Berlin 2024 – scientific programme

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ST: Fachverband Strahlen- und Medizinphysik

ST 2: Radiation Therapy I

ST 2.3: Talk

Tuesday, March 19, 2024, 10:30–10:45, PC 203

Total Reaction Cross Section Measurements for Proposed Technique in Proton Therapy Range-Verification — •Laila Weisel, Devin Hymers, Markus Schiffer, and Dennis Mücher — Institut für Kernphysik, Universität zu Köln, Köln, Germany

The use of proton beams in cancer treatment offers significant advantages compared to photon therapy due to their depth-dose distribution which is characterized by a small entrance dose and a sharp maximum at the Bragg peak. To ensure the prescribed dose is properly delivered, precise knowledge of beam range in the patient is required. A proposed technique for in vivo range verification by Kasanda et al. [1] uses an implanted hadron tumor marker (HTM) which emits characteristic γ-rays when activated by the treatment beam, with intensities which are maximized for energies near the Bragg peak. Previous investigations, which used an HTM consisting of two materials, have demonstrated a sub-milimeter precision in range verification. The ratio of the γ-ray yield from two reactions of interest ⁸⁹Y(p,n)⁸⁹Zr and ⁹²Mo(p,n)⁹²Tc has been measured for different initial proton beam energies. In previous experiments the γ-ray ratios were related to a beam energy at the marker position by using calculated reaction cross sections. In order to obtain a more precise calibration of the correspondence between γ-ray ratios and energy, an experimental setup is currently being finalized at the Cologne 10 MV tandem accelerator, to measure the total cross sections in small energy steps. The status of these measurements and preliminary results will be presented.

[1] E Kasanda et al 2023 Phys. Med. Biol. 68 185005

Keywords: Proton Therapy; Range-Verification