Every day, 40,000 patients undergo diagnostic scans using radioactive isotopes in the U.S. to help detect cancer and other diseases. Argonne scientists specialize in research and development of the radioactive isotopes that shine a light on what’s happening inside the body during these procedures. In addition to such diagnostic isotopes, other isotopes are being developed at Argonne for therapeutic applications.
These procedures rely on radioisotopes that may be in short supply or not commercially available at all. The laboratory’s scientists and engineers are stepping in to help make these critical isotopes more readily available to detect and treat diseases.
Much attention goes to the scientists leading medical isotope research. Yet a group of intrepid engineers and designers in the lab’s Experimental Operations and Facilities (EOF) division are playing a vital supporting role in two medical isotope programs — Argonne’s Radioisotope Research and Production Program (R2P2) as well as its Molybdenum-99 program.
Station to station
The R2P2 studies ways to produce radioisotopes that have been recognized as high priority for medical applications. Right now, chemist and Deputy Program Manager Dave Rotsch and his colleagues have started to produce the isotope copper-67 with the electron linear accelerator (linac) at Argonne’s Low-Energy Accelerator Facility (LEAF). Argonne is working towards making 67Cu available through the U.S. Department of Energy’s Isotope Program.
The team points a beam of electrons at atomic nuclei to form photons, which then slam into a target made of zinc. The process generates intense heat, so EOF engineers James Bailey and Phil Strons ensure the target is amply cooled with water.
With funding from the DOE Isotope Program, starting in 2015, Bailey and Strons, along with EOF designer Ron Kmak, helped Rotsch and team design and build one of the LEAF’s most innovative features — the RadioIsotope Target Station (RITS). “Jim, Ron and Phil transformed my box model design of the target station into a very efficient, safe system,” said Rotsch.
Previously, scientists used an awkward and inefficient target station that loaded the accelerator targets with a series of complex pulleys. Rotsch needed a new system that was simple to use and minimized radiation exposure to his team.
“Jim, Ron, and Phil helped design and build a top-loading, modular system with more flexibility and safeguards,” said Rotsch. The new system ensures that scientists are always shielded from radiation and can handle up to 20 kilowatts of beam power—twice the team’s original goal. “Without their help, we would have been unable to complete this project,” he said.
Keeping it cool
The EOF team also deftly supports the lab’s Molybdenum-99 program managed by chemist and Program Manager Peter Tkac. Argonne’s Mo-99 program supports the NNSA’s partners in their efforts to develop a domestic supply of Molybdenum-99 for hospitals.
One challenge for all researchers who produce radioisotopes, including Tkac and his colleagues, is converting one isotope into another. The team uses the beam of LEAF’s electron linac to convert a stable isotope, Mo-100, into the desired radioactive isotope, Mo-99. During subsequent processing, the target is chemically dissolved, which produces a great deal of heat, water vapor, and oxygen gas.
Within seconds, the temperature in the reaction vessel rises to 120 degrees Celsius. “If you want to perform the reaction in a hot cell (a shielded room that protects scientists from radiation), you need a robust high-efficiency condenser,” which cools gases, converting them to liquids. In fact, during the fifteen minutes of reaction, we condense about one liter of water, said Tkac. “Without an efficient condenser, we would flood the hot cell with steam.”
To avoid this, Bailey and designer Stan Wiedmeyer helped to design a system for hot cell operations with a high-efficiency condenser that can cool and condense extreme amounts of water vapor. The engineers’ condenser has performed flawlessly in 15 full-scale dissolutions so far and Tkac plans to use it in many more.
EOF engineers and designers, as well as, the EOF electron linac operations team play central roles in both the R2P2 and Molybdenum-99 research, which promotes operational excellence at the lab. “They really care about the projects and programs which help make Argonne a great place to work,” said Rotsch.
By Dave Bukey (CPA)
Photo: Postdoctoral researcher Robin de Kruijff (PHY) helps Dave Rotsch (CFC) (left) and his team study radioisotopes for medical applications.
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The R2P2 is a cross-directorate collaboration with scientists from the Chemical and Fuel Cycle Technologies (CFCT) and Physics (PHY) divisions. This program is supported by the DOE’s Isotope Program and involves research at both the EOF’s electron linac and the Physics division’s DOE National User Facility ATLAS. The Molybdenum-99 program involves scientists from the CFCT and EOF divisions and is supported by the National Nuclear Security Administration Office of Materials Management and Minimization.
