POUŽITÍ RADIOCHROMNÍHO GELOVÉHO DOZIMETRU PRO VERIFIKACI DÁVKOVÉ DISTRIBUCE VE STEREOTAKTICKÉ RADIOCHIRURGII

DOSE DISTRIBUTION VERIFICATION IN STEREOTACTC RADIOSURGERY USING RADIOCHROMIC GEL DOSIMETER. 3D verification in stereotactic radiosurgery is not a trivial task since there is not available appropriate detector and the process of verification is time consuming as well. The aim of the study was to perform assessment of radiochromic gel dosimeter based on Turnbull blue dye for verification of patient treatment plan at Leksell Gama Knife Perfexion. Gel dosimeter was fixed with stereotactic frame and irradiated with a prescription dose of 40 Gy to 50% isodose. Dosimeter was evaluated two hours after irradiation using home made optical CT scanner. The comparison between the gel measurements and the treatment planning system calculation are presented in the form of 2D isodoses, 1D profile and gamma analysis (1 mm 3%) for the central slices. Measured relative dose distribution in a central slice and measured profiles show excellent correspondence with TPS. There were observed small discrepancies in low dose region according to gamma analyses results. This was probably caused by problems with dose distribution coregistration and set up positioning errors