Currently used temperature sensor systems do not provide sufficient spatial
resolution and can not be used as an integrated part of minimally invasive
treatment. Few magnetic resonance (MR) compatible sensor systems are avail
able. A distributed fibre Bragg-grating sensor system for use in biological
tissue was constructed. Ten Bragg gratings were inscribed in the core of a
n optical fibre. The fibre was mounted into tubes made of MR-compatible mat
erials. An opto-electronic unit connected to the fibre was used for signal
generation and detection. Communication with a PC allowed presentation and
logging of temperature data. The system was calibrated to the temperature r
ange -195.8 degreesC to 100 degreesC. Experiments were conducted during fre
ezing (cryoablation) of porcine liver in vivo. The system yielded a tempera
ture profile with 6.5 mm spatial resolution and 5 s temporal resolution. Bo
th mechanical stability and MR compatibility were acceptable and will allow
routine use.