title: Build-up effects at air cavities measured with thin thermoluminescent dosimeters.
abstract: The build-up and build-down situation around air cavities of various size in a polystyrene phantom was evaluated by measurements with LiF-Teflon disks with a thickness of about 1.6 X 10(-2) kg/m2. The measurements demonstrate that when irradiating with two opposed beams the surface dose at the cavity (depth 39 mm) is 74% of the maximum dose for 60 Co, 77% for 6 MV and 87% for 42 MV roentgen radiation.
mesh_terms: D000388:Air; D003037:Cobalt Radioisotopes; D005720:Gamma Rays; D008961:Models, Structural; D011867:Radioisotope Teletherapy; D011879:Radiotherapy Dosage; D012142:Respiratory Tract Neoplasms / Q000532:radiotherapy*; D013819:Thermoluminescent Dosimetry
chemical_list: D003037:Cobalt Radioisotopes