Comparison of intratumoral distribution of 99mTc-MIBI and deoxyglucose in mouse breast cancer models.

Abstract

UNLABELLED:

The aims of this study were to evaluate the distribution of 99mTc-methoxyisobutylisonitrile (MIBI) in 3 animal models of breast cancer, the effect of radiotherapy on 99mTc-MIBI uptake, and the relationship between uptake and microvessel density.

METHODS:

We used syngeneic, subcutaneously transplanted FM3A, MM48, and Ehrlich mouse breast cancer. 99mTc-MIBI and FDG were injected intravenously, and tumor uptake was measured 30 min later. Double-tracer macroautoradiography (ARG) images were prepared with 99mTc-MIBI and 2-deoxy-D-[1-14C]-glucose (14C-DG), analyzed quantitatively, and compared with histology. The radiotherapeutic effects of 20 Gy x-ray irradiation were monitored by measuring tumor volume, tumor uptake, and ARG findings using 99mTc-MIBI and FDG in FM3A tumors. Microvessel density was quantified by immunohistochemical staining for CD34 and compared with ARG using 99mTc-MIBI in FM3A tumors.

RESULTS:

FM3A, MM48, and Ehrlich tumors showed different growth rates and radiosensitivities. Uptake of FDG, but not of 99mTc-MIBI, correlated significantly with growth rates. Compared with 14C-DG, 99mTc-MIBI accumulated more in cancer cells and less in infiltrating fibroblasts and macrophages in all tumor models. Irradiation significantly decreased 99mTc-MIBI uptake, but a rapid increase was noted at recurrence on day 7. Changes in FDG uptake were not significant at recurrence. Microvessel density in tumor tissue correlated significantly with 99mTc-MIBI uptake on ARG.

CONCLUSION:

Accumulation of 99mTC-MIBI in cancer cells is preferential and can be used as a sensitive marker to examine the response to radiotherapy. Angiogenesis seems to enhance accumulation of 99mTc-MIBI in tumors. These characteristics may be favorable for tumor imaging using 99mTC-MIBI.

• Authors: H Ohira, K Kubota, N Ohuchi, Y Harada, H Fukuda, S Satomi
• Journal: Journal of nuclear medicine : official publication, Society of Nuclear Medicine (J Nucl Med) Vol. 41 Issue 9 Pg. 1561-8 (Sep 2000) ISSN: 0161-5505 [Print] United States
• PMID: 10994739 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Carbon Radioisotopes
• Radiopharmaceuticals
• Technetium Tc 99m Sestamibi
• Deoxyglucose

Topics

• Animals
• Biological Transport
• Carbon Radioisotopes (pharmacokinetics)
• Carcinoma, Ehrlich Tumor (diagnostic imaging, metabolism, pathology, radiotherapy)
• Deoxyglucose (pharmacokinetics)
• Female
• Mammary Neoplasms, Experimental (diagnostic imaging, metabolism, pathology, radiotherapy)
• Mice
• Mice, Inbred C3H
• Microcirculation (diagnostic imaging)
• Neovascularization, Pathologic (diagnostic imaging)
• Radionuclide Imaging
• Radiopharmaceuticals (pharmacokinetics)
• Technetium Tc 99m Sestamibi (pharmacokinetics)
• Tissue Distribution
• X-Rays