Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Common errors in opg

Common errors in opg

  • Login to see the comments

Common errors in opg

  1. 1. SUBMITTED TO – SUBMITTED BY -HARKARANPREET SINGH
  2. 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. 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. 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. 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.
  6. 6. 2. LEAD APRON ARTIFACT Lead apron artifact appears as a large cone shaped radiopacity obscuring the mandible
  7. 7. 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
  8. 8. 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.
  9. 9. 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
  10. 10. 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).
  11. 11. An exaggerated smile seen on a panoramic film when the patient’s chin is tipped down
  12. 12. 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.
  13. 13. The anterior teeth appear narrow and blurred on a panoramic film when the patient is positioned too far forward on the bite block
  14. 14. 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.
  15. 15. The anterior teeth appear widened and blurred on a panoramic film when the patient is positioned too far back on the bite block
  16. 16. 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.
  17. 17. The patient’s posterior teeth and ramus appear to be magnified on the panoramic film when the head is not centered
  18. 18. 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.
  19. 19. 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
  20. 20. 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
  21. 21. 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.
  22. 22. If the patient is not standing erect, superimposition of the cervical spine may be seen on the center of the panoramic film
  23. 23. 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.
  24. 24. 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.
  25. 25. 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
  26. 26. 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
  27. 27. 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.
  28. 28. 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.
  29. 29. 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.
  30. 30. 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

×