DETERMINATION OF DOSIMETRIC PARAMETERS OF ORION (4 MV) PENUMBRA MODE

In this study, dosimetric parameters of ORION penumbra mode were determined and compared with standard mode data. Cirus Co-60 and ORION penumbra mode profile curves were measured in different field sizes and depths to compare penumbra width by film dosimetry. Energy and relative dose factors were measured using RW 3 solid water phantom, Farmer electrometer and 0.6 cc ion chamber. The difference was less than 1 % for Quality Index and 2% for relative dose factors. The results showed that standard dosimetric data for ORION could be used for penumbra mode irradiations. The penumbra width of ORION penumbra mode and Cirus Co-60 were similar.

Keywords: perumbra, linear accelerator, dose