Radiology (Medical Imaging)

RADIOLOGY (MEDICAL IMAGING)

Radiology is the study of radiation. It involves the diagnosis and treatment of diseases using radiation. Radiation is the emission (sending forth) of waves or particles of radiant energy. Examples of radiation are radio waves, infra-red waves, ultraviolet light, x-rays, alpha particles, beta particles and gamma rays. A substance that is radioactive has the property of spontaneously emitting some form of radiant energy eg a radioisotope.

Root word / Combining form / Meaning
radi / radi/o / Invasive rays produced by an x-ray machine
roetgen / roentgen/o / x-rays
cine / cine, cinemat/o / Moving film
tom / tom/o / Slice or section
Son / son/o / sound
echo / echo- / Reflection of sound
therm / therm/o / heat
scint / scint/i, scintilla/a / emitting sparks/light

X-RAY

The most common use of radiation is x-rays. X-rays pass through the body and expose an x-ray film, producing a photographic image called a radiogram. A radiogram provides a two-dimensional shadow image of the interior of the body. Parts of the body block the x-rays and these structures are said to be radio-opaque, they appear light or white on x-ray film, eg bones. From these images diagnoses can be made eg fractures. Other parts of the body are not radio-opaque and the x-rays pass through them so they do not show up on film, eg the gastrointestinal tract. In order to x-ray these areas, a contrast medium is inserted into the body. Barium (Ba) is a radio-opaque substance or contrast medium is used either orally or rectally to make the GIT more visible on film. Barium studies - can be meals or enemas. Contrast mediums can also be injected into the body.

X-rays compress body images onto a flat sheet of film, often resulting in an overlap of organs and tissues that can make diagnosis difficult.

CT Scan

These diagnostic difficulties have been virtually eliminated by the use of an x-ray technique called CT (computed tomography) scanning. CT scanning combines the principles of x-ray and advance computer technologies. An x-ray source moves in an arc around the part of the body being scanned and repeatedly sends out x-ray beams. The beams are then converted into electronic impulses that produce thousands of readings of the density of the tissue in a 1cm (or smaller) slice of the body tissue. Next, the computer produces a graphic, detailed sketch from these readings called a CT scan, which can be viewed on a TV screen. The CT scan produces very accurate cross-sectional (slices) pictures of any area of the body. The CT scan permits a significant differentiation of body parts that was never possible with conventional x-rays. The entire CT scan process tales only seconds, it is completely painless and the x-ray dose is equal to or less than that of many other diagnostic procedures.

MRI

Nuclear magnetic resonance or more commonly magnetic resonance imaging (MRI) is a technique that does not expose the patient to ionizing radiation and its associated hazards. MRI has a greater sensitivity to detecting malignancies, ischaemic regions and other functional changes in the tissue of an organ before they have progressed so far that gross anatomical changes have been produced. The contrast between grey and white matter in the brain is much more distinct with MRI, while the image is almost unaffected by bone. Computer technology can then be combined with the detailed imaging data to produce a cross-sectional image in almost any plane, or sequence of these to give a ‘slice’ effect.

Ultrasonography

Another type of image is created by high frequency sound waves - an ultrasound. An ultrasound is a record of sound waves as they are reflected from internal structures. Internal organs and masses reflect sound to a different extent, giving different echo textures. These internal echoes are detected and converted into an image.

Treatment

Radiation is also used to treat diseases, usually cancer. This is called radiotherapy or radio oncology. Radiation is used to shrink or kill tumours.

Radiography - is the process of making film records

Radiogram - is the film produced by this process.

Radiologist - is a specialist in the field of radiology.

Radiographer - is the technician who takes the film.

Radioisotopes - behave like transmitters passing radiation from inside to the outside of the body. Used as diagnostic labels to trace the route and uptake of chemicals administered into the body.

Activity 1 write the meaning of ;

tomogram

/ ______
radiotherapy / ______
radiotherapist / ______
echocardiogram / ______
echoencephalogram / ______
fluoroscope / ______
echogenic / ______
echogram / ______

RADIOTHERAPY 2