In vivo behavior of /sup 99m/Tc-fibrinogen and its potential as a thrombus- imaging agent
We have investigated the in vivo behavior of /sup 99m/Tc-fibrinogen, prepared by a mild and efficient electrolytic method employing tin electrodes. The clearance mechanisms of this agent were studied, and its efficacy for imaging deep-vein thrombi in dogs with an Anger camera was determined. The /sup 99m/Tc- fibrinogen preparations, which are stable in vitro, undergo partial rapid exchange of the technetium with other plasma proteins and with anions of the blood buffer system in vivo, resulting in an early drop in the percent of radioactivity associated with clottable protein. However, very little or no oxidation to pertechnetate occurs. The nonclottable material is much more rapidly cleared from the blood than the remaining /sup 99m/Tc-fibrinogen, and the proportion of clottable protein activity increases with time. The fraction of / sup 99m/Tc-fibrinogen that remains intact in vivo is biologically active and will incorporate into thrombi. Higher thrombus-to-blood activity ratios are obtained with /sup 99m/Tc-fibrinogen than with radioiodinated fibrinogen when both agents are injected into dogs 4 hr after induction of femoral vein thrombosis. Clearly delineated images of the thrombi are obtained, beginning about 2.5 hr after injection. Thus, /sup 99m/Tc-fibrinogen may be of clinical use as a thrombus- imaging agent in patients undergoing active thrombosis, especially in regions of high blood pool. (auth)
- Research Organization:
- Edward Mallinckrodt Inst. of Radiology, St. Louis
- NSA Number:
- NSA-33-009715
- OSTI ID:
- 4131999
- Journal Information:
- J. Nucl. Med., v. 17, no. 1, pp. 40-46, Journal Name: J. Nucl. Med., v. 17, no. 1, pp. 40-46; ISSN JNMEA
- Country of Publication:
- United States
- Language:
- English
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