Tumor imaging via indium 111-labeled DTPA-adenosylcobalamin

Vitamin B-12 is essential for life. Lack of it results in pernicious anemia and death, Conversely, the demand for vitamin B-12 increases in rapidly dividing tumors. This is secondary to the direct involvement of vitamin B-12 in mitochondrial metabolism as well as its indirect role in the production of thymidylate and S-adenosylmethionine. The latter 2 substances are needed for DNA synthesis and cellular methylation reactions, respectively. Novel radiolabeling of adenosylcobalamin has proven to be useful in the imaging of transplanted and spontaneous tumors in animals. Herein, we describe what we believe to be the first human to have imaging with conventional gamma cameras of vitamin B-12 metabolism in a breast tumor.