Experimental evaluation of scattered X-ray spectra due to X-ray therapeutic and diagnosis equipment for eye lens dosimetry of medical staff

Kowatari, Munehiko*; Nagamoto, Keisuke*; Nakagami, Koichi*; Tanimura, Yoshihiko   ; Moritake, Takashi*; Kunugita, Naoki*

For proper monitoring of the eye lens dose, an appropriate calibration factor of a dosimeter and information about the mean energies of X-rays are indispensable. The scattered X-ray energy spectra should be well characterized in medical practices where eye lenses of medical staffs might be high. Scattered X-ray energy spectra were experimentally derived for three different types of X-ray diagnostic and therapeutic equipment. A commercially available CdZnTe (CZT) spectrometer with a lead collimator was employed for the measurement of scattered X-rays. From the obtained energy spectra, the mean energies of the scattered X-rays lied between 40 and 60 keV. This also agreed with that obtained by the conventional half value layer method. The obtained mean energies of the scattered X-rays were found to match the flat region of the dosimeter response.