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RADT 456 Image Acqu
AART reg review
Question | Answer |
---|---|
Define the term recorded detail | refers to the sharpness of the structural detail borders 298 |
Misrepresentation of the actual size or shape is called _______? | distortion pg 299 |
T or F? Density and fog have no effect on how sharply an image detail is rendered? | True pg 299 |
which has a greater impact on recorded detail if changed? SID or OID? | changes in OID have a greater impact on detail pg 301 |
Structures farther from the IR will be distoted or _________ more than thoes closer th the IR | magnified pg 303 |
If a linear structure is angled within the body, that is, not parallel with the long axis of the body and not parallel to the IR, that anatomic structure will be ___________? | Foreshortened pg 303 |
This occurs when the x-ray tube is angled? | Elongation pg 303 |
Localized melting of the target material, and anoded ______ and/or cracking can occur more easily. | Pitting pg 306 |
What are the two best methods to minimizing voluntary motion? | Good communication and suspended respiration pg 309 |
At least a _______% change must be made in mAs for there to be a perceptible change in radiographic density | 30 pg 318 |
If you want to double the density, yet it is impossible to adjust the mAs, a similar effect can be done how? | By increasing the kV by 15% pg 320 |
List the 5 common grid errors. | angulation error, off-level error, off-focus error, off-center error, and upside-down grid pg 325 |
What are the grid ratios for a 5:1 grid, 8:1 grid, and a 16:1 grid? | 2, 4, and 6 pg 327 |
What is the single most important way to decrease scatter radiation? | collimation pg 329 |
If a patient has any of the following disease, would you increase or decrease your technique? Ascites, congestive heart failure, paget disease | You would increase your technique to compensate for the additive pathologies pg 333 |
Optical density increase as developer temperature ________ | increase pg 339 |
__________ is the result of differential absorption of x-rays by body tissues having different attenuation coefficients | Subject contrast pg 340 |
T or F? Scatted radiation carries useful information and adds noise that impairs visibility of image detail? | False- scatter radiation carries no useful info and does add noise to the image pg 346 |
In regards to the PSP, why is cesium iodide needle shaped or columnar? | that way it has a better advantage of better x-ray absorption and less light diffusion ph 358 |
name the order of the PSP as the x-ray hits the imaging plate | protective layer, barium fluorohalide layer, reflective layer, base, antistatic layer, and then lead foil backing pg 358 |
What is the latent image and manifest image? | Latent image is the unprocessed image, where the manifest image is the processed image that comes up on the screen pg 359 |
What is the purpose of a PMT or photodiode (PD) | It is used to detect the PSL and convert it to electrical signals pg 360 |
T or F? DR exposures can be lower because of the detector's higher DQE? | True pg 363 |
Compare the terms given to CR/DR imaging terminology? Density, recorded detail, and latitude? | brightness, SNR, and dynamic range pg 363 |
T or F? Softwear processing algorithms control digital image brightness? | True pg 366 |
MTF is used to describe ____ _______; SNR is used to describe _____ ______ | Spatial resolution ; contrast resolution pg 367 |
in CR and DR, x-rays are converted to light and then to a ________ | electrical signal pg 367 |
T or F? spatial resolution of direct digital systems is fixed and is not related to the detector element DEL size of the TFT? | False - spatial resolution is related to the detector element DEL size pg 367 |
CR image ________ can occur if there is a delay in reading/processing the PSP/SPS | Fading pg 367 |
In film processing, describe what the developer and wash do? | Developer reduces the exposed silver bromide to black metalic silver and the wash removes processing chemicals and permits archival quality pg 386 |
List the order of the processing chemicals | developer, fixer, wash, and dryer pg 387 |