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RAD 121 - PST 2

flashcards for RAD 121

QuestionAnswer
What is the ability of an imaging system to sharply define an edge called? acutance (part of spatial resolution)
***The three factors that influence geometric sharpness are called _____, _____ and _____. SID, OID, and FSS
State the formula to calculate geometric unsharpness. P = FSS x OID / SOD
State the formula to calculate the Magnification Factor based on distances. MF = SID / SOD
State the formula to calculate the Magnification Factor based on object and image. MF = IW / OW or MF = IW / OW = SID / SOD
State the formula to calculate the percentage of magnification based on distance. % magnification = SID - SOD / SOD x 100
State the formula to calculate the percentage of magnification based on object and image: % magnification = IW - OW / OW x 100
State the formula to calculate Grid Ratio GR = Height of lead strips / distance between lead strips
What is acutance? a measure of steepness or abruptness of an edge in a photographic image
What is Ceiszynski's Law? an isometric angle, equal to 1/2 of the angle formed between the object and IR, will eliminate or minimize distortion (think AP Sacrum)
What is another name for the geometric unsharpness formula? Penumbra formula
What is penumbra? The region of partial illumination or radiation caused by x-rays not originating from the point source; also called geometric unsharpness.
What is distortion? Any misrepresentation of size/shape of object being imaged.
Name the types of distortion. A) Size distortion B) Shape distortion
Created by: Larobbins