Methods of Dosimetry and Treatment Planning for Second Generation Linear Sources

Transperineal interstitial permanent prostate brachytherapy is the preferred choice of a large proportion of patients diagnosed with prostate carcinoma. Despite the remarkable success of this approach, the technique and the current generation sources suffer from a number of deficiencies, such as nligration, lack of precision for placement of the seeds, and difficulty in achieving the targeted dose volume histogram (DVH). The second-generation linear brachytherapy sources based on I03Pd isotopes, currently under development, are specifically designed to address the above-identified shortcomings. These sources are in the form of a wire, are extremely flexible, have a uniform activity, have a very thin profile, and can be cut to any desired length. For success of second-generation linear brachytherapy sources, there is a need to perform accurate dosimetry for dose planning and design an improved treatment planning program. The current proposal addresses dosimetry issues associated with these new sources. Dosimetry of the wires has been performed for sources with only 3.5% of the required activity. This program will extend the previous dosimetry of the linear source from low-intensity prototypes to full-strength sources. This information is of vital interest for performing any anima! or clinical studies prior to release and market launch of this product.