Validation of ELP Dosimetry Using PRESAGE Dosimeter

The purpose of this research is to validate the use of a PRESAGE dosimeter as a method to quantitatively measure dose distributions of injectable brachytherapy based on elastin-like polypeptide (ELP) nanoparticles. ELP has several useful properties for treatment purposes, including the ability to be tagged with a radioactive element, an inverse temperature phase transition useful for self-assembly into hydrophobic aggregation upon injection, and a highly tunable threshold temperature based on the amino acid composition and concentration. PRESAGE is a solid, transparent polyurethane-based dosimeter whose dose is proportional to a change in optical density, making it useful for visualizing the dose from a radionuclide-tagged-ELP injection. Initial experiments with the gel phantoms demonstrate viability for assessing I-125 dose deposition, as the image analysis showed the similar relative dose distributions compared with a MATLAB simulation.