A PORTABLE DIFFUSE REFLECTANCE SPECTROPHOTOMETER FOR RAPID AND AUTOMATIC-MEASUREMENT OF TISSUE

A portable reflectance spectrophotometry system which can measure a wider dynamic range of absorbance and has fibre-optic probes with a contact sensor and a pressure sensor was developed to improve the availability of noninvasive reflectance spectrophotometry. A flexible fibre-optic probe which is highly durable and biologically inert was developed as the standard probe. Attachments of the probe for sensing the contact between the probe and the measured tissue and the pressure of the probe head on the tissue were developed to avoid the disturbance in the haemodynamics of the tissue caused by the pressure of the probe contact. A Czerny-Turner type spectrometer which can be connected to an optical fibre probe was developed, and a linear CCD was used as its light detector to increase the data acquisition speed. The scanning time of the linear CCD is automatically controlled in accordance with the reflectance of the tissue to increase the dynamic range of absorption. Therefore this system has a dynamic range as large as 30 dB.