Pain Management imaging equipment needs are typically C-Arms and Ultrasound.  C-Arms are used primarily used for needle guidance and checking anatomical features.  Ultrasound is used for musculoskeletal assessment and examination for small and large joints.

Siemens Arcadis Varic C-Arm
Low-Cost option for Pain Management application.
GE/OEC 9800 Plus Super C
This excellent "workhorse" is the gold-standard of pain management systems. Upgraded with LCD monitors, and sold with a One-Year Warranty, you can't go wrong with the GE 9800 Plus.