The interventional radiologist is a medical doctor who has completed four years of study in radiology. The interventional radiologist is then eligible to take the board examination given by the American Board of Radiology. Following board certification, the interventional radiologist completes an interventional radiology fellowship training program. Today, there are about 4,000 interventional radiologists in the US, mainly practicing in academic medical centers and in larger community hospitals. Interventional radiologists work closely with other physicians and play an important role on the treatment team.