Purpose
The most powerful tip when troubleshooting image quality is verifying that the office is properly exposing. More often than not, offices are underexposing. If the office is willing to increase exposure, the returned raw image will have less enhancement required, which assists in diagnosing, and makes troubleshooting much simpler.
Establishing an acceptable raw image
The best possible raw image can be established by finding the tubehead values that produce an image on an average sized adult that is almost overexposed. This means that the office should test (with no post capture filters) exposing with incrementally increased radiation, until the raw image that is returned has some kind of missing data from overexposure (e.g. edge of crown looks to have decay, bone loss increased). Then reduce radiation until the overexposure is no longer apparent.
This process can be repeated for a child + large adult to find best recommended values for respective patient sizes.
Understanding Exposure
Exposure is in reference to tubehead radiation exposure. A good exposure has 2 important things - good placement, and sufficient radiation exposure.
A good rule of thumb: If it’s too dark, decrease exposure number; if too light, increase the exposure
Placement
Both tubehead and sensor placement must be good for the image that is produced to be acceptable. If the tubehead or sensor are not aligned properly, the produced image could be cone cut. This means that the focused beam of the tubehead did not cover the sensor, and therefore the anatomy in that area did not get exposed. This typically produces as a while section of the image.
Many more examples of placement errors can be found in Sensor Placement Errors. Example of proper sensor placement also available in Sensor Placement Instructions - Schick.
Sufficient Exposure
The tubehead settings should be sufficient to penetrate the soft tissue and impact the receptor enough to return a good working raw image.
Common issues, and exposure recommendation:
The left image is slightly under-exposed. This can be recognized by the lack of contrast in the crowns of the teeth and the gray areas between them, in the interproximal regions and behind the molars, as well as the presence of the positioning tab in the interproximal. While under-exposed images can be darkened using software, contrast may still be lacking. Note – this image is also unacceptable due to poor positioning recognized by the overlap of the contacts.
The middle image is correctly exposed – apices, DEJ and bone detail are all clearly visible.
Over-exposure is recognized by an image being too dark – typified by the cervical burnout on the bicuspids in the above image (ie. what appears to be decay). This can be corrected by software, but to keep with the ALARA (as low as reasonably achievable) principle, the technique factors (exposure time or pulses) should be reduced to provide acceptable imaging.
Different types of filters
Gamma - Adjusts the greyscale histogram by bending the median values. This helps to retain data while increasing contrast.
Sharpen - It is believed that Apteryx imaging uses an ‘unsharpen mask’ as the algorithm for sharpening an image. This process works by utilizing a slightly blurred version of the original image. This is then subtracted away from the original to detect the presence of edges, creating the unsharp mask (effectively a high-pass filter). Contrast is then selectively increased along these edges using this mask — leaving behind a sharper final image.
Blur - This enhancement has the effect of reducing the image's high-frequency components; a Gaussian blur is thus a low pass filter. Typically, settings can benefit from both a blur and a sharpen filter. This increases apparent edges, while having reduced grain.
Article Version 1.0 08-05-2026