How do you minimize image shape distortion?

• A. Proper receptor and beam alignment
• B. Increase exposure time
• C. Increase receptor size
• D. Use higher kVp

Answer: (A)

Minimizing image shape distortion comes down to geometry: keep the receptor parallel to the tooth’s long axis and direct the x-ray beam perpendicular to the receptor. When the receptor and tooth are aligned and the beam hits perpendicularly, the object-to-image relationship is maintained, so the image reflects the true size and shape and prevents elongation or foreshortening. This alignment principle underlies the common paralleling technique, which consistently produces undistorted images.

Increasing exposure time doesn’t fix distortion and only raises dose (and can worsen motion blur); increasing receptor size doesn’t solve geometric distortion, and using higher kVp affects contrast rather than shape.