Patient Positioning

In order to obtain diagnostically useful images, patients must be positioned carefully within the image layer or focal trough, which is a three-dimensional curved zone (Figure 5). Structures found within the image layer will be reasonably well-defined.5 The patient must be positioned correctly so that the proper structures are aligned within the image layer.

Figure 5.

Image of correct patient positioning with the tongue pressed against the palate, teeth in the groove of the bite-block, and the indicator light for the midsagittal plane centered and perpendicular to the floor.
Example of correct patient positioning with the tongue pressed against the palate, teeth in the groove of the bite-block, and the indicator light for the midsagittal plane centered and perpendicular to the floor.

If patient positioning is incorrect, errors are likely to occur. Patient positioning errors are the most common type of error when performing panoramic radiography.8 For instance, in a study evaluating 460 panoramic radiographs, careless head positioning accounted for 38% of the errors.5 Patient positioning errors accounted for 85% in a sample of 1,813 panoramic radiographs.5

The most common patient positioning error occurs when the tongue is not placed close enough to the palate.5 This may be due to the patient misunderstanding the instructions and only placing the tip of their tongue on the palate. Incorrect positioning of the tongue creates radiolucency near the apices on the maxilla, which makes diagnosis of periodontitis and root resorption challenging.5

It is helpful to note that each manufacturer provides specific operation instructions in the manual that accompanies the unit. It is worth the time and effort for each team member to become acquainted with the contents of the manual. While the instructions make panoramic imaging easy to perform well, it is equally as easy to perform badly when manufacturers’ instructions are not followed.2 Proper patient positioning (Table 4) will help reduce the possibility of errors in panoramic imaging.

Table 4. Patient Positioning Guidelines.5,8
Standing/Sitting
  • If patient is able to stand, have them stand erect without the spine being slumped.
  • If patient is seated, they should sit as upright as possible.
  • It helps to do a test run with the panoramic machine to make sure it will not hit the patient’s shoulders.
Mouth position
  • Patient needs to place maxillary/mandibular incisors correctly on bite block in order to achieve proper alignment of the teeth.
  • Most units have a notch in the bite block indicating the proper location for the patient to bite.
Midsagittal Plane
  • The patient’s head must be straight & not tilted.
  • The midsagittal plane must be kept perpendicular to the floor.
Frankfort Plane
  • Keep the Frankfort plane parallel with the floor.
Tongue
  • Instruct the patient to place their ENTIRE tongue on the hard palate and leave it there for the duration of the exposure.
Lips
  • Instruct patient to keep their lips together for the duration of the exposure.
Eye
  • Have patient close their eyes so they do not follow the movement of the tube head.