In vivo comparison of copper blood-pool agents: potential radiopharmaceuticals for use with copper-62

J Nucl Med. 1991 Mar;32(3):475-80.

Abstract

Two techniques for labeling of albumin with copper-67 (67Cu) and 62Cu were investigated; one using the native Cu(II) binding site of the protein and the other employing a bifunctional chelate, 6-bromoacetamidobenzyl-1,4,8,11-tetraazacyclotetradecane- N,N'N",N"'-tetraacetic acid (Br-benzyl-TETA or BAT), conjugated to the protein. Rat biodistribution experiments with 67Cu demonstrated retention of i.v. 67Cu-benzyl-TETA-albumin in the blood pool identical to co-injected 125I-albumin. By contrast, i.v. administration of either [67Cu]-Cu-acetate or [67Cu]-Cu-acetate pre-mixed with albumin results in relatively rapid clearance of blood-pool radioactivity as the tracer is excreted into the urine. The 62Cu-benzyl-TETA-albumin radiopharmaceutical was obtained in ca. 17% radiochemical yield (end of synthesis, without decay correction) following a procedure that can be completed in 15-18 min. In PET experiments with a baboon, myocardial blood volume images with 62Cu-benzyl-TETA-albumin were identical to those obtained with C15O. Use of the 62Cu-benzyl-TETA-albumin image for blood-pool subtraction of a 62Cu-PTSM myocardial perfusion image is illustrated. Copper-62-benzyl-TETA-HSA should be a useful, generator-produced radiotracer for the detection of the vascular pool at PET facilities without cyclotrons.

Publication types

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

MeSH terms

  • Animals
  • Blood Volume Determination / methods*
  • Copper / pharmacokinetics*
  • Female
  • Heart / diagnostic imaging*
  • Heterocyclic Compounds / pharmacokinetics*
  • Isotope Labeling / methods
  • Male
  • Organometallic Compounds / pharmacokinetics*
  • Papio
  • Rats
  • Rats, Inbred Strains
  • Serum Albumin / pharmacokinetics*
  • Serum Albumin, Human
  • Tissue Distribution
  • Tomography, Emission-Computed*

Substances

  • Heterocyclic Compounds
  • Organometallic Compounds
  • Serum Albumin
  • copper acetamidobenzyl-1,4,8,11-tetraazacyclotetradecane-N,N',N'',N'''-tetraacetic acid-serum albumin
  • Copper
  • Serum Albumin, Human