# Unit 1 (Contrast)

 The flashcards below were created by user nenyabrooke on FreezingBlue Flashcards. Contrast is the second of the two major __________ properties. photographic What is contrast? differences in adjacent densities If you decrease the exposure range, does the contrast increase or decrease? increase If you decrease dynamic range, does the contrast increase or decrease? increase If you narrow the latitude, will the contrast increase or decrease? increase Is there more or less contrast on a short scale when compared to a long scale? more contrast Is contrast affected more by window level or window width? window width What is the name of the device used to show "steps" of contrast? a penetrometer If you increase the kVp, will the contrast increase or decrease? decrease If you increase the kVp, will the dynamic range increase or decrease? increase What is the analog equivalent for dynamic range? exposure range If you increase the kVp, will the scale be longer or shorter? long scale If you decrease the kVp, will there be more or less photoelectric absorption? more If you increase the kVp, will there be more or less scatter? more When does compression or expansion occur? after the image is taken, on the computer/monitor Does compression increase or decrease the contrast? increase Does expansion increase or decrease the contrast? decrease What three ways can you utilize to achieve compression/expansion? change the D log E curveadjust the kVpadjust the window width If you decrease window width, does it result in compression or expansion? compression What entity makes up the y-axis of the D log E curve? density For the D log E curve, the steps in the contrast scale are measured in increments of _________. .3 (log exposure) What is the purpose of the D log E curve? It is used to plot the differences of contrast in each "step" if you decrease the window width, is the contrast higher or lower? higher contrast On the D log E curve, does a curve that is more vertical signify high contrast or low contrast? high contrast On the D log E curve, does a curve that is more horizontal signify high contrast or low contrast? low contrast If there is too much density, will the log exposure fall on the shoulder or the toe of the D log E curve? the shoulder Which film offers higher contrast? Film A What are the two types of image contrast? Image receptor contrastSubject contrast Describe contrast's proportional relationship with density. If density becomes too high OR too low, the contrast decreases. What is image receptor contrast? the range of densities the film is able to record What are 4 factors that affect image receptor contrast? Intensifying ScreensFilm DensityD log E CurveFilm ProcessingDigital Image Receptors*** (digital, not analog) What are 3 factors that affect subject contrast? KilovoltageAmount of Irradiated MaterialType of Irradiated Material Which has lower contrast, directly exposed film or screen film? directly exposed film Which film was exposed with a screen, and which film was exposed without a screen? A: with screenB: without screen (ex. exposed with just cardboard) Which of these films displays high contrast? Film A Would a low contrast film present as a vertical curve or a horizontal curve on the D log E Curve? Horizontal If there is not enough density on a film, would the curve it presents for the D log E curve fall on the shoulder or on the toe? Toe What has happened to curve A in this D log E curve representation? The A curve has an increase of "base density" most likely due to a processing error. What is subject contrast? range of variations in intensity after attenuation of the beam Using _____________ means that you are using a wider range of photon energy. higher kVp Using higher kVp offers greater ___________, ________, __________, and a _________ scale of contrast. penetrabilityrange of exposuresamounts of scatterlonger What does the amount of Irradiated Material depend on? the thickness of the partfield size If there is an increase in the thickness of the part being x-rayed, does the amount of scatter increase or decrease? increase If there is a decrease in field size, does the scale of contrast get longer or shorter? short scale If there is an increase in thickness of the part and in field size, will there be an increase or decrease in contrast? decrease What influences the type of Irradiated Material? The atomic numberTissue Density If there is a high atomic number and tissue density, will there be greater or lesser attenuation? greater What is attenuation? absorption of the x-ray as it passes through matter If there is small difference in atomic number and tissue density as compared to adjacent tissues, will there be high contrast or low contrast? low contrast What is a tool we use to improve visualization when evaluating an area of a film? a contrast mask Is Kilovoltage inversely or directly related to contrast? inversely (a.k.a. indirectly) Extreme overexposure, where you reach the top of the D log E Curve and beyond is called _________. What happens to the image on the film when this occurs? Dmax This causes the areas of higher density to look lighter and the areas of lower density to look darker, the opposite of what they should (negative image) If the focal spot size gets smaller, does the contrast increase or decrease? neither, it remains the same What controls the focal spot size? mA What is the focal spot size the area on the anode where the x-ray photons are produced How does the anode heel effect affect contrast? It doesn't. (it affects density...it's "hotter" on the cathode side) Does the Air Gap technique increase or decrease scatter? decrease Does the Air Gap technique increase or decrease contrast? increase Does the Air Gap technique increase or decrease patient exposure? increase Does increased filtration increase or decrease contrast? decrease Does increased filtration increase or decrease the average beam energy? Increase Does increased filtration increase or decrease intensity? decrease Does beam restriction increase or scatter? decrease Does beam restriction increase or decrease contrast? increase Does the left film or the right film display more contrast? the one on the right (it has too much contrast) There is a pathology present in one of these films. What is it, and which film shows it? The film on the right is too dense, indicating that emphysema is likely. Which projection is showing more contrast? Which one has more scatter? The hand is higher contrastThe abdomen has more scatter Does increasing the Grid Ratio increase or decrease contrast? increase Authornenyabrooke ID99397 Card SetUnit 1 (Contrast) DescriptionChapter 29: Contrast for Unit 1 in Imaging Principles Updated2011-12-04T01:23:18Z Show Answers