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

放射性同位素构成了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石油生产和供应中发挥了关键作用。最常见的核成像同位素Tc-99m每天用于7.5万名患者。世界上大约40%的Tc-99m供应是在安大略省乔克河的核反应堆生产的。加拿大的核反应堆和其他三个设施最近的停工造成了全球范围内的“同位素危机”——延误了各种疾病患者的成像和治疗。这三个设施加起来满足了全球90%以上的需求。为了避免未来发生这种情况，加拿大政府要求加拿大研究界研究替代同位素生产。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年获得了NSERC Brockhouse奖。许多新的回旋加速器设施现在已经在加拿大各地得到资助和建造，这使得为当地研究团体提供同位素成为可能。****拟议的研究计划利用日益增加的医疗回旋加速器的可用性，并调查用于制造这些同位素的目标。它特别研究了为什么液体和气体目标的放射性同位素产率往往远低于理论上可实现的产率。我们假设液体和气体中发生的输运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目标中发生的输运现象。这个问题属于在输运现象文献中发现的流固相互作用问题的大类。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。拟议方案的愿景是为现有医用同位素开发更多的新生产解决方案，并使新的和正在出现的同位素能够生产。********

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.********