Conventional X-ray images (radiographs) are produced by passing high-energy electromagnetic rays (“X-rays”) through the body before inducing an image on a photographic plate/film (“analogue” image) or an electronic detector (“digital” image). The denser the tissue, the less residual energy or rays will pass through, so the resulting image will have:

Computerized scans (CT scans) use similar technology, but the rays are captured in a computer and a cross sectional body image is produced.

Magnetic Resonance Imaging (MRI) is accomplished using very strong magnetic fields and radio waves. Final images are generated by computers and are displayed on computer screens or TV monitors.

Nuclear medicine imaging (“scintigraphy”) is produced by recording ionizing radiation emitted after a substance marked with a radioactive isotope is (mostly intravenously) injected. Various substances and isotopes are used; they will accumulate more in certain pathologic processes, such as a fracture or tumour formation, than in surrounding, normal tissue.

Ultrasound imaging is based on the differential reflection of high frequency sound waves as they pass from one tissue surface to the next. The returning wave pattern is recorded as an image. Ultrasound is less expensive than the other techniques and is especially useful for examination of the abdomen.

Conventional X-ray imaging is the most readily available technique at the district hospital. It is important to decide what information is needed before ordering or asking for an X-ray. If the outcome would not change your treatment, do not waste resources taking the X-ray.

In many locations the equipment is not available to take reliable X-ray images. You must be able to initiate treatment with or without X-ray studies. Do not wait for X-rays or refer patients long distances to obtain them in acute or emergency situations. This handbook explains methods of diagnosis and treatment of most injuries, with and without the use of X-ray imaging.

Techniques

X-ray imaging requires a generator powered by electricity to produce the X-ray, a film to capture the image and a method to develop the film. This equipment can be stationary in an X-ray department or mobile for use in the hospital ward, operating theatre or emergency room. Mobile units usually do not produce an image of such high quality, but are useful for patients with fractures treated in traction, or for those with severe injuries who cannot be moved safely to a remote X-ray department.

The following are basic examinations and projections for commonly ordered studies. Since all diagnostic imaging procedures should be “tailor-made” to the specific patient, try to inform the radiological technologist or radiologist about the diagnostic information you need and what you would like to prove or exclude.

Head

Chest

Abdomen: acute abdominal pain

Abdomen: abdominal trauma

Spine

Pelvis

Extremities

Shoulder

Ankle