Ultrasounds, also known as ultrasonography, is a form of sonography. At approximately 18 to 20 weeks of pregnancy, a woman will undergo an ultrasound examination to ensure her fetus' healthy growth and development. Ultrasounds can also be used when diagnosing injuries, torn ligaments, growths, cysts and other ailments.
Medical imaging generally utilizes ionizing radiation. Sonography is the one form of medical imaging that does not utilize this type of radiation, but rather uses high-frequency sound waves to create an image. This fact makes sonography an attractive option for pregnant women and for children. Whenever possible, sonography is used over traditional minor medical imaging methods.
The differences between medical imaging and sonography become apparent when focusing on the full body versus parts of the body. While medical imaging techniques like CAT scans and MRIs can address both smaller parts and larger section of a body, sonography traditionally has been used to take images of small portions of the body. Sonography is not used to take a medical image of a large section of a person's body.
Traditionally, mammography has been done with an x-ray machine. The medical image would be taken in the form of an x-ray of the woman's breasts. The image is then used as an initial screening for breast cancer. Digital mammography is a newer type of medical imaging that allows for digital analysis of the medical images taken during the mammogram. Additionally, sonography can be used as a tool in diagnosing breast cancer. Particularly effective in younger women with dense breast tissue, a sonography can be done on breasts to help diagnose cysts, tumors or any other tissue or glandular problem in the breasts.