Experimental study and simulation of 63Zn production via proton induce reaction

Expanding the PET radioisotope universe utilizing solid targets on small medical cyclotrons

Molecular imaging with medical radioisotopes enables the minimally-invasive monitoring of aberrant biochemical, cellular and tissue-level processes in living subjects. The approach requires the administration of radiotracers composed of radioisotopes attached to bioactive molecules, the pairing of which considers several aspects of the radioisotope in addition to the biological behavior of the targeting molecule to which it is attached. With the advent of modern cellular and biochemical techniques, there has been a virtual explosion in potential disease recognition antigens as well as targeting moieties, which has subsequently opened new applications for a host of emerging radioisotopes with well-matched properties. Additionally, the global radioisotope production landscape has changed rapidly, with reactor-based production and its long-defined, large-scale centralized manufacturing and distribution paradigm shifting to include the manufacture and distribution of many radioisotopes via a worldwide fleet of cyclotrons now in operation. Cyclotron-based radioisotope production has become more prevalent given the commercial availability of instruments, coupled with the introduction of new target hardware, process automation and target manufacturing methods. These advances enable sustained, higher-power irradiation of solid targets that allow hospital-based radiopharmacies to produce a suite of radioisotopes that drive research, clinical trials, and ultimately clinical care. Over the years, several different radioisotopes have been investigated and/or selected for radiolabeling due to favorable decay characteristics (i.e. a suitable half-life, high probability of positron decay, etc.), well-elucidated chemistry, and a feasible production framework. However, longer-lived radioisotopes have surged in popularity given recent regulatory approvals and incorporation of radiopharmaceuticals into patient management within the medical community. This review focuses on the applications, nuclear properties, and production and purification methods for some of the most frequently used/emerging positron-emitting, solid-target-produced radioisotopes that can be manufactured using small-to-medium size cyclotrons (≤24 MeV).

Determination of scale deposition in a flare line by neutron back-diffusion

Flares are used in the oil industry and other industries to dispose of waste gasses by burning. Damaged or blocked flares can lead to incomplete combustion and the release of contaminating gasses into the atmosphere. In this study, the neutron back-diffusion technique was used to measure the scale inside a flare stack. The neutron source employed was ²⁴¹Am-Be with an activity of 1.11 × 10¹¹ Bq (3 Ci), and a BF₃ slow neutron detector. Scanning was conducted for scale in the stack at a refinery. Back-diffused neutron counts were doubled when moving from no scale to a scale thickness of about 17 cm. The scale thickness measured up to 20 cm and a change in the thickness of about 0.25 cm could be detected in a counting time of 1 min. The counting system weighed about 3 kg and it allowed scanning at a high stack elevation. The source employed yielded a total dose of 0.12 mSv h^-1 at 1 m, which is significantly smaller than the doses from sources used in industrial radiography.

Investigation of the thermal performance of natCu target for 63Zn production

The flow rate of coolant and the particle beam current are important when high beam current irradiations are intended for production of radionuclides. The beam current on ^natCu target to produce ⁶³Zn via the ^natCu(p,n)⁶³Zn reaction was investigated and the beam current was obtained more than 350 μA that is the maximum allowed beam current used for producing medical radioisotopes in Nuclear Science and Technology Research Institute of Iran. In addition, the temperature distribution on the target under the different cooling water flow rates has been simulated based on finite element analysis program. The results show that the cooling water flow rate can be brought down to 1.5 L/min without the risk of melting of target material and boiling water.