Chapter 11 Principles of Radiographic Imaging

Restriction of the primary beam to the anatomy of interest: reduces patient exposure is a major cause of repeated images reduces the amount of scatter produced A and C

A and C (Reduces patient exposure & Reduces the amount of scatter produced)

For radiographic procedures, scatter radiation is primarily the result of: photoelectric interaction Compton interaction classical scattering

Compton interaction

The exam room in our lab that offers automatic collimation is: Room 1 Room 2 Room 3 Room 4

Room 3

The volume of tissue irradiated is determined by: the area of collimation patient thickness field size all of the above

all of the above

When imaging the pelvis, changing from 14 X 17 collimation to 8 X 10 collimation requires: an increase in kVp a decrease in kVp an increase in mAs a decrease in mAs

an increase in mAs

The beam-restriction device that results in the images with the most unsharpness around the edge of the image is the: aperture diaphragm collimation cone or cylinder none of the above

aperture diaphragm

The flat piece of lead with a hole in it is the: aperture diaphragm collimator cone or cylinder none of the above

aperture diaphragm

The automatic collimator: automatically collimates to the anatomy of interest is required by law on all new equipment is seldom found on modern x-ray equipment automatically collimates to the IR size

automatically collimates to the IR size

The grid is located: just below the x-ray tube window between the patient and IR just below the IR none of the above

between the patient and IR

The beam-restriction device that includes a visible light projecting the x-ray field size onto the patient is the: aperture diaphragm collimation cone or cylinder none of the above

collimator

The most effective and often used radiographic beam-restricting device is the: aperture diaphragm collimation cone or cylinder none of the above

collimator

A flat piece of lead with a hold in it that has a flange directed toward the patient is a(n): aperture diaphragm collimation cone or cylinder none of the above

cone or cylinder

Beam restriction serves which two main purposes: decrease patient dose and decrease scatter decrease patient dose and increase scatter increase patient dose and decrease scatter increase patient dose and increase scatter

decrease patient dose and decrease scatter

___________ collimation means _________ field size. decreasing; increasing increasing; increasing decreasing; decreasing none of the above

decreasing; increasing

Which of the following produces the greatest amount of scatter radiation exiting the patient? low kVp and small field size low kVp and large field size high kVp and small field size high kVp and large field size

high kVp and large field size

The purpose of automatic collimation is: improved image quality limiting patient exposure increasing the cost of equipment none of the above

limiting patient exposure

When there is significant collimation, the amount of radiation reaching the IR is: reduced increased the same none of the above

reduced

The unrestricted primary x-ray beam is: round oval square rectangular

round

The probability of a Compton interaction occurring is related to: the energy of the x-ray photon the atomic number of the matter the mAs used all of the above

the energy of the x-ray photon

The two major factors that affect the amount of scatter radiation produced and exiting the patient are: kVp and mAs volume of tissue irradiated and mAs volume of tissue irradiated and kVp kVp and the use of a grid

volume of tissue irradiated and kVp