Appraisal and simulation of 125I production yield with Low/Medium energy proton and deuteron particles on tellurium targets

Abstract

Background

The radioisotope iodine-125 has been proposed for use in brachytherapy in nuclear medicine. Currently, ¹²⁵I is mainly produced by neutron irradiation of xenon gas in nuclear reactors, although cyclotron-based production can also be investigated.

Methods

In this research, the cyclotron in Karaj with deuteron energy of 20 MeV and proton energy of 30 MeV was considered to simulate the production of ¹²⁵I using ^124/125Te targets. Here, the ¹²⁵Te(p,n)¹²⁵I and ¹²⁴Te(d,n)¹²⁵I reactions cross sections were analyzed via TALYS code in optical potential model by changing diffusivity and radius, level density model, density of exciton model constituents, pre-equilibrium and equilibrium model by Hauser-Feshbach formalism, branching rates, and possibility of derived particle generation. Additionally, the cross section of ¹²⁶Te(p,2n)¹²⁵I reaction was evaluated besides the cross sections of competing reactions. The production yields of the two types of interactions were calculated at different incident particles energies.

Results

The maximum cross-section data for ¹²⁵I production via (p,n) reaction was estimated to be 684 mb at 11 MeV and for the (d,n) reaction to be 233 mb at 9 MeV. These reactions gave the ¹²⁵I production yield of 1.22 and 0.188 MBq/µA.h at these energies, respectively. The calculated cross-sections data for both incident particles energies were plotted and compared with other reports. In curve fitting, the least-square Pade approximation was used with distinct parameters on designated points with χ2 of 0.98 and 0.87 for (d,n) and (p,n) reactions, correspondingly. The maximum uncertainty was estimated to be 6.5 % for 12 MeV deuterons and 12.9 % for 9 MeV protons.

Conclusion

The combination of ¹²⁵I with other therapeutic radionuclides such as gold and terbium may improve the chances of treatment by increasing the rate of cancer cell killing. Remarkably, the integration of therapy and diagnosis can represent a significant advance in tailored cancer treatment.