title: Buildup factors and dose around a 137Cs source in the presence of inhomogeneities.
abstract: The effect of inhomogeneities on dose near a gamma-ray source has been investigated. Experimental measurements were made with a 137Cs source in a polystyrene phantom at a distance of 5 cm from the source. Inhomogeneities consisted of 2-cm-thick slabs interposed between the source and the plane of measurement. Dose correction factors (DCF) for 2-cm-thick aluminum, bone, lung, and air have been determined. Our results show that for 137Cs source the dose correction factors are of the order of 3% to 8%. A theoretical model for calculation of dose correction factor in brachytherapy in the presence of inhomogeneities has been developed. The model calculates DCF using buildup factors for the water-equivalent path between the source and the point of calculation. Good agreement was found between calculations and experimental measurements.
mesh_terms: D001918:Brachytherapy / Q000379:methods*; D002588:Cesium Radioisotopes; D011879:Radiotherapy Dosage
chemical_list: D002588:Cesium Radioisotopes