Preliminary results of the experimental cross sections of the long-lived β⁺ emitters of interest in PET range verification in proton therapy at clinical energies

¹ Dept. de Física Atómica, Molecular y Nuclear. Universidad de Sevilla. Avda. Reina Mercedes s/n, Seville 41012, Spain.
² Centro Nacional de Aceleradores (Universidad de Sevilla-Junta de Andalucía-CSIC). C/ Thomas Alva Edison 7, Seville 41092, Spain.
³ TU Dortmund University, Faculty of Physics, Otto-Hahn-Str. 4a, D-44227 Dortmund, Germany.
⁴ West German Proton Therapy Centre Essen, Hufelandstr. 55, D-45147 Essen, Germany.
⁵ West German Cancer Center, Hufelandstr. 55, D-45147 Essen, Germany.
⁶ University Hospital Essen, Hufelandstr. 55, D-45147 Essen, Germany.
⁷ German Cancer Consortium (DKTK), Heidelberg, Germany.
⁸ University Hospital Essen, Clinic for Nuclear Medicine, Hufelandstr. 55, D-45147 Essen, Germany.
⁹ University Hospital Essen, Department of Particle Therapy, Hufelandstr. 55, D-45147 Essen, Germany.

^* Corresponding author: mrodriguezg@us.es
^** Corresponding author: cguerrero4@us.es

Published online: 11 April 2022

Abstract

In proton therapy, offline PET range verification requires a comparison of the measured and expected β⁺ activity distributions produced by the proton field in the body, looking at the the long-lived β⁺ emitters. The reliability of the expected activity distributions depends on the Monte Carlo simulations and hence on the accuracy of the underlying cross section data. However, several studies confirm the need for more and better measurements and evaluations of these cross sections.

In this work, the employed method to measure the production yields of the long-lived β⁺ emitters of interest in PET range verification ¹¹C (t_1/2 = 20 min), ¹³N (t_1/2 = 10 min) and ¹⁵O (t_1/2 = 2 min) in C, N and O is presented. The method combines the multi-foil activation technique with the subsequent measurement of the induced activity in a clinical PET scanner. The preliminary results of the¹²C(p,pn)¹¹C reaction cross sections is presented.