UC Irvine

This thesis introduces the novel concepts of FLASH proton therapy and the use of Protoacoustics for in vivo dosimetry. FLASH proton therapy applies ultra-high dose rates to radiation therapy, which is beneficial in tissue sparing compared to conventional radiation therapy. By combining this characteristic with the elusive Bragg peak found in proton therapy, a highly effective therapy is formed. However, there is a need for a dosimeter that can accurately pinpoint and quantify the dose. In the text, current dosimeters are discussed as well as the trade-offs, leading into the significance of protoacoustics. Protoacoustics, which takes the concepts of radiation acoustics, is investigated through multiple simulation works, specifically in the context of FLASH proton therapy. Using the k-Wave toolbox in MATLAB, the protoacoustic signal amplitude was compared to changes in first the dose per pulse, then in pulsewidth. The relationship between the parameters were investigated and protoacoustic reconstructions were performed as well. The novel concept of spatially fractioned radiation therapy (SFRT) was also investigated in the form of Lattice Radiation Therapy (LRT) through a multibeam spot simulation. 3D reconstructions with varied pulse widths were observed for the spatial resolution and the feasibility of 3D imaging with protoacoustics.