1. Grids, use of them and selection/problems, etc
1. Which of the following is NOT a grid positioning error?
A. air-gap technique
B. Lateral decentering
C. Off center grid
D. off focus grid
E. Off level grid

2. The MOST common grid used in portable imaging is:
A. Crossed grid
B. A focused, moving grid
C. A focused stationary grid
D. A. Parallel, moving grid
E. A parallel, stationary grid

3. Grids generally: A. Must be cleaned on schedule
B. Require faster image receptors
C. Require less mAs
D. Require periodic replacement due to radiation fatigue
E. Use of required increased patient dose

4. Which of the following will result in the lowest patient dose?
A. High kVp and high-ratio grid
B. High kVp and low-ratio grid
C. High kVp and no grid
D. Low kVp and high-ratio grid
E. Low kVp and low-ratio grid

5. Grid cutoff: A. Is measured by the Bucky Factor (BF)
B. Is more pronounced with high-ratio grids
C. Is more pronounced with low-ratio grids
D. Never occurs with focused grids
E. Occurs only with focused grids

6. Air-gap technique: A. Increases the Bucky Factor
B. Reduces contrast by absorption of scattered radiation in air
C. Requires that the grid and the film must be separated by at least 30 cm
D. Results in approx. the same patient dose as non-grid
E. Results in image magnification

7. Which grid would be MOST likely to produce grid cut-off?
A. 5:1
B. 6:1
C. 8:1
D. 12:1
E. 16:1

8. Which grid has the GREATEST contrast improvement factor?
A. Crossed grids
B. Focused grids
C. Moving grids
D. Parallel grids
E. Zero grids

9. What is the result of replacing an 8:1 grid with a 12:1 grid?
A. Greater positioning latitude
B. Higher pt. dose
C. Less contrast
D. Less spatial resolution
E. Lower pt. dose

10. Grid ratio refers to: A. The height of the pb strips to their width
B. The length of the pb strips to the space between them
C. The height of the pb strips to their thickness
D. The height of the pb strips to the space between them

11. Most grids in RAD rooms are:
A. 5:1 parallel
B. 8:1 parallel
C. 8:1 focused
D. 12:1 focused