This work involves the design, testing and use of radionuclide generators to produce alpha-emitters to be attached to proteins for use in radiotherapy. A new radionuclide generator has replaced the previous design which used Th-228 as the parent. The long half-life, two years, made it unsuitable for use by personnel without training in the handling of long-lived activity. We have undertaken a project with the Chemistry Division at Argonne National Laboratory to develop a new generator system based on the parent Ra-224. This radionuclide has a 3.5 day half-life reducing the potential problems associated with a longer lived radionuclide. We designed and tested a separation systemto separate thorium and radium in a manipulator-equipped shielded cave. We have had this system in operation for one year. Simultaneously, we developed a new generator which will use the radium parent. This sytstem uses a disposable generator package to minimize shipping and handling. An organic cation exchanger is eluted with hydrocloric acid to yield either the bismuth daughter or lead daughter. Work with this system has shown that the generator is safe, has good operating characteristics and can be produced on a regular basis. Similar results have been seen with the thorium-radium separation. The system can be used repeatedly with a minimum of trouble. We are currently building a new thorium separator to handle higher levels of radioactivity in a """"""""senior"""""""" remote handling facility to minimize personnel exposure.
