The department involves several different healthcare professions working as a team. A radiologist is a medical doctor who has completed the appropriate post-graduate training and interprets medical images, communicates these findings to other physicians by means of a report or verbally, and uses imaging to perform minimally invasive medical procedures, the radiographer may specialize in imaging modalities or have expanded roles in image reporting. A variety of imaging techniques such as X-ray radiography, ultrasound, computed tomography (CT),  are used to diagnose or treat diseases. Interventional radiology is the performance of usually minimally invasive medical procedures with the guidance of imaging technologies such as those mentioned above.