1998 Volume 1 Issue 1 Pages 141-147
Radiosurgery is a procedure that uses high dose smallest external beams for a single treatment of small intracranial lesion. Accurate determination of the absorbed dose is very difficult because the lateral components of secondary electrons are not in equilibrium. In this experiment, the calibration was performed using 6MV-photon beams(Mitsubishi ML-6M LINAC) to a water phantom. Ionization chambers of different size used to evaluate the maximum dose and the peripheral dose in the clinical target volume(CTV) from the depth dose rate on each percentage center dose ratio. From our measurement, it was found that distance of displacement has direct relation to the dose and the degree of displacement depends on the size of the ionization chamber volume.
