There are 4 types of Imaging Instruments. They are:
1. CT Scanning(computed tomography)
2. Positron emission tomography (PET)
3. MRI (Magnetic Resonance Imaging)
4. Ultrasound
1. CT Scanning(computed tomography)
Computerized (or computed) tomography, and often formerly referred to as computerized axial tomography (CAT) scan, is an X-ray procedure that combines many X-ray images with the aid of a computer to generate cross-sectional views and, if needed, three-dimensional images of the internal organs and structures of the body. Computerized tomography is more commonly known by its abbreviated names, CT scan or CAT scan. A CT scan is used to define normal and abnormal structures in the body and/or assist in procedures by helping to accurately guide the placement of instruments or treatments.
A large donut-shaped X-ray machine or scanner takes X-ray images at many different angles around the body. These images are processed by a computer to produce cross-sectional pictures of the body. In each of these pictures the body is seen as an X-ray "slice" of the body, which is recorded on a film. This recorded image is called a tomogram. "Computerized axial tomography" refers to the recorded tomogram "sections" at different levels of the body.
CT scan or computerized tomography scan was first invented by Godfrey Hounsfield in the early 1970's at the EMI Laboratories in England. It is also referred to as CAT scan (Computerized Axial Tomography). The technology uses X-ray and complex computers to create a cross sectional slice of the body.
2. Positron emission tomography (PET)
Positron emission tomography (PET) is a specialized radiology procedure used to examine various body tissues to identify certain conditions. PET may also be used to follow the progress of the treatment of certain conditions. While PET is most commonly used in the fields of neurology, oncology, and cardiology, applications in other fields are currently being studied.
PET is a type of nuclear medicine procedure. This means that a tiny amount of a radioactive substance, called a radionuclide (radiopharmaceutical or radioactive tracer), is used during the procedure to assist in the examination of the tissue under study.
Specifically, PET studies evaluate the metabolism of a particular organ or tissue, so that information about the physiology (functionality) and anatomy (structure) of the organ or tissue is evaluated, as well as its biochemical properties. Thus, PET may detect biochemical changes in an organ or tissue that can identify the onset of a disease process before anatomical changes related to the disease can be seen with other imaging processes, such as computed tomography (CT) or magnetic resonance imaging (MRI).
PET is most often used by oncologists (doctors specializing in cancer treatment), neurologists and neurosurgeons (doctors specializing in treatment and surgery of the brain and nervous system), and cardiologists (doctors specializing in the treatment of the heart). However, as advances in PET technologies continue, this procedure is beginning to be used more widely in other areas. PET is also being used in conjunction with other diagnostic tests such as computed tomography (CT) to provide more definitive information about malignant (cancerous) tumors and other lesions. The combination of PET and CT shows particular promise in the diagnosis and treatment of many types of cancer. Until recently, PET procedures were performed in dedicated PET centers. The equipment used in these centers is quite expensive.
However, a new technology called gamma camera systems (devices used to scan patients who have been injected with small amounts of radionuclides and currently in use with other nuclear medicine procedures) is now being adapted for use in PET scan procedures. The gamma camera system can complete a scan more quickly, and at less cost, than a traditional PET scan.
3. MRI (Magnetic Resonance Imaging)
MRI (Magnetic Resonance Imaging) scanning is a medical investigation that uses an exceptionally strong magnet and radio frequency waves to generate image of your body. An MRI scan is one of the most sophisticated diagnostic tools available to help a referring clinician understand the cause of your particular health issue. By scanning the relevant sector(s) of a patient’s body, an MRI scan can help to diagnose the following:
i. most ailments of the brain, including tumours and dementias
ii. sports injuries
iii. musculoskeletal problems
iv. most spinal conditions/injuries
v. vascular abnormalities
vi. female pelvic problems
vii. prostate problems
viii. some gastrointestinal tract conditions
ix. certain ear, nose and throat (ENT) conditions
x. soft tissue and bone pathology/conditions
4. Ultrasound
An ultrasound scan is a medical test that uses high-frequency sound waves to capture live images from the inside of your body. The technology is similar to that used by sonar and radar, which help the military detect planes and ships. An ultrasound allows your doctor to see problems with organs, vessels, and tissues without needing to make an incision.
Unlike other imaging techniques, ultrasound uses no radiation, so it is the preferred method for viewing a developing fetus during pregnancy. Ultrasound is also known as Sonography.
