title: DOSE AND GAMMA-RAY SPECTRA FROM NEUTRON-INDUCED RADIOACTIVITY IN MEDICAL LINEAR ACCELERATORS FOLLOWING HIGH-ENERGY TOTAL BODY IRRADIATION.
abstract: 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 include187W,63Zn,56Mn,24Na and28Al in both linac models. The dose rate was measured at the beam exit window (12.6 µSv 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 μSv at the patient location. This can be further reduced to 65 μSv by closing the jaws before re-entering the treatment bunker.
authors.affiliation: School of Applied Sciences, RMIT University, Melbourne, Australia stephanie.keehan@rmit.edu.au.
authors.forename: S
authors.initials: S
authors.lastname: Keehan
authors.affiliation: School of Applied Sciences, RMIT University, Melbourne, Australia.
authors.forename: M L
authors.initials: ML
authors.lastname: Taylor
authors.affiliation: School of Applied Sciences, RMIT University, Melbourne, Australia.|William Buckland Radiotherapy Centre, Alfred Hospital, Melbourne, Australia.
authors.forename: R L
authors.initials: RL
authors.lastname: Smith
authors.affiliation: Australian Clinical Dosimetry Service, ARPANSA, Yallambie, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Dunn
authors.affiliation: School of Applied Sciences, RMIT University, Melbourne, Australia.|Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Kron
authors.affiliation: School of Applied Sciences, RMIT University, Melbourne, Australia.
authors.forename: R D
authors.initials: RD
authors.lastname: Franich
mesh_terms: D005720:Gamma Rays; D006282:Health Personnel; D006801:Humans; D009010:Monte Carlo Method; D009502:Neutrons / Q000009:adverse effects*; D016273:Occupational Exposure / Q000032:analysis* / Q000517:prevention & control*; D010315:Particle Accelerators / Q000295:instrumentation*; D017785:Photons; D011834:Radiation Monitoring; D011835:Radiation Protection; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy / Q000009:adverse effects*; D018570:Risk Assessment; D014916:Whole-Body Irradiation / Q000379:methods*