The role of a Rad Tech in DBS in my experience is in performing the CT scan (while the patient is wearing what is called a "head frame" and an MRI scan which is also necessary. I’ve not had them come to the OR for the procedure. That being the case, I rely on my MR techs to help me "tweak" our protocol to get optimal views of the structures we target from (anterior and posterior commisures).

The CT scan and MRI scans are "fused" by a surgical navigaton system (Stealth by Medtronic, Omnisight by Radionics, and there are others).

The procedure in brief (if you want more detail, email me):
1. Diagnosis (Parkinson’s disease or Essential Tremor)
2. Usual preop testing: May include neuropsych eval
3. Baseline neuro assessment to check tremor, etc.
4. MRI scan: In navigational system protocol (axial images, slices at 1-2 mm, contiguous)
5. Day of surgery: Frame placed on patient’s head
6. CT scan: Done in navigational protocol, 1mm contiguous cuts, field of view must encompass headframe entirely.
7. Scans fed to Surgical Navigation System. CT and MRI are "fused" by surgical personnel w/surgeon because it requires correlation of anatomic locations on CT to same places on MRI,
8. Targeting done by neurosurgeon, using known landmarks e.g. Find anterior and posterior commisures, plot 1/3 of this distance and add 1/2 of the width of the 3rd ventricle, etc. Sounds like I’m making this up – I’m not.
9. Enter coordinates to the target on a "phantom" and on "arc" to make sure they line up —
10. Put arc on patient’s head frame, make incision, burr hole, etc. and insert lead to the target
11. During lead placement, do testing of tremor to assure good placement, symptom control
12. Repeat steps 8-11 on other side if bilateral treatment is indicated.

Below is one link to some of Medtronic’s info – may be helpful.