The reasoning
Guidance: US (real‑time, no radiation, superficial and solid organs), CT (deep, lung, bone, retroperitoneum), fluoroscopy (biliary, urinary, GI), MRI (rare). Pre‑procedure: indication, consent, coagulation (INR, platelets; hold anticoagulants per SIR guidelines), allergy, safe window and track avoiding vessels, bowel and pleura.