EVALUATION OF IN-111 AS A NEW HIGH PHOTON YIELD GAMMA-EMITTING PHYSIOLOGICAL PLATELET LABEL

Abstract

Rabbit platelets were labeled in vitro with 111In-8-hydroxyquinoline. The in vivo behavior of 111In labeled platelets was compared with that of 51Cr labeled platelets in the rabbit. Unlike 51Cr, reasonable platelet labeling efficiency was achieved with 111In, even when the platelets were suspended in small amounts of autologous plasma. The initial recovery of platelets at 20 min after infusion was significantly higher for the 111In labeled platelets than popr 51Cr labeled platelets, providing the platelets were suspended and washed in plasma. The mean survival time of 111In labeled platelets, as estimated using 4 different mathematical models, was comparable with that of 51Cr labeled platelets. The high photon yield of .alpha. emitting 111In, unlike 51Cr, permits quantitative .gamma. camera imaging of the in vivo distribution of labeled platelets. This nuclide possesses advantages as a platelet label that will foster statistically more accurate kinetic research as well as quantitative in vivo distribution studies in humans.