PDD AND DOSE PROFILE FOR NARROW BEAMS OF A COBALT - 60THERAPY UNIT TO BE USED IN STEREOTACTIC RADIOSURGERY

摘要

In this work we determined PDD curves and dose profiles for narrow beams produced by a cobalt-60 therapy unity aimed to be used in radiosurgery through the cone beam technique. PDD curves were obtained by three techniques, namely diode dosimetry, ionization chamber dosimetry and radiochromic film dosimetry. The results present a good agreement. The dose profiles obtained for cobalt-60 were compared to those ones generated by a linac 2300C accelerator. For a same cone collimator, the area of treatment generated by cobalt -60 beam was smaller. The mean responsible for this situation is the wider penumbra present by the cobalt-60 beam.