Thermoluminescence dosimetry of model line sources containing vanadium-48

Among several types of sources used or suggested for intravascular brachytherapy (IVBT) an interesting proposition is a positron–gamma emitter, vanadium 48 V ( E max , β + 0.7 MeV, t 1 / 2 = 15.97  d), which can be produced by proton or deuteron activation of ready-to-use titanium-rich stents. Accurate mapping of doses delivered by IVBT sources is essential. In this work, dosimetry of model line sources containing 48 V was performed by means of the thermoluminescence method, aiming at high spatial resolution. The sources were made of 0.25 mm titanium wire activated with 17 MeV protons in the AIC-144 cyclotron. The radial dose distribution was measured using a batch of sandwich detectors of 2 mm diameter, with 0.05 mm MCP (LiF:Mg,Cu,P) radiation-sensitive layer. The 2-D dose distribution was mapped with a batch of large-area sintered MCP detectors of 19 mm diameter, which were further scanned on a protype 2-D thermoluminescent reader equipped with a CCD camera. Spatial resolution of both types of the detectors was sufficient to reveal anisotropies of the sources. The results were in accordance with earlier dosimetric data concerning stent-based 48 V sources. Applicability of the new detectors in mapping doses delivered by line sources is discussed.