DIAGNOSIS OF HEAD AND NECK MALIGNANT TUMORS BY SCINTIGRAM USING 67Ga-CITRATE

Abstract

Scintigram with the use of 67Ga-citrate was taken from the patients with head and neck tumors, of whom 86 were with malignant tumors and other 16 with benign tumors or suspected tumors. Positive rate was studied according to the site, size and type of the tumors. The effect of the therapy and intake of 67Ga-citrate in the patients with recurrent tumor were also investigated.Accumulation of 67Ga-citrate in the normal head and neck tissue and tumor was determined by an animal experiment using rabbits.For the group of those with malignant tumors in the throat, nasal and paranasal cavity, epipharynx and tonsil, positive rate was more than 60% while it was less than 35% for the group with malignant tumors of the tongue, oral cavity or thyroid gland. Tumor of less than 1cm in diameter could not be delineated while it was possible with that of more than 1cm. The positive rate of reticulosarcoma and squamous cell carcinoma was higher than that of adenocarcinoma. Accumulation of 67Ga-citrate in the recurrent tumors was high. This method was also useful for detection of tumor spread by lymphatic permeation. Accumulation of 67Gacitrate was lowered by radiotherapy and chemotherapy.67Ga-citrate was occasionally found accumulating in abscess as well as in benign tumor, and therefore the differential diagnosis of these two necessitated concurrent employment of other tests.In the animal experiment, a high accumulation of 67Ga-citrate in the normal bone tissue was observed in contrast with the cartilaginous, membranous and soft tissue where its accumulation was low. There is a difference noticed between the ratio of tumor vs bone and that of tumor vs muscle with the result that tumor of the soft tissue was more easily identified than that of the bone tissue.From the foregoing finding, 67Ga-citrate scintigram was proved useful in making diagnosis of head and neck malignant tumor.