Dose assessment by TL dosimetry according to parameters used in treatment plans for obsessive compulsive disorder using the Gamma Knife@ Perfexion™ device

The objective of this work was to assess the response of TLDs inserted in an anthropomorphic phantom for an OCD treatment considering the planning methodologies, dimensions of an isodose projection in a plan, detector dimensions, uncertainty of mechanical movement of the patient positioning system, dose calculation algorithms and dose rate in Gamma Knife Perfexion™ equipment. The doses to the brainstem were evaluated as well as the possibility of alopecia occurrence. Considering the dosimetry of the internal capsule region, differences seen were within the error of the method. The measured doses to the brainstem, due to the treatment of OCD, were lower than the limits considered relevant. However, for the scalp region, dose values, higher than the desirable limiting ones to determine alopecia were observed. Results showed that it is possible to establish a methodology that allows characterizing a treatment plan of OCD using TLDs.