The innovative $^{52g}$Mn for PET imaging: production cross section modeling and dosimetric evaluation

Background: Recently, the reaction $^{nat}$V($\alpha$,x)$^{52g}$Mn has been proposed as a possible alternative to the standard $^{nat}$Cr($p$,x)$^{52g}$Mn one, but improvements in the modeling were needed to better compare the two production routes. Purpose: This work focuses on the development of precise simulations and models to compare the $^{52g}$Mn production from both reactions in terms of amount of activity and radionuclidic purity (RNP), as well as in terms of dose increase (DI) due to the co-produced radioactive contaminants, with respect to a pure $^{52g}$MnCl$_2$ injection. Methods: The nuclear code Talys has been employed to optimize the $^{nat}$V($\alpha$,x)$^{52g}$Mn cross section by tuning the parameters of the microscopic level densities. Dosimetric assessments of [$^{xx}$Mn]Cl$_2$ have been accomplished with OLINDA software 2.2.0 using female and male phantoms. At the end, the yield of $^{xx}$Mn radioisotopes estimated for the two production routes have been combined with the dosimetric results, to assess the DI at different times after the end of the irradiation. Results: Good agreement was obtained between cross sections calculations and measurements. The comparison of the two reaction channels suggests that $^{nat}$V($\alpha$,x)$^{52g}$Mn leads to higher yield and higher purity, resulting in a less harmful impact on patients' health in terms of DI. Conclusions: Both $^{nat}$V($\alpha$,x) and $^{nat}$Cr($p$,x) production routes provide clinically acceptable $^{52g}$MnCl$_2$ for PET imaging. However, the $^{nat}$V($\alpha$,x)$^{52g}$Mn reaction provides a DI systematically lower than the one obtainable with $^{nat}$Cr($p$,x)$^{52g}$Mn and a longer time window in which it can be used clinically (RNP $\ge$ 99\%).