Experimental analysis of radiation dose distribution in radiosurgery: I. Dose hot spot inside target volume.

ABSTRACT

INTRODUCTION: Radiosurgery is currently performed with different systems of focused radiation providing different dose heterogeneities within the target volume. Here, we aimed to study histological consequences of different dose distributions inside the target area in an experimental model of Gamma Knife irradiation in the rat striatum. MATERIAL AND METHODS: Twelve rats were irradiated by Gamma Knife at the same volume in the right striatum; the same margin dose of 45 Gy was prescribed for all rats. Three different dose distributions inside the target volume were applied. Brain sections at the level of the target area were histologically analyzed 3 months after irradiation. RESULTS: Of the 7 histopathological reactions found as a consequence of the irradiation, 6 of them were significantly related to the gradient of dose heterogeneity within the target volume. CONCLUSIONS: Dose distribution inside the target volume could influence the histological effects of radiosurgical irradiation on tissue included in the target. A high dose in the target volume is more likely to lead to the desired radiobiological result.