Pharmacokinetic-rate images of indocyanine green for breast tumors using near-infrared optical methods.

In this paper, we develop a method of forming pharmacokinetic-rate images of indocyanine green (ICG) and apply our method to in vivo data obtained from three patients with breast tumors. To form pharmacokinetic-rate images, we first obtain a sequence of ICG concentration images using the differential diffuse optical tomography technique. We next employ a two-compartment model composed of plasma, and extracellular-extravascular space (EES), and estimate the pharmacokinetic rates and concentrations in each compartment using the extended Kalman filtering framework. The pharmacokinetic-rate images of the three patient show that the rates from the tumor region and outside the tumor region are statistically different. Additionally, the ICG concentrations in plasma, and the EES compartments are higher around the tumor region agreeing with the hypothesis that around the tumor region ICG may act as a diffusible extravascular flow in compromised capillary of cancer vessels. Our study indicates that the pharmacokinetic-rate images may provide superior information than single set of pharmacokinetic rates estimated from the entire breast tissue for breast cancer diagnosis.