The value of chemotherapeutic agents lies not only in their cytotoxic effectiveness against malignant cells, but also equally in the degree that normal tissue can tolerate them. The resistance of tumor cells growing in vitro against these drugs is often quantitative in nature with the tumor seeming completely resistant unless sufficiently high concentrations of the agent reach the tumor. Since the concentration of the cytotoxin that will reach the tumor growing in vivo is dependent on the characteristics of the tumor's blood supply, the feasibility of delivering a curative dose of this agent will be apparent from a hemodynamic evaluation of the vasculature of the tumor and surrounding tissue. For this reason, a hemodynamic investigation of tumor vasculature and its host's vessels has been made.
The first part of this study was devoted to the validation of a clearance technique for the measurement of tumor blood flow in the canine.