Module 8

Proper choice of exposure factors

The quality of radiograph depends so much on the

proper combination of exposure factors, i.e. kVp, mA,

and time. Wrong selection of exposure factors can

cause poor radiograph and/or may lead to unnecessary

retakes

high kVp - low mAs technique

Furthermore a ___ is

preferred over a low kVp - high mAs setting, as it

results to low exposure to the patient. However, the

kVp should not be too high as to degrade image quality

Correct Positioning of the patient

Many retakes which result in needless patient

exposure are caused by hasty positioning of the

patient. The number of retakes could be reduced if

technologist will take their time in positioning the

patient carefully and properly.

Immobilization

sometimes needed to prevent the

image-degrading effects of motion.

Positioning aids

May also be used such as sandbags, angle sponges, foam pads, and radiographer’s tape

Human Immobilizers

Are the last resort. If there are no

other resort, male relatives are the first choice,

preparably older than the normal reproductive age.

They should also be provided with shielding, minimally

lead aprons and gloves

Inherent filtration

- Glass envelope encasing the x-ray tube

- Insulating oil surrounding the tube

- Glass window in the tube housing

Added filtration

- Sheets of aluminum (or the equivalent) of appropriate

thickness

Gadolinium, lanthanum, and yttrium

Elements used to make screens with phospors

Mobile radiographic units

require special precautions to

ensure patient safety.

30 cm (12 inches)

When operating the unit, the radiographer must use a

source-skin distance (SSD) of at least __

5-minute reset timer

on all fluoroscopes reminds

the radiologist that a considerable amount of fluoroscopic

time has elapsed.