An Analytical Expression for Generating Proton Radiographs Using Energy-Resolved Dosimetry Technique

Proton radiography is one of the promising techniques in proton therapy to reduce the range uncertainty that arises from the conversion of x-ray Hounsfield Units (HU) into relative stopping power (RSP) of protons. However, the quality of the obtained proton images is deteriorated due to the multiple Coulomb scattering (MCS) effects. There are various approaches proposed to improve the proton images and one of the recent techniques is the energy-resolved dosimetry (ERD) technique. This method uses a simple setup with a single detector and multiple beam energies to measure the dose in contrast to the tracking system which uses a complex setup with multiple detectors. The distribution of dose as a function of energy is known as the energy-resolved dose function (ERDF) which is unique for a given water equivalent path length (WEPL) and a pattern-matching algorithm is used to relate the ERDF to a specific WEPL. In this work, we tried an alternative approach to estimate WEPL using an analytical expression relating the energy, dose and the corresponding WEPL. We present the preliminary results from the generic formula in terms of the required imaging time and the accuracy in WEPL estimation.