Panel Disdussion

3rd International Congress 3rd International of Nuclear Congress Medicine of Nuclear & 15th Medicine Iranian Annual & 15th Iranian Congress Annual of
Nuclear Congress Medicine of Nuclear Medicine
Shahid Beheshti Shahid Beheshti University University of Medical Sciences of Medical 19-21 Sciences May 201119-21 May 2011
Preparation and evaluation of 99mTc-cefotaxime for infection
imaging
Mostafa Erfani (Gandomkar), Fatameh Mirshojaei
Nuclear Science Research School, Nuclear Science & Technology Research
Institute (NSTRI), Atomic Energy Organization of Iran
Introduction: A wide range of radiopharmaceuticals have been
proposed to visualize infection and inflammation scintigraphically.
The use of radiolabeled antibiotics is fast emerging as a promising
diagnostic test for the detection of infective lesions. Second and third
generation cephalosporines, including cefuroxime and ceftizoxime
have been labeled with 99mTc. In this study we describe the
optimum condition for radiolabeling of cefotaxime with the most
widely used imaging radionuclide, 99mTc.
Method: The radiolabeling was performed by the sodium dithionite
as the reducing agent. The labeling yield and radiochemical purity
were determined by thin layer chromatography. The affinity of the
labeled antibiotic to human serum proteins was examined by mixing
1 mL of labeled cefotaxime with activity between 5 and 20 mCi to 1
mL of human serum in a vial. Binding of 99mTc-cefotaxime to
bacteria was assessed in S. aureus suspention. Animal biodistribution
was evaluated in mice with infectious thigh muscle.
Result: The maximum radiolabeling yield was 92±2% and was stable
for up to 12 h. This antibiotic showed an improvement in excretion
pathway from the liver to the kidney followed by an accumulation of
radioactivity in infected areas. Images showed minimal accumulation
in non-target tissues, with an average target/non-target ration of
2.89±0.58%.
Conclusion: The promising characteristics make our new radiotracer
a very suitable candidate for diagnostic of infectious foci in nuclear
medicine
Keywords: 99mTc, Cefotaxime, Infection imaging
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