The DMX (Digital Motion X ray) is an x-ray in real time. It represents the next evolution to the normal x-rays and combines digital with optical technology. It offers patients the advantage that you can scan the spine in extreme positions and in real time. It is carried out under normal weight bearing, while standing or sitting. The DMX is used to diagnose ligament damages that normal static x-rays miss.
There are no scientific publications about the safety of this technique and the radiation exposure is not clear. Most informations I could find online are from the manufacturer of DMX.
Every x ray comes with a radiation exposure but DMX seems to have a significant higher radiation. Some doctors highly support the usage of DMX especially for cervical spine injuries, some on the other hand advise against DMX because of the unclear radiation.