THE ELECTRON BEAM ATTENUATING PROPERTIES OF SUPERFLAB, PLAY-DOH, AND WET GAUZE, COMPARED TO PLASTIC WATER

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Address correspondence and reprint request to Koichi Nagata, Pittsburgh Veterinary Specialty and Emergency Center, 807 Camp Horne Road, Pittsburgh, PA 15237. E-mail: knagat@hotmail.com

Abstract

Bolus material is used commonly with electron treatments. The purpose of this study was to compare the electron beam attenuating properties of SuperFlab, Play-Doh, and wet gauze to that of plastic water, and evaluate their characteristics as bolus materials for electron beam therapy. Electron beams of 5, 6, 7, 8, 10, and 12 MeV were used. Dose reduction from a range of bolus thicknesses from 2 mm to a thickness well beyond the thickness required to reach peak ioization was measured for each of the bolus materials to establish independent isodose curves. Measurements performed at the known water Dmax for all bolus materials indicated similar results for SuperFlab and plastic water with less than 3% difference for most energies. Play-Doh resulted in more attenuation or less dose buildup compared with plastic water, especially at lower energies. The difference was as high as 24.7% for the beam energy of 5 MeV for Play-Doh. Evaluation of the dose build up curves for all materials indicated the peak dose build up for wet gauze and Play-Doh occurred at lesser thicknesses compared to plastic water and SuperFlab, particularly at lower energies. If Play-Doh and wet gauze are to be used for electron bolus materials, dose build up curves should be established for the machine being used and the appropriate thickness of bolus material be chosen based on those curves.

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