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image aquisition 2
Question | Answer |
---|---|
1.Diagnostic xrays are produced within the xray tube? | True, pg 431 |
2.How are diagnostic xrays produced? | When high speed electrons are rapidly decelerated upon collision with an anode's tungsten atoms. pg 431 |
3.What is the source of electrons in the tube? | A heated cathode filament will boil off electrons. pg 431 |
4.How are the majority of images produced in today's world? | electronically. pg 297 |
5. What does APR stand for? | Anatomically Programed Radiography. pg 297 |
6. What are factors that make up image QUALITY? | density, contrast (grey scale), recorded detail,and distortion pg 298 |
7. All geometric factors apply to digital imaging as well as screen/film imaging. | True. All OID, SID, focal spot size, distortion, structural position, shape, size, and motion apply to either DR or CR pg 298 |
8. What does recorded detail mean? | Clarity or resolution of anatomic structures present in an xray. pg 298 |
9. What is distortion? | Refers to the misrepresentation of the actual size or shape of an object on an xray. This can be caused by object unsharpness. pg 299 |
10. What is one line pair? | One line pair refers to one line and the one space adjacent to it. pg 299 |
11. Geometrically recorded detail improves as OID is decreased. | true. pg 301 |
12. Geometric recorded detail improves as SID increases. | True, pg 301. |
13. What are the two types of shape distortion? | foreshortening and elongation. pg 303 |
14. Elongation occurs when the xray tube is at an angle. | True, pg 303 |
15. Divergent rays affect distortion. | True, if an object is placed away from the path of the central beam it is exposed to more divergent ray, resulting in rotation distortion. pg 304 |
16. When will blur or unsharpness occur? | When the edges of a 3 dimensional object do not conform to the shape of the xray beam. pg 304 |
17. The border of unsharpness around image details is referred to as: | focal spot blur, geometric unsharpness, or edge gradient. pg 305 |
18. The smaller the focal spot size the greater the recorded detail. | true, pg 305 |
19. What is the AFS? | The actual focal spot size (AFS) is the area on a tungsten anode that is bombarded by electrons from the filament. pg 305 |
20. What is the EFS? | The effective (projected)focal spot size is the foreshortened size of the focus as it is projected downward toward the IR. pg 305 |
21. The angle of the anode effects recorded detail? | True. pg 305 |
22. What happens when using a small anode angle? | A small anode angle allows for a large AFS, and a small EFS, therefore improving recorded detail. This is good for magnification of small vessels. pg 306 |
23. Intensifying screens are a component of digital radiography. | FALSE! They are only apart of screen/film imaging. pg 310 |
24. What produces light in intensifying screens? | The fluorescent phosphor functions to change xray photons energy into fluorescent light energy. pg 311. |
25. A phosphors ability to absorb xray energy and convert it to fluorescent light is referred to as: | conversion efficiency pg 312 |
26. What is phosphorescence? | It refers to luminescence from fluorscopic screen phosphors. pg 312 |
27. 98% of fluorescent light received by film emulsion is emitted from intensifying screen phosphors. | true, pg 311 |
28. Fluorescence terminates at the same time the xray source does. | true, it should not continue after exposure is made if it does it is called lag and contributes to overexposure of the image. pg 312 |
29. Quantum mottle is more likely to occur when using fast screens with low mAs and high KVP. | true, pg 313 |
30. What do high speed screens produce? | Poor recorded detail as a result of greater fluorescent light diffusion. pg 313 |