I am trying to locate an understandable answer to the question: When do you have to use a Nurse Practicioners NPI vs the Radiologist's NPI for billing?

Understanding is that Paracentesis, Thoracentesis, LP etc done by the NP are to be billed under the NP-but, can we charge for the guidance that the Radiologist dictates under their own NPI? That is where we get confused.

Also, IDTF 26/TC billing and also HOSPITAL -26 for ER/IP/OP. Is there a difference?