In 1911 the Department of Physical therapy (precursor of nowaday's Department of Radiology) was established in the SotokufuHospital (the predecessor of the current National Taiwan University Hospital) when Taiwan was still under Japanese occupation. Later in 1937, it was renamed as the Department of Radiology as the mother hospital also renamed to Empire University Hospital (Taipei). After the Second World War, the sovereignty of Taiwan returned to Republic of China, the name of the department was changed to Department of Physical Therapy and the mother hospital adopted its current name. In 1954, the Division of Radiation Therapy and Isotope room were integrated into the Department of Radiology in National Taiwan University Hospital.

In 1990, the Department of Radiology was functionally divided into 3 divisions, namely Diagnostic Radiology, Nuclear Medicine and Therapeutic Radiology. As new imaging modalities such as ultrasonography and magnetic resonance imaging, which do not possess the property of radiation, added to the basic arsenals of X-ray machines, the Division of Diagnostic Radiology was renamed as Department of Medical Imaging in 1993.

Functionally, there are 5 subspecialties in the Department of Medical Imaging including the neural, chest, body, musculoskeletal, and pediatrics groups and each has a chief who is responsible to the Chairman of the department. According to daily practice, the Department of Medical Imaging has 5 categories of work: plain film (those examinations not requiring special technique nor preparation, e.g. routine chest, abdomen, and skeleton x-rays, etc).; special examinations (those requiring special technique, contrast medium, as well as preparation, and are performed by radiologist, e.g. barium meal and enema studies, intravenous urograms, etc.); Computed Tomography (CT), a sophisticated X-ray whole body scanning technique capable of producing high resolution cross sectional images of the body; Magnetic Resonance Imaging (MRI), another sophisticated whole body scanning technique capable of producing high resolution sectional (not limited to axial) images of the body and does not require ionization radiation; Vascular and Interventional Radiology which deals with examinations of the vascular system of the body and a wide spectrum of therapeutic works that helps in treating patients, e.g. embolization therapy of cancer of the liver or aneurysm of the brain, dilatation of a narrowed artery or vein, drainage of obstructed bile ducts or urinary tract, biopsy of various body parts or drainage of abscesses, etc. Ultrasonography is a powerful tool that has been known as the doctors' second stethoscope. It does not produce ionization and is a very convenient tool to examine the solid organs of the body, e.g., the liver, kidneys, the female genital organs, thyroid glands, etc. Owing to its versatility, the machine can be brought into the Intensive Care Unit to facilitate bed-side examinations. In our hospital, the administration of this modality is under Integrated Departments, but radiologists do take part in the daily service as well as using this modality to guide us in certain therapeutic procedures, for example, biliary drainage in obstructive jaundice.

In summary, nowadays the Department of Medical Imaging not only deals with diagnostic work, but also with tremendous applications in the treatment side, so that some in-operable cancers can be embolized, aneurysm in the brain or aorta that formerly should require open surgery can now be treated with coil embolization or stenting, so on and so forth, resulting in dramatically shortened hospital-stay (meaning less economical burden) and remarkably reduced discomfort of patients.