title: Evaluation of air photoactivation at linear accelerators for radiotherapy.
abstract: High-energy x-rays produced by radiotherapy accelerators operating at potentials above 10 MV may activate the air via (γ, n) reactions with both oxygen and nitrogen. While the activation products are relatively short-lived, personnel entering the accelerator room may inhale some radioactive air, which warrants internal dosimetry assessments. This work illustrates a method based on the use of ammonium nitrate solutions for the evaluation of photon-induced air activation and for the estimate of internal doses to radiotherapy personnel. Air activation and internal dosimetry assessments based on our method are presented for some widespread radiotherapy linear accelerator models. Our results indicate that the equivalent dose to the lungs of radiotherapy personnel is negligible for beam energies below 18 MeV.
authors.affiliation: Health Physics Unit, University-Hospital of Pisa, Via Roma 67, I-56126 Pisa, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Tana
authors.forename: Riccardo
authors.initials: R
authors.lastname: Ciolini
authors.forename: Eva
authors.initials: E
authors.lastname: Ciuffardi
authors.forename: Chiara
authors.initials: C
authors.lastname: Romei
authors.forename: Francesco
authors.initials: F
authors.lastname: d'Errico
mesh_terms: D000388:Air / Q000032:analysis; D001822:Body Burden; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008168:Lung / Q000737:chemistry*; D016273:Occupational Exposure / Q000032:analysis*; D010315:Particle Accelerators / Q000295:instrumentation*; D011829:Radiation Dosage; D000069079:Radiation Exposure / Q000032:analysis*; D011834:Radiation Monitoring / Q000295:instrumentation / Q000379:methods; D011868:Radioisotopes / Q000032:analysis*; D011878:Radiotherapy / Q000295:instrumentation*; D014965:X-Rays
chemical_list: D011868:Radioisotopes