MEDICINE
RADIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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density.
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contrast.
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resolution.
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magnification.
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Detailed explanation-1: -Size and shape of the focal spot is determined by the size and shape of the electron beam when it strikes the anode 1. Size and shape of the electron beam is determined by: dimensions of the filament tungsten coil. construction of the focusing cup.
Detailed explanation-2: -In radiography, fluoroscopy, and CT, the x-ray tube normally has two focal spot sizes, with nominal sizes of 0.6 and 1.2 mm.
Detailed explanation-3: -Why are x-ray tubes manufactured with two focal spots? The small focal spot is used when better spatial resolution is required. The large focal spot is used when large body parts are imaged and when other techniques that produce high heat are required.
Detailed explanation-4: -The size of the focal spot affects radiographic sharpness in so far as it directly affects penumbra size. Blurring due to this factor is determined by the relative sizes of the penumbra and the radiographic image.