Characteristics of 23 MV Photon Beam from a Mevatron KD 8067 Dual Energy Linear Accelerator / 대한치료방사선과학회지

ABSTRACT

The characteristics of 23 MV photon beam have been presented with respect to clinical parameters of central axis depth dose, tissue-maximum ratis, scatter-maximum ratios, surface dose and scatter correction factors. The nominal accelerating potential was found to be 18.5+/-0.5 MV on the central axis. The half-value layer (HVL) of this photon beam was measured with narrow beam geometry from central axis, and it has been showed the thickness of 24.5 g/cm2. The tissue-maximum, ratio values have been determined from measured percentage depth dose data. In our experimental dosimetry, the surface dose of maximum showed only 9.6% of maximum dose at 10x10cm2, 100cm SSD, without blocking tray in. The TMR'S of 0x0 field size have been determined to get average 2.3% uncertainties from three different methodis; are zero effective attenuation coefficient, non-ilnear least square fil of TMR's data and effective linear attenuation coefficient from the HVL of 23 MV photon beams of dual energy linear accelerator.