Comparison of Dose Distribution Effects for Various Bolus Materials in Electron Conformal Radiotherapy

Abstract

In this study, the effects of various bolus materials on dose distributions were compared in electronconformal radiotherapy (ECRT). Superflab, Super Stuff pink wax and Paraffin wax bolus materials areused with 15 MeV electron energy for dosimetric comparison. Additionally, 10 mm thick Super Stuff pinkwax bolus and paraffin wax bolus materials were placed on the right eyelid of a patient. Using electrondose calculation algorithm and ion chamber measurements, dosimetric comparisons were made in theEclipse treatment planning system (TPS). Both for measured and calculated dose, values were acquired 3times and averaged for each case. Resulting differences are expressed as percentage differences. Dosedifferences were obtained in measurements with and without using bolus at several locations of the solidphantom, performed by the Roos Ion chamber. Dosimetric differences of 7-7.5% for Superflab, 10-10.5%for paraffin bolus and 13-14% for Super Stuff pink wax bolus are obtained. Besides, when dosimetriccomparisons are made in the treatment planning system for cases with and without bolus; Dosedifferences were calculated to be 2-2.5% for superflab silicon bolus, 3-3.5% for paraffin wax bolus and 5-6% for Super Stuff pink wax bolus. To increase skin dose in curved anatomical structures in radiotherapy,it is safe to use the paraffin wax bolus material in radiotherapy clinic, as an alternative to Superflab siliconbolus and Super Stuff pink wax bolus materials, due to its low cost and ease of conforming to bodysurface contours.Sağlık Bilimleri Üniversitesi, Haseki Eğitim ve Araştırma Hastanesi