Common errors in opg

1. SUBMITTED TO –
SUBMITTED BY -HARKARANPREET SINGH

2. 1. GHOST IMAGES
 This is a radiopaque artifact seen on a panoramic film
that is produced when a radiodense object is
penetrated twice by the Xray beam

3.  The characteristics of a ghost image are:
i. A ghost image resembles it's real counterpart and has the
same morphology.
ii. It is found on the opposite side of the film from it's real
counterpart.
iii. It appears indistinct, the horizontal components are more
blurred than the vertical components of a ghost image.
iv. The ghost image is always larger than the real counterpart,
the horizontal component is severly magnified, whereas
the vertical component is not as severly magnified.
v. It is usually placed higher than its actual counterpart.
vi. Ghost images are always reversed. Left and right being
sifted.

4.  Anatomical structures which are most
oftenghosted are:
i. Hyoid bone
ii. Cervical spine
iii. Inferior border of the mandible
iv. Posterior border of the mandible
v. The Meatuses
vi. The turbinates

5. • Non-anatomical structures which are often
ghosted are:
i. Chin rest
ii. (R) or (L) Markers of the machine
iii. Neck chains
iv. Napkin chains
v. Earrings
vi. Shoulder straps of protective aprons.

8. 2. LEAD APRON ARTIFACT
Lead apron artifact appears as a large cone
shaped radiopacity obscuring the mandible

9. 3.PATIENT POSITIONING ERRORS:
I. POSITIONING OF THE LIPS AND
TEETH
If the lips are not closed on the bite block, a dark
radiolucent shadow obscures the anterior teeth

10. II.POSITIONING OF THE
FRANKFURT PLANE
 a. Upward :
If the patient's chin is positioned too high or tipped up (i.e. the chin is
too far forward while the forehead is titled towards the back):
– The hard palate and the floor of the nasal cavity appear superimposed
over the roots of the maxillary teeth.
– Loss of density in the middle of the radio-graph, usually characterized
by an hour glass shape.
– There is a loss of detail in the maxillary incisor region, magnification.
– The maxillary incisors appear blurred and magnified.
– Loss of one or both condyles at the side of the film.

11. The chin and the occlusal plane are rotated upward, resulting in the
overlapping of the images of the teeth and an opaque shadow (the hard
palate) obscuring the roots of the maxillary teeth

12. b. Downward
Ala-tragus line greater than 5° downward, the patient's chin is
positioned too low or is tipped down (i.e. chin positioned back and the
forehead is positioned forward);
– The mandibular incisors appear blurred.
– There is a loss of detail in the anterior apical region of the mandible.
The apices of the lower incisors are out of focus and blurred.
– The condyles may not be visible, as they may be cut off at the top of the
radiograph.
– Shadow of the hyoid bone is superimposed on the anterior aspect of the
mandible.
– Premolars are severly overlapped.
– An 'exaggerated smile line' is seen on the radiograph (severe curvature
of the occlusal plane).

13. An exaggerated smile seen on a panoramic film
when the patient’s chin is tipped down

14. III. POSITIONING OF THE TEETH:
a. Anterior to the focal trough
Patient's head is positioned too far forward.
– If the anterior teeth are not positioned in the
groove of the bite block, the teeth appear blurred.
– If the teeth are positioned too far Forward on the
bite block, the anterior teeth appear 'skinny' and
out of focus (Blurred and narrow).
– Spine is superimposed on the ramus areas.
– Premolars are severely overlapped.

15. The anterior teeth appear narrow and blurred on a panoramic film
when the patient is positioned too far forward on the bite block

16. b. Posterior to the focal trough:
Patient's head is positioned too far back
– If the anterior teeth are not positioned in the groove of
the bite block, the teeth appear blurred.
– If the teeth are positioned too far back on the bite
block, the anterior teeth appear 'fat' and out of focus
(blurred and wide).
– Excessive ghosting of mandible and spine.

17. The anterior teeth appear widened and blurred on a panoramic
film when the patient is positioned too far back on the bite block

18. IV. POSITIONING OF THE
MIDSAGITTAL PLANE:
If the patient's head is not centered, the
ramus
and the posterior teeth appear unequally
magnified. The side farthest from the film
appears magnified and the side closest to
the
film appears smaller.

19. The patient’s posterior teeth and ramus appear to be
magnified on the panoramic film when the head is not centered

20. a. Patient's head is tilted to one side.
– The side tilted towards the X-ray tube is enlarged.
– One condyle appears larger than the opposite one, the
neck also appears longer on the larger side.
– Image appears to be tilted, one angle of the mandible
is higher than the other.

21. b. Patient's head is twisted to one side causing the
mandible to fall outside the image layer, (one side is in
front of the image layer while the other side is behind
the image layer).
– Teeth on one side of the midline appear wide and have
severe overlapping of contacts, whereas the teeth on
the other side appear very narrow.
– Ramus on one side is much wider than the other side.
– Condyles differ in size

22. c. Whole head is off center position (patient
biting the block off center with lateral incisors or
cuspids).
– The molar teeth and the mandibular ramus are
magnified on the side farther from the film.
– Anterior teeth are blurred with overlapping

23. V. POSITIONING OF THE SPINE
If the patient is not sitting or standing with a
straight spine, the cervical spine appears as a
pyramid shaped radiopacity in the center of
the film and obscures diagnostic
information.

24. If the patient is not standing erect, superimposition of the cervical
spine may be seen on the center of the panoramic film

25. VI. PATIENT'S SHOULDER
TOUCHING THE CASSETTE
DURING EXPOSURE:
This will slow the cassette rotation, resulting in
prolonged exposure or completely stop the film
movement.
– Produces a dense black band, which is the area of
overexposure or a dense black edge may be seen at the
end of the radiographic image, due to eventual
stoppage of rotation.

26. VII. POSITION OF PATIENT'S TONGUE
DURING EXPOSURE:
If the tongue is not fully placed against the
roof of the mouth.
– A dark shadow appears in the maxilla
below the palate, and the apices of the
maxillary incisors are obscured.

27. If the tongue is not placed on the roof of the mouth, a radiolucent
shadow will be superimposed over the apices of the maxillary teeth

28. VIII. DISTORTION DUE TO PATIENT
MOVEMENT
a. Movement in the same direction as the beam.
– There is prolonged exposure of the same area, with
increase in horizontal dimension of the image
b. Movement in the opposite direction as the
beam.
– The horizontal dimension of the image in the
region is decreased

29. c. Sudden jerky movement in the same direction as
the beam.
– The area may be portrayed twice.
d. Sudden jerky movement in the direction
opposite the beam movement.
– A part of the object may be missing in the image.
e. If the patient moves up or down during exposure.
– Indentation in the lower border of the mandible
(mimicing a fracture)
– Blurring and unsharpness.

30. 4. CASSETTE POSITIONING ERRORS:
i. Patient's shoulders touching the cassette during the
movement in the exposure cycle. This may happen if
the patient has a short neck and well developed
shoulders.
– Alternating vertical dark and light bands appear on the
radiograph due to improper movement of the cassette
behind the slit in the cassette holder or the tube head
cassette holder assembly around the patient's head.

31. ii. Cassette placed too high.
– Lower border of the mandible is cut off.
iii. Cassette placed too low.
– Diagnostic information in the maxilla will be cut off.
iv. Two exposures on a single film.
Undiagnostic radiograph, with unnecessary exposure
to the patient.

32. v. Cassette placed backwards.
– This is common in panorex the X-rays must penetrate
the metal latch, which will present as a radiopaque
broad horizontal line through the middle of the
radiograph