Intramuscularly administered isotope is used in determining regional blood flow. The purpose of the experiment is to determine whether acute occlusion of the femoral artery or vein can be detected by the washout technique. Control washout times are obtained in the hind legs of rats after which either the femoral artery or vein is ligated and the disappearance curves of intramuscularly administered, krypton clathrate Kr 85 are determined.
Occlusion of either the artery or vein can be detected reliably by a prolonged half-time of the krypton clathrate Kr 85 washout. Although the group with vein obstruction could be distinguished from the arterial occlusion group, determination of the kind of block on the basis of a single injection is unreliable because of the overlap of the two groups.