Biodistribution and imaging studies of technetium-99m-labeled liposomes in rats with focal infection.
We have recently developed a procedure to label liposomes containing reduced glutathione (GSH) with 99mTc using the lipophilic chelator, hexamethylpropyleneamine oxime (HMPAO). In the present study, we evaluated the use of 99mTc-liposomes to detect focal infection sites in rats. Rats were infected in the thigh by intramuscular injection with Staphylococcus aureus followed 24 hr later by an intravenous injection of 99mTc-liposomes, 67Ga-citrate, or 99mTc-human serum albumin (HSA). The animals were imaged under a gamma camera and subsequently killed at 4, 24 or 48 hr for tissue biodistribution studies. In contrast to infected rats receiving 67Ga-citrate or 99mTc-HSA, abscesses were prominently localized within 2 hr in rats after 99mTc-liposome injection, and continued to increase in activity up to 24 hr. Abscess-to-muscle ratios calculated from 24-hr biodistribution data obtained from tissue sampling were 35.3 +/- 7.6 for 99mTc-liposomes, 4.1 +/- 0.7 for 67Ga-citrate and 8.0 +/- 1.0 for 99mTc-HSA. These studies show the potential of using 99mTc-liposomes to localize infection.
Goins
B
B
Radiology Department, University of Texas Health Science Center at San Antonio 8284-7800.
Klipper
R
R
Rudolph
A S
AS
Cliff
R O
RO
Blumhardt
R
R
Phillips
W T
WT
D000818:Animals; D005490:Focal Infection / Q000000981:diagnostic imaging*; D008081:Liposomes / Q000493:pharmacokinetics; D008297:Male; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D010091:Oximes / Q000493:pharmacokinetics; D011877:Radionuclide Imaging; D051381:Rats; D017207:Rats, Sprague-Dawley; D013203:Staphylococcal Infections / Q000000981:diagnostic imaging*; D019690:Technetium Tc 99m Exametazime; D014018:Tissue Distribution
D008081:Liposomes; D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime