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

Abstract

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.

Radiochromic film dosimetry of HDR 192Ir source radiation fields

“…The authors observed no significant difference between nylon catheters and a hypothetical catheter made of water. Hood et al 34 also justified the lack of a correction for the applicator material in most treatment planning systems by noting that there is no significant difference between the use of catheters and needles for interstitial brachytherapy treatments or measurements. The current work adopted the approach of Sarfehnia et al 35 where stainless steel catheters were used that did not cover the source.…”