title: Field separation of adjoining therapy fields.
abstract: The question of optimal portal separation between two contiguous fields is of importance in radiotherapy. An analytical linear model based on experimental data has been developed for a Co-60 unit (Siemens Gammatron S 65 K). It allows the computation of the separation distance for any combination of field sizes not necessarily having the same source-surface-distance, defined either with penumbra trimmers or focused shaping blocks.
mesh_terms: D003037:Cobalt Radioisotopes / Q000627:therapeutic use; D006801:Humans; D011867:Radioisotope Teletherapy / Q000379:methods; D011874:Radiometry / Q000379:methods*; D011878:Radiotherapy / Q000379:methods*; D011879:Radiotherapy Dosage
chemical_list: D003037:Cobalt Radioisotopes