Ultrasonography (Sonography) is widely used in medicine. It is possible to perform both diagnosis and therapeutic procedures, using ultrasound to guide interventional procedures (for instance biopsies or drainage of fluid collections). Sonographers are medical professionals who perform scans which are then   typically interpreted by themselves or the radiologists, physicians who specialize in the application and interpretation of a wide variety of medical imaging modalities, or by cardiologists in the case of cardiac ultrasonography (echocardiography). Sonographers typically use a hand-held probe (called a transducer)   that is placed directly on and moved over the patient. Increasingly, clinicians (physicians and other healthcare professionals who provide direct patient care) are using ultrasound in their office and hospital practices.

   Medical ultrasound is used in the study of many different systems:
  System/Specialty – Anesthesiology – Angiology – Cardiology – Emergency Medicine – Gastroenterology/Colorectal surgery – Gynecology – Head and Neck Surgery /Otolaryngology – Neonatology – Neurology – Obstetrics – Ophthalmology – Pulmonology – Urology – Musculoskeletal – Cardiovascular   system.

   Other types of uses include:
 – Interventional ultrasonography; biopsy, emptying fluids, intrauterine Blood transfusion (Hemolytic disease of the newborn)
 – Contrast-enhanced ultrasound
 – Quantitative ultrasound: an adjunct diagnostic test for myopathic disease in children; estimates of lean body mass in adults; proxy measures of muscle quality (i.e., tissue composition) in older adults with sarcopenia.
  A general-purpose ultrasound scanner may be used for most imaging purposes. Usually specialty applications may be served only by use of a specialty   transducer. Most ultrasound procedures are done using a transducer on the surface of the body, but improved diagnostic confidence is often possible if a   transducer can be placed inside the body. For this purpose, specialty transducers, including endovaginal, endorectal, and transesophageal transducers are commonly employed. At the extreme of this, very small transducers can be mounted on small diameter catheters and placed into blood vessels to image the   walls and disease of those vessels.