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Digital Imaging 4
Module 4: Image Analysis
| Question | Answer |
|---|---|
| The radiographic density of a lumbar spine radiograph is too low. What are the possible causes of this image to have insufficient density? | 1)Decreased kVp; 2)Insufficient mAs; 3)Slower than expected speed receptor; 4)Less processing time; 5)Developer temp too low; 6)Decreased chemical concentration |
| Blurred images are caused by what? | Motion or changes in geometric factors during image production. |
| What is the predominate cause of blur in radiographic images? | Motion |
| When blur is caused by geometric factors what is the best way to assess these factors? | Using specific test phantoms |
| Gross overexposure involves the use of excessive ____________. | Radiation |
| Excessive Radiation is defined as: | More than 3 to 4 times the level of radiation needed to produce a diagnostic quality image |
| This kind of error is caused by a computer's inability to identify the edges of collimation: | Exposure Field Recognition Error |
| Exposure Field Recognition Errors can cause a _______________ error during the ___________ analysis because the ___________ ____________ weren't recognized and all of the data on the PSP plate were included in the values distribution. | Rescaling; Histogram; Field Borders |
| Improper alignment of a radiographic grid in Digital Imaging can lead to __________ __________. | Grid Cutoff |
| Selecting the incorrect histogram model for analysis can cause the _________ _____ _________ to display incorrect ___________ and __________. | Look Up Table; Brightness and Contrast |
| Grid Cutoff will reduce the demonstrated ______________ of the image regardless of the receptor used. | Contrast |
| Scatter radiation is especially hard to interpret during histogram analysis when it occurs where? | Outside the collimated borders (computer won't recognize the exposure field borders and will include the scatter in the histogram) |
| Improper brightness in a digital image can be caused by (give 3) | 1)Scatter Radiation; 2)Unrecognized exposure field borders; 3)Overexposure |
| When the exposure absorbed by the Image Receptor surpasses the level the receptor can respond to what happens? | Reaches a Saturation Point and all pixels values are raised to their maximum level |
| Most image blur is caused by ___________ _________. | Patient Motion |
| _________ and ________ are responsible for image Size distortion because they affect the distance between the ___________ of interest and the ___________ _________. | SID and OID; Object of interest and the image receptor |
| Shape distortion is caused by a change in the ____________ relationship between the ________, the __________ and the __________ ___________. | Angular; Tube; Part; Image Receptor |
| The size of the image receptor affects the size of the __________ __________ but should not be confused with magnification of the image by changes in _________ and _________. | Image display; SID and OID |
| Noise in a digital image can be caused by what 3 things? | 1)Insufficient Signal Strength; 2)Excessive Scatter; 3)Excessive Fog |
| Quantum noise in digital images is caused by __________ ___________ ________. | Insufficient Signal Strength |
| _________ _________ _________ is sometimes used as an indicator of exposure and is an actual measure of patient dose and depends on ____________ factor and ________ size. | Dose Area Product (DAP); Exposure; Field |
| The accuracy of the Exposure indicator is influenced by __________ ___________ recognition along with unexpected structures in the __________ ___________. | Exposure Field; Exposure Field |
| A chest radiograph was produced using an appropriate kVp and mAs value, if a lead apron was included in the exposure field there would be an error in the ___________ ____________. | Histogram Analysis |
| If a lead apron is included in the exposure field a priori histogram analysis would produce an extra ________ at the ________-__________ area of the histogram and a miscalculation would suggest a gross ___________. | Peak; Low-Intensity; Underexposure |
| Recording multiple images on a single receptor can cause ___________ and ___________ areas as well as _____________ exposure fields in the center. | Underexposed; Overexposed; Overlapping |
| The current recommendation is to record ____ image per receptor to avoid __________ _________ errors. | 1; Data analysis |
| Most Digital Artifacts appear ___________. | Bright |
| Cassette-Based PSP artifacts occur because each time a cassette is processed the plate reader moves the _________ _________ in and out of the cassette which can cause dust and dirt to get in the cassette. | PSP Plate |
| The PSP plate in a cassette-based image receptor can get _________ or __________ during processing which can cause artifacts. The chemicals used to clean the plate can also _________ the cassette. | Scratched or Bent; Stain |
| Since Cassette-Less imaging systems are sealed, ________ and ________ are less likely to cause artifacts. | Dust and Dirt |
| Cassette-Less artifacts can occur because of malfunction of a single ________ or multiple rows of _________. | DEL; DELs |
| The major source of artifacts in Cassette-Less Systems are _________. (However artifacts can also be caused by _______, _______, __________ and staining. | DELs; Dust; Dirt; Bending |
| If an artifact does not run along the entire axis and does not appear on every image it is most likely a __________ Artifact. | Plate Artifact |
| If an Artifact runs along the entire axis and appears on every image it most likely a ________________ Artifact. | Processing Artifact |
| A line running the entire length of the plate and parallel to the direction the plate traveled through the reader is most likely an artifact caused by a dirty __________ ________ in the plate ____________. | Light Guide in the plate Reader |
| A dirty light guide will cause dirt to block the plate's _________ through the light guide to the ________________ tube and to the ______. | Signal; Photomultiplier; ADC |
| A Wavy appearance that runs across the entire plate is an artifact caused because the ___________ or ___________ was disturbed when the ____________ was being read or processed. | Laser; Plate; Plate |
| The Wavy appearance that runs across the entire image caused because the laser or plate was disturbed during processing is considered a ____________ artifact. | Processing Artifact |
Created by:
foster1317
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