When one diagnoses a cancer patient, it's important to gather as much information about that person as possible. But who would have thought an accurate diagnosis would depend on throwing some of that information away?
That's key to the technique employed by researchers at Rice University and the University of Texas M.D. Anderson Cancer Center as they bolster the efficiency of scanners that find and track lung and thoracic tumors.
In a paper published last month in The Journal of Nuclear Medicine, a team led by fifth-year Rice graduate student Guoping Chang described an amplitude gating technique that gives physicians a clearer picture of how tumors are responding to treatment.
Chang's technique works in conjunction with PET/CT scanners, commonly used devices that combine two technologies into a single unit.
CT (computed tomography) scanners capture a three-dimensional image of the inside of the body. PET (positron emission tomography) scanners look for a radioactive signature. Before a PET scan, a patient is injected with slightly radioactive molecules tagged to track and adhere to particular cancer cells. As the molecules gather at those cells and decay, they give off a signal that the PET scanner can read.
Together, the scanners give physicians a good idea of a tumor's location and whether it's malignant or benign. Subsequent scans can show how it's responding to treatment.
But there's a problem. While CT scans take relatively quick snapshots, PET scanners need as long as three minutes to capture an image from a single section of the body. Because patients have to breathe, the images don't always correlate well.
"Patients might have lesions located in organs that move due to respiratory motion," said Chang's technical adviser, Osama Mawlawi, an associate professor in the Department of Imaging Physics at M.D. Anderson and an adjunct lecturer in electrical and computer engineering at Ric
|Contact: David Ruth|