Board Prep- Image Production

Question 1

What law does the following pair of exposure factors represent: 100 mA/100ms & 200mA/50ms.

Answer 1

Reciprocity Law

Question 2

What rule allows you to double or decrease the receptor exposure by half w/o adjusting the mAs?

Answer 2

15%rule

Question 3

According to inverse square law: as the distance between the x-ray tube & IR increases, the exposure rate ____.

Answer 3

decreases in direct proportion

Question 4

What happens to scatter radiation when the size of the x-ray field is reduced?

Answer 4

It is also reduced

Question 5

T or F: X-ray photons can penetrate thru the part, scatter w/in the part, & be absorbed by the part.

Answer 5

True

Question 6

The number of lead strips per inch in a grid is it’s ____.

Answer 6

Frequency

Question 7

What can you use to produce the similar effect as using a grid?

Answer 7

Air Gap Technique

Question 8

Noise (graininess) on a digital image is caused by what?

Answer 8

Underexposure

Question 9

Automatically program technique (APR) requires the radiographer to select what before imaging a patient?

Answer 9

Anatomic Part

Question 10

Digital imaging can compensate for approximately __% underexposure & __ % overexposure.

Answer 10

80; 500

Question 11

What relationship exists between resolution and magnification in imaging?

Answer 11

Inversely

Question 12

What do you use to rescale pixel values in digital imaging?

Answer 12

Look Up Tables (LUT)

Question 13

What relationship exists between SID and receptor exposure?

Answer 13

Indirect (as SID increases, receptor exposure decreases)

Question 14

Where is the mA selector found in the x-ray circuit?

Answer 14

the filament circuit

Question 15

For digital imaging, the receptor exposure is controlled by adjusting what?

Answer 15

the window level

Question 16

In fluoro exams, if the tech selects the mag setting, the magnified image is the result of a decrease in the size of what?

Answer 16

the size of the input phosphor

Question 17

According to the line-focus principle, the effective focal spot is always ___ the actual focal spot.

Answer 17

Smaller than

Question 18

What effect with increasing the OID have on the spatial resolution of an image?

Answer 18

Decrease spatial resolution

Question 19

In digital imaging, each pixel represents a 3-D volume of tissue known as a what?

Answer 19

Voxel

Question 20

If you increase the FSS, how does that affect the spatial resolution of your image?

Answer 20

Decreases spatial resolution

Question 21

The longer the SID, the ____ the distortion.

Answer 21

less the size of

Question 22

Using a technique of 400 mA, 0.25s and no grid can be converted to 200 mA at what time with an 8:1 grid?

Answer 22

2s (mAs1/GCF1= mAs2/GCF2)

Question 23

If the SID is cut in half, what change must occur to the mAs to maintain the exposure?

Answer 23

mAs decreased by 4x

Question 24

According to the Nyquist frequency, an analog signal must be sampled at what frequency to avoid aliasing or Moire effect on digital images.

Answer 24

2x per cycle

Question 25

The difference between light & dark areas on a radiography is a definition for what?

Answer 25

contrast

Question 26

Density was the term to describe overall blackening in film-screen; what term is used in digital imaging to describe this radiographic quality?

Answer 26

Receptor Exposure

Question 27

What term is used when changing the shape of an object occurs?

Answer 27

Distortion

Question 28

Size distortion is controlled by what?

Answer 28

Radiographic Distances (SID, OID)

Question 29

Line pairs per millimeter are used to measure what id digital imaging?

Answer 29

Spatial resolution

Question 30

What is the best method to reduce scatter radiation, which causes fog?

Answer 30

Collimation