The effect of the administration of iron on gallium 67 citrate uptake in tumours.

Consideration has been given to the use of iron as an aid in 67Ga scanning. The effects of various doses and the time of injection have been measured quantitatively in four transplantable rodent tumours. It was found most effective to administer the iron, as ferric ammonium citrate, before the 67Ga injection. The experimental tumours respond to different extents, and the tumour:non-tumour ratios at four hours after 67Ga injection have been found to be from two to four times better than those obtained at 24 hours with 67Ga alone. The effects of administered iron on the rate of blood clearance and the plasma binding of 67Ga have been measured. The use of carrier gallium or scandium was found to be less advantageous than the use of iron.