Hi Stingray - I've had several sympathetic nerve blocks done this way. They use fluoroscopy, which is 'real time' x-ray - often with contrast dye as well - which helps identify the precise point at which to target the nerve.
All the best with your block *gentle hugs*
CRPS since 1999, diagnosed in 2005 and since spread to full body, spasms, dystonia & contractures, gastroparesis, orthostatic hypotension,bradycardia/tachycardia, bone spurs, bursitis, carpal tunnel syndrome, osteoporosis, osteopenia.
On Oxycontin/Endone, Topamax, Mobic, Magnesium, Florinef, Midodrine, Somac, Cipramil. Have SCS, intrathecal pump with baclofen & bupivacaine and doing physio