IMAGE QUALITY AND ARTIFACTS 1

2 WHY YOU SEE WHAT YOU SEE… 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. 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.

3 IMAGE PRODUCTION 1. Primary Beam – The beam of photons, B4 it interacts with the pt’s body. 2. Remnant (exit) Beam- The resulting beam that is able to exit from the patient. 3. Scatter Radiation – Radiation that interacts with matter & only continues in a different direction – not useful for image production. 4. Attenuated Beam – Primary radiation that is changed (partially absorbed) as it travels through the pt.

IMAGE QUALITY AND ARTIFACTS Density Contrast Detail Distortion Artifacts 4

IMAGE QUALITY AND ARTIFACTS Density Contrast Detail Distortion Artifacts 5

IMAGE QUALITY AND ARTIFACTS Density Contrast Detail Distortion Artifacts 6

THE OVERALL DARKENING OF THE IMAGE DENSITY 7

DENSITY (OPTICAL DENSITY, IMAGE DENSITY) Prime Controlling Factor mAs Influencing Factors kVp SID Beam Filtration Beam restriction Body part thickness grids 8

10 mA1000 mA 9

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DENSITY (OPTICAL DENSITY, IMAGE DENSITY) Prime Controlling Factor mAs Influencing Factors kVp SID Beam Filtration Beam restriction Body part thickness grids 11

 KVP MORE ENERGY = MORE PHOTONS PASSING THOUGH TISSUE & STRIKING THE IMAGE  15% kVp = doubling of exposure to the film  15% kVp = halving of exposure to the film 15% rule will also change the contrast of the image because kV is the primary method of changing image contrast. Remember : 15% change (  ) KVP has the same effect as doubling or ½ the MAS on density 12

This is an actual arm tatoo. Now that’s dedication ! 13

COLLIMATORS Always collimate smaller than the image receptor 14

3 DIFFERENT BODY HABITUS HYPERSTHENIC STHENIC HYPOSTHENIC 15

16 GOAL: PRODUCING OPTIMAL RADIOGRAPHS DENSITY Too dark Too light

THE RANGE OF DARK, LIGHTS, GRAYS IN THE IMAGE CONTRAST 17

RADIOGRAPHIC CONTRAST Primary controlling factor kVp Influencing Factors Subject contrast mAs SID Filtration Beam restriction grids 18

CASCADE Patient Interactions 19

COMPTON SCATTERING 1.Outer shell electron in body 2.Interacts with x-ray photon from the tube 3. Moderate energy electron Patient Interactions 20

SCALE OF CONTRAST? WHICH ONE IS “BETTER” HOW DOES THE KVP AFFECT THESE IMAGES? 21

RADIOGRAPHIC CONTRAST Subject Contrast Tissue thickness Tissue density Tissue type (atomic #) Contrast agents Scatter radiation 22

10 mA1000 mA 23

This is an actual arm tatoo. Now that’s dedication ! 24

RADIOGRAPHIC CONTRAST Primary controlling factor kVp Influencing Factors Subject contrast mAs SID Filtration Beam restriction grids 25

26 EFFECTS OF COLLIMATION (BEAM RESTRICTION) ON SCATTER

27 GRIDS 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

28 GRIDS

29 GRIDS ABSORB SCATTER – PREVENTS IT FROM REACHING THE IMAGE

30 GRID NO GRID Controls contrast

RESOLUTION, ABILITY TO DISTINGUISH SHAPES DETAIL 31

DETAIL Image sharpness Spatial resolution Smallest separation of two lines or edges Measured by lp/mm Motion SID Focal spot size OID Image receptor type Factors that affect detail 32

RECORDED DETAIL The degree of sharpness in an object’s borders and structural details. How “clear” the object looks on the radiograph 33

RESOLUTION TEST TOOLS LINE PAIRS/ MM Depicts how well you can see the differences in structures More lines=more detail 34

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

37 Blurring of image due to patient movement during exposure.

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SID Shine a flashlight on a 3-D object, shadow borders will appear “fuzzy” -On a radiograph called penumbra Penumbra (fuzziness) obscures true border Farther the flashlight from object = sharper borders. Same with radiography. 39

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41 OID OBJECT TO IMAGE DISTANCE The closer the object to the film, the sharper the detail. 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.

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43 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

THE IMAGING OF THE TRUE SHAPE AND SIZE OF THE OBJECT DISTORTION 44

DISTORTION Misrepresentation of the size or shape of an object Two types: Size Distortion magnification Shape distortion Foreshortening elongation FACTOR INFLUENCING DISTORTION SID OID Beam Angulation Body Part-Beam alignment 45

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40” SID VS 72” SID WHICH ONE IS WHICH? 47

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49 Minimal magnification small OID

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SIZE DISTORTION & OID If source is kept constant, OID will affect magnification As OID , magnification  The farther the object is from the film, the more magnification 51

DISTORTION Misrepresentation of the size or shape of an object Two types: Size Distortion magnification Shape distortion Foreshortening elongation FACTOR INFLUENCING DISTORTION SID OID Beam Angulation Body Part-Beam alignment 52

DISTORTION Misrepresentation of the size or shape of an object Two types: Size Distortion magnification Shape distortion Foreshortening elongation FACTOR INFLUENCING DISTORTION SID OID Beam Angulation Body Part-Beam alignment 53

A = TRUE SHAPE B & C = SHAPE DISTORTION (ELONGATION OF PART) 54

D & E = SHAPE DISTORTION (FORESHORTENING OF PART) 55

IMAGE DISTORTION When the part to be imaged – does not lay FLAT with the IR (cassette) If the Central Ray is not perpendicular to the IR CR should be at right angle with the cassette 56

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ELONGATION FORESHORTENED NORMAL 59

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THINGS ON THE IMAGE THAT DISTRACT ARTIFACTS 61

62 ARTIFACTS: AN UNWANTED DENSITY ON THE FILM

ARTIFACTS TYPES Processing Artifacts Exposure Artifacts Handling and Storage Artifacts 63

PROCESSING ARTIFACTS Emulsion pickoff Chemical fog Guide-shoe marks Water marks Chemical spots Guide-shoe & roller scratches 64

Developer spots 65

Water mark 66

67 Discolored film due to FIXER RETENTION Chemicals not washed off – over time will turn film brown

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EXPOSURE ARTIFACTS Motion Improper patient position Wrong screen-film match Poor film/screen contact Double exposure Warped cassette Improper grid position Patient artifacts 69

70 ARTIFACT

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72 HANDLING & STORAGE ARTIFACTS Light fog Radiation fog Static Kink marks Scratches Dirty cassettes

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75 __________________

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___________________ 78

______ ______ _____ 79

PATIENT ____________ 80

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DOUBLE EXPOSURE CHILD 82

POOR SCREEN CONTACT 83

DOUBLE EXPOSURE 84

85 EXTRA SET OF HANDS

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2 chest tubes in the patient 88

Patient Swallowed Batteries 89

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PATHOLOGY NOT ARTIFACT 91

NAME & CAUSE OF THIS? 92

Digital image Mis- Registration error 93

GRID ARTIFACT 94

REVIEW RADIATION BIOLOGY REVIEW QUESTION 95 The type of shield that is attached to the side of the collimator on a radiographic tube is : A. flat contact B. Detachable C. Shaped shield D. shadow

REVIEW THE HISTORY OF X-RAYS REVIEW QUESTION 96 On what date were x-rays discovered? A.January 4, 1886 B.November 8, 1895 C. October 9, 1898 D. November 18, 1808

REVIEW THE REGULATORY BODIES REVIEW QUESTION 97 What agency regulates the quality of care provided to patients and the way the organization is supervised and operated for the purposes of providing continuous quality care? A.JRCERT B. ARRT C.JCAHO D. AHRA

REVIEW REGULATORY BODIES REVIEW QUESTION 98 Which organization provides a C.R.T. in general Radiography and Fluoroscopy? A.Joint Commission on Accreditation of Health Care Organizations B. California Department of Public Health- Radiologic Health Branch C. American registry of Radiologic Technologists D. Joint Review Committee on Education in Diagnostic Medical Sonography

REVIEW X-RAY EQUIPMENT REVIEW QUESTIONS 99 The collimator controls the: A.Target material B. Amount of x-rays produced C. Type of x-rays produced D. Size of the x-ray field

REVIEW X-RAY PRODUCTION 100 During x-ray production when an electron is knocked out of its shell by a projectile electron. An electron from an outer shell fills the vacancy, what is produced? A. radio waves B. scatter radiation C. characteristic radiation D. brem’s radiation

REVIEW X-RAY PRODUCTION REVIEW QUESTION 101 Thermionic emission at the filament releases: A. protons B. photons C. electrons D. neutrons

REVIEW PATIENT INTERACTIONS REVIEW QUESTION 102 This interaction an incoming photon enters with an energy, changes directions, and exits with the same amount of energy. A. Heat B. Brems C. Compton D. Coherent

REVIEW RADIATION BIOLOGY REVIEW QUESTION 103 All the following are radiation protection devices EXCEPT: A. lead apron B. contact shield C. film badge D. collimators

REVIEW RADIATION BIOLOGY REVIEW QUESTION 104 What is the most radiosensitive component of the cell? A. protein B. cytoplasm C. nucleus D. mitochondria