Mahdi Ghorbani
Benyamin Khajetash
Fatemeh Seif

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