Purdue engineer Babak Ziaie shows the prototype wireless tumor tracker and radication counter he has developed with doctoral student Chulwoo Son. Purdue News Service photo/David Umberger

Injecting a wireless device into a tumor could tell doctors its exact position during radiation treatment and tally the precise dose of radiation received during treatment. The information would help to more effectively kill tumors, says Babak Ziaie, an associate professor in the School of Electrical and Computer Engineering and a researcher at Purdue's Birck Nanotechnology Center. “Organs and tumors shift inside the body during treatment so doctors need a way to tell the exact dosage of radiation received by a tumor and its location,” says Ziaie. He leads a team testing a prototype micro-dosimeter that could be in clinical trials by 2010. The prototype is enclosed in a glass capillary small enough to inject by syringe into a tumor.

Conventional imaging systems can provide a 3D fix on a tumor's shifting position during therapy, but these methods are costly, difficult to use during radiation therapy, and sometimes require X-rays, which can damage tissue if used too often. The new device uses RFID technology which does not emit damaging X-rays.

The device has no batteries and will be activated with electrical coils placed next to the patient. It contains a miniature dosimeter that provides up-to-date information about the cumulative dose a tumor has received.

A key advantage of the technology is that it does not require intricate circuitry, which could make it easier and less expensive to manufacture than more complex designs. It's about 2.5-mm diameter and 2-cm long, small enough for a large syringe. The current size is small enough to be used in tumors, but researchers will work to shrink the device to about 0.5-mm diameter and 0.5-cm long. Ziaie is working with Byunghoo Jung, a Purdue assistant professor of electrical and computer engineering, and researchers at the U. of Texas Southwest Medical Center at Dallas.