beam restriction

Question 1

scatter radiation is produced during what what interaction

Answer 1

Compton scattering

Question 2

2 ways to minimize Compton scatter are

Answer 2

beam restriction and grid

Question 3

factors contributing to Compton scattering is

Answer 3

KVP and volume of irradiated field

Question 4

Increase Kvp interaction
a) increase transmission, decreased photoelectric absorption. increase Compton scatter

b) decrease trasnmission, increase photoelectric ab,
decrease Compton scatter

Answer 4

a

Question 5

decrease kvp interaction
a) decrease transmission, increase photoelectric absorption, decrease Compton scatter
b) increase transmission, decrease photoelectric ab,
increase Compton scatter

Answer 5

a

Question 6

interaction where a primary photon interacts with an outer shell electron and changes direction

Answer 6

Compton scattering

Question 7

The volume of irradiated material is controlled by

Answer 7

field size and PT thickness

Question 8

Increased F S increases volume of tissue irradiated
Results in
a) decrease scatter
b) increase scatter

Answer 8

a

Question 9

By decreasing F S, fewer photons reach image receptor
Image receptor exposure decreased
Increase in WHAT must accompany significant reduction in F S to maintain image receptor exposure

Answer 9

mAs

Question 10

thicker/ denser body parts produce more or less scatter

Answer 10

more scatter

Question 11

Compression devices used to improve

Answer 11

spatial resolution and contrast

Question 12

Brings tissue closer to receptor does what to OID and spatial resolution ?

Answer 12

decrease OID and improve spatial resolution

Question 13

compressing device are used in what modality to compress tissue ?

Answer 13

mammography

Question 14

what is the most commonly used beam restrictor in radiography ?

Answer 14

collimator

Question 15

diaphragms and cones/cylinders are considered what ?

Answer 15

beam restrictors

Question 16

Two sets of shutters that permits infinite number of field sizes
Length and width of field independently controlled

Answer 16

collimators

Question 17

Bottom or top shutters? reduce penumbra

Answer 17

bottom

Question 18

penumbra

Answer 18

edge unsharpness

Question 19

Off-focus radiation occurs

Answer 19

from areas of x-ray tube other than focal spot area

Question 20

Positive Beam Limitation (P B L) Devices

Answer 20

Automatically collimates beam to size of image receptor

Question 21

Ancillary Devices for beam restriction are

Answer 21

lead blockers, lead masks