LRA 222 Quiz Test Questions and Answers

LRA 222 Quiz Test Questions and Answers A significant amount of collimation will have what effect on the amount of radiation - Answer-reduced. When imaging the pelvis, changing from 14 × 17 collimation to 8 × 10 collimation requires - Answer-an increase in mAs. A flat piece of lead with a hole in it that has a flange directed toward the patient is a(n) - Answer-cone or cylinder. The most effective and often used radiographic beam-restriction device is the - Answer-collimator. The beam-restriction device that results in images with the most unsharpness around the edge of the image is the - Answer-aperture diaphragm. The field shape produced by a collimator is - Answer-rectangular. The automatic collimator - Answer-automatically collimates to the IR size. The grid is located - Answer-between the patient and IR. Grids are typically used when: - Answer-part measures more than 10 cm and at least 60 kVp needed for the exam only. . Grids absorb scatter radiation because the scattered photons - Answer-travel at an angle to the transmitted photons. The number of lead lines per inch or centimeter is the grid - Answer-frequency. The relationship between the height of the lead strips and the distance between them is the grid - Answer-ratio. Which of the following is the formula used to determine grid ratio? - Answer-Grid ratio = height of the lead strips/distance between the lead strips What is the grid ratio if the lead strips are 2.4 mm high, 0.02 mm wide, and 0.3 mm apart? - Answer-8:1