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UNIT 6 RADIOLOGY
PRINCIPLE OF EXPOSURE AND IMAGE QUALITY
Question | Answer |
---|---|
DESCRIBE ONE PRIME FACTORS OF EXPOSURE - mA | CONTROLS THE # OF ELECTRONS PRODUCED AT THE FILAMENT AND THE QUANITY OF XRAY PHOTONS PRODUCED AT THE NODE |
DESCRIBE ONE PRIME FACTOR OF EXPOSURE - Exposure Time | CONTROLS HOW LONG THE ELECTRONS CROSS FROM CATHODE TO ANODE. AND HOW LONG THE EXPOSURE WILL LAST |
DESCRIBE ONE PRIME FACTOR OF EXPOSURE - kVp | CONTROLS THE SPEED (kinetic energy) OF THE ELECTRONS CROSSING FROM CATHODE TO ANOTE AND THE QUALITY (PENETRATING ABILITY) OF THE XRAY PHOTONS PRODUCED |
DESCRIBE ONE PRIME FACTOR OF EXPOSURE - SID | THE DISTANCE BETWEEN THE XRAY TUBE TARGET AND THE IR |
DEFINE DENSITY: | REFERS TO HOW DARK OR BLACK AND IMAGE APPEARS |
DEFINE CONTRAST: | REFERS TO THE DIFFERENCE IN DENSITY BETWEEN ADJACENT AREAS ON AND IMAGE |
DEFINE DISTORTION | REFERS TO MISREPRESENTATION IN SIZE AND/OR SHAPE OF AN OBJECT ON AN IMAGE |
DEFINE DETAIL: | REFERS TO THE VISUAL CLARITY OR SHARPENESS OF AN IMAGE |
LIST THE PRIMARY CONTROLLER OF DENSITY AND WHAT HAPPENS TO DENSITY IF IT IS CHANGED. | A) mAs B) mAs increase = Density Decreased C) mAs decreased = Density Increased |
LIST THE PRIMARY CONTROLLER OF CONTRAST AND WHAT HAPPENS TO CONTRAST IF IT IS CHANGED. | A)kVp B) AS kVp Increase - Contrast Decreases C) As kVp Decreases - Contrast Increases |
DIFFERENTIATE BETWEEN SHORT-SCALE AND LONG-SCALE CONTRAST | A) LONG-SCALE = LOW CONTRAST B) SHORT-SCALE = HIGH CONTRAST |
DESCRIBE WHAT HAPPENS TO SIZE DISTORTION WHEN SIDE & OID ARE CHANGED | SID INCREASED = SIZE DISTORTION DECREASES SID DECREASED = SIZE DISTORTION INCREASES OID INCREASED = SIZE DISTORTION INCRESES OID DECREASED = SIZE DISTORTION DECREASES |
DESCRIBE WHAT HAPPENS TO SHAPE DISTORTION WHEN BEAM ANGLE, CR/IR/BODY PART ALIGNMENT IS CHANGED | A BEAM ANGULATION INCREASES - SHAPE DISTORTION INCREASES - WHEN ANGULATION DECREASES SHAPE DISTORTION DECREASES |
DESCRIBE THE EFFECTS OF SIZE AND SHAPE DISTORTION ON RECORDED DETAIL | AN IMAGE VARIES IN ITS SHARPNESS |
DESCRIBE HOW VOLUNTARY AND INVOLUNTARY MOTION CAN BE AVOIDED | VOLUNTARY - GOOD PT INSTRUCTION AND COMMUNICATION INVOLUNTARY - PROPER POSITIONING - IMMOBILIZATION - SHORT EXPOSURE TIME |