open access

Vol 26, No 1 (2021)
Research paper
Published online: 2021-01-22
Submitted: 2021-01-12
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In-vivo dose measurements with MOSFET dosimeters during MV portal imaging

Sathish Kumar, Rabi Raja Singh, Henry Finlay Godson, Retna Ponmalar, Paul Ravindran, Sunil Dutt Sharma, Subhashini John
DOI: 10.5603/RPOR.a2021.0016
·
Rep Pract Oncol Radiother 2021;26(1):93-100.

open access

Vol 26, No 1 (2021)
Original research articles
Published online: 2021-01-22
Submitted: 2021-01-12

Abstract

Background: The purpose of this study was to investigate the feasibility of MOSFET dosimeter in measuring eye dose during 2D MV portal imaging for setup verification in radiotherapy.

Materials and methods: The in-vivo dose measurements were performed by placing the dosimeters over the eyes of 30 brain patients during the acquisition of portal images in linear accelerator by delivering 1 MU with the field sizes of 10 × 10 cm2 and 15 × 15 cm2.

Results: The mean doses received by the left and right eyes of 10 out of 30 patients when both eyes were completely inside the anterior portal field were found to be 2.56 ± 0.2 cGy and 2.75 ± 0.2, respectively. Similarly, for next 10 patients out of the same 30 patients the mean doses to left and right eyes when both eyes were completely out of the anterior portal fields were found to be 0.13 ± 0.02 cGy and 0.17 ± 0.02 cGy, respectively. The mean doses to ipsilateral and contralateral eye for the last 10 patients when one eye was inside the anterior portal field were found to be 3.28 ± 0.2 cGy and 0.36 ± 0.1 cGy, respectively.

Conclusion: The promising results obtained during 2D MV portal imaging using MOSFET have shown that this dosimeter is well suitable for assessing low doses during imaging thereby enabling to optimize the imaging procedure using the dosimetric data obtained. In addition, the documentation of the dose received by the patient during imaging procedure is possible with the help of an in-built software in conjunction with the MOSFET reader module.

Abstract

Background: The purpose of this study was to investigate the feasibility of MOSFET dosimeter in measuring eye dose during 2D MV portal imaging for setup verification in radiotherapy.

Materials and methods: The in-vivo dose measurements were performed by placing the dosimeters over the eyes of 30 brain patients during the acquisition of portal images in linear accelerator by delivering 1 MU with the field sizes of 10 × 10 cm2 and 15 × 15 cm2.

Results: The mean doses received by the left and right eyes of 10 out of 30 patients when both eyes were completely inside the anterior portal field were found to be 2.56 ± 0.2 cGy and 2.75 ± 0.2, respectively. Similarly, for next 10 patients out of the same 30 patients the mean doses to left and right eyes when both eyes were completely out of the anterior portal fields were found to be 0.13 ± 0.02 cGy and 0.17 ± 0.02 cGy, respectively. The mean doses to ipsilateral and contralateral eye for the last 10 patients when one eye was inside the anterior portal field were found to be 3.28 ± 0.2 cGy and 0.36 ± 0.1 cGy, respectively.

Conclusion: The promising results obtained during 2D MV portal imaging using MOSFET have shown that this dosimeter is well suitable for assessing low doses during imaging thereby enabling to optimize the imaging procedure using the dosimetric data obtained. In addition, the documentation of the dose received by the patient during imaging procedure is possible with the help of an in-built software in conjunction with the MOSFET reader module.

Get Citation

Keywords

MV portal imaging; setup verification; in vivo dosimetry; MOSFET

About this article
Title

In-vivo dose measurements with MOSFET dosimeters during MV portal imaging

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 26, No 1 (2021)

Article type

Research paper

Pages

93-100

Published online

2021-01-22

DOI

10.5603/RPOR.a2021.0016

Bibliographic record

Rep Pract Oncol Radiother 2021;26(1):93-100.

Keywords

MV portal imaging
setup verification
in vivo dosimetry
MOSFET

Authors

Sathish Kumar
Rabi Raja Singh
Henry Finlay Godson
Retna Ponmalar
Paul Ravindran
Sunil Dutt Sharma
Subhashini John

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