New projects challenge, excite Jefferson Lab's Detector Group

06/03/04

Physicists from the Department of Energy’s Jefferson Lab Detector Group are beginning to develop a compact heart imager that can be quickly deployed and easily moved between such hospital areas as emergency departments and intensive care units.



The Detector Group

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Concerned family members rush a potential heart-attack sufferer to a local emergency room. There, physicians hurry to ensure the patient doesn't go into full cardiac arrest. Using a portable imager to pinpoint blood flow through the heart, a cardiologist determines within minutes that there's a small blockage in one of the major vessels. A minimally invasive procedure is performed and the vessel is cleared. Within a day or so, the patient will be resting comfortably at home.

Thanks to work being done by physicists from the Department of Energy's Jefferson Lab Detector Group that scenario, or one like it, could soon be more common. Underwritten by the U.S. Army and in collaboration with the University of Florida, the Group is beginning development of a compact heart imager that can be quickly deployed and easily moved between such hospital areas as emergency departments and intensive care units. The Group will build and test the heart imager in stages, and although the work has only recently begun, the eventual practical results could prove dramatic. "It's the most challenging project we've ever taken on," says Stan Majewski, Detector Group leader. "It will be incredibly gratifying if we're successful."

The $1.2 million, three-year heart-imager project is but one of several multiyear projects in which the Group is engaged. Two others involve application of small, portable breast imagers that make use of the positron emission mammography, or PEM, technique to detect cancerous breast lesions and help guide physicians in the taking of biopsies in hopes of identifying early-stage cancers. Another centers around gamma-ray detectors that could be used by neurologists to better monitor special radiation treatment of brain cancer. A fifth is concentrating on the development of a high-resolution gamma imager using single-photon emission-computed tomography, or SPECT, to reveal basic metabolic processes in small, unanesthetized animals.

Each of the projects is being funded in full or in part by monies provided by either the Department of Energy's Office of Biological and Environmental Research, the Army or the National Institutes of Health. Each of these imager-development efforts will continue for three to five years; as innovative technology of this kind requires time to devise, test and verify.

"If we want to have assured funding support, we have to be involved in more than one project at a time," Majewski says. "There's really no failure mode allowed. Even in the worst case we end up with improved instruments. But we have no doubts that these devices will be useful. Some are actually already useful."

Whether used to diagnose maladies in the brain, heart or breast, all of these detectors owe their genesis to the expertise of the Detector Group members, developed as spin-offs of the sensitive gear used in Jefferson Lab's experimental halls to detect subatomic particles resulting from the collision of JLab's accelerated electron beam with a target material.

The Lab's scientists have adapted similar instrument concepts to sense the presence of trace amounts of injectable solutions containing slightly radioactive isotopes known as radiopharmaceuticals. One such radiopharmaceutical is fluorine-18 deoxyglucose, or FDG. As a harmless solution containing FDG circulates throughout the body, it tends to migrate to and accumulate in malignant cells because malignancy hungers for energy in the form of sugars to grow and spread.

Once congregated in diseased tissues, the radiopharmaceuticals emit gamma rays, which are sensed by the detectors and then converted into electronic signals that can be rendered into a visible image. Depending on the kind of image processing employed, small tumors or other abnormalities usually reveal themselves as bright spots in the image.

In a series of clinical trials conducted at university hospitals and regional medical centers, the breast imagers developed by the Detector Group have proven exceptional performers, able to distinguish small tumors that otherwise would go unnoticed. Now, with one heart, one brain and two breast imagers at various stages of maturation, the Group's goal is to meet the competing requirements of practicality and cost, while retaining top-notch technical performance.

"We're getting into development of the most sophisticated instruments that we have ever built," Group leader Majewski explains. "These are complicated packages. Our challenge is to satisfy an array of specifications."

The Group has already "handed off" a market-ready version of one of its earliest detectors -- a "gamma camera" licensed to the Newport News, Va.-based Dilon Technologies. The Dilon 6800 camera has completed successful clinical trials to indicate areas of hard-to-identify breast-cancer malignancies and received FDA (Food and Drug Administration) approval. The Dilon 6800 is smaller, mobile and more sensitive than larger, traditional nuclear-medicine diagnostic equipment, with an articulating arm and movable sensing plate that can be easily applied to the breast with little discomfort.

In the future, Lab-derived detector technology will be smaller, thinner and even more mobile, with detectors able to "see" at a much higher resolution. Results should improve even further as next-generation radiopharmaceuticals hit the market, enabling enhanced visual clarity. Ultimately, says Detector Group physicist and staff scientist Drew Weisenberger, the purpose is to make devices to preserve and protect human health.

"We want to make these detectors even better," Weisenberger asserts. "Yes, we want to do the [basic] science, but we don't want to build machines that will sit on the sidelines."

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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