Imaging Instruments used in Medical Science

1. X-Ray

X-rays are one of the most useful forms of energy. Their main use have been in the field of medicine. X-rays find wide use in medicine because they can pass through flesh and produce photographic images of what lies beneath the skin. X-rays also have many uses in science. Scientists now know that X-rays are one of several forms of electromagnetic radiation. The German physicist Wilhelm C.Roentgen discovered X-Rays in 1895.

2. Tomography

Also known as sectional radiography, tomography was invented and patented in France in 1934 by the German inventor Gustave Grossmann. British radiologist Edward Wing Twining adopted the word tomography to describe the technology that reveals details within pre-determined planes of the body in the form of radiographs that blur structures in other planes. 

3. Computerized Tomographic Scanning (CT Scanning)

It is an x-ray system used to produce images of various parts of the body, such as the head, chest and abdomen. Doctors use CT images to help diagnose and treat diseases. The technique is also called computer tomography or computerized axial tomography. To produce a CT image, the patient lies on a table that passes through a circular scanning machine called a gantry. The table is positioned so that the organ to be scanned lies in the centre of the gantry.

4. CAT Scanning (Computerized Axial Tomography)

It helps to show condition of soft tissues of body through use of X-Ray. Widely used to image brain tumour. Godfrey Newbold Hounsfield (England) and Allan MacLeod Cormack (South Africa) shared the 1979 Nobel Prize for medicine and physiology for their invention and development of computerized axial tomography (CAT Scan).

5. Magnetic Resonance Imaging (MRI)

MRI was originally discovered in 1946 independently by Felix Bloch and Purcell. MRI is a diagnostic technique that provide high quality cross sectioned or three dimensional image of the organ without using X-ray or radiation. It uses magnetic field and radio waves. Magnetic Resonance Imaging is a technique used in medicine for producing images of tissues inside the body. Doctors use these images to diagnose some diseases, disorders and injuries. MRI is an important diagnostic tool because it enables doctors to identify abnormal tissue without opening the body through surgery. MRI does not expose the patient to radiation, unlike tests that use x-rays. Also MRI lets doctors see through bones and organs. MRI is safe for most people. But MRI uses a powerful magnet and so cannot be used on people with metal implants, such as pacemakers or artificial joints. An MRI unit consists mainly of a large cylindrical magnet, devices for transmitting and receiving radio waves and a computer. During the examination, the patient lies insides the magnet and a magnetic field is applied to the patient's body.

6. Ultra Sound Scanning (Echography or Sonography)

It is used to reveal the structural anatomy or stone in urinary tract or kidney, widely used in obstetrics.

7. Nuclear Magnetic Resonance Spectroscopy (NMR)

NMR is used for detection of chemicals such as phosphorus and calcium. Nuclear Magnetic Resonance was independently discovered in 1946 by Swiss-born American physicists Felix Bloch and Edward Purcell, who shared the Nobel Prize for physics in 1952 for their work. The first medical use of NMR was introduced by Erich Odeblad in Sweden in the 1950's. Paul Lauterbur (England) obtained the first NMR image of body tissues in 1973. By 1977, NMR Images were being made of human tissue and soon thereafter of the brain.

8. Endoscope

Instrument used for internal examination by direct vision through a lighted tubes fitted with a system of lens. It is a medical instrument used to examine the interior of a hollow organ or a cavity of the body. Unlike most other medical imaging devices, endoscopes are inserted directly into the organ or cavity being examined. There are several types of endoscopes. Most endoscopes consist of a flexible or rigid hollow tube with a lens at one end. Arnaud designed the first endoscopic lamp used to illuminate the interior of orifices in humans around 1819. He built his instrument with a biconvex lens.

9. Positron Emission Tomography Scan (PET Scan)

Positron Emission Tomography is a technique used to produce images of the chemical activity of the brain and other body tissues. PET enables scientists to observe chemical changes in specific regions of a person's brain while the person performs various tasks, such as listening, thinking or moving an arm or leg. Scientists use PET to compare the brain processes of healthy people and people with diseases of the brain. Research is being done to see if it is possible to use these comparisons to identify abnormalities that underlie various brain disorders. These disorders include such mental illnesses as manic depression and schizophrenia, as well as such conditions as Alzhelmer's disease, cerebral palsy, epilepsy and stroke. PET also helps doctors diagnose certain other disorders, including heart disease and cancer.