Perfusion Measurements Using a Non-Invasive Thermal Probe in a Phantom Test Stand

Blood perfusion represents the local, multi-directional blood flow through capillaries and intracellular spaces of living tissue. Blood perfusion is crucial in the assessment of many physiological phemonena, such as skin grafts, burn injuries, and head traumas. Current methodologies are often invasive or highly sensitive to environmental factors [1]. Previous studies have focused on the development of a noninvasive measurement system to accurately measure blood perfusion. The objective of this study is to validate the system performance via experiments using a phantom test stand. Several previous studies hae been conducted on canines; these tests demonstrated that changes and trends in perfusion can be detected using this system [2,3]. The use of a phantom test stand was motivated by the large range of blood perfusion values reported for human tissue (i.e., 0.002–3 mL/mL/s. [4]) This large perfusion range is thought to be due to several factors: measurement device sensitivity, envoronmental factors, and state, type, and location of the tissue of interest. An agar solution phantom test stand was developed to eliminate physiolocigial factors in evaluating the thermal probe’s function and veriability [4]. The overall blood perfusion measurement system consists of a probe with a heat flux sensor and air housing (see Fig. 1), a bioheat transfer model of the probe and tissue, and a parameter estimation program as described below and in [2].