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Imaging - Leaderboard
Imaging - Details
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72 questions
| 🇬🇧 | 🇬🇧 |
| Line focus principle | Relationship between actual and effective focal spots |
| What is the actual focal spot | Where electrons from tube current bombard the target, dependant of size of filament |
| Effective focal spot size | Focal spot size measured under the anode target |
| What is the difference between a large focal and a small | Large can withstand heat, small has better image quality |
| What determines the size of effective focal spot | Target angle |
| The relationship between target angle and effective focal spot is? | Directly proportional |
| Anode heel effect | X-ray beam has more x-rays on the cathode side because of target angle |
| Spatial resolution determines | Accuracy anatomic structural lines |
| Spatial resolution refers to? | The smallest detectable object in an image |
| Greater spatial resolution means | Sharper image |
| First and second step for controlling voluntary patient movement | Communication and reduced exposure time |
| Patient movement while imaging does what? | Decrease sharpness |
| Diagnostic quality is achieved by? | Maximizing spatial resolution and minimizing distortion |
| Distortion is | Misrepresentation of size or shape of anatomic structure |
| Another name for size distortion | Magnification |
| Name two types of shape distortion | Elongation and foreshortening |
| What can cause shape distortion? | Alignment of tube, body part or IR |
| Spatial frequency | Unit of lines per mm |
| Small focal spot size range | .5-.6mm |
| Large focal spot range | 1-1.2mm |
| Focal spot size is determined by | Filament size |
| What can focal spot size effect? | Spatial resolution |
| What happens if you use the small focal spot for many images? | Tube overheating and decrease tube lifetime |
| What is a benefit of a small focal spot? | Increased spatial resolution |
| Inverse square law | Intensity of x-ray beam is inversely proportional to the square of the distance from the source |
| As SID increases what happens to the x-ray beam? | The intensity spreads over a larger area, decreasing IR exposure |
| What does an air gap do | Reduces scatter |
| What does reducing scatter do? | Increases radiographic contrast |
| How can size distortions from OID be reduced? | Increasing SID |
| Magnification factor | Indicates how much distortion or magnification is in an image |
| What is the magnification formula? | MF=SID/SOD |
| What does SOD stand for? | Source to object distance |
| Formula for SOD? | SOD=SID-OID |
| What does am MF of 1 mean? | No magnification |
| Size distortion can be increased by | Decreasing SID or increasing OID |
| Geometric properties look at? | Shapness of the image |
| What increases when there is no patient movement? | Spatial resolution |
| What is the point of the line focus principle? | Target angle so the actual focal spot stays large and the effective spot stays small |
| The accuracy of the anatomic structural lines displayed in a radiographic image is determined by? | Spatial resulution |
| Size distortion is known as? | Magnification |
| Increasing the focal spot size? | Decreases the spatial resolution |
| Spatial resolution is decreased by? | Patient movement |
| As SID increases | Beam intensity decreases |
| The air gap technique | Improves radiographic contrast and decreases scatter photons reaching the IR |
| Increasing pixel density means? | Increases spatial resolution |
| The misrepresentation of an image is? | Distortion |
| The smaller the anode target angle | The smaller the effective angle |
| If sod increases and sid decreases what happes? | Increase magnification |
| What is the only geometric factor that increases image contrast? | Air gap because scatter is decreased |