[Energy spectra of radiation from radiotherapeutic equipment]

The X-ray photon spectra of a number of generally used radiotherapeutic systems have been studied by using a semiconductor Ge detector. The voltage ranges from 80 to 200 kV. The procedure of converting pulse-height distributions into photon spectra is described. The relation between the shape of the spectrum and the anode current is discussed. The data are useful for more precise calculations of the absorbed dose when planning radiotherapy.