Optimization of 68Ga production at an 18 MeV medical cyclotron with solid targets by means of cross-section measurement of 66Ga, 67Ga and 68Ga

Abstract

The future development of personalized nuclear medicine relies on the availability of novel medical radionuclides. In particular, radiometals are attracting considerable interest since they can be used to label both proteins and peptides. Among them, the β⁺-emitter ⁶⁸Ga is widely used in nuclear medicine for positron emission tomography (PET). It is used in theranostics as the diagnostic partner of the therapeutic β^--emitters ¹⁷⁷Lu and ⁹⁰Y for the treatment of a wide range of diseases, including prostate cancer. Currently, ⁶⁸Ga is usually obtained via ⁶⁸Ge/⁶⁸Ga generators. However, their availability, high price and limited produced radioactivity per elution are a major barrier for a wider use of the ⁶⁸Ga-based diagnostic radiotracers. A promising solution is the production of ⁶⁸Ga by means of proton irradiation of enriched ⁶⁸Zn liquid or solid targets. Along this line, a research program is ongoing at the Bern medical cyclotron, equipped with a solid target station. In this paper, we report on the measurements of ⁶⁸Ga, ⁶⁷Ga and ⁶⁶Ga production cross-sections using natural Zn and enriched ⁶⁸Zn material, which served as the basis to perform optimized ⁶⁸Ga production tests with enriched ⁶⁸Zn solid targets.

Keywords: Cross-section; Ga-68; Medical cyclotrons; PET; Solid target; Theranostics.