Linear image distortion of different patients' head position using dimax direct digital panoramic x-ray system

الملخص EN

Background: The aim of this study is to show the effect of improper patient head positioning on the distortion amount of x-ray images.

Material and method: Distortion amount is measured using a special ball phantom which contain 23 balls to check the patient positioning mechanisms using Planmeca 2002 CC Praline Digital X-ray unit by adjustment the position to 00 both x- and y- directions, then linear movement was done by displacement of the ball phantom +5mn anteriorly and-5mm posteriorly.

Exposure to X-rays was done for each position.

The three images were seen on computer screen, balls and space in between dimensions were measured using Dimax software.

Results: The results revealed that at zero position, balls appear round, all with same size, every spaced with constant magnification factors.

When the ball phantom displaced, different distortion amount in the balls will take place especially in the anterior region.

Conclusion: Exact head positioning must be taken in consideration to ensure that wanted area is included within the zone of sharpness.

Key words: Radiography distortion digital panoramic.

(J Bagh Coll Dentistry 2007; 19(1)65-68)