Table 3. Tumor volume, blood flow and interstitial fluid sources.
Tumor volume | |||
Fractional tumor volume | |||
Blood flow through tumor boundary | |||
IF influx (tumor) | |||
IF uptake (tumor) | |||
IF influx (normal) | |||
IF uptake (normal) | |||
Ratio of IF extravasation to blood flow. |
and the quantities involving were computed by numerical integration, i.e. summation over grid cells, weighted by or as required by the respective region. Tumor blood flow was computed by summing over vessels where (i) the sign of changes between the endpoints, (ii) blood flow is directed into the tumor, which is straight forward to check based on the nodal blood pressures and . Of course, mass is preserved, i.e. inflow and outflow are equal (in particular since we neglect extravasated fluid). Also due to mass conservation, the IF uptake in normal tissue is slightly higher than influx because flux from the tumor is absorbed as well. Uptake within the tumor is low due to the lack of lymphatics. is the ratio of to , indicating that only a very small fraction of the blood plasma which is entering the tumor is lost into the tumor interstitium.