Replacing 99mTc with 111In improves MORF/cMORF pretargeting by reducing intestinal accumulation

UMMS Affiliation

Department of Radiology, Division of Nuclear Medicine

Publication Date


Document Type



Animals; Indium Radioisotopes; Intestines; Mice; Morpholines; Morpholinos; Positron-Emission Tomography; Radiopharmaceuticals; Technetium Compounds; Tissue Distribution; Whole Body Imaging


Bioimaging and Biomedical Optics | Radiology


PURPOSE: To reduce accumulation in the abdomen by MORF/cMORF pretargeting, 111In was compared to 99mTc as the radiolabel.

PROCEDURES: After receiving either 99mTc (MAG3)-cMORF or 111In (DTPA)-cMORF, normal mice were imaged and sacrificed for pharmacokinetics. Thereafter, tumored mice were pretargeted withMORF-antibody, 48 h later were given an injection of 99mTc- or 111In-cMORF, and finally were imaged repeatedly.

RESULTS: The cMORF biodistribution in both normal and pretargeted tumored mice was influenced by its radiolabel. While excretion of both 99mTc-cMORF and 111In-cMORF was rapid and mainly through the kidneys, about 2% of 99mTc accumulated in the intestines compared to essentially no intestinal accumulation for 111In at any time. Tumor accumulation was unchanged.

CONCLUSION: In applications of MORF/cMORF pretargeting intended to image organs deep within the abdomen such as the pancreas, radiolabeling with 111In may be superior to 99mTc.


Pretargeting, Anticancer, Antibodies, Tumor, Radioimmunotargeting

DOI of Published Version



Mol Imaging Biol. 2009 Sep-Oct;11(5):303-7.Link to article on publisher's site.Epub 2009 Mar 27.

Journal/Book/Conference Title

Molecular imaging and biology : MIB : the official publication of the Academy of Molecular Imaging

Related Resources

Link to Article in PubMed

PubMed ID