Quality Control for Film Processing

A step wedge is used to evaluate the radiograph/development system. Expose multiple films at small dog technique. Every other day, process one film. Ten steps should be discernable. If the steps can't be clearly seen, usually the processing chemicals are exhausted and need changing.

Step wedge used to make exposures to examine the radiograph production and developing process.

New chemicals - Observe 10 steps

Exhausted chemicals - Note blurred steps.

Positioning Errors

Elongated image. Too little vertical angle of tube head.

Foreshortened image from too much vertical angulation

Processing Errors

Poor contrast. Too little time in fixer.

Same film processed normally.

"Frosty" coating on film from fixer remaining on film (need to wash better).

Exposure Techniques Errors

Image too dark. Possible causes include too high kV, too long in developer, or developing solution too warm.

Patient motion and scratch defect

Dots on side. Back rather than front of cassette exposed.

Double exposure. Molar exposed on top of incisors.