So far as I'm concerned intravenous DMPS is extremely dangerous. I'd highly recommend you avoid it.
If you need any incentive for this, you could have a look at the dmpsbackfire website if you can find it. (Not sure if it's still there - but when it was, it was filled with people's stories of lasting damage from IV DMPS.)
I have often used oral DMPS as part of the Cutler protocol. It's not as effective a chelator as ALA (which chelates the brain), but is an effectual adjunct to ALA, and appears to be pretty safe if you start low dose & work up carefully.
Did somebody had some serious side effects due to heavy metal chelation by IV DMPS/DMSA?
Think about to do it but Im afraid of the possible rare side effects...