Verification using in vivo optically stimulated luminescent dosimetry of the predicted skin surface dose in patients receiving postmastectomy radiotherapy & nbsp;

摘要

The purpose of this study was to evaluate whether dose to the skin surface underneath bolus, was accurately predicted by a 3D treatment planning system (TPS) in patients receiving 50 Gy/25# postmastectomy radiotherapy (PMRT) using optically stimulated luminescent dosimetry (OSLD) for verification. In vivo dosimetry using OSLDs was performed in 20 consecutive patients receiving PMRT. An array of 9 OSLDs were applied to the chest wall or neobreast in a grid arrangement. Dosimetry data were recorded on 3 separate treatment fractions, averaged, and extrapolated to 25 fractions. On the 3D TPS, the predicted dose was calculated using the departmental planning algorithm at points corresponding to the OSLDs. The mean within patient difference between the planned and measured dose at each of the 9 points was calculated and Bland-Altman limits of agreement used to quantify the extent of agreement. Paired t-tests were used to test for evidence of systematic bias at each point. The coefficient of variation of the 3 OSLD readings per patient at each of the 9 points was low for 8 points ( 0.97 but < 1. This practical and feasible OSLD assessment of only 3 of 25 fractions facilitates quality assurance of a TPS in predicting skin surface dose under bolus. (c) 2020 Published by Elsevier Inc. on behalf of American Association of Medical Dosimetrists. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )