Feasibility study of the photonuclear reaction cross section of medical radioisotopes using a laser Compton scattering gamma source

In recent years,the gap between the supply and demand of medical radioisotopes has increased,necessitating new methods for producing medical radioisotopes.Photonuclear reactions based on gamma sources have unique advantages in terms of producing high specific activity and innovative medical radioisotopes.However,the lack of experimental data on reaction cross sections for photonuclear reactions of medical radioisotopes of interest has severely limited the development and production of photonuclear transmutation medical radioisotopes.In this study,the entire process of the generation,decay,and measurement of medical radioisotopes was simulated using online gamma activation and offline gamma measurements combined with a shielding gamma-ray spectrometer.Based on a quasi-monochromatic gamma beam from the Shanghai Laser Electron Gamma Source(SLEGS),the feasibility of this measurement of production cross section for surveyed medi-cal radioisotopes was simulated,and specific solutions for measuring medical radioisotopes with ultra-low production cross sections were provided.The feasibility of this method for high-precision measurements of the reaction cross section of medical radioisotopes was demonstrated.

Simulating the Production of Medical Radioisotopes in a Fast Thorium-Cycle ADS with SERPENT

Radiopharmaceuticals are used in nuclear medicine for diagnostic or therapeutic acts. The short decay half-lives of medical radioisotopes, especially those used for diagnostics, imply that they should be produced continuously and transported as quickly as possible to the medical units where they are used. Neutron-rich medical radioisotopes are generally produced in research reactors, like technetium-99m, lutetium-177, holmium-166 and iodine-131. On the other hand, proton-rich radioisotopes are produced via reactions with charged particles from accelerators like fluorine-18, gallium-67, iodine-123 and thallium-201. Beside this, innovative nuclear reactors are advocated as solutions to the issues of nuclear waste production and proliferation threats. Fast neutron, thorium-cycle and accelerator-driven subcritical (ADS) reactors are some of the most promising of them, proposed as safer fuel breeders and “waste burners”. This article examines the use of a fast thorium-cycle ADS with liquid lead-bismuth eutectic coolant for the production of molybdenum-99/technetium-99m and lutetium-177. Burnup simulation has been made with the Monte-Carlo (MC) code SERPENT. It is demonstrated that MC codes can advantageously be used to determine the optimal irradiation time for a given radioisotope in a realistic reactor core. It is also shown that fast thorium-cycle ADS is an economical option for the production of medical radioisotopes.

Progress of photonuclear cross sections for medical radioisotope production at the SLEGS energy domain

Photonuclear reactions using a laser Compton scattering(LCS)gamma source provide a new method for producing radioisotopes for medical applications.Compared with the conventional method,this method has the advantages of a high specific activity and less heat.Initiated by the Shanghai Laser Electron Gamma Source(SLEGS),we conducted a survey of potential photonuclear reactions,(γ,n),(γ,p),and(γ,γ')whose cross sections can be measured at SLEGS by summarising the experimental progress.In general,the data are rare and occasionally inconsistent.Therefore,theoretical calculations are often used to evaluate the production of medical radioisotopes.Subsequently,we verified the model uncertainties of the widely used reaction code TALYS-1.96,using the experimental data of the^(100)Mo(γ,n)^(99)Mo,^(65)Cu(γ,n)^(64)Cu,and^(68)Zn(γ,p)^(67)Cu reactions.

Feasibility study of laser-driven neutron sources for pharmaceutical applications

We predict the production yield of a medical radioisotope^(67)Cu using^(67)Zn(n,p)^(67)Cu and ^(68)Zn(n,pn)^(67)Cu reactions with fast neutrons provided from laser-driven neutron sources.The neutrons were generated by the p+9Be and d+9Be reactions with high-energy ions accelerated by laser–plasma interaction.We evaluated the yield to be(3.3±0.5)×10^(5) atoms for^(67)Cu,corresponding to a radioactivity of 1.0±0.2 Bq,for a Zn foil sample with a single laser shot.Using a simulation with this result,we estimated^(67)Cu production with a high-frequency laser.The result suggests that it is possible to generate^(67)Cu with a radioactivity of 270 MBq using a future laser system with a frequency of 10 Hz and 10,000-s radiation in a hospital.