99mTc labeled VIP analog: evaluation for imaging colorectal cancer

Nucl Med Biol. 2001 May;28(4):445-50. doi: 10.1016/s0969-8051(01)00205-0.


Early and reliable diagnosis of colorectal cancer continues to be demanding and challenging. Colorectal cancer cells express Vasoactive Intestinal Peptide (VIP) receptors in high density. We have prepared a VIP analog (TP3654), labeled it with (99m)Tc, and evaluated it in experimental animals as an agent for imaging colorectal cancer. The tissue distribution of (99m)Tc-TP3654 has been compared with that of (111)In-DTPA-Octreotide and (99m)Tc-anti-CEA scan in nude mice bearing human colorectal cancer LS174T. Finally, pharmacokinetic and tissue distribution studies of (99m)Tc-TP3654 have been performed in four normal human volunteers. Data suggest that (99m)Tc-TP3654 can be prepared efficiently without loss of its receptor specificity and biological activity. Although the 24 hr tumor uptake of (99m)Tc-TP3654 in the animal model used was modest (0.21 +/- 0.07% I.D./g), the tissue distribution profile was more favorable than that of (111)In-DTPA-Octreotide or (99m)Tc-anti-CEA scan. Human studies indicated that (99m)Tc-TP3654 had no adverse effect in any subject. Within 24 hours, approximately 70% of the injected dose cleared through the kidneys, and approximately 20% through the hepatobiliary system. In these non-fasting volunteers hepatobiliary clearance was slow and in cancer patients tumor uptake was rapid. Data suggest that (99m)Tc-TP3654 is a promising agent for imaging colorectal cancer.

Publication types

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

MeSH terms

  • Colorectal Neoplasms / diagnostic imaging*
  • Humans
  • Indium Radioisotopes
  • Kidney / metabolism
  • Octreotide / analogs & derivatives
  • Oligopeptides* / metabolism
  • Quality Control
  • Radionuclide Imaging
  • Radiopharmaceuticals* / metabolism
  • Receptors, Vasoactive Intestinal Peptide / metabolism*
  • Technetium / chemistry
  • Tissue Distribution
  • Vasoactive Intestinal Peptide* / metabolism


  • Indium Radioisotopes
  • Oligopeptides
  • Radiopharmaceuticals
  • Receptors, Vasoactive Intestinal Peptide
  • TP 3654
  • Vasoactive Intestinal Peptide
  • Technetium
  • Octreotide