title: Tissue-air ratios for narrow 60Co gamma-ray beams.
abstract: This study introduces a table of tissue-air ratios (TAR) for narrow 60Co gamma-ray beams. The table is consistent with recently published TAR data for broad 60Co gamma-ray beams [Table 4.1, Br. J. Radiol. Suppl. 25 (1996)]. Narrow-beam TARs are derived analytically from broad-beam data of Table 4.1 and are tabulated for circular fields ranging from 0.2 to 2.2 cm in radius--an approximate equivalent of a 0.4 cm x 0.4 cm to 4 cm x 4 cm square-field range. The extent of depth is from 0.5 to 30 cm in water.
authors.affiliation: Baylor College of Medicine, Department of Radiology, Houston, Texas, USA. pnizin@bcm.tmc.edu
authors.forename: P S
authors.initials: PS
authors.lastname: Nizin
authors.forename: R B
authors.initials: RB
authors.lastname: Mooij
mesh_terms: D000388:Air; D003037:Cobalt Radioisotopes / Q000627:therapeutic use*; D005720:Gamma Rays / Q000627:therapeutic use*; D006801:Humans; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D012542:Scattering, Radiation
chemical_list: D003037:Cobalt Radioisotopes