DK Science: Medical Technology
Technology plays an increasingly important role in modern medicine. Today, HI-TECH IMAGING allows doctors to view internal body structures in amazing detail, while, SURGERY relies heavily on technologies such as lasers, robots, and computers. ARTIFICIAL DEVICES are commonly used either to replace diseased body parts completely, or to provide assistance to failing organs.
Modern imaging methods can provide detailed pictures of body parts, whether by injecting dyes that highlight specific structures on X-ray viewing, or by using methods that provide cross-sectional or 3-D scans. Some techniques provide information on body activity, not just structure. For example, special forms of ultrasound (high-frequency sound) can be used to monitor the flow of blood within blood vessels. The internal structures of the body can also be examined directly by means of fibreoptic endoscopes (viewing tubes).
MRI (magnetic resonance imaging) is an advanced imaging technique. The body part to be examined is placed inside a powerful magnet, and harmless radio waves are released towards it. A computer then builds an image by analysing the pattern of radio waves returned from the part. MRI is often used to examine the brain and other soft tissues.
Surgical techniques are constantly being improved and new ones developed. Today, the trend is towards using keyhole surgery, in which the cuts made into the body are kept as small as possible. Microsurgery is another important field. Here, the surgeon uses tiny instruments to repair delicate structures such as nerves, while viewing the operation site through a microscope. Transplant surgery offers hope to people with damaged internal organs – the kidney, heart, liver, small intestine, and lungs can now all be transplanted, although there is often a shortage of donor organs.
Keyhole surgery relies on using fibreoptic endoscopes, viewing instruments that may be rigid (as shown in this knee operation) or flexible. The cuts made to insert the surgical instruments and endoscope into the body are smaller than those used in other types of surgery. The main benefit is the short recovery time.
Laser beams are used as cutting and burning tools in various types of surgery, including eye surgery. A laser can be used to treat disease of the retina at the back of the eye and to reshape the cornea for treating short-sightedness. Lasers are also used to treat some skin conditions, such as birthmarks, and to remove tattoos.
The range of artificial devices used in treatment increases all the time. Devices available today include replacements for damaged hip and knee joints and an implant into the cochlea of the ear to help some types of deafness. A cataract (clouding of the lens in the eye) can now be treated by insertion of a plastic lens. It is also possible to replace defective heart valves, either with a valve constructed from human or animal tissue, or with one made out of metal and plastic.
This chest X-ray shows an artificial pacemaker that has been inserted beneath the skin of the chest. Pacemakers are given to people whose hearts have a defective electrical system. The pacemaker delivers electrical signals to the heart via wire leads – these signals trigger contractions of the heart muscle and maintain a regular heart beat.
