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Ideal radiograph

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Ideal radiograph

  1. 1. OMR, CODS, DVG www.indiandentalacademy.com
  2. 2. OMR, CODS, DVG www.indiandentalacademy.com
  3. 3. OMR, CODS, DVG www.indiandentalacademy.com
  4. 4. OMR, CODS, DVG www.indiandentalacademy.com
  5. 5. An ‘Ideal Radiograph’ is the one with optimum density, maximum detail and sufficient contrast to make the detail apparent. The image should be sharp, centered and have the same size and shape as that of the object. OMR, CODS, DVG DEFINITION Image Attributes (Qualities / Properties) (Other attributes : Film latitude, Radiographic mottle, Image clarity) density density density Density, contrast contrast contrast Contrast, detail detail detail Detail, sharp sharp sharp Sharpness,Speed www.indiandentalacademy.com
  6. 6. OMR, CODS, DVG DENSITY “Overall degree of darkening of a processed film” Dark Radiograph Light RadiographJust Right! High Density Low DensityOptimum Density = 0.5 to 2.0 www.indiandentalacademy.com
  7. 7. OMR, CODS, DVG DENSITY “Overall degree of darkening of a processed film” • Exposure factors - kVp, mA, S, Filtration, Collimation, TID • Subject thickness & density • Processing factors - developing time, temperature, concentration Factors Affecting Density: www.indiandentalacademy.com
  8. 8. OMR, CODS, DVG CONTRAST “Difference in densities in different regions of the film” Low Contrast High Contrast Sufficient Contrast www.indiandentalacademy.com
  9. 9. OMR, CODS, DVG CONTRAST “Difference in densities in different regions of the film” OPTONICA SUPER SHARP OPTONICA SUPER SHARP Low Contrast High Contrast Useful for study of periodontal bone loss Useful for study of periodontal bone loss Useful for detection of dental caries Useful for detection of dental caries www.indiandentalacademy.com
  10. 10. OMR, CODS, DVG CONTRAST “Difference in densities in different regions of the film” • Exposure factors - kVp • Subject contrast • Film fog due to scattered radiation • Processing factors - temperature, concentration Factors Affecting Contrast: www.indiandentalacademy.com
  11. 11. OMR, CODS, DVG DETAIL(RESOLUTION) “Ability of a radiograph to separately record closely spaced objects” www.indiandentalacademy.com
  12. 12. OMR, CODS, DVG DETAIL(RESOLUTION) “Ability of a radiograph to separately record closely spaced objects” Silver bromide crystalwww.indiandentalacademy.com
  13. 13. OMR, CODS, DVG DETAIL(RESOLUTION) • Size of silver bromide crystals • Use of intensifying screens • Motion • Film contrast Factors Affecting Detail: “Ability of a radiograph to separately record closely spaced objects” www.indiandentalacademy.com
  14. 14. OMR, CODS, DVG SHARPNESS (DEFINITION) “Effectiveness of a radiograph to precisely define an edge” www.indiandentalacademy.com
  15. 15. OMR, CODS, DVG SHARPNESS (DEFINITION) • Size of the focal spot • Focal spot to object and object to film distance • Motion • Size of the silver bromide crystals • Use of intensifying screens Factors Affecting Sharpness: “Effectiveness of a radiograph to precisely define an edge” www.indiandentalacademy.com
  16. 16. OMR, CODS, DVG SPEED “Amount of radiation required to produce density of 1” More the radiation required, slower is the film. Lesser the radiation required, faster is the film. Film speed is designated by alphabets A, B, C, D, E‘A’ is the slowest film. ‘E’ is the fastest film. www.indiandentalacademy.com
  17. 17. OMR, CODS, DVG SPEED “Amount of radiation required to produce density of 1” Small crystal size --> Slow film Large crystal size --> Fast film www.indiandentalacademy.com
  18. 18. OMR, CODS, DVG DEFINITION An ‘Ideal Radiograph’ is the one with optimum density, maximum detail and sufficient contrast to make the detail apparent. The image should be sharp, centered and have the same size and shape as that of the object. www.indiandentalacademy.com
  19. 19. OMR, CODS, DVG www.indiandentalacademy.com
  20. 20. OMR, CODS, DVG 1. The size of the focal spot should be as small as possible. 2. The focal spot to object distance should be as large as possible. 3. The object to image receptordistance should be as small as possible. 4. The image receptorshould be placed parallel to the object. 5. The central ray should be perpendicularto object and image receptorin both vertical and horizontal planes. 6. The object should be centered on the image receptor. www.indiandentalacademy.com
  21. 21. OMR, CODS, DVG 1. The size of the focal spot should be as small as possible. Pin point focal spot 1 x 0.8 mm focal spot Limiting factor : Heat dissipation www.indiandentalacademy.com
  22. 22. OMR, CODS, DVG 2. The focal spot to object distance should be as large as possible. Largerpenumbra (zone of unsharpness) & Image magnification Smallerpenumbra (zone of unsharpness) &Less image magnification Limiting factor : Inverse square lawwww.indiandentalacademy.com
  23. 23. OMR, CODS, DVG 3. The object to image receptordistance should be as small as possible. Largerpenumbra (zone of unsharpness) & Image magnification Smallerpenumbra (zone of unsharpness) &Less image magnification Limiting factor : Oral anatomy www.indiandentalacademy.com
  24. 24. OMR, CODS, DVG 4. The image receptorshould be placed parallel to the object. Size and shape distortion if image receptornot parallel to the object. www.indiandentalacademy.com
  25. 25. OMR, CODS, DVG 4. The image receptorshould be placed parallel to the object. Limiting factor : Oral anatomy www.indiandentalacademy.com
  26. 26. OMR, CODS, DVG 5. The central ray should be perpendicularto object and image receptor in both vertical and horizontal planes. Image size < Object sizeImage size > Object sizeImage size = Object size www.indiandentalacademy.com
  27. 27. OMR, CODS, DVG 5. The central ray should be perpendicularto object and image receptor in both vertical and horizontal planes. If the central ray is not perpendicular in the horizontal plane, overlapping of shadows of adjacent structures results. e.g. overlapping of proximal surface shadows in periapical and bitewing radiography. If the central ray is not perpendicular in the horizontal plane, overlapping of shadows of adjacent structures results. e.g. overlapping of proximal surface shadows in periapical and bitewing radiography. www.indiandentalacademy.com
  28. 28. OMR, CODS, DVG 6. The object should be centered on the image receptor. Complete Image Incomplete Image www.indiandentalacademy.com
  29. 29. OMR, CODS, DVG Summary of Factors Directly Affecting Image Attributes Density Contrast Detail Sharpness kVp mA No Collimation Focal Spot Size Focal Spot- Object Distance Expo. Time www.indiandentalacademy.com
  30. 30. OMR, CODS, DVG Summary of Factors Directly Affecting Image Attributes Density Contrast Detail Sharpness Object- Film Distance Motion Subject Density & Thicknes s Developing Time, Temp. & Concentration AgBr Crystal Size www.indiandentalacademy.com

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