Lymphoscintigraphy by sc injection of 67Ga-citrate.

Lymphoscintigraphy with SC injection of 67Ga-citrate was carried out on patients with lymph node metastasis and malignant lymphoma. The dose given at each injection site was about 200 muCi and scintigraphy was started about 5 min after injection. Metastatic lymph nodes and malignant lymphoma were successfully imaged. This positive delineation corresponded well to cold lesions detected by lymphoscintigraphy with 99mTc-rhenium colloid in metastatic lymph nodes. Hotter lesions in malignant lymphoma were scanned positively with 99mTc-rhenium colloid by this method. In in vitro studies, incorporation of 67Ga-citrate in HeLa S3 cells was about 4 times that in macrophages, when the incubation time was 1 h, while colloidal uptake by macrophages was 13 times that by HeLa S3 cells. The binding of 67Ga to transferrin in lymph and pinocytosis are suggested mechanisms of localization. A combination of colloid- and sc 67Ga-lymphoscintigraphy would be of value in the diagnosis of lymph node disease.