Hepatic Tumor Radioembolization in a Rat Model Using Radioactive Rhenium (¹⁸⁶Re/¹⁸⁸Re) Glass Microspheres

Abstract

Purpose: the aim of this study was to fully characterize newly developed radioactive rhenium glass microspheres in vivo by determining their biodistribution, stability, antitumor effect, and toxicity after hepatic arterial injection in a syngeneic rat hepatoma model. The dose response of the tumors to increasing amounts of radioactive 186Re and 188Re microspheres was also determined. Methods and Materials: Rhenium glass microspheres were made radioactive by neutron activation and then injected into the hepatic artery of Sprague-Dawley rats containing 1-week-old Novikoff hepatomas. The biodistribution of the radioactivity and tumor growth were determined 1 h and 14 days after injection. Results: Examination of the biodistribution indicated a time-dependent, up to 7-fold increase in Novikoff hepatoma uptake as compared to healthy liver tissue uptake. After 14 days, the average T:L ratio was 1.97. Tumor growth in the rats receiving radioactive microspheres was significantly lower than in the group receiving nonradioactive microspheres (142% vs. 4824%, p = 0.048). Immediately after injection, 0.065% of the injected radioactivity was measured in the thyroid; it decreased to background levels within 24 h. Conclusion: Radioactive rhenium microspheres are effective in diminishing tumor growth without altering hepatic enzyme levels. The microspheres are safe with respect to their radiation dose to healthy tissue and radiation release in vivo and can be directly imaged in the body with a gamma camera. Furthermore, rhenium microspheres have an advantage over pure beta-emitting microspheres in terms of preparation and neutron-activation time. In sum, this novel radiopharmaceutical may provide an innovative and cost-effective approach for the treatment of nonresectable liver cancer.

Department(s)

Materials Science and Engineering

Keywords and Phrases

186Re; 188Re; Animal Model; Radioembolization; Rhenium Radioisotope; Hepatoma; Liver - Tumors; Microspheres; Rhenium

International Standard Serial Number (ISSN)

0360-3016; 1879-355X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1999 Elsevier, All rights reserved.

Publication Date

01 Apr 1999

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