Nanomaterials for radionuclide generators

99mTc is one of the most often used radionuclides in nuclear medicine, good for about 20 million procedures worldwide annually. At the hospital, it is eluted from a generator containing both 99Mo (the mother isotope) and 99mTc. Most of the 99Mo is currently  produced from the fission of 235U in reactors worldwide, which results in about 6% 99Mo, and 94% radioactive waste products. There is an alternative method of producing 99Mo, namely through a neutron capture reaction from 98Mo: 98Mo(n,y)99Mo. However, through this method the target and product nuclides are the same element and cannot be separated using conventional chemical methods, resulting in a large amount of molybdenum in the generator. Using the conventional alumina-based column for the 99Mo/99mTc generator therefore means that the column needs to be very large to be able to contain enough molybdenum for the generator. 

We are working on the development of a new type of target material based on Mo-containing nanoparticles, which will function both as target as well as generator material. Advantages of this method include not requiring fissile 235U target material, small generators as no column material is needed, and reusable targets. However, this puts some very strict constraints on the target material options. Obviously, the target material needs to consist to a large degree of molybdenum, but it must also be very stable in e.g. aqueous solutions for extractions of the 99mTc, and under increased temperatures during irradiation. Next to that, it is important to keep in mind that other elements of which the nanoparticles are composed should not activate (too much). In this project, you will investigate the feasibility of Mo-based nanoparticles as target material, like molybdenum carbides or molybdenum disulfides.