SBRT 2016

Recently… New identical Linac…

Why did QART fail? • Full tests from CT scanning to irradiation of phantoms have been performed. The measurements were performed on the right linac. But the calculations were performed using the existing Linac model in the TPS. • Routinely EPID patient dosimetry QA is performed at this institution. But this is a relative measurement (scaled to coincide with calculations in normalisation point). Occasionally Matrix-measurements are performed at a linac, e.g., if beams do not fit on the EPID. But on the new linac only small fields were used. (HD 2.5 mm MLC)