Patent ID: 8818472

Claim:
A method for use in determining a tissue energy absorber concentration in an individual's blood, said method comprising: (a) using a photometric device to measure a change in mass of said tissue energy absorber within a particular volume of said individual's blood between a first point in time and a second point in time, said particular volume of blood being blood within at least a first particular portion of at least one vascular structure, said vascular structure comprising at least one of said individual's vessels; (b) using an ultrasound imaging device to measure a change in interior volume, between about said first point in time and about said second point in time, of a second particular portion of said at least one vascular structure, wherein the ultrasound imaging device measures a volume of the second particular portion of the at least one vascular structure by measuring a long-axis cross-sectional area and a short-axis cross-sectional area of the second particular portion of the at least one vascular structure, said second particular portion at least generally corresponding to said first particular portion; and (c) using said measured change in said mass of said tissue energy absorber, and said measured change in interior volume to determine at least an approximate blood total concentration of said tissue energy absorber within said individual's blood.