click below
click below
Normal Size Small Size show me how
RADT465 Direct Study
Unit 3- Image Acquisition and Evaluation
Question | Answer |
---|---|
What are the four radiographic qualities? | Density, contrast, recorded detail, and distortion (Wallace, p. 4) |
Overall blackness of a radiograph | Density (Wallace, p.4) |
What is the difference between adjacent densities on a radiograph? | Contrast (Wallace, p. 5) |
_______ _______ is the sharpness of the lines of the image. | Recorded detail (Wallace, p. 5) |
This is the misrepresentation of the true size and shape of the image as compared to the object. | Distortion (Wallace, p. 5) |
List the two photographic properties. | Density and contrast (Wallace, p. 4) |
List the two geometric properties. | Distortion and recorded detail (Wallace, p. 4) |
The controlling factor for density is _______. The controlling factor for contrast is__________. | mAs; kVp (Wallace, p. 6) |
What is the two ways a radiographer can reduce magnification? | Short OID, long SID (Wallace, p. 28) |
What is also known as focus-film distance? | SID (Wallace, p. 34) |
______ _______ is the misrepresentation of the true shape of the image as compared to the object. | Shape distortion (Wallace, p. 36) |
This occurs when the object is angled, but the central ray remains perpendicular to the film? | Foreshortening (Wallace, p. 38) |
This occurs when the object is parallel to the film, but the central ray is angled? | Elongation (Wallace, p. 44) |
______ ______ occurs when two objects normally superimposed, but appear as separate structures due to an angle of the central ray. | Spatial distortion (Wallace, p. 44) |
List the two exposure factors that directly control radiographic density and quantity of x-rays. | mA and exposure time (Wallace, p. 48) |
______ represents the total quantity of x-rays produced in a beam. | mAs (Wallace, p. 53) |
mAs has a ______ relationship in density on the radiograph. | Direct (Wallace, p. 54) |
This reduces the chance of motion blur? | Short time (Wallace, p. 59) |
What size focal spot improves recorded detail? | Small focal spot (Wallace, p. 59) |
What can the radiographer use to create a breathing technique? | Low mA and long time (Wallace, p. 60) |
What is the current in the x-ray tube at the time of exposure? | mA (Wallace, p. 62) |
What determines how long the mA will be working? | Exposure time (Wallace, p. 62) |
What does the reciprocity law state? | Two different sets of mA and time selections can produce the same mAs (Wallace, p. 62) |
This states the intensity of radiation is inversely proportional to the square of the distance from the source of radiation. | The Inverse Square Law (Wallace, p. 64) |
If the SID is doubled, radiation intensity becomes_____ times less. | 4 (Wallace, p. 66) |
If the SID is cut in half, the radiation intensity becomes _____ times greater. | 4 (Wallace, p. 66) |
How will a high contrast image appear? | Black and white (Wallace, p. 75) |
How will a low contrast image appear? | Many shades of gray (Wallace, p. 75) |
Short scale is _____ contrast. Long scale is _____ contrast. | High; low (Wallace, p. 75) |
What is the atomic number of iodine? | 53 (Wallace, p. 80) |
What is the atomic number of barium? | 56 (Wallace, p. 80) |
List three most common types of contrast. | Air, barium, iodine (Wallace, p. 80) |
What contrasts are used for the GI tract? | Air and barium (Wallace, p. 80) |
What type of contrast would a radiographer use for kidneys or gallbladder? | Iodine (Wallace, p. 80) |
What is caused by the composition of the patient’s body parts? | Subject contrast (Wallace, p. 85) |
What can be used to increase subject contrast? | Contrast media (Wallace, p. 85) |
Scatter radiation ______ radiographic contrast. | Reduces (Wallace, p. 86) |
Optimum kVp for small extremities | 55-60 (Wallace, p. 89) |
Optimum kVp for large extremities | 65-70 (Wallace, p. 89) |
Optimum kVp for skull, CXR w/o grid, spine | 80 (Wallace, p. 89) |
Optimum kVp for ABD with barium | 110 (Wallace, p. 89) |
Optimum kVp for ABD w/o barium, ribs, shoulder, pelvis and hip | 70 (Wallace, p. 89) |