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Champa Ch 1
Radiology
Principles of Radiographic Exp | Answer |
---|---|
Photopic | Cones |
Scotopic | Rods |
Photographic Properties | Density, Contrast |
Geometric Properties | Detail, Distortion |
Density | Overall Blackness |
Contrast | Differences in adjacent densities |
Detail | Sharpness of lines |
Distortion | Misrepresentation of the true size or shape of the image as compared to the object |
Low Contrast | Many shades of grey |
High Contrast | Black and white |
Day Vision | Photopic |
Night Vision | Scotopic |
Veil Glare | Bright light floods the eye and reduces contrast perception |
Mach Effect | The eye percieves a boundary between differing densities |
Pattern Recognition | Comparing mental images of patterns to arrive at a diagnosis |
Why two images at 90 * angles | To achieve a three dimensional image |
Recorded Detail | What is on film |
Visibility Detail | What we can see |
mAs | Milliamp seconds-current times seconds |
kVp | Kilovolt peak-energy of x-ray |
Screen | turns x-ray into light |
Grid | absorbs x-rays and improves contrast |
Filtration | Absorbs low energy x-rays |
Pathology | Changes density of tissues |
SID | Source to Image Distance |
High Density | Too Dark |
Low Density | Too Light |
Size Distortion | Always Magnification |
Motion | Destroys detail |
Communication to patient | Best way to control motion |