A preliminary investigation of 67Ga citrate distribution in hyperferraemic patients.

Scanning for malignant or inflammatory lesions with 67Ga citrate currently has a number of major limitations. In an effort to improve visualisation of the abdomen and pelvis, and to reduce the time between 67Ga citrate injection and the scan (usually 72 h) a series of patients was given an intramuscular injection of 100 mg iron-sorbitol citric acid complex (jectofer) two hours prior to receiving an intravenous injection of 67Ga citrate. Laboratory measurements on blood samples removed at different times showed that this pre-treatment altered radically both the amount of free transferrin and the level of 67Ga activity in the blood pool for the majority of patients. Follow up of 30 patients entered in this preliminary trial showed that when 24 h and 48 h scans were analysed together, accuracy in the diagnosis and localisation of pathological lesions was at least as good as by the standard method. We believe that by saturating the free transferrin with iron, uptake into normal soft tissues may be modified sufficiently to enhance significantly the tumour to background ratio, thereby making earlier scanning possible. Investigations are continuing.