One of the most serious limitations to the success of perfusion of certain regions of the body is leakage of the chemotherapeutic agent into the systemic circulation. At the M. D. Anderson Hospital the amount of leakage has been determined with the use of radioactive iodinated serum albumin (RISA); expressed in percentages, this determination is called the "leakage factor." In a general sense the term denotes the extent of cross-circulation between the perfused region and the remainder of the body. Specifically, it represents the amount of RISA in the general circulation at a particular time in relation to the amount which would be present if mixing between the perfused region and the remainder of the body were complete.
Formerly, after the injection of RISA into the perfusion circuit, the leakage factor was calculated from specimens of blood withdrawn at intervals of 10 minutes during perfusion,1 and the adequacy or