Compact Neutron Source for Medical Isotope Production

如果你心脏病发作，医生很可能会给你注射锝-99示踪剂。当示踪剂在你的血液中循环时，锝就像x光机一样发出x射线。然而，与x光机不同的是，示踪剂只显示有血流的区域，因此可以清楚地看到阻塞。锝还被用于许多其他医疗程序中，以区分软组织中的其他差异：例如，癌症肿瘤比正常组织更多地吸收某些放射性示踪剂，因此与周围环境相比，它们会“发光”。通过将钼-99包装在发电机中向医院提供锝：钼-99在发电机中衰变为锝，大约一周后，锝被提取出来用于诊断程序。但是有一个问题。目前，大量的钼-99只能在少数几个专门的核反应堆中生产，这些反应堆都变得太老，无法安全运行，最近两个主要反应堆的故障造成了供应危机，而此时需求却在不断增长。在此背景下，去年进行了3600万次核医学手术，其中大部分需要锝。曼彻斯特大学和兰开斯特大学的研究人员正在研究一种使用粒子加速器生产锝的新方法。他们采用与大型强子对撞机（LHC）等粒子对撞机类似的技术，建议使用高功率射频四极杆（RFQ）加速离子进入目标以产生中子。就像他们打算替换的反应堆一样，这些中子可以用来制造钼-99。虽然RFQ不能像反应堆那样产生那么多的中子，但它的建造和运营成本要低得多，而且可以在全国各地建造很多，以提供国内钼-99的供应，尽管英国每年使用超过一百万剂的锝，但目前还没有钼-99。一旦RFQ和目标得到优化，研究人员计划建造一个原型加速器来证明该技术的商业可行性，并且已经在与公司讨论如何做到这一点。

If you have a heart attack, it's fairly likely that the doctor will inject you with a Technetium-99 tracer. As the tracer circulates through your bloodstream, the Technetium emits X-rays just like an X-ray machine. However, unlike an X-ray machine, the tracer shows up just those regions where there is blood flow, so that blockages can be seen clearly. Technetium is also used in a host of other medical procedures to distinguish other differences in soft tissues: for example, cancer tumours take up certain radiotracers more than normal tissue, so that they 'light up' compared to their surroundings. Technetium is supplied to hospitals by packaging Molybdenum-99 into a generator: Molybdenum-99 decays into Technetium in the generator over about a week, and the Technetium extracted and used for diagnostic procedures. But there's a problem. Right now, large quantities of Molybdenum-99 can only be made in a few specialised nuclear reactors, all of which are becoming too old to be run safely, and recent failures in the two principal reactors have created a crisis in supply, at a time when there is an ever-growing demand. To put it into context, 36 million nuclear medicine procedures were carried out last year, most of which need Technetium. Researchers from the Universities of Manchester and Lancaster are looking at a new method to produce Technetium using a particle accelerator. Using similar technology to that used in particle colliders like the LHC, they propose using a high-power radio-frequency quadrupole (RFQ) to accelerate ions into a target to generate neutrons. Like in the reactors they intend to replace, these neutrons can then be used to make Molybdenum-99. Although an RFQ cannot make as many neutrons as a reactor, it is much cheaper to build and operate, and so many could be built around the country to provide a domestic supply of Molybdenum-99, which the UK doesn't have at the moment despite using over a million doses of Technetium a year. Once the RFQ and target are optimised, researchers plan to build a prototype accelerator to demonstrate the commercial viability of the technique, and are talking to companies already about how to do this.