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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 |