Answer Happy

OBJECTIVES After completing this chapter, the reader will be able to perform the following: 1. Define all the key terms in this chapter. 2. State all the important relationships in this chapter. 3. Explain how scatter radiation affects radio- graphic images. 4. State the purpose of beam-restricting devices. 5. Describe each type of beam-restricting device. 6. State the purpose of automatic collimators or positive beam-limiting devices. 7. Describe the purpose of a radiographic grid. 8. Describe the construction of grids, including the different types of grid patterns, dimensions, and grid focus. 9. Calculate grid ratio. 10. List the various types of stationary grids and describe the function and purpose of a moving grid. 11. Demonstrate the use of the grid conversion formula. 12. Describe the different types of grid alignment errors that can occur to cause grid cutoff. 13. Identify the factors to be considered in using a grid. 14. Recognize how beam restriction and the use of grids affect patient radiation exposure. 15. Explain the air gap technique and describe its use.