Lymphatic Clearance of Radioactive Sulfur Colloid

Abstract

Lymphatic clearance of radioactive sulfur colloid is
measured in the hind limb of five mongrel dogs. A
solid state Si(Li) detector is placed onto the skin to
continuously record activity over the site of subcutaneous
injection. Decrease in activity follows an
exponential decay which is modeled as a dual decay
occurring from both the radioactive decay of the
tra cer and the lymph clearance of the tagged sulfur
co lloid. The calculated decay constants for lymph
clearance flow per tissue volume result in a mean
value of 0.233 ± 0.077 ml/ hr/ml which is consistent
with results of other investigators. Adjacent lymph
nodes are monitored with a scintillation detector to
show that the colloid is absorbed by the lymph vessels.
The carotid artery and liver are similarly monitored
to show that there is little or no capillary absorption
of the tagged colloid.