Sonography is closely related to sonar in the way it works. Diagnostic equipment transmits an ultrasonic signal into the selected area of a patient's body. These high frequency sound waves are deflected at varying rates, according to the density of the tissues they encounter. The echoes are gathered and used to plot an image of the area under observation. The technician has responsibility for assessing and preserving images that will be useful for diagnostic purposes. Typically, the technician will also make a report to the physician, pointing out areas of interest or concern.
The best-known specialties within the field are obstetric and gynecological sonography, which are concerned with women's reproductive systems. However, sonographic imaging has many uses aside from monitoring the health of babies. Abdominal sonographers are able to detect and help diagnose many malfunctions of the body's glands and internal organs. Neurosonographers observe the function of the brain and nervous system, oncological sonography images tumors and cardiac sonographers specialize in the human heart. Breast sonographers use specialized high-frequency transducers made specifically for the purpose.
There are many ways to enter into a career in sonography. Those who are already certified technicians in another field may take an accelerated one-year course. For those who are not already qualified elsewhere, two-year associate's degree programs or four-year bachelor's degree programs are available. Many programs are accredited by Commission on Accreditation of Allied Health Education Programs (CAAHEP). These courses may be taught at universities, vocational and technical schools, community colleges or in a clinical setting by healthcare providers. Clinical experience is a part of most programs, and it is possible to qualify in sonography solely on the strength of clinical experience. However, formal training is preferred by most employers.
There is no licensing requirement for diagnostic sonographers, but some form of certification is generally advisable. There are a number of credentialing bodies to choose from. These include the American Registry for Diagnostic Medical Sonography (ARDMS), American Registry of Radiologic Technologists (AART) and Cardiovascular Credentialing International. The criteria will vary according to organization and credential, but generally applicants must have a suitable combination of experience and/or training, must pass an examination, and must maintain their certification by formal professional development.