Novel Production Methods of Medical Isotopes: Securing Canada's Supply Chain

放射性同位素构成所有核成像和治疗性核医学应用的支柱。从历史上看，加拿大在国内和国际上的生产和供应中发挥了关键作用。最常见的核成像同位素Tc-99 m每天用于75，000名患者。世界上大约40%的Tc-99 m供应是在安大略乔克河的核反应堆生产的。最近加拿大反应堆与其他三个设施的停机时间，共同供应了全球90%以上的需求，造成了世界范围的“同位素危机”-延迟了各种疾病患者的成像和治疗。为了避免这种情况在未来发生，加拿大政府要求加拿大研究界调查替代同位素生产。有几种解决方案是可能的，由温哥华的TRIUMF领导的低能量回旋加速器（< 30 MeV）的路线非常有前途，并于2015年获得NSERC Brockhouse奖。现在，加拿大各地已经资助和建造了许多新的回旋加速器设施，从而有可能为当地研究团体提供同位素。拟议的研究计划利用日益增加的医用回旋加速器，并调查用于制造这些同位素的目标。特别是，它着眼于为什么液体和气体目标的放射性同位素产量往往远低于理论上可实现的产量。我们假设，在液体和气体中发生的传输现象正在影响可采产量。因此，该计划通过模拟和实验研究质子轰击下液体和气体靶中发生的传输现象。这个问题福尔斯属于广泛的一类流体-固体相互作用的传输现象的文献中发现的问题。使这个问题特别困难的是，在反应速率和流体性质之间存在双向耦合。拟议计划的愿景是为现有的医用同位素开发新的生产解决方案，并使新的和新兴的同位素的生产成为可能。

Radioisotopes form the backbone of all nuclear imaging and therapeutic nuclear medicine applications. Historically, Canada has played a key role in its production and supply at home as well as internationally. The most common nuclear imaging isotope, Tc-99m, is used on 75,000 patients daily. Around 40% of the world's supply of Tc-99m is being produced at the nuclear reactor in Chalk River, Ontario. The recent down time of the Canadian reactor with the three other facilities that together supply more than 90% of the global demand caused a worldwide ‘isotope crisis' - delaying imaging and treatment of patients with a variety of illnesses. To avoid this scenario in the future, the Canadian government asked the Canadian research community to investigate alternative isotope production. Several solutions are possible and the route via low-energy cyclotrons (< 30 MeV), led by TRIUMF in Vancouver, is very promising and received the NSERC Brockhouse Award in 2015. Numerous new cyclotron facilities have now been funded and built across Canada, making it possible to supply local research communities with isotopes.****The proposed research program taps into the increasing availability of medical cyclotrons and investigates the targets used to make these isotopes. In particular it looks at why the radioisotopic yield of liquid and gas targets is often far below the theoretically achievable yield. We hypothesize that transport phenomena occurring in the liquid and gas are affecting the recoverable yield. The program is therefore investigating the transport phenomena occurring in liquid and gas targets under proton bombardment via simulation and experiment. This problem falls into the broad class of fluid-solid interaction problems found within the transport phenomena literature. What makes this problem particularly difficult is that there is a two-way coupling between the reaction rates and the properties of the fluid. The vision of the proposed program is to develop new production solutions for existing medical isotopes in higher quantities as well as to enable the production of new and emerging isotopes.********