Efficiency of ¹²⁴I radioisotope production from natural and enriched tellurium dioxide using ¹²⁴Te(p,xn)¹²⁴I reaction.

Abstract

Background ¹²⁴I Iodine (T[Formula: see text] = 4.18 d) is the only long-life positron emitter radioisotope of iodine that may be used for both imaging and therapy as well as for ¹³¹I dosimetry. Its physical characteristics permits taking advantages of the higher Positron Emission Tomography (PET) image quality, whereas the availability of new molecules to be targeted with ¹²⁴I makes it a novel innovative radiotracer probe for a specific molecular targeting. Results In this study Monte Carlo and SRIM/TRIM modelling was applied to predict the nuclear parameters of the ¹²⁴I production process in a small medical cyclotron IBA 18/9 Cyclone. The simulation production yields for ¹²⁴I and the polluting radioisotopes were calculated for the natural and enriched ¹²⁴TeO₂ + Al₂O₃ solid targets irradiated with 14.8 MeV protons. The proton beam was degraded energetically from 18 MeV with 0.2 mm Havar foil. The ¹²⁴Te(p,xn)¹²⁴I reactions were taken into account in the simulations. The optimal thickness of the target material was calculated using the SRIM/TRIM and Geant4 codes. The results of the simulations were compared with the experimental data obtained for the natural TeO₂ +Al₂O₃ target. The dry distillation technique of the 124-iodine was applied. Conclusions The experimental efficiency for the natural Te target was better than 41% with an average thick target (>0.8 mm) yield of 1.32 MBq/μAh. Joining the Monte Carlo and experimental approaches makes it possible to optimize the methodology for the ¹²⁴I production from the expensive Te enriched targets.