A team of medical engineers in Germany has developed an implant to continuously monitor tumor growth in cancer patients. The device, designed to be implanted in the patient near the tumor site, uses chip sensors to measure oxygen levels in the blood, an indicator of growth. The data is then transmitted wirelessly to an external receiver carried by the patient and transferred to his or her doctor for remote monitoring and analysis.
“We developed the device to monitor and treat slow-growing tumors that are difficult to operate on, such as brain tumors and liver tumors, and for tumors in elderly patients for whom surgery might be dangerous,” said Helmut Grothe, head of sensor technology at the Heinz-Nixdorf Institute for Medical Electronics at the Technical University of Munich.
The roughly two-centimeter-long device, dubbed the IntelliTuM (Intelligent Implant for Tumor Monitoring), includes a self-calibrating sensor, data measurement and evaluation electronics, and a transmitter. All the components are contained within a biocompatible plastic housing.
The device sensor detects the level of dissolved oxygen in the fluid near the tumor; a drop in that measure suggests the metabolic behavior of the tumor is changing, often in a more aggressive way. So far, researchers have tested the device in tissue grown in culture. The next step is to test it in live animals.
Most monitoring of tumor growth is currently done via CT scans, MRI, and other forms of external imaging. “The advantage of an implant over external imaging is that you can monitor the tumor on the go,” says Sven Becker of the Technical University of Munich. “This means patients would have to pay fewer visits to the hospital for progression and postsurgery monitoring of tumors. They also wouldn’t have to swallow contrast agents.”
In addition to the oxygen sensors, researchers have equipped the device with sensors to monitor pH, another indicator of tumor growth. The oxygen sensors can be calibrated inside the body, though the researchers have not yet developed this capability with the pH sensors.