OPTIma: simplifying calorimetry for proton computed tomography in high proton flux environments

Phys Med Biol. 2024 Feb 12. doi: 10.1088/1361-6560/ad2883. Online ahead of print.ABSTRACTOBJECTIVE: Proton computed tomography (pCT) offers a potential route to reducing range uncertainties for proton therapy treatment planning, however the current trend towards high current spot scanning treatment systems leads to high proton fluxes which are challenging for existing systems. Here we demonstrate a novel approach to energy reconstruction, referred to as "de-averaging", which allows individual proton energies to be recovered using only a measurement of their integrated energy without the need for spatial information from the calorimeter.APPROACH: The method is evaluated in the context of the OPTIma (Optimising Proton Therapy through Imaging) system which uses a simple, relatively inexpensive, scintillator based calorimeter that reports only the integrated energy deposited by all protons within a cyclotron period, alongside a silicon strip based tracking system capable of reconstructing individual protons in a high flux environment. GEANT4 simulations have been performed to examine the performance of such a system at a modern commercial cyclotron facility using a σ ≈ 10mm beam for currents in the range 10-50 pA at the nozzle.MAIN RESULTS: Apart from in low-density lung tissue, a discrepancy of less than 1% on the Relative Stopping Power is found for all other considered tissues when embedded within a 150 mm spherical Perspex phantom in the 10-30 pA current range, and for som...
Source: Physics in Medicine and Biology - Category: Physics Authors: Source Type: research