title: A study of dose distribution patterns from cobalt-60 and Varian Clinac-4 beams.
abstract: Dose distribution patterns of 4 MV x-rays from a Varian Clinac 4 linear accelerator are compared with those from a 60Co teletherapy machine. Field flatteners of lead and depleted uranium were used. Dose distribution maps display the off-axis high dose or "horns" with lead filters and circular dose distribution patterns. The uranium field flattener clearly "clipped the horns" and eliminated circular dose distribution patterns with larger fields.
mesh_terms: D003037:Cobalt Radioisotopes / Q000627:therapeutic use*; D010315:Particle Accelerators; D011867:Radioisotope Teletherapy / Q000295:instrumentation*; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy
chemical_list: D003037:Cobalt Radioisotopes