DOSE AND GAMMA-RAY SPECTRA FROM NEUTRON-INDUCED RADIOACTIVITY IN MEDICAL LINEAR ACCELERATORS FOLLOWING HIGH-ENERGY TOTAL BODY IRRADIATION

作者：Keehan S^*; Taylor M L; Smith R L; Dunn L; Kron T; Franich R D

来源：Radiation Protection Dosimetry, 2016, 172(4): 327-332.

DOI：10.1093/rpd/ncv480

Production of radioisotopes in medical linear accelerators (linacs) is of concern when the beam energy exceeds the threshold for the photonuclear interaction. Staff and patients may receive a radiation dose as a result of the induced radioactivity in the linac. Gamma-ray spectroscopy was used to identify the isotopes produced following the delivery of 18 MV photon beams from a Varian 21EX and an Elekta Synergy. The prominent radioisotopes produced include W-187, Zn-63, Mn-56, Na-24 and Al-28 in both linac models. The dose rate was measured at the beam exit window (12.6 mu Sv in the first 10 min) following 18 MV total body irradiation (TBI) beams. For a throughput of 24 TBI patients per year, staff members are estimated to receive an annual dose of up to 750 mSv at the patient location. This can be further reduced to 65 mSv by closing the jaws before re-entering the treatment bunker.

• 出版日期2016-12-2