Abstract
The metal-tipped fibre or ‘laser probe’ developed for angioplasty comprises a metallic probe at the end of an optical fibre. The probe is heated by an argon or Nd: YAG laser and applied against the tissue to be vapourised. The heated probe generates infra-red radiation which is proportional to the temperature of the probe. The paper investigates the feasibility of a feedback control system that measures the temperature of the probe by detecting the infra-red radiation transmitted back through the fibre. The probe was initially heated by physical contact with a hot surface, and then by an argon laser via the optical fibre. The returning IR radiation was sensed by a lead sulphide detector, while probe temperature was simultaneously measured by a thermocouple. Temperatures as low as 200°C were measured through a 5 m long fibre during the laser heating of the probe. The detector signal increased in an exponential fashion as the probe temperature increased. A resolution of 1°C was obtained at a probe temperature of 400°C. It can be concluded that, for the laser probe, it is feasible to use a feedback control system which measures the infra-red radiation transmitted back through the same fibre that carries the heating laser light.
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Torres, J.H., Ghaffari, S. & Welch, A.J. Laser probe temperature control by measuring the returning infra-red radiation. Med. Biol. Eng. Comput. 28, 1–7 (1990). https://doi.org/10.1007/BF02441670
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DOI: https://doi.org/10.1007/BF02441670