New Cyclotron to Enhance Cancer, Heart Disease Diagnosis

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MADISON – UW Health physicians’ ability to make diagnoses related to cancer, heart disease and neurological disorders will be greatly expanded soon, thanks to a $1.5 million grant for a significantly upgraded positron emission tomography (PET) tracer production facility at the University of Wisconsin School of Medicine and Public Health (SMPH).
 
With a new 30-ton cyclotron as the centerpiece, the facility will also allow SMPH scientists to expand their research on normal and abnormal tissue and organ function. The cyclotron will be located in the new Interdisciplinary Research Complex (IRC), which is currently under construction.
 
The grant is part of the National Institutes of Health’s National Center for Research Resources High-End Instrumentation program, which funds cutting-edge equipment needed to advance biomedical research. The SMPH is one of 14 institutions to receive the grant.
 
“With this generous award, faculty led by researchers in medical physics, radiology and human oncology will enjoy new vistas of targeted, disease-based research not possible in the past,” says Paul DeLuca, PhD, SMPH vice dean. “As such, the imaging sciences facility at the IRC will enjoy a national leadership position.”
 
Since 1985, SMPH medical physicists have used an 11-megavolt proton cyclotron housed in the basement of the Medical Science Center to make tracers, or markers, for PET studies conducted at UW Hospital and Clinics and the Waisman PET Center. The new cyclotron will be a higher energy, state-of-the-art machine.
 
Unlike CTs and MRIs, which display anatomical structures, PET images provide information about the biochemistry and function of normal and diseased tissues and organs. PET images can reveal the level of tumor activity, for example, and can distinguish regions in the heart that may be completely damaged by infarction or only somewhat damaged by ischemia.
 
“Simply put, PET involves four steps; shooting, cooking, imaging and diagnosis,” explains PET technology expert Jerry Nickles, PhD, SMPH professor of medical physics and radiology. “Since most positron emitters are short-lived, these steps are locked into a time-critical sequence.”
 
In the first step, the cyclotron and its high-energy beam make the initial product, a positron-emitting radioactive isotope, by accelerating, or shooting, atomic and sub-atomic charged particles onto a target.
 
In the second step, a natural biochemical substance is combined with minute amounts of the radioactive isotope. The tagged substance will go to places in the body where it normally functions. Dozens of substances can be used for this step, but the most common is the glucose look-alike FDG, an energy source used in many parts of the body. Since tumors metabolize more glucose than normal tissue, their activity shows up very clearly in a PET image.
 
Tracers have a short half life, so they are quickly transferred to the PET imaging facility to be injected into the patient. As the radioisotopes are annihilated, or “decay,” they produce radiation that is captured by a camera and used to generate a three-dimensional color image, the third step in the process.
 
In the final step, the clinician uses the information seen in the image to make a diagnosis.
 
“The new cyclotron, and the much-needed auxiliary equipment, will open a new horizon for PET research at Wisconsin, with the ultimate goal being to bring molecular imaging to bear on the diagnosis of disease,” says Nickles.

Date Published: 07/26/2007


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