Table of Contents
Advertisement
16. Appendices
Correct positioning of the arches in the superior- inferior dimension requires that the
patient stand with erect posture while tucking the chin in and down slightly, a direction
that both adults and pediatric patients often find difficult to follow without specific
guidance. The result is often a slumped position with the patient hunching the neck
and shoulders over in an attempt to place the chin on the chin rest. The vertebrae
collapse causing attenuation of the x-ray beam that produces a triangular radiopacity
superimposed over the mandible, and if severe, over the maxillary anterior regions as
well.
Depending on the manufacturer, panoramic x-ray machines direct the operator to
position the Frankfort or the canthomeatal plane parallel to the floor, or the ala-tragus
line 5° down toward the floor. This is achieved by raising or lowering the chin rest so
that the appropriate landmark lines up with indicators on the machine (Figure 2). The
patient should be directed to stand in front of the panoramic x-ray machine allowing
the operator to place the chin rest into a position that is slightly higher than the
patient's chin. The patient is then requested to move into the overhead assembly of
the machine and remain standing tall. If further adjustment is needed, it is usually to a
lowered chin position. Once the patient's chin is resting on the chin rest, it is easier to
move to a lower position than to a higher one. To assist with placing the chin on the
chin rest while maintaining an erect posture, the pediatric patient can be directed to
stand like a soldier. Most children are familiar with the straight back, chest forward,
tucked chin position demonstrated by military persons, and can readily mimic this
stance.
Further Recommendations
Prior to beginning the exposure, the patient should be directed to close the lips around
the bite block and to place the tongue against the palate. Leaving the lips open will
create a soft tissue shadow across the teeth that that can be mistaken for caries.
Leaving the tongue at rest during the exposure allows the radiation to easily penetrate
190
PaX-i3D Green Premium™ User Manual
7
Advertisement
Table of Contents
