MEDICAL ELECTRONICS

X-Rays

• extremely short wavelength of electromagnetic waves is directed at a part of the body providing images on a photographic film placed behind the patient.
• causes no immediate sensation but frequent exposure could damage skin and internal organs and also could cause cancer later in life
• X-rays were discovered by Wilhelm Roentgen in 1895

Angiography

• an imaging technique that enables blood vessels to be clearly seen on X ray film following the injection of a contrast medium

Digital Subtraction Angiography

• a type of angiography that uses computers to process images and remove unwanted background leaving only the blood vessels to be studied

CT Scanning

• Computed Tomography
• uses combination of computer and X-rays
• X-rays are passed through different angles of the body creating cross sectional images of tissues to be examined
• images can be computer processed to create 3D images

Radionuclide Scanning

• a radioactive substance is introduced into a patient's body and a gamma camera detects the emission of radiation of these radionuclides to create an image

PET

• Positron Emission Tomography
•  a type of radionuclide scanning that produces 3D images
• based on the detection of positrons (positively charged electrons) emitted by labeled substances introduced into the body

MRI

• Magnetic Resonance Imaging
• provides high quality cross sectional or 3D images of organs and structures in the body by detecting the alignment of hydrogen atoms
• a patient is exposed to short bursts of very powerful magnetic field and radio waves ,these bursts stimulate protons( hydrogen nuclei) to emit radio signals, which are further detected and analyzed  by a computer

Ultrasound

• similar principle as used on the naval Sonar (imaging by the use of reflected sound waves)
• used primarily in obstetrics because it causes no discomfort and is completely safe to both mother and fetus 

EEG

• electroencephalogram
• records the minute electrical impulses produced by the brain
• first used in 1928

EMG

• electromyogram
• recording of electrical activity of the muscles

ECG

• electrocardiogram
• a record of the electrical impulses that immediately precede contraction of the  heart muscle

Electronystagmography

• recording the various types of abnormal jerky movements of the eye to investigate their cause

Lithotripsy

• uses ultrasound to pulverize calculi (stones) in the body

Radiotherapy

• treatment of cancer by X-rays or other sources of radioactivity

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