Tumour imaging using radiolabeled AFP:
Following the injection of 131I-MoAFP, spontaneous mouse mammary carcinomas could be clearly
imaged31 allowing, in some cases, the visualization of tumours as small as 3 mm in diameter32. In
the latter study, eleven out of twelve tumors were detected using a standard gamma camera
linked to a computer. Another study in mice showed that transplanted C1300 neuroblastoma
tumours could be imaged as well33.
These considerations, along with the high quality of the images obtained in animals, prompted us
to scan patients injected with 131I-HuAFP. As the uptake of AFP is related to the degree of cell
differentiation, it was possible that undifferentiated cell precursors in organs such as the gonads
and the bone marrow could be adversely affected by the accumulation of radioactivity. In order to
address this possibility, we injected twelve female and six male mice with a dose of 0.1 mCi of
131I-AFP per animal, the equivalent, weight-to-weight, to 25O mCi for an adult human being. No
abnormalities were detected in these mice, which had a normal life span. When mated, fertility
was normal, and two generations of their offspring were also normal.
Two healthy individuals (including the author) and three cancer patients were thus injected with
300-600 ug of 131I-HuAFP (~0.6 mCi) and scanned 2 to 7 days later34. Figure 1 shows the image of
a male patient bearing a large abdominal tumour (diagnosed as a stomach carcinoma). The
arrows point to large radioactive spots on the area of the palpable mass.