Nuclear excitation functions for medical isotope production: targeted radionuclide therapy via natIr(d,x)193mPt

TL;DR

This study measures deuteron-induced reaction cross sections on natural iridium and other metals to optimize production of the therapeutic radionuclide 193mPt, revealing gaps in nuclear reaction models and suggesting improved data for medical isotope manufacturing.

Contribution

It provides new experimental cross section data for natIr(d,x) reactions, compares these with models, and highlights deficiencies in current nuclear reaction codes for medical isotope production.

Findings

Identified an optimal energy window (11-18 MeV) for 193mPt production.

First experimental cross sections for several deuteron-induced reactions on iridium, nickel, copper, and iron.

Revealed limitations of existing nuclear reaction models in predicting experimental data.

Abstract

193mPt is an Auger emitting radionuclide which may have therapeutic potential, particularly when labeled to the chemotherapeutic drug cisplatin. One challenge to broader explorations of its clinical potential is the need for production routes with high specific activity. As part of a larger campaign to address gaps in reaction data for emerging medical radionuclides, this work seeks to characterize the natIr(d,x) reactions as a potential production pathway for 193mPt. A stacked target irradiation, consisting of natural iridium, iron, nickel, and copper foils, was performed using a 33 MeV deuteron beam at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. This measurement, along with previous experimental data, suggests an energy window between 11 to 18 MeV to maximize the production and radiopurity of 193mPt. This experiment has yielded cross sections for 43 channels of deuteron-induced reactions from threshold to 30 MeV, including the first experimental results of natIr(d,x)188m1+g,190m1+gIr (cumulative), natNi(d,x)56,57,58m,58gCo (independent), natCu(d,x)61Co (cumulative) and natFe(d,x)53Fe, 48V (cumulative). The results were compared with literature data, the TENDL-2023 database, and default theoretical calculations from the TALYS-2.04, CoH-3.6.0, EMPIRE-3.2.3, and ALICE-2020 reaction modeling codes. This work presents another example of the lack of predictive capabilities for this set of modern nuclear-reaction modeling codes, and highlights the unsatisfactory modeling of experimental cross sections. Experimental data are important to improve the codes in general, and new experimental results can be used to improve the models. Finally, this measurement has revealed the need for an updated evaluation of the natCu(d,x)63Zn deuteron monitor reaction.