An interdisciplinary program based on neutron capture therapy (NCT) to kill cancerous tumor cells using high-energy radiation from neutron capture reactions in selected nuclei has been initiated. An epithermal neutron beam from the Illinois TRIGA reactor is being modified for NCT use. Neutron autoradiography (NARG) in association with magnetic resonance imaging (MRI) is being developed to study the effectiveness of possible new drug carriers in depositing neutron-absorbing nuclei as NCT agents in tissue. Boron-10 is currently the popular choice of absorbing nuclei, but gadolinium, with its higher neutron-capture cross section and tumor-to-blood concentration, is being evaluated for overcoming radiation damage to blood vessels resulting from boron use.

The magnetically assisted chemical separation (MACS) program is being developed by ANL in response to the need for simple, efficient, and compact extraction processes for the removal of transuranic species from liquid waste streams produced by DOE laboratories. The MACS process utilizes octyl(phenyl)-N,N-diisobutyl carbamoyl methyl phosphine oxide (CMPO) sorbed onto magnetic microparticles. To better understand the extraction chemistry of the MACS process, experiments are being conducted at UIUC on determining the sorption isotherms. The sorption curves will be compared to various theoretical models (e.g., Langmuir) to quantify the bonding nature. Europium is being used as an analog for the transuranics and will be monitored by neutron activation analysis.

Phosphate fertilizers have the potential of being an important factor in the contamination of the environment. One of the by-products of the fertilizer industry is phospho-gypsum. It was proven that the gypsum contained large amounts of radium. One of the techniques adopted for its disposal is stacking it in piles. An environmental threat exists should any leak occur in these piles, with the consequence of groundwater contamination. We have started a project to investigate the possible role that fertilizers have on the ecosystem. Initially a number of phosphate fertilizers are being analyzed for uranium and heavy elements.

Ion-chelate complexes have many applications in tumor diagnosis and therapy. Radioactive isotopes of technetium, yttrium, indium, and samarium offer applications in radioscintography and radiotherapy. Gadolinium has applications in magnetic resonance imaging and neutron capture therapy. We have attached ion-chelate complexes to Starburst ® dendrimers. Folic acid was attached to these poly mers. They specifically bind to tumor cells that express the high affinity folate receptor. We are using these polymers to diagnose and treat tumors that express this receptor in vivo. Tumors of epithelial origin express this receptor. These include 90% of ovarian tumors, ependymomas, and choroid plexus tumors.