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Sci‐Sat AM (1) General‐07: Water equivalent dosimeter array for small fields external beam radiotherapy
Author(s) -
Archambault L,
Frelin AM,
Gingras L,
Beddar A,
Beaulieu L
Publication year - 2006
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2244694
Subject(s) - dosimeter , scintillation , scintillator , optics , ionization chamber , optical fiber , detector , physics , dosimetry , dose profile , beam (structure) , scintillation counter , particle detector , materials science , radiation , nuclear medicine , ion , ionization , medicine , quantum mechanics
Scintillation dosimeters consisting of a scintillating fiber coupled to an optical fiber and read with a CCD camera have shown accurate dose measurement in external beam radiotherapy. This work presents the next step, which is to investigate the development of a multi‐channel dosimeter array in conjunction with a CCD camera for dose measurement that includes small fields. The light collection of the CCD camera was studied to evaluate the number of detectors that can be read simultaneously. We also looked at possible sources of dose perturbation with a single‐fiber detector surrounded by other optical fibers. We then constructed a prototype array with 10 detectors and compared with measurements taken with small ion chambers. No dose perturbations were seen when a plastic optical fiber was used to transmit the scintillation light to the CCD. Depth dose curves measured in water with a scintillation dosimeter with up to 75 plastic optical fibers in the beam showed no discrepancy to within 0.3% when compared to the same curve taken with an ion chamber and without the plastic fibers. Agreement within 0.6% was seen for output factor measured with the scintillator and the A16 Exradin chamber for fields of 1×1 cm 2 and 5×0.5 cm 2 . The ten‐fiber prototype allowed precise evaluation of profile and depth dose curves in a single irradiation. This work has shown that use of a multi‐channel scintillation dosimeter is feasible. The prototype of 10 detectors produced excellent results and could be extended up to 3000 detectors in the near future.