With DTPA presently unavailable in the USA - available everywhere else in the world. This ofcourse is unacceptable, but the present reality. I have devised an alternative approach using Ca- disodium EDTA. The rationale for regimen differs for DTPA and EDTA, and I will explain the rationale for EDTA below. EDTA stability constant is 17 with Gd, while DTPA is 22.5- DTPA roughly 500,000 times more stable with Gd than EDTA. This means that re-distribution is much more of an issue