Miniature LiF:Mg,Cu,P TLDs to study the effect of applicator material in 192-Ir brachytherapy

Dose calculations in brachytherapy planning typically don't take into account inhomogeneities and the material of applicators. We evaluated the justification of the latter by investigating the dose delivered in 192-Ir interstitial implants employing plastic catheters and steel needles using miniature LiF:Mg,Cu,P thermoluminescence dosimeters (TLDs) which fit in the applicators. Within the uncertainty of the measurement (+/- 5%) no difference could be found in the dose distribution from 192Ir in steel needles or plastic catheters. Computerized treatment planning (Philips/ADAC Pinnacle) was in good agreement with the measured data.