Analysis of Heat Loads During Production of Radioactive Medical Isotopes

在过去的40年里，通过不断开发新的同位素和新的输送机制，医用同位素的改进使多种癌症的有效治疗成为可能。ABKBiomedical正在开发一套可想象的栓塞微球，用于治疗某些癌症。他们的产品之一是一种新的和独特的方法，将同位素直接输送到受影响的细胞，包括将放射性物质精确和局部地注射到微小的球体内的癌变区域。生产过程包括将含有合适目标同位素的非放射性球体包装成相对较小的体积，然后在核反应堆中激活它们。由于中子和伽玛辐射与这些球体的相互作用，每个球体都经历了这些相互作用中沉积的能量的体积加热。根据材料、球体几何形状、辐照时间和反应堆中的中子/伽马场，沉积在球体上的热量可能是显著的，并且可能超过组件的热量去除能力。在这种情况下，球体将熔化，导致被辐照的那批同位素的损失。ABK生物医学公司希望制定辐照方案，以最大限度地提高其产量。该项目将开发和测试用于模拟此类栓塞球体的新工具和方法，并尝试开发更强大的辐照方法，以最大限度地提高产量。

Over the last 40 years the improvement in medical isotopes has allowed for the effective treatments of manytypes of cancer through the continuous development of both new isotopes and new delivery mechanisms. ABKBiomedical is developing a suite of imageable embolic microspheres for the treatment of some cancers. One oftheir products is a new and unique method of isotope delivery directly to the affected cells involves the preciseand localized injection of radioactive materials within micro-sized spheres to a cancerous region. Theproduction process involves taking non-radioactive spheres containing suitable target isotopes and packingthem into a relatively small volume and then activating them in a nuclear reactor. Due to neutron and gammaradiation interaction with these spheres each undergoes volumetric heating from the energy deposited in theseinteractions. Depending on the materials, sphere geometry, irradiation time and neutron/gamma fields in thereactor, the heat deposited in the spheres may be significant, and possibly exceed the heat removal capacity ofthe assembly. In such cases the spheres will melt resulting in a loss of the batch of isotopes being irradiated.ABK Biomedical wishes to develop the irradiation protocols such as to maximize their production output. Thisproject will develop and tests new tools and methods for the simulation of such embolic spheres and attempt todevelop more robust irradiation methods where production can be maximized.