Figure 10. Image processing artefact. Owing to lack of primary beam collimation on this lateral lumbar spine, the amount of unattenuated radiation striking the imaging plate (IP) (anterior and posterior to the patient) altered the histogram so that it was outside the normal range for that body part selection. Artefact remedy: use the smallest IP practicable and collimate the beam to the body part. This is particularly important on small or slim patients.