DEPTH-DOSE IN AN ANTHROPOMORPHIC HEAD PHANTOM FOR MONOENERGETIC PHOTONS

Depth-dose distribution measurements in an anthropomorphic phantom exposed to a broad parallel beam of different monoenergetic photons (X-ray, Cs-137 and Co-60) were studied. The depth dose was measured by setting BeO-TLDs in the phantom. From the view point of clinical dosimetry, for low energy X-rays < 100 keV, the dose is high and jumps at the head bone interface while for high energy photons, the differential at the interface is not great. The dose to tissue at the interface is high. Thus, in the case of higher energy photon beams, higher doses can be delivered to the deep-seated tumours without exceeding the tolerance of the scalp.