Replacing 99mTc with 111In improves MORF/cMORF pretargeting by reducing intestinal accumulation.
OBJECTIVE
To reduce accumulation in the abdomen by MORF/cMORF pretargeting, 111In was compared to 99mTc as the radiolabel.


METHODS
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.


CONCLUSIONS
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.
Liu
Guozheng
G
Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655-0243, USA. guozheng.liu@umassmed.edu
Cheng
Dengfeng
D
Dou
Shuping
S
Chen
Xiangji
X
Liang
Minmin
M
Pretorius
P Hendrik
PH
Rusckowski
Mary
M
Hnatowich
Donald J
DJ