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

UMMS Affiliation

Department of Radiology, Division of Nuclear Medicine



Document Type


Medical Subject Headings

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.

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

Related Resources

Link to Article in PubMed


Pretargeting, Anticancer, Antibodies, Tumor, Radioimmunotargeting

PubMed ID