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Updated: Jun 24, 2026

Preparation and Evaluation of 99mTc-labeled Tridentate Chelates for Pre-targeting Using Bioorthogonal Chemistry
Published on: February 4, 2017
Replacing 99mTc with 111In improves MORF/cMORF pretargeting by reducing intestinal accumulation
Guozheng Liu1, Dengfeng Cheng, Shuping Dou
1Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655-0243, USA. guozheng.liu@umassmed.edu
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 killed 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 toessentially 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.

