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Dose perturbations at interfaces in photon beams: Annihilation radiation
Author(s) -
Werner Barry L.
Publication year - 1991
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.596664
Subject(s) - annihilation , photon , physics , radiation , dosimetry , optics , medical physics , nuclear physics , nuclear medicine , medicine
A model is presented for estimating the contribution of annihilation radiation to the dose perturbation at interfaces between high and low atomic number materials. The contribution is small, but not negligible relative to the total interface dose perturbation. The maximum contribution occurs for photon beams of about 8 MeV in energy. For an 8‐MeV beam passing first through lead, then through polystyrene, the annihilation radiation contribution to the interface dose perturbation is about 8%, at a copper/polystyrene interface, the contribution is about 7%, and at an aluminum/polystyrene interface, the contribution is about 3%.