### 146 terms by debbslack

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D

A

C

photon

D

True

False

True

False

True

a

a

a

d

### ________ is the boiling off of electrons from the filament when current is applied.

thermionic emission

b

d

b

b

### _____ results in the process of the image formation, whereby the x-ray beam interacts with the anatomic tissue and a portion of the beam strikes the image receptor.

Differential absorption

Attenuation

True

c

b

c

False

d

c

d

d

c

True

### If a person stands 12 ft from the source of exposure, receives an exposure of 16 R/min, and then moves 3 ft from the source of exposure, what would be the new exposure rate according to the inverse square law? a. 256 R/min b. 64 R/min c. 1 R/min d. 4 R/min

a; I1/I2 = (D2/D1)^2

### If the first radiograph of a chest is done using 72" and 12 mAs and a second radiograph is done using 40 ", how much mAs should be used to maintain density? a. 7 mAs b. 2 mAs c. 9 mAs d 4 mAs

d; mAs1/mAs2=(D1/D2)^2

### If a person stands 3 ft from the source of exposure, receives an exposure of 16 R/min and then moves to 6 ft from the source of exposure, what would the new exposure rate according to the inverse square law? a. 4 R/min b. 64 R/min c. 256 R/min d. 1 R/min

a; I1/I2=(D2/D1)^2

### If the first radiograph of a foot is done using 4 mAs at 40" and a second radiograph is done using 50", how much mAs should be used to maintain density? a. 12 b. 1 c. 2 d. 6

d; mAs1/mAs2=(D1/D2)^2

b

higher, lower

d

30%

d

4-5 cm

### A quality radiograph is dones using 10 mAs, 70 kVp, and 12:1 ratio grid. How much mAs is needed to produce an image with the same density when the grid is removed? a. 50 b. 15 c. 2 d. 5

c; mAs1/mAs2=grid1/grid2
none = 1
5:1 = 2
6:1 = 3
8:1 = 4
12:1 = 5
16:1 = 6

True

photographic

photographic

### Density is:

measuring of the overall blackening of the radiographic image

### If kVp decreased 15% and no change to mAs then:

density would decrease contrast would increase

twice the mAs

### Assuming all exposure factors remain unchanged what is result of changing to an IR with higher relative speed?

Density increases

### Assuming all produce appropriate density images, which of hte following would be best exposure technique choice when perform cxr on infant?

use 40 ms exposure time; shortest exposure time

### When radiograph need to repeat bc its too dark, minimum change in mAs needed is:

reduce mAs by 50%

hypersthenic

increase kVp

decrease SID

emphysema

increase kVp

### What are the four primary exposure factors?

kVp, mAs, time and SID

### An increase in mAs causes _______ in beam quality and _____ in beam quantity

no change, increase

double

c

15%

### A radiograph taken using 75 kVp @ 20 mAs. Which change in technique would increase contrast but maintain the same density? a. 85 kVp @ 10 mAs b. 85 kVp @ 40 mAs c. 65 kVp @ 20 mAs d. 65 kVp @ 40 mAs

d, decrease kVp = increase contrast

30

a

d

### Added filtration has the effect of ______ beam quality and ______ patient dose.

increasing, reducing

b

a

a

b

a

a

increases

d

d

image noise

patient dose

kVp

b

a

b

### Lower kVp _____ patient dose and _______ image contrast.

increases, increases

a

b

b

mAs

highest kVp

0-9

### Xray interaction contribute to clear part image:

photoelectric interaction

### 3 primary factor influencing intensity of scatter in image forming beam:

kVp, field size, patient thickness

### Contrast resolution is improve by ____

tight collimation, lower kVp, patient compression

contrast

### PBL assure that ray beam is collimate ______

image receptor size

### How can you improve image contrast w/ heavy pt w/o increase pt dose?

use tight collimation

focused grid

false

1.7

False

grid frequency

most absorbed

increase

grid ratio

mAs

8:1

### Waht influence amt scatter strike IR not production scatter?

increase grid ratio

highest kVp

highest kVp

### Why is scatter radiation exposure undesireable?

Decrease contrast

### Collimation acts to reduce scatter and its resultant image fog primarily by which of the following?

limiting area of exposure

increase

d

wide, low

noise

b

d

.25 and 2.5

OD= log10(I0/It)

1

shoulder

wide latitude

### Subject contrast is affected by

patient thickness

c

d

foreign object

handling

grid cut off

patient motion

bending of film

d

each tube

d

measure the part

b

2 kVp

fixed kVp

doubled

true

false

### Departmental standard such as the SID or whether an exam is done table top or bucky should be determined.

prior to the development of technique chart

### Accurate patient measurement is most critical for the:

variable kVp/ fixed mAs

### Generally speaking patient dose will decrease with the:

fixed kVp/variable mAs

False

100 mAs @ 75 kVp

Example: