Modification of gallium-67 citrate distribution in man following the administration of iron.

Current imaging techniques with 67Ga citrate for the localization of malignant or inflammatory lesions have a number of major limitations. In an effort to improve the lesion-to-background ratio and to reduce the time between 67Ga citrate injection and performing the scan, the 67Ga citrate injection is now routinely preceded by injection of iron-sorbitol citric acid (Jectofer). A series of 147 patients has been studied and shows that (a) the diagnosis can be made at 24 h in 80% of the cases, and (b) when 24 h and 48 h images are read together, diagnosis is at least as accurate as by the standard method, which requires a 72 h interval between injection and scanning. The major differences in appearance are lower activity in the soft-tissue background, relative absence of colonic activity at 24 h and visualization of the bladder in about 40% of cases. We believe that by saturating the free transferrin with iron, uptake into soft tissues and bone is sufficiently modified to enhance the lesion-to-background ratio, thereby making earlier imaging and diagnosis possible.