We have developed a non-invasive technique to measure the human serum lipid level using backscattered near-infrared light. In this special research project, we established the measurement principle and promoted the development of the prototype instrument. The following results were obtained.

(1) In theoretical analysis, the conditions for a practical device were clarified. The measurable region in mammalian body tissue was found by analyzing the light propagation path in a turbid medium using the equation of energy transfer. 

(2) A simulation program was developed which simulates the light propagation in human adult forearm. In comparison with the Monte Carlo simulation, the accuracy of the developed program was verified. In the simulation analysis, the conditions were optimized to measure the turbidity of the blood caused by the serum lipids.

(3) A prototype system for the non-invasive blood lipid measurement was developed.

(4) The research results were presented in international symposia.

Through this research activity, we confirmed the promising prospect for the future advancement of the proposed technique.