Abstract
A quasi-distributed temperature sensor consisting of an array of fibre Bragg gratings (FBG) illuminated by a superluminescent diode (SLD) was described. The sensor combined in vivo operation, quasi-distributed sensing and the stability at 0.1° centigrade required for providing diagnostic measurements of tumor margins for human hyperthermia techniques. The good thermal isolation between gratings, low thermal mass and loose adhesion between fibre and liver tissue helped in making accurate measurements.