White polystyrene as a substitute for water in high energy photon dosimetry
- 1 December 1995
- journal article
- research article
- Published by Wiley in Medical Physics
- Vol. 22 (12) , 2097-2100
- https://doi.org/10.1118/1.597652
Abstract
White polystyrene (C8H8 with 2 wt.% to TiO2) has been compared to water using photon beams with nominal accelerating potential of 4 MV, 6 MV, 15 MV and 25 MV. The absolute reading and hence the measured absorbed dose is found to be up to 3% lower in white polystyrene which can be taken into account by using a correction factor. From these data differences in relative measurements (TMR or percentage depth dose) can be calculated showing differences of less than 0.7% normalized to maximum dose. Since the correction factor shows a dependence on photon energy and field size the use of a common scaling factor is not possible. The effect on photon dosimetry is discusssed.Keywords
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