Open AccessComparison of the Convolution algorithm with TMR 10 for Leksell Gamma knife and dosimetric verification with radiochromic gel dosimeter
Author(s) -
Osmancikova Petra,
Novotny Josef,
Solc Jaroslav,
Pipek Jan
Publication year - 2018
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.12238
Subject(s) - imaging phantom , dosimeter , convolution (computer science) , dosimetry , algorithm , nuclear medicine , physics , computer science , mathematics , materials science , medicine , artificial intelligence , artificial neural network
Abstract The Convolution algorithm, implemented in Leksell GammaPlan ® ver. Here, 10, is the first algorithm for Leksell Gamma Knife that takes heterogeneities into account and models dose build‐up effects close to tissue boundaries. The aim of this study was preliminary comparison of the Convolution and TMR 10 algorithms for real clinical cases and dosimetric verification of the algorithms, using measurements in a phantom. A total of 25 patients involved in comparison of the Convolution and TMR 10 algorithms were divided into three groups: patients with benign tumors close to heterogeneities, patients with functional disorders, and patients with tumors located far from heterogeneities. Differences were observed especially in the group of patients with tumors close to heterogeneities, where the difference in maximal dose to critical structures for the Convolution algorithm was up to 15% compared to the TMR 10 algorithm. Dosimetric verification of the algorithm was performed, using a radiochromic gel dosimeter based on Turnbull blue dye in a special heterogeneous phantom. Relative dose distributions measured with the radiochromic gel dosimeter agreed very well with both the TMR 10 and Convolution calculations. We observed small discrepancies in the direction in which the largest inhomogeneity was positioned. Verification results indicated that the Convolution algorithm provides a different dose distribution, especially in regions close to heterogeneities and particularly for lower isodose volumes. However, the results obtained with gamma analyses in the gel dosimetry experiment did not verify the assumption that the Convolution algorithm provides more accurate dose calculation.