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Assessment of leakage doses around the treatment heads of different linear accelerators

journal contribution
posted on 2024-11-01, 11:51 authored by Peta Lonski, Michael Taylor, Rick FranichRick Franich, P Harty, Tomas Kron
Out-of-field doses to untargeted organs may have long-term detrimental health effects for patients treated with radiotherapy. It has been observed that equivalent treatments delivered to patients with different accelerators may result in significant differences in the out-of-field dose. In this work, the points of leakage dose are identified about the gantry of several treatment units. The origin of the observed higher doses is investigated. LiF:Mg,Cu,P thermoluminescent dosimetry has been employed to quantify the dose at a several points around the linac head of various linear accelerators (linacs): a Varian 600C, Varian 21-iX, Siemens Primus and Elekta Synergy-II. Comparisons are also made between different energy modes, collimator rotations and field sizes. Significant differences in leaked photon doses were identified when comparing the various linac models. The isocentric-waveguide 600C generally exhibits the lowest leakage directed towards the patient. The Siemens and Elekta models generally produce a greater leakage than the Varian models. The leakage 'hotspots' are evident on the gantry section housing the waveguide on the 21-iX. For all machines, there are significant differences in the x and y directions. Larger field sizes result in a greater leakage at the interface plate. There is a greater leakage around the waveguide when operating in a low-energy mode, but a greater leakage for the high-energy mode at the linac face.

History

Journal

Radiation Protection Dosimetry

Volume

152

Issue

4

Start page

1

End page

9

Total pages

9

Publisher

Oxford University Press

Place published

Oxford, United Kingdom

Language

English

Copyright

© The Author 2012. Published by Oxford University Press. All rights reserved.

Former Identifier

2006039524

Esploro creation date

2020-06-22

Fedora creation date

2013-02-04

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