Optics 101

Medical Diagnostic Imaging Systems - Brief Descriptions of Commonly Used Medical Diagnostic Imaging Systems

Magnetic Resonance Imaging - MRI
Ultrasound
X-Ray
Computed Tomography - CT
Positron Emission Tomography - PET

Magnetic Resonance Imaging - MRI

Magnetic resonance imaging or abbreviated as MRI is a scan that uses radio waves and a magnetic field to generate images or photographs inside the human body. Magnetic resonance imaging is used to collect images of soft tissues such as muscles and organs.

Unlike x-rays which image calcium in bones, MRI scans image water. Since all tissues inside the human body contain certain amounts of water, this makes magnetic resonance imaging very practical. High-resolution images of various organs and tissues can be taken using magnetic resonance imaging which appears invisible in normal x-rays.

Ultrasound

Ultrasound works by transmitting high frequency sound waves directed at the internal organ being examined. This high frequency sound wave cannot be heard by the human ear. The echoes or reflected sound waves are recorded to generate an image that can be seen on a monitor. A small hand-held probe is used to emit the sound wave. Ultrasound scans are also referred to as sonogram and ultrasonography.

X-Ray

X-ray uses electromagnetic radiation to create pictures of human teeth, bones and internal organs. X-rays is one of the oldest forms of medical imaging. X-ray is a medical examination that can assist doctors and physicians in diagnostics and treatments even in medical emergencies.

Computed Tomography - CT

Computed tomography or CT is a medical imaging system that uses digital computer technology as well as x-rays to generate 2D or 3D detailed images. Computed tomography scans are also sometimes referred to as computer assisted tomography.

Computed tomography scans can create images of every type of body structures at once including blood vessels, soft tissues and bones.

The computed tomography instrument is composed of a large square machine with a circular hole. A rotating gantry carrying an x-ray source and electronic x-ray detector lies inside the machine. An attached table is used to slide the reclining person into the circular hole.

Multiple x-rays are taken in thin cross-sections along the body of the person. The electronic x-ray detector collects the x-ray images from each cross-section and a computer then combines these x-ray images and turns them into a single image.

Positron Emission Tomography - PET

Positron Emission Tomography or abbreviated as PET is a form of nuclear medicine technology that utilizes short-lived radioisotopes to permit non-invasive imaging of metabolic functions within the human body. Unlike other imaging techniques such as computed tomography and magnetic resonance imaging which mainly provides information concerning anatomical structures, position emission tomography allows the imaging and quantifications of biochemical as well as the physiological functions.

Source: AZoOptics

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