Cyclotron streamlines isotope production
Medical scanning equipment is complex, and producing the medical isotopes used in scanning can be even more so. For cardiac PET (Positron Emission Tomography) scans, doctors inject an imaging agent (tracer) into the bloodstream. During the PET scan, the tracer is used to evaluate heart health by measuring the blood flow transported through the coronary arteries to the heart muscle. Doctors use PET scans to safely and accurately identify the presence or absence of coronary artery disease.
The scanning machine is a complicated piece of technology, but it can't function as designed without the tracer. Rubidium 82 is the active pharmaceutical ingredient in one of the imaging agents used for PET scans. This isotope, which is essential to the functionality of a PET scan, is costly and difficult to produce.
One production process for manufacturing tracers is through the use of a cyclotron, a particle accelerator that produces a beam whose purpose is to irradiate different targets, in this case Rubidium metal. This process converts it into Strontium 82, a radioactive isotope. Strontium 82, which decays into Rubidium 82, has no commercial supplier and has only been produced at U.S. Government and foreign-based national laboratories. Until now.
Zevacor Molecular, a healthcare firm that manufactures PET and SPECT radiopharmaceutical products, has installed the first and the largest commercial 70-million electron volt (MeV) cyclotron dedicated to producing medical isotopes for the global market. Based in Noblesville, IN, Zevacor's primary focus is to manufacture Strontium 82 and Germanium 68, although it is capable of producing a wide variety of other radioisotopes (atoms with excess energy) for both research and clinical applications.
The Cyclotron
The cyclotron is housed in an 11,000-cubic-yard concrete vault with 300 tons of reinforcing steel rod. The concrete "raft" cannot shift and have a deflection of more than 1 mm without degrading the energy beam.
Manufacturing Strontium 82 requires a lot of energy. Most of the equipment involved in the process is powered pneumatically with compressed air, but Zevacor estimates its annual power bill at $1 million, with three-fourths of that energy spent cooling water to keep the cyclotron and targets from overheating.
The cyclotron is housed with six other vaulted areas, each supplied with two separate sets of copper pipes—one for feed water to make the purified water supply and the other to extract the heat. Because purified water is extremely corrosive to copper, the copper pipe does not come in contact with that water. It only goes to the filtration system that purifies the water upon which it is transferred to the target through a PVC line.
"The integrity of that chilled water system is critical," Hockemeyer said. "If the cooling system shuts down, so does our cyclotron."
That's why Zevacor chose Viega ProPress Copper over soldering. Zevacor also chose Viega to reduce the danger of contamination and particles in the piping, which can become radioactive and create different problems with hazardous waste water.
Andrew Smith, Project Manager at Leach and Russell Mechanical, took the lead on the installation of ProPress. It was utilized for the compressed air lines that ran the pneumatic equipment connected to the cyclotron as well as the water lines that went to the purified water source used to cool the targets.
According to Smith, the installation of the ProPress lines went well. The sensitivity of the project and the time required for all the pieces to come together made it difficult for him to outline an installation plan in advance.
Smith knew they needed a solution that could be installed quickly.
"The clock was ticking the whole time," Smith said, "so if we had an opportunity to steer toward a type of system that was time-saving, we did. That's how we got involved with Viega. We had to have systems that would go in at a pretty quick pace."
