Performance evaluation of an inorganic optical fibre dosimeter for use in external beam radiotherapy with pulsed beams.

Autor:	McDonnell C; Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast BT9 7AE, United Kingdom., McLaughlin O; Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast BT9 7AE, United Kingdom., McGarry CK; Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast BT9 7AE, United Kingdom.; Department of Radiotherapy Medical Physics, Northern Ireland Cancer Centre Belfast Health and Social Care Trust, Belfast BT9 7AB, United Kingdom., Hounsell AR; Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast BT9 7AE, United Kingdom.; Department of Radiotherapy Medical Physics, Northern Ireland Cancer Centre Belfast Health and Social Care Trust, Belfast BT9 7AB, United Kingdom., O'Keeffe S; Optical Fibre Sensors Research Centre University of Limerick, Limerick, Ireland., Lewis E; Optical Fibre Sensors Research Centre University of Limerick, Limerick, Ireland., Prise KM; Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast BT9 7AE, United Kingdom.
Jazyk:	angličtina
Zdroj:	Physics in medicine and biology [Phys Med Biol] 2024 Oct 18; Vol. 69 (21). Date of Electronic Publication: 2024 Oct 18.
DOI:	10.1088/1361-6560/ad84b7
Abstrakt:	Objective . Optical fibre dosimeters (OFDs) offer great promise for real-time in vivo dose measurement in radiation-based treatment modalities such as radiotherapy and brachytherapy. This is attributed to their many useful qualities such as high spatial resolution and sensitivity. However, there are several requirements that an optical fibre dosimeter must meet to be acceptable for dose measurement in a specified treatment modality. In this work, the dosimetric performance of a novel optical fibre dosimeter for use in external beam radiotherapy is presented. Approach . The dosimeter was characterised for photon beam energies between 6-15 MV using a Varian TrueBeam Linac at dose rates between 100-2400 MU/min and assessed based on its repeatability, dose dependence, dose rate dependence, energy dependence and dose-per-pulse dependence. Main Results . The results demonstrated excellent short-term repeatability of 0.3%, good linearity in response (R2>0.9997), and minor dose rate dependence between 0.53%-2.49% for all beam qualities investigated. As the scintillator of the OFD is non-water equivalent, Monte-Carlo-TOPAS simulations were used to calculate the absorbed dose energy dependence. A dose-per-pulse dependence was also investigated and compared with dosimetry measurements made with an ionisation chamber and simulated from the treatment planning system. An over-response of 20%was found at the lowest investigated dose-per-pulse, and an under-response of 34%was found at the highest investigated dose-per-pulse. This is believed to be due to an intrinsic energy dependence making this type of OFD unsuitable for external beam radiotherapy dosimetry. Significance . The OFD evaluated in this work was primarily designed for high-dose-rate brachytherapy whereas this study includes the first measurements made in external beam radiotherapy and highlights the challenges of transferability of the dosimeter to a different radiation source. (Creative Commons Attribution license.)
Databáze:	MEDLINE
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