Method and apparatus for performing optical measurements of a material

Abstract

A method of determining an optical parameter or function thereof for a liquid, the method comprising: flowing the liquid through a flow cell; transmitting a pulse of light into the liquid in the flow cell; generating a signal responsive to energy that the material emits responsive to a portion of the light from the light pulse that is absorbed by the liquid; and using the signal to determine the optical parameter or function thereof.

1 . An apparatus for determining an optical parameter or function thereof for blood ex vivo, the apparatus comprising:
 (a) a first conduit through which blood flows from a patient's vascular system into a flow cell ex vivo, the flow cell having a cross-section dimension greater than an absorption length in the blood for light which the optical parameter or function thereof is determined;   (b) a pump which circulates the patient's blood through the flow cell;   (c) a light source that transmits a pulse of light in the blood in the flow cell along the cross section dimension;   (d) a detector that receives energy emitted by the material responsive to light from the light pulse that is absorbed by the material and generates a signal responsive to the received energy;   (e) a processor that receives that signal and uses it to determine the optical parameter or function thereof; and   (f) a second conduit through which blood from the ex vivo flow cell recirculates into the patient's vascular system.