Module 5 Rad

DH103 Key Chapters 3, 22, 23, 28, & 29

DH103 Chapter 3

1. The indirect theory of radiation injury involves the absorption of an x-ray photon by water within a cell which can form toxins and free radicals that damage cells.

2. The direct theory of radiation injury involves a direct hit to and absorption of an x-ray photon within critical areas of a cell

3. A non-threshold dose-response curve suggests that no matter how small the amount of radiation received, some biologic damage occurs.

4. List some examples of stochastic effects: genetic effects, leukemia, cancer

5. List some examples of a non-stochastic (deterministic) effect: skin erythema, loss of hair, cataract formation, decreased fertility, radiation sickness, fetal death

6. What type of cells are more sensitive to the effects of radiation? Cells that divide rapidly, immature cells that are not highly specialized, and cells w/ a higher metabolism: blood cells, immature reproductive cells, and young bone cells (the most radiosensitive cell is the small lymphocyte)

7. List the most radioresistant cells: bone cells, muscle and nerve cells

8. List the sequence of radiation injury: Latent period, period of injury, recovery period (radiation has cumulative effects- it is additive over time)

9. List some signs of acute radiation syndrome: hair loss, nausea, vomiting, diarrhea, and hemorrhage

10. If my offspring exhibit a mutation caused by exposure to radiation, but I do not, which of my cells have been affected? Genetic cells

11. One gray is equivalent to 100 rads; one sievert is equal to 100 rem.

12. List the ways we can decrease patient exposure and dose: receptor choice (digital sensor is lowest dose), collimation, technique, shielding

DH103 Chapter 23

13. The exam used to examine large areas of the upper and lower jaw is the occlusal.

14. An occlusal exam for an adult would require a size 4 receptor.

15. An occlusal image taken on a 3-year-old patient for growth and development would require a size 2receptor.

16. If a radiographer needed to capture a salivary stones location in the floor of the mouth, he/she should use the cross-sectional projection. This is known as the right-angle technique.

17. When taking occlusal images, a receptor holder is not necessary.

18. The occlusal projection used to image the maxilla and the palate would be the topographic occlusal projection.

19. The pediatric projection is recommended for use in children 5 years old or younger.

20. A dental image is a 2-dimensional picture of a 3-dimensional object.

21. A dental image captures the length and width of an object but fails to capture depth.

22. The buccal object rule depends on a horizontal (mesial or distal) shift in the 2nd image to identify the location of an object. If, in the 2nd image the object moves in the same direction as the horizontal shift of the tube, the object would be located lingual.

23. The mnemonic SLOB stands for:

Same-Lingual​Opposite-Buccal

DH103 Chapter 25

24. What are the uses of a panoramic images: evaluation of large areas of the maxilla or mandible (impacted molars, evaluation of dentition and surrounding structures, growth and development, diseases, lesions, and conditions of the jaw, evaluation of trauma)

25. Panoramic images should not be used to diagnose decay,periodontaldisease, or periapical lesions.

The focal trough is the 3-dimensional curved zone on a panoramic Image where the anatomic structures are clearly demonstrated.

26. The thyroid collar should not be used when performing panoramic imaging as this will block the x-ray beam and could obscure information.

27.The Frankfort plane is an imaginary plane that passes through the top of the ear canal and the bottom of the eye socket (orbit).

27. The collimator in a panoramic imaging unit is a lead plate with an opening that is the shape of a narrow vertical slit.

28. The midsagittal plane must be positioned perpendicular to the floor.

29. List advantages and disadvantages of panoramic imaging:

a. Advantages are field size, simple to use, easy for patients to cooperate, minimal patient exposure to radiation.

b. Disadvantages are quality, limitations imposed by the focal trough, image distortion, and the high cost of the equipment.

30. What error causes an exaggerated frown on a panoramic image:

a. Chin tipped up too high

31. What error causes an exaggerated smile (jack-o-lantern):

a. Chin tipped down too far

32. What error causes the anterior teeth to appear magnified:

i. Patient is too far back on the bite block (posterior to the focal trough)

33. What error causes the anterior teeth too appear narrow(shoe peg corn):

a. Patient is too far forward on the bite block (anterior to focal trough)

34. What error occurred if one side of the ramus and teeth appear magnified or larger than the other side:

a. Patients head is not centered (turned slightly more to one side)

                                                                            DH103 Chapter 28

35. Cortical bone is another name for compact bone.

36. Cancellous bone contains trabeculae which give it a “sponge-like” appearance. Cancellous bone is located between two layers of cortical bone.

37. A linear protrusion of bone would be identified as a ridge.

38. A pointed, spiked looking protrusion of bone would be called a spine.

39. The large radiolucent spaces seen on maxillary posterior images are the sinus.

40. A foramen is an opening or hole that permits the passage of nerves and blood vessels.

41. An immovable joint between two bones, as seen in the skull, is called a suture.

42. A bony partition that divides two spaces (as in the nose) is known as a septum.

43. The almond shaped foramen located between the maxillary central incisors on a radiograph is the incisive foramen.

44. The median palatal suture is located between the two palatine processes and appears radiolucent on an image.

45. On a maxillary anterior PA, the nasal septum may be superimposed over the median palatal suture.

46. On a maxillary PA the anterior nasal spine appears as a V-shaped radiopacity at the intersection of the floor of the nasal cavity and the nasal septum.

47. The inverted Y is a radiopaque line above the maxillary canine created by the intersection of the maxillary sinus and the nasal cavity.

48. The maxillary tuberosity appears as a rounded radiopaque prominence posterior to the maxillary thirdmolar region.

49. The hamulus extends from the medial pterygoid plate of the sphenoid bone.

50. The genial tubercles appear as a ring-shaped radiopacities below the apices of the mandibular incisors.

51. The lingual foramen is a radiolucent finding in the center of the genial tubercles.

52. Nutrient canals appear as radiolucent lines on a PA image.

53. On a dental image, the mental ridge often appears superimposed over the mandibular anterior teeth.

54. The mental foramen is located in the area of the mandibular premolars and is often mistaken as a periapical abscess due to its apical location.

55. The mandibular canal extends from just below the ramus to the premolar region of the mandible.

56. The ridge that extends from the 3rd molar region on the mandible to the 2nd premolar area is the mylohyoid ridge.

57. The external oblique ridge appears radiopaque and extends from the anterior border of the ramus down and forward.

58. The coronoid process of the mandible can be viewed on a maxillary molar PA.

59. The radiolucent space visualized between the alveolar bone and the root of the tooth is the periodontal ligament space.

60. In a healthy mouth, the crest of the alveolar bone is located 1.5-2.0 mm below the CEJ.

61. The most radiopaque part of a tooth on x-ray is the enamel.

DH103 Chapter 29

62. The best image to take to visualize the maxilla and mandible in a single image would be a panoramicimage.

63. The maxillary sinus are located above the apices of maxillary molars and premolars and appear radiolucent on the panoramic image.

64. The mastoid process is a sizable curved radiopacity that is not visualized on a PA.

65. The lateral pterygoid plate is part of the sphenoid bone.

66. The long, thin, pointed process below the external auditory meatus is the styloid process.

67. The mandibular condyle articulates with the glenoid fossa and comprises the TMJ.

68. The articular eminence is a radiopaque projection of bone located anterior to the glenoid fossa.

69. On a panoramic image, the infraorbital foramen may be superimposed over the maxillary sinus.

70. Only the inferior border of the orbit is seen on a panoramic image.

71. The nasal cavity is also known as the nasal fossa

72. The mental foramen may be seen on both PA and panoramic images.

73. On a panoramic image, the nasopharyngeal air space appears as a diagonal radiolucency located superior to the radiopaque shadow of the soft palate and uvula.

74. On a panoramic image the ear appears superimposed over the styloid process.

75. If the tongue is not placed at the roof of the mouth during a panoramic exam, a radiolucent artifact will appear obstructing the maxillary anterior teeth.

76. The J or U-shaped radiopacity that is located superior to the maxillary 1st molars is the zygomaticprocess.