Experimental and Monte Carlo determination of the TG-43 dosimetric parameters for the model 9011 THINSeed brachytherapy source.

PURPOSE: AAPM TG-43 brachytherapy dosimetry parameters for a new, smaller diameter 1251 brachytherapy source (THINSeed, model 9011) were determined using LiF:Mg,Ti thermoluminescent dosimeter (TLD-100) microcubes and Monte Carlo simulations.
METHODS: Two polymethyl methacrylate phantoms were machined to hold TLD-100 microcubes at specific locations for the experimental determination of the radial dose function, dose-rate constant, and anisotropy functions of the new source. The TG-43 parameters were also calculated using Monte Carlo simulations. For comparison, the model 6711 source was also investigated.
RESULTS: Experimental results for both models 9011 and 6711 sources showed good agreement with Monte Carlo values, as well as with previously published values.
CONCLUSIONS: The TG-43 parameters for the new source model are similar to those of model 6711; however, they represent two separate sources and TG-43 parameters used in treatment planning must be source specific.