Evaluation of Fricke gel dosimeter layers for stereotactic radiosurgery

PEDRO PÉREZ; P. RICO TORRES; A. BRUNA; M. BRUNETTO; FACUNDO MATTEA; MAURO VALENTE

Simposio; XX International Symposium on Solid State Dosimetry (ISSSD 2020); 2020

Stereotactic radiosurgery is a highly precise form of radiation therapy to treat brain abnormalities that requires accurate treatment verification. Dose distributions in radiosurgery were verified by Fricke gel dosimeter layers, radiochromic films and Monte Carlo simulations adapting a head-like phantom scanned by computed tomography for further planning with the Blue Frame SRS - FiMe treatment planning system. Radiosurgery plan consisted of two small targets irradiated with a 10 MV photon beam. Dose distributions were compared by means of the Gamma index. Dose distributions were directly measured with film dosimeters and Fricke gel layers analyzed by visible light transmission, while treatment planning and Monte Carlo simulations were based on tomography images. Results from exhaustive evaluation of dose profiles and two dimensional maps showed good performance when comparing treatment planning system with Monte Carlo simulation, film and Fricke gel dosimeters. Additionally, three dimensional dose distributions were obtained by Fricke gel stack layers and further image processing with the toolkit. This work presents investigations regarding the feasibility, reliability and accuracy of Fricke gel dosimeter layers for stereotactic radiosurgery. Good agreement was found between experimental and calculated dose distributions in different regions close to the target. The capability of the developed system for 3D dose mapping was shown, obtaining promising results when compared with well-established dosimetry methods, thus supporting the viability of Fricke gel dosimeter layers analyzed by optical methods for stereotactic radiosurgery.