Modern fluoroscopic equipment has computer controlled preset techniques.
However, if the automatic controls are turned off, the average machine settings for
fluoroscopy range from 0.5 to 5 mA (milliamperes), and 90 to 120 kVp (kilovolts peak).
Positioning for fluoroscopy depends upon the part to be examined and the patient's
condition. In general, part or all of the chest, upper gastrointestinal, and bronchial
fluoroscopic examinations are performed with the patient erect; colon and myelographic
examinations are usually made with the patient lying on the x-ray table.
Examination techniques vary not only for different types of examinations, but also
from radiologist to radiologist. Each radiologist develops his own routine procedure for
a given examination. All these methods require teamwork between the examiner and
the specialists; hence, each must be familiar with the routine procedure to expedite the
examination. Chest fluoroscopy usually precedes a gastrointestinal examination and is
done with the patient upright if his condition permits. It consists basically of examining
the various portions of the chest in various projections and phases of respiration; a
swallow of barium paste is used to outline the esophagus. Upper gastrointestinal
fluoroscopy is performed with the patient upright at first, later horizontal. Colon studies
require the patient to be in a horizontal position. The specialist must know when the
radiologist wants a cup of barium mixture handed to the patient, when the empty cup is
to be taken from the patient, and when the table is to be tilted in a different position.
The radiologist, in turn, seeks to guide the specialist by adhering to a routine in his
examination and in his remarks to the patient. The specialist knows, for example, that
when the examiner tells the patient, "Face me, now," the next step will be to hand the
patient the glass of contrast medium. The patient is not dark-adapted. Therefore, when
he steps into the "dark" room, he requires guidance. Effort must be made to allay his
worry and fear of the examination. The patient's peace of mind must be assured.
The following precautions will be observed:
a. A diagnostic-type protective tube housing will be used with equivalent of
2.0 mm lead (IAW TB MED 521).
b. Distance should be utilized as a protective measure. Radiologic technologists
must remain away from the fluoroscopic unit whenever their services are not required in
the examination. Decreased distance from the source of both primary and secondary
radiation accounts for a greater radiation exposure to the radiologist and radiologic
technologist during horizontal, as opposed to vertical, fluoroscopy.