Infrared fiber radiometer for thermometry in therapeutic microwave and radio frequency heating

Hyperthermia in cancer treatment involves heating malignant tumors to 42.5-43.0°C for an extended period (e.g. 30 min) in an attempt to obtain remission. For superficial and some deep seated tumors electromagnetic (microwave or radio frequency) field induced heating is often used. One of the severe problems with this therapeutic modality is the accurate measurement of temperature in the presence of a strong electromagnetic field. We have under development an infrared fiber-radiometer system which quantifies temperatures by measuring black body emission from the surface. This radiometer is based on a non-metallic, infrared fiber probe, which can operate either in contact or in non contact modes. When the fibers are incorporated in endoscopic catheters, internal body temperatures may be measured at those sites accessible via body orifices. In preliminary investigations the radiometer worked well in a strong microwave field, with an accuracy of ±0.5°C.