Some of the most commonly used types of diagnostic imaging equipment include x-ray machines, computerized tomography (CT) scanners, magnetic resonance imaging (MRI) scanners, positron emission tomography (PET) scanners, and ultrasound machines. Each of these pieces of diagnostic imaging equipment allows health-care providers to study various internal structures of the body. While similar in title, each piece of equipment performs a different function that aids professionals in diagnostics and treatment.
X-ray machines work by sending a small amount of radiation, in the form of electromagnetic waves, through the body onto film or a special plate. The electromagnetic waves are typically absorbed by the bones, dense tissues, and any metallic objects within the body and pass through soft tissues, such as skin, muscle, and fat. When the film or plate is developed into a radiograph, any areas where the electromagnetic waves from the x-ray machine were absorbed appear white. Areas where the waves went all the way through to the film or plate appear black. X-rays are often used to help diagnose bone problems, such as fractures or dental cavities, and to identify foreign objects in the body, such as bullets or nails.
CT scanners are a special type of X-ray machine. In general, CT scanners include a large ring that emits electromagnetic waves and captures those that pass through the body. The scanner is hooked up to a computer that helps interpret the x-ray pictures and typically displays them as cross-sectional or two-dimensional views of the x-rayed sections of the body. CT scanners generally capture more detail than x-ray machines, so they may be used to help show bones, organs, tumors, and other tissues in the body.
Another type of diagnostic imaging equipment is an MRI scanner. Unlike X-ray machines and CT scanners, an MRI scanner does not use radiation; instead, it uses magnetic and radio waves. An MRI scanner typically includes a large cylinder-shaped magnet with a hole in the middle that the patient slides into. This magnet creates a magnetic field that surrounds the patient as he or she enters the scanner. In general, radio waves are then passed through the body at regular intervals, thereby creating data that is transmitted to an attached computer, which translates the data into cross-sectional images of organs, blood vessels, and bones.
PET scanners are yet another type of diagnostic imaging equipment that uses a ring that a patient slides into. In this case, the ring detects radioactive material, which a patient usually swallows, inhales, or receives via intravenous injection immediately before having a PET scan. A patient then typically lies on a table and slides into the PET-scanner ring, where the detectors track the radioactive material as it moves through the body. The ring is attached to a computer, which uses information about how much radioactive material is being absorbed to create a picture of what is occurring inside the body. In general, PET scanners can be used to help see how certain organs, such as the heart and brain, and body functions, such as blood flow, are working.
The final common type of diagnostic imaging equipment is the ultrasound machine. Ultrasound machines are typically made up of several components, including a transducer, computer, and video monitor. The transducer sends high frequency sound waves through the body and then listens for the echoes. This information is translated by the computer into an image, which is typically displayed on the video monitor. Ultrasound machines are often used to help view the soft tissues of the body, such as organs and blood vessels, and to see inside the uterus during pregnancy to monitor fetal development.