Dose quality assurance for stereotactic radiotherapy treatments

A simple Perspex phantom is presented for routine dosimetry checks of stereotactic radiotherapy procedures, along with a procedure for checking the planning process. The phantom is hemispherical and water filled. It can be fitted into the Brown-Robert-Wells fiducial system for CT scanning and attached to the stereotactic frame for treatment. Both arcing and fixed field plans can be carried out on the phantom. We present our results, performed on a Varian 600C linac, which were found to be within 2% of the expected dose.