December 11, 2008
Mikro Systems fabricated a critical component for an innovative mobile “gamma camera,” used by surgeons in a recent clinical trial at the University of Virginia (UVA) Hospital. The trial evaluated performance of the mobile gamma camera for surgical guidance in sentinel lymph node biopsies for cancer patients.
Mikro Systems produced the custom collimator for this camera. The polymer-tungsten collimator is fundamentally a screen, or grid, a crucial, ray-focusing component of the gamma imaging device. The full system was designed by Dr. Stanley Majewski of Thomas Jefferson Lab National Accelerator Facility and UVA researcher Mark B. Williams, PhD, associate professor of radiology, biomedical engineering and physics. The camera was used on 20 surgical patients over a six month period by a team of physicians led by Dr. Craig Slingluff, nationally known clinician and researcher in the field of melanoma.
In sentinel lymph node biopsy, a mildly radioactive substance is injected in the area of the malignant tumor; it flows and collects in the nearest lymph node (or nodes), providing an accurate indication of the path that cancer cells would also take. The nodes are removed and examined to determine if the cancer has already begun to spread. Identifying and biopsying “sentinel” nodes in this manner eliminates the need to remove excess nodes and the attendant side effects. The mobile camera was used in these trials as a supplement to a standard fixed gamma camera, used prior to surgery to provide the doctors with a static map of sentinel nodes.
“The mobile gamma camera gave us an interactive, real-time map,” said surgery resident Lynn Dengel, a member of Slingluff’s team. “In several instances it provided us with more information than originally expected.” These included several cases in which the camera identified additional nodes requiring extraction after the planned surgery was completed; and several instances where the mobile camera was able to differentiate what appeared as a single node to the fixed camera into several smaller nodes, thus making the surgery more efficient and precise.
Previous collimators used in such applications, said Mikro Systems project manager Jill Klinger, were made out of lead, which is very soft and damages easily — “plus, the precision of the cells is not as good, so the images were quite poor and not up to the surgeons’ standards,” she said. Mikro Systems’ patented TOMOSM process, she added, “enabled us to create the different cell geometry required, and thus get higher efficiency — and better images.”
Mikro Systems, which has worked on previous projects with Jefferson Lab and with UVA’s Williams, has a “unique ability” to build such novel, tailor-made parts “which are integrated with devices such as these gamma ray detectors,” says Williams. “They’re flexible enough that when we said we needed a collimator that has exactly these specifications, they just went ahead and built it, and they did it fast. It would’ve been ridiculously expensive coming from any of the big collimator makers — if they could’ve done it at all, considering how long it would’ve taken for tooling.”
Mikro Systems did it quickly and relatively inexpensively, Williams said, echoing what more than a few Mikro Systems clients identify as a principal benefit of doing business with the growing company. Because of these benefits, Mikro’s TOMOSM technology is also being applied to make similar grids for use in airport baggage scanner systems used for Homeland Security as well as in computed tomography (CT) imaging systems for medical diagnostics.