[Implementation of stereotactic focal radiotherapy using 10 MV x-ray].

ABSTRACT

Stereotactic focal irradiation is also called stereotactic radiosurgery by some neurosurgeons. This irradiation is used for the treatment of brain AVM (arterio-venous malformation) and small tumor. Application of stereotactic focal irradiation was developed with CRW (Cosman-Roberts-Wells) stereotactic device and two dimensional (2D) computer treatment planning system using 10 MV x-ray from a linear accelerator. This process of irradiation includes (a) Identification and localization of a target volume in CRW stereotactic frame by CT scan or angiography. (b) To verify the alignment, a linear accelerator was used as a simulator to take portal films in anterior and lateral views. This was done to ascertain the angles between arc therapy, to encompass the target volume, and to exclude the critical organs such as lens at 0 degrees, 45 degrees, 90 degrees and 315 degrees couch angles. (c) A 2D computer treatment planning system was used to generate an isodose curve distribution for each couch angle. Then this was used to calculate the monitor unit per degree for rotation treatment. (d) 10 MV x-ray was used to implement the stereotactic focal radiotherapy.