title: Tissue-air ratios for cobalt 60 therapy units.
abstract: Tissue-air ratio (TAR) is the widely used dosimetric parameter for treatment planning in radiation therapy. Comparison of the measured TAR values of 19 60Co therapy units of eight different types was made with the widely used tabulated data of Gupta & Cunningham (1966). The experimental data, and the analysis of the variation in the TAR values caused by individual, unit by unit features, show that discrepancies may be up to +/- 4%.
mesh_terms: D000388:Air; D003037:Cobalt Radioisotopes / Q000627:therapeutic use*; D006801:Humans; D008961:Models, Structural; D010347:Patient Care Planning; D011867:Radioisotope Teletherapy / Q000379:methods*; D011879:Radiotherapy Dosage; D012016:Reference Values; D014867:Water
chemical_list: D003037:Cobalt Radioisotopes; D014867:Water