2. 1 Components of Image Quality & Radiographic Artifacts Radiologic Technology A SPRING 2012

3. 2 X-ray Exposure Factors X-ray Exposure Factors Radiographic Density & Contrast Radiographic Density & Contrast Components of Image Quality Components of Image Quality Radiographic Artifacts Radiographic Artifacts

4. 3 Review Primary radiation exits the tube Primary radiation exits the tube Interacts with various densities in the body Interacts with various densities in the body Photons may be absorbed Photons may be absorbed Scattered Scattered Passed through without any interference to the cassette or image receptor (IR) Passed through without any interference to the cassette or image receptor (IR)

5. 4 How well we can see something on the image

6. 5 Image detail is affected by: Photographic properties and Geometric properties

7. 6 Photographic Properties 1.Contrast 2.Density

8. 7 Factors Affecting Density Primary control factor Primary control factor –mA –Time (seconds) Influencing factors Influencing factors –kVp –Grids –Beam restriction –Body structures (size of pt, pathology –Processing –SID & OID –Film Screen combinations

9. 8 Primary Controlling Factor of Density mAs mAs mA = AMOUNT of electrons sent across the tube combined with TIME (S) = mAs mA = AMOUNT of electrons sent across the tube combined with TIME (S) = mAs mAs controls DENSITY on radiograph mAs controls DENSITY on radiograph primary function of mAs is DENSITY primary function of mAs is DENSITY

10. 9 Imagine this… If the mA station is changed from 200 to 400 mA, twice as many electrons will flow from the cathode to the anode. If the mA station is changed from 200 to 400 mA, twice as many electrons will flow from the cathode to the anode. From 10 mA to 1000 mA = 100 x more From 10 mA to 1000 mA = 100 x more mA controls how many electrons are coming at the target mA controls how many electrons are coming at the target mAs is a combination of how many and for how long (seconds) mAs is a combination of how many and for how long (seconds)

11. 10 10 mA1000 mA

12. 11

13. 12 Changing Mas – Changes Density + 25 % + 50 % mas

14. 13 Influencing Factor on Density: kVp

15. 14 Change in kVp kVp controls the energy level of the electrons and subsequently the energy of the x-ray photons. kVp controls the energy level of the electrons and subsequently the energy of the x-ray photons. A change from 72 kVp will produce A change from 72 kVp will produce x-rays with a lower energy than at 82 kVp Difference between a ball traveling 72 mph and 82 mph (how much energy did it take to throw the ball at the rates?) Difference between a ball traveling 72 mph and 82 mph (how much energy did it take to throw the ball at the rates?)

16. 15 + 15% kvp - 15% kvp Increasing kVp = increase energy reaching the IR This will also influence the density on the image

17. 16 Radiolucent vs. Radiopaque Radiolucent materials allow x-ray photons to pass through easily (soft tissue). Radiolucent materials allow x-ray photons to pass through easily (soft tissue). Radiopaque materials are not easily penetrated by x- rays (bones) Radiopaque materials are not easily penetrated by x- rays (bones)

18. 17 Creating the Image 1. Transmission –no interaction –Responsible for dark areas 2. Scatter 1.(grays) – produces no diagnostic info 3. Absorption 1.(photoelectric effect) –Responsible for light areas

19. 18 Images DENSITY = THE AMOUNT OF BLACKENING “DARKNESS” ON THE RADIOGRAPH (mAs) DENSITY = THE AMOUNT OF BLACKENING “DARKNESS” ON THE RADIOGRAPH (mAs) CONTRAST – THE DIFFERENCES BETWEEN THE BLACKS TO THE WHITES (kVp) CONTRAST – THE DIFFERENCES BETWEEN THE BLACKS TO THE WHITES (kVp)

20. 19 Why you see what you see… The films or images have different levels of density – different shades of gray The films or images have different levels of density – different shades of gray X-rays show different features of the body in various shades of gray. X-rays show different features of the body in various shades of gray. The gray is darkest in those areas that do not absorb X-rays well – and allow it to pass through The gray is darkest in those areas that do not absorb X-rays well – and allow it to pass through The images are lighter in dense areas (like bones) that absorb more of the X-rays. The images are lighter in dense areas (like bones) that absorb more of the X-rays.

21. 20 Patient Body Size and Pathology

22. 21 3 Different Body Habitus Hypersthenic Sthenic Hyposthenic Thank you to the 3 men in my life ! DCharman Dr. Charman, Eric Guzman, Adam Guzman

23. 22 PATHOLOGY Pleural Effusion Excessive fluid in lung More dense than air

24. 23 Pneumonia

25. 24 The right lung is almost completely collapsed; vascular shadows can not be seen in this area (arrow). Pneumothorax Lung collapses No tissue in space Easy to penetrate with x-ray photons

26. 25 Lung Cancer

27. 26 LUNG CANCER

28. 27 Density and Images

29. 28 Goal: Producing optimal radiographs DENSITY Too dark Too light

30. 29

31. 30 Controlling Factor of Contrast

32. 31 Controlling Factor of Contrast 1. Kilovolts to anode side – kVp 2. Kilovolts controls how fast the electrons are sent across the tube 3. kVp – controls CONTRAST on images

33. 32 Producing optimal radiographs Contrast Scale Long scale short scale

34. 33

35. 34 Scale of Contrast? Which one is “better” How does the kVp affect these images?

36. 35 Beam Restriction and Grids

37. 36 Scatter –Creates fog –Lowers contrast (more grays) Increases as Increases as –kV increases –Field size increases –Thickness of part increases

38. 37 Effects of collimation (beam restriction) on scatter

39. 38 Collimate to area of interest - reduces scatter and radiation dose to the patient Collimate to area of interest - reduces scatter and radiation dose to the patient

40. 39 Grids A device with lead strips that is placed between the patient and the cassette A device with lead strips that is placed between the patient and the cassette Used on larger body parts to reduce the number of scattering photons from reaching the image Used on larger body parts to reduce the number of scattering photons from reaching the image

41. 40 Basic Grid Construction Radiopaque lead strips Radiopaque lead strips Separated by radiolucent interspace material - Typically aluminum Separated by radiolucent interspace material - Typically aluminum Allow primary radiation to reach the image receptor (IR) Allow primary radiation to reach the image receptor (IR) Absorb most scattered radiation Absorb most scattered radiation Primary disadvantage of grid use Primary disadvantage of grid use –Grid lines on film

42. 41 GRIDS

43. 42 Grid is placed between patient (behind table or upright bucky) & cassette

44. 43 Grids absorb scatter – prevents it from reaching the image GRID STOPS SCATTER

45. 44

46. 45 Contrast changes with the use of a grid Less scatter radiation – shorter scale = “better contrast” With Grid No Grid

47. 46 GRIDS CAN LEAVE LINES ON THE IMAGE

48. 47 GEOMETRIC Properties 1. Recorded Detail 2. DISTORTION 1.Size distortion 1. Magnification 2.Shape distortion 1. Elongation 2. Foreshortening

49. 48 RECORDED DETAIL

50. 49 RECORDED DETAIL The degree of sharpness in an object’s borders and structural details. The degree of sharpness in an object’s borders and structural details. How “clear” the object looks on the radiograph How “clear” the object looks on the radiograph

51. 50 Recorded Detail The degree of sharpness in an object’s borders and structural details. The degree of sharpness in an object’s borders and structural details. Other names: Other names: -sharpness of detail -definition-resolution -degree of noise

52. 51 RESOLUTION TEST TOOLS LINE PAIRS/ MM Depicts how well you can see the differences in structures More lines=more detail

53. 52

54. 53 Factors that affect Recorded Detail Geometric unsharpness Geometric unsharpness OID SID SIZE SHAPE OID SID SIZE SHAPE Motion unsharpness (blurring) Motion unsharpness (blurring) Intensifying Screens Intensifying Screens Film Speed / Composition Film Speed / Composition Film – Screen contact Film – Screen contact Kvp & Mas (density / visibility) Kvp & Mas (density / visibility)

55. 54

56. 55 MOTION AKA Blurring

57. 56 Motion Can be voluntary or involuntary Can be voluntary or involuntary Best controlled by short exposure times Best controlled by short exposure times Use of careful instructions to the pt. Use of careful instructions to the pt. Suspension of pt. respiration Suspension of pt. respiration Immobilization devices Immobilization devices

58. 57

59. 58 Decrease Motion Unsharpness 1. Instruct patient not to move or breath 2. Use Immobilization devices 3. Use Short exposure times 4. Lock equipment in place

60. 59 Blurring of image due to patient movement during exposure.

61. 60

62. 61 Object Unsharpness Main problem is trying to image a 3-D object on a 2-D film. Main problem is trying to image a 3-D object on a 2-D film. Human body is not straight edges and sharp angles. Human body is not straight edges and sharp angles. We must compensate for object unsharpness with factors we can control: focal spot size, SID & OID We must compensate for object unsharpness with factors we can control: focal spot size, SID & OID

63. 62 SID Source to Image Distance The greater the source X-ray tube) to image (cassette) distance, the greater the image sharpness. The greater the source X-ray tube) to image (cassette) distance, the greater the image sharpness. Standard distance = 40 in. most exams Standard distance = 40 in. most exams Exception = Chest radiography 72 in. Exception = Chest radiography 72 in.

64. 63 The SID will influence magnification. The farther away – the less magnified ↑SID ↓ MAGNIFICATION

65. 64SID Shine a flashlight on a 3-D object, shadow borders will appear “fuzzy” Shine a flashlight on a 3-D object, shadow borders will appear “fuzzy” -On a radiograph called Penumbra Penumbra (fuzziness) obscures true border – umbra Penumbra (fuzziness) obscures true border – umbra Farther the flashlight from object = sharper borders. Same with radiography. Farther the flashlight from object = sharper borders. Same with radiography.

66. 65

67. 66 OID Object to Image Distance The closer the object to the film, the sharper the detail. The closer the object to the film, the sharper the detail. OID , penumbra , sharpness  OID , penumbra , sharpness  OID , penumbra , sharpness  OID , penumbra , sharpness  Structures located deep in the body, radiographer must know how to position to get the object closest to the film. Structures located deep in the body, radiographer must know how to position to get the object closest to the film.

68. 67 The position of the structure in the body will influence how magnified it will be seen on the image The farther away – the more magnified

69. 68

70. 69 Distortion Misrepresentation of the true size or shape of an object Misrepresentation of the true size or shape of an object –MAGNIFICATION –size distortion –TRUE DISTORTION –shape distortion

71. 70 MAGNIFICATION TUBE CLOSE TO THE PART (SID) TUBE CLOSE TO THE PART (SID) PART FAR FROM THE CASSETTE (OID) PART FAR FROM THE CASSETTE (OID)

72. 71

73. 72 http://www.coursewareobjects.com/ob jects/mroimaging_v1/mod04i/0416a.ht m http://www.coursewareobjects.com/ob jects/mroimaging_v1/mod04i/0416a.ht m

74. 73 Size Distortion & OID If source is kept constant, OID will affect magnification If source is kept constant, OID will affect magnification As OID , magnification  As OID , magnification  The farther the object is from the film, the more magnification The farther the object is from the film, the more magnification

75. 74

76. 75 In terms of recorded detail and magnification the best image is produced with a small OID & large SID

77. 76 Minimal magnification small OID Magnification - large OID

78. 77 Size Distortion & SID Major influences: SID & OID Major influences: SID & OID As SID , magnification  As SID , magnification  Standardized SID’s allow radiologist to assume certain amt. of magnification factors are present Standardized SID’s allow radiologist to assume certain amt. of magnification factors are present Must note deviations from standard SID Must note deviations from standard SID

79. 78

80. 79

81. 80

82. 81 40” SID VS 72” SID

83. 82

84. 83 SHAPE DISTORTION Elongation and Foreshortening

85. 84 Shape Distortion Misrepresentation of the shape of an object Misrepresentation of the shape of an object Controlled by alignment of the beam, part (object), & image receptor Controlled by alignment of the beam, part (object), & image receptor Influences: Central ray angulation & body part rotation Influences: Central ray angulation & body part rotation

86. 85 A = good B & C = shape distortion (elongation of part)

87. 86 D & E = shape distortion (foreshortening of part)

88. 87 Image Distortion When the part to be imaged – does not lay parallel with the IR (cassette) When the part to be imaged – does not lay parallel with the IR (cassette) If the Central Ray is not perpendicular to the part If the Central Ray is not perpendicular to the part –CR should be at right angle with the cassette

89. 88 Central Ray Angulation Body parts are not always 90 degrees from one another Body parts are not always 90 degrees from one another Central ray angulation is used to demonstrate certain details that can be hidden by superimposed body parts. Central ray angulation is used to demonstrate certain details that can be hidden by superimposed body parts. Body part rotation or obliquing the body can also help visualize superimposed anatomy. Body part rotation or obliquing the body can also help visualize superimposed anatomy.

90. 89 Central Ray Radiation beam diverges from the tube in a pyramid shape. Radiation beam diverges from the tube in a pyramid shape. Photons in the center travel along a straight line – central ray Photons in the center travel along a straight line – central ray Photons along the beam’s periphery travel at an angle Photons along the beam’s periphery travel at an angle When central ray in angled, image shape is distorted. When central ray in angled, image shape is distorted.

91. 90

92. 91

93. 92

94. 93 Elongation Foreshortened Normal

95. 94

96. 95 Distortion (object & film not parallel) Distortion (x-ray beam not centered over object & film)

97. 96 Distortion of multiple objects in same image (right) due to x-ray beam not being centered over objects.

98. 97 Focal Spot Size Smaller x-ray beam width will produce a sharper image. Smaller x-ray beam width will produce a sharper image. Fine detail = small focal spot (i.e. small bones) Fine detail = small focal spot (i.e. small bones) General radiography uses large focal spot General radiography uses large focal spot Beam from penlight size flashlight vs. flood light beam Beam from penlight size flashlight vs. flood light beam

99. 98 ANODE

100. 99 THE SMALLER THE BEAM TOWARDS THE PATIENT - THE BETTER THE DETAIL OF THE IMAGE PRODUCED

101. 100 FOCAL SPOT ANGLE SMALLER ANGLE – SMALLER BEAM AT PATIENT

102. 101 ARTIFACTS: AN UNWANTED DENSITY ON THE FILM http://www.xray2000.co.uk/

103. 102 Artifacts - Types Processing Artifacts Processing Artifacts Exposure Artifacts Exposure Artifacts Handling & Storage Artifacts Handling & Storage Artifacts

104. 103 Processing Artifacts Emulsion pickoff Emulsion pickoff Chemical fog Chemical fog Guide-shoe marks Guide-shoe marks Water marks Water marks Chemical spots Chemical spots Guide-shoe & roller scratches Guide-shoe & roller scratches

105. 104 Developer Spots

106. 105 Water spot

107. 106 Discolored film due to hypo (fixer) retention. Chemicals not washed off – over time will turn film brown

108. 107 Scratch marks from rollers in automatic processor.

109. 108 Exposure Artifacts Motion Motion Improper patient position Improper patient position Wrong screen-film match Wrong screen-film match Poor film/screen contact Poor film/screen contact Double exposure Double exposure Warped cassette Warped cassette Improper grid position Improper grid position

110. 109 Artifact

111. 110

112. 111 Blurred image due to patient motion

113. 112 PATIENT ARTIFACT - JEWERLY

114. 113 Handling & Storage Artifacts Light fog Light fog Radiation fog Radiation fog Static Static Kink marks Kink marks Scratches Scratches Dirty cassettes Dirty cassettes

115. 114 Crimping /cresent mark

116. 115 Double Exposure 2 exposures made on top of each other – from poor handling of cassettes

117. 116

118. 117 Static electricity

119. 118 Dirt on screen mimicking a foreign object.

120. 119 Scratch marks from improper handling.

121. 120 Light fog

122. 121 Kink mark or nail pressure mark

123. 122 cast

124. 123 POOR SCREEN CONTACT

125. 124 Patient motion

126. 125 motion

127. 126 Double exposure Child

128. 127 Poor screen contact

129. 128 Double exposure

130. 129 ?

131. 130 ?

132. 131

133. 132 Pt clothing

134. 133 Hip replacement

135. 134 2 chest tubes in the patient

136. 135 Patient swallowed batteries What size are they?

137. 136

138. 137 PATHOLOGY NOT ARTIFACT

139. 138 Name & cause of this?

140. 139 scratches

141. 140 Digital image Mis- Registration error

142. 141 Roller marks from film stuck – then pulled from processor

143. 142 Hardware In cervical spine

144. 143 Dust in imaging plate can cause white marks on image Dust in imaging plate can cause white marks on image Both in film/screen and computed radiography Both in film/screen and computed radiography

145. 144 E E G MONITOR

146. 145 What do you See? 2 exposures

147. 146

148. 147

149. 148 Evaluating Images What do you think?

150. 149 See anything wrong with this image?

151. 150 Contrast? What influences this? (kVp in f/s)

152. 151 Collimation – reducing the size of beam helps to improve the image, and reduce the dose to the patient

153. 152 ?