The e ects of plaster on radiation doses given to patients

Abstract

The purpose of this investigation is to measure the total attenuation coe cients (TACs) of plaster materialsusing di erent geometries of the plaster, eld sizes, and photon beam energies. The percent depth dose measurementswere made using X-rays at 6 MV and 18 MV from the linear accelerator in order to plan the probable radiation dose tobe given to the patient wearing a plaster cast. The TAC was experimentally determined in solid phantoms of variousthicknesses both with and without plaster over areas of 5 5 cm2, 10 10 cm2, and 15 15 cm2. The experimentallymeasured TAC for plaster was compared to that of the NIST program. The TAC of solid phantom with plaster wasfound to be larger than without plaster. This means that dmaxis very close to the skin and that in these situationsplaster has a bolus e ect, increasing the skin's dose.