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Ch.10 Image quality
Equipment. Chap 10. Image Quality
Question | Answer |
---|---|
A radiograph that faithfully reproduces structure and tissues is ID'd as | a high-quality radiograph |
4 most important characteristics of image quality? | spatial resolution, contrast resolution, noise, artifacts |
Resolution is the ability to | image 2 separate objects and visually distinguish one from the other |
__________ refers to the ability to image small objects that have high subject contrast | spatial res |
spatial res improves with a reduction in ____, ______, and _____. | screen blur, motion blur, geometric blur. |
What is contrast resolution? | ability to distinguish structures of similar subject contrast. |
_______ is a less precise term sometimes used instead of spatial and contrast res, is refers to the degree of sharpness. | recorded detail |
_______________ refers to the ability to visualize recorded detail when image contrast and optical density are optimized. | visibility of detail |
_______ is the random fluctuation in the OD of the image | Noise |
what 3 things reduce quantum mottle? | high mAs, low kVp, slower image receptors |
fast image receptors have ____ noise, and _____ spatial and contrast resolution. | high, low |
Reciprocity law? | The OD will be the same if the mAs value is constant. |
3 geometric factors? | magnification, distortion, focal spot blur |
** magnification factor? (3 ways) ......pg 174 | MF= image size/object size. MF= SID/SOD. MF=Image size/object size = SID/SOD. |
Two factors that affect image magnification? | SID and OID |
Focal spot blur is caused by what the ___________, which is larger to the ____ side of the image. | effective size of the focal spot, cathode (so cathode side has greatest blur) |
What is the most important factor for determining spatial resolution? | focal spot blur |
How to minimize focal spot blur? | Small OID |
Radiographic contrast, what is the equation? | Contrast = IR contrast x Subject contrast |