New wireless device the size of a grain of rice to treat tumors
Engineers at Purdue University are developing a new a wireless device about the size of a rice grain which will be used as an implant in tumors to provide doctors with precise information about the dose of radiation received and to better locate tumors during treatment, according to a release.
"Currently, there is no way of knowing the exact dose of radiation received by a tumor," said Babak Ziaie, an associate professor in the School of Electrical and Computer Engineering. "And, because most organs shift inside the body depending on whether a patient is sitting or lying down, for example, the tumor also shifts. This technology will allow doctors to pinpoint the exact position of the tumor to more effectively administer radiation treatments."
Previously, researchers at Purdue's Birck Nanotechnology Center have tested a dime-size prototype to prove the concept and expect to have the miniature version completed by the end of summer, said Ziaie. The device, called a "passive wireless transponder," has no batteries and will be activated with electrical coils placed near the body. "It will be like a capsule placed into the tumor with a needle," said Ziaie.
Imaging systems can provide a 3D fix on a tumor's shifting position during therapy, these methods are not easy to use during radiation therapy, are costly and sometimes require X-rays, Ziaie said.
Researchers tested the prototype with a radioactive material called cesium. The device, which contains a miniature version of dosimeters worn by people in occupations involving radioactivity, could provide up-to-date information about the cumulative dose a tumor is receiving over time.

The technology uses the same principle as electret microphones, popular products found in consumer electronics stores.
"It's basically like a very small tuning circuit in your radio," Ziaie said. "This will be a radiation dosimeter plus a tracking device in the same capsule. It will be hermetically sealed so that it will not have to be removed from the body."