Sheep IgG antibody to alpha-fetoprotein was labelled with '3'I and used to identify human germ-cell tumours by emission scanning. Eleven patients were studied after resection of their primary tumours. Ten had malignant teratoma and one an endodermal sinus tumour. All eight patients with raised serum alphafetoprotein concentrations had metastases apparent in the antibody scans. Of the remaining three patients witil normal serum alpha-fetoprotein concentrations, two had positive scans. Three of the patients with positive results were scanned twice; the second scans were negative after treatment, when the alpha-fetoprotein concentrations had returned to normal.These results suggest that antibody scans are useful in the clinical management of patients with germ-cell tumours.

Sheep IgG antibody to alpha-fetoprotein was labelled with '3'I and used to identify human germ-cell tumours by emission scanning. Eleven patients were studied after resection of their primary tumours. Ten had malignant teratoma and one an endodermal sinus tumour. All eight patients with raised serum alphafetoprotein concentrations had metastases apparent in the antibody scans. Of the remaining three patients witil normal serum alpha-fetoprotein concentrations, two had positive scans. Three of the patients with positive results were scanned twice; the second scans were negative after treatment, when the alpha-fetoprotein concentrations had returned to normal.These results suggest that antibody scans are useful in the clinical management of patients with germ-cell tumours.primary and secondary tumours is upwards of 75 °0.' The specific uptake of radiolabelled antibody into the tumour ranges from two to five times the surrounding normal tissues.3 One promising application of the technique is in detecting tumours that produce alpha-fetoprotein. Germ-cell tumours such as malignant teratoma and endodermal sinus tumour, though uncommon, are amenable to chemotherapy even when widely disseminated.6 Though alpha-fetoprotein is not a cellsurface marker (being associated with the cytoplasm of yolk-sac