Liquid helium calorimetry and energy-based dosimetry for low-energy brachytherapy sources

Graduate Investigator: Martha Malin

Summary of Research: Calorimetric determination of low-energy brachytherapy source strength has remained elusive due to the small size of the anticipated signal, but a liquid helium calorimetry system at the UWMRRC is currently capable of measuring the total energy released from a low-energy brachytherapy source due to radioactive decay (called contained power). This work involves redesigning the calorimeter for measurements of the portion of the contained power that escapes the seed cladding and delivers dose to the patient (called emitted power). Characterizing a seed by the emitted power and spectroscopic output provides sufficient data to compute the dose to a medium of interest from the seed through Monte Carlo or Boltzman-based solvers. Along with the emitted power measurements, this work explores the potential and feasibility of a new energy-based dosimetry formalism to provide improved and more direct input parameters for complex treatment planning.