From Wake Forest University Baptist Medical Center
New PET machine will open door to cancer research
WINSTON-SALEM, N.C. - A new type of Positron Emission Tomography (PET) scanner at Wake Forest University Baptist Medical Center for the first time will open the way to use PET imaging in basic cancer research, as well as expanding research on drug and alcohol addiction.
The new scanner, called a MicroPET, is the second scanner of its kind in the United States. "The MicroPET is opening up a whole new line of research that we were not capable of doing before the scanner arrived," said Robert H. Mach, Ph.D., professor and vice chairman for research of the Division of Radiologic Sciences (Radiology) and professor of physiology and pharmacology. "Cancer research is by and large limited to rodent models--mice and rats. This MicroPET enables us to use imaging in these animal models."
The $750,000 scanner was paid for by a $400,000 grant from the National Institutes of Health (NIH) and $350,000 in institutional funds.
Mach said the "dramatically higher" resolution of the MicroPET "will enable us to look at structures in the monkey brain that we're currently not capable of seeing and it's going to enable us to do imaging studies in small animals."
It has a resolution of 2.2-2.4 millimeters compared to about 8.5 millimeters with an older clinical PET scanner, roughly like seeing a toothpick compared to a pencil.
Investigators at Wake Forest have been using PET scanners for several years for addiction studies and other behavioral disorders associated with chronic disease in monkeys, but the MicroPET is the first device that is intended strictly for animal use.
In fact, ongoing studies on the existing PET scanner, the ECAT 951, won't be switched to the MicroPET because they are longitudinal studies that are following the same animals over a period of several years and comparing data over that time in the same portion of the brains.
Mach said that engineering jump from the ECAT 951 to theMicroPET was so big that switching machines might threaten these studies -- because the scientists would no longer be sure they were comparing the same things. "So we will continue to use the ECAT 951 for our existing protocols."
The large team of monkey investigators working on addiction studies who helped win the NIH grant will eventually have their new protocols go on the MicroPET. But not yet. The MicroPET is so new that the software is still being prepared that will correct for the absorption of photons passing through the thick monkey skulls.
In small animals this is less of a problem since their skulls are thin, so work on rats and mice is under way. "We have been conducting imaging studies in small animals to see how small we can go with respect to being able to image structures," he said. "We can image the rat striatum [a part of the brain] with the same degree of precision on the MicroPET as we can with the monkey on the ECAT 951," Mach said.
"The MicroPET is really good for imaging tumors," he said. "The key thing in cancer research is early diagnosis and understanding the molecular properties of tumors so you can design an appropriate treatment strategy. We hope to use this scanner as a means of initiating a program on the molecular imaging of cancer."
In the meantime, Mach and others are working to get the MicroPET validated and in operation for the primate studies.
And he predicts that much other research is just around the corner. "People are continually asking me when they will get to use the MicroPET. There is going to be a lot of grant money available for doing research on these scanners."
"I believe our program, with its rich history of animal imaging, postures us quite nicely to be competitive for grants supporting imaging research using animal models of disease."