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RT IT RT296
RT film it class
| Question | Answer |
|---|---|
| Film screen images are: | hard copy and analog |
| Digital images are: | soft copy and digital |
| Roentgen's are equal to: | air kerma |
| Rad's are equal to: | grays |
| Rem's are equal to: | seiverts |
| Rad's are what kind of dose? | Patient dose |
| Rem's are what kind of dose? | Occupational dose |
| What are the image characteristics of film? | Density, Contrast, Recorded detail, and Distortion |
| What is SNR? | signal to noise ratio |
| What is density? | amount of blackness |
| What is the primary controlling factor of density? | mAs |
| What are the 2 controlling factors of density? | mAs and kV |
| How much of a % change does it take for kV to make a difference? | 4% change |
| What is the same as a 15% change in kV? | doubling or halving the mAs |
| What is contrast? | variation in density |
| What is the controlling factor for contrast? | kV |
| High contrast has what type of scale? | short scale |
| Low contrast has what type of scale? | long scale |
| What are the 2 types of motion and an example of each? | Voluntary (breathing) and involuntary (peristalsis) |
| What helps the image quality? | 1.short exposure time 2.film screen speed |
| What are the geometric factors? | 1.small focal spot 2.SID 3.OID |
| The radiographic film image is composed of what on a polyester base? | metallic silver |
| Which specific exposure factor controls the quality or penetrating ability of the xray beam? | kV |
| Exposure time is usually expressed in units of? | milliseconds |
| The recorded sharpness of structures or objects on the radiograph defines what? | resolution |
| The lack of visible sharpness is called? | blur or unsharpness |
| The term that describes the unsharp edges of the projected image is? | penumbra |
| The greatest contributor to image unsharpness as related to positioning is? | motion |
| The misrepresentation of an object size or shape projected onto a radiographic recording medium is called? | distortion |