Villa Rotograph EVO, Руководство по обслуживанию

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SERVICE MANUAL
Troubleshooting
Rotograph EVO (Rev. 1) 8-72
This is not true, because it is derived from the projection
geometry used to obtain the panoramic image. The effect can be
more evident if the film in underexposed due to wrong
radiological parameters.
With reference to the previous Figure 8-12, let’s analyse the cause
and remedy.
•
Wrong positioning of the spine
In the case the image shows a too clear and unfocussed area in the
central portion (see point "4" - Figure 8-12), this is probably caused
by the wrong position of the spine that has not been properly
extended by the patient. In this case, the spine absorbs a too big
quantity of radiation that therefore causes the image to be too clear.
This lightness can be noticed especially in the lower part of the film,
while it’s normally less visible on the upper part of the film.
Remedy:
Ask the patient to step forward thus extending the spine, in order to
reduce X-ray absorption.
•
Shadows or bright artefacts
The most common cause for the presence of these artefacts is the
presence of metal objects worn by the patient (ear-rings, necklace).
The necklace worn on the neck of the patient can normally result in a
radio-opaque arch positioned in the chin area. This arch normally
overlaps the chin itself and the shadow of the spine, disturbing the
diagnosis of possible problems in the chin area and in the area of the
superior apex.
The ear-rings instead creates real images in the proper position and
shadow images projected in the contro-lateral area, thus hiding
possible problems or generating bright areas within the paranasal
sinuses.
In some cases, that may depend either on the trajectory of the
panoramic machine or on the position of the metal objects, they can
generate up to three images (one real ad two shadows), thus further
disturbing the correct diagnosis.
This situation may occur especially if the patient has large prothesis
or metal cures and if it is associated to a positioning error, that
projects the shadow of the metal part on wide area of the image.