RADIOGRAPHY
You  have read  in GNM courses about radiographical examination. In this text the discussion will be on the following radiographical tests.  
Chest Roentgenogram

• Normal pulmonary tissue is radiolucent. Thus densities produced by  tumors, foreign bodies, etc. can be detected. 
• Shows position of normal structures, displacement and presence of abnormal shadows.
• Chest X-rays may reveal extensive pathology in the lungs in  the absence of symptoms.

Tomography  (Planigraphy)

• Provides films of sections of  lungs at different levels within the thorax.
• Useful in demonstrating presence of small, solid lesions, calcification, or cavitation within a  lesion.

Computed Tomography:

An  imaging method in which  the lungs are scanned in successive layers by a nmow beam x-ray. A computer printout is obtained of the absorption values of the tissues in the plane that  is being scanned.