Technetium-99m-human polyclonal IgG radiolabeled via the hydrazino nicotinamide derivative for imaging focal sites of infection in rats

J Nucl Med. 1990 Dec;31(12):2022-8.


The biologic behavior of human polyclonal immunoglobulin (IgG) radiolabeled with technetium-99m (99mTc) by a novel method, via a nicotinyl hydrazine derivative, was evaluated in rats. Technetium-99m- and indium-111-IgG were co-administered to normal rats and biodistribution was determined at 2, 6, and 16 hr. The inflammation imaging properties of the two reagents were compared in rats with deep-thigh infection due to Escherichia coli. Blood clearance of both antibody preparations was well described by a bi-exponential function: (99mTc-IgG: t1/2 = 3.82 +/- 0.89 and 57.52 +/- 1.70 hr. 111In-IgG: 3.93 +/- 0.117 and 40.71 +/- 1.26 hr). Biodistributions in the solid organs were similar, however, small but statistically significant differences were detected: 99mTc-IgG greater than 111In-IgG in lung, liver, and spleen; 99mTc-IgG less than 111In-IgG in kidney and skeletal muscle (p less than 0.01). At all three imaging times, target-to-background ratio and percent residual activity for the two compounds were remarkably similar. These studies establish that human polyclonal IgG labeled with 99mTc via a nicotinyl hydrazine modified intermediate is equivalent to 111In-IgG for imaging focal sites of infection in experimental animals.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Drug Stability
  • Escherichia coli Infections / diagnostic imaging*
  • Humans
  • Immunoglobulins* / pharmacokinetics
  • Isotope Labeling / methods*
  • Male
  • Radionuclide Imaging
  • Rats
  • Rats, Inbred Strains
  • Technetium* / pharmacokinetics
  • Tissue Distribution


  • Immunoglobulins
  • technetium Tc 99m immunoglobulin
  • Technetium