Accelerator-based photoproduction of promising beta-emitters ⁶⁷Cu and ⁴⁷Sc

In this paper we discuss our experimental work in photoproducing two medically-useful radioisotopes (⁶⁸Zn(γ,p) ⁶⁷Cu and ⁴⁸Ca(γ,n)⁴⁷Ca → ⁴⁷Sc) using an electron linear accelerator. We further address the issues of production and separation of medical isotopes arising from photoneutron (γ,n) and photoproton (γ,p) reactions. While (γ,n) reactions typically result in greater yields, separating product nuclides from the target is challenging since the chemical properties of both nuclides are identical. Although the yields of (γ,p) reactions are typically lower than for (γ,n), these proton-rich isotopes have the advantage that target and product nuclides belong to different chemical species allowing for more straightforward chemical separation. We conclude the paper by touching upon the dire necessity of experimentally revisiting a broad swath of photonuclear reactions in the 10- to 50-MeV regime. The very paucity of empirical cross-sectional data makes it altogether impossible to realistically predict accelerator-based photoproduction of many promising radiopharmaceuticals. (author)