06a - Errors in Radiographic Technique

cause of unsharpness and distortion

• source-to-object distance → increasing distance between focal spot and object results in image with increased sharpness and less magnification

• object-to-receptor distance → decreasing distance between object and film increases sharpness and results in less magnification

• foreshortening → x-ray perpendicular to image receptor but not object

• elongation → x-ray is perpendicular to object but not film

errors that can occur during exposure

• underexposure → increased brightness of image or noise

• overexposure → decreased brightness

• cone cut → x-ray beam fails to fully cover image receptor

  • bright areas on periphery with straight edges indicating rectangular cone and rounded edges indicating round cone

• double image → duplicated image of teeth due to incomplete erasure of PSP

• horizontal misangulation → x-ray aimed from mesial or distal angle instead of straight at the buccal surface

• vertical misangulation → x-ray aimed at teeth from superior or inferior angle instead of straight at buccal surface

• image receptor backwards → will cause reversed or mirrored image

  • image receptors typically have check systems to notify that the image receptor was backwards like foil in film, magnet in PSP, or wires and circuitry in digital sensors

errors between exposure and development

• exposure of PSP to light → causes partial erasure that appears similar to underexposure

• image receptor bending → can cause elongation or radiopacity 

• scratched image receptor → will cause radiopaque lines

errors that occur during development

• damaged digital sensor → artifacting that causes distortions in image

• sensor delamination → sensor eventually deteriorates and peels at corners, causing dark spots in image

• thyroid shielding → causes radiopacity in image due to lead apron

• radiograph with fingers → from someone helping to hold the head into x-ray machine

  • young patients or patients with special needs