Equipment Operation and Quality Control 1.2 Imaging equipment II

Focal-spot blur is greatest



A
 
toward the anode end of the x-ray beam 


B
 
toward the cathode end of the x-ray beam 


C
 
directly along the course of the CR 


D
 
as the SID is increased

Which of the following will occur as a result of a decrease in the anode target angle?

1.	Less pronounced anode heel effect
2.	Decreased effective focal spot size
3.	Greater photon intensity toward the cathode side of the x-ray tube

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

The output phosphor can be coupled with the Vidicon TV camera or charge-coupled device (CCD) via

1. fiber optics.


2. an image distributor or lens.


3. closed-circuit TV.

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

f the distance from the focal spot to the center of the collimator's mirror is 6 in., what distance should the illuminator's light bulb be from the center of the mirror?



A
 
3 in. 


B
 
6 in. 


C
 
9 in. 


D
 
12 in.

Off-focus, or extrafocal, radiation is minimized by



A
 
avoiding the use of very high kilovoltages 


B
 
restricting the x-ray beam as close to its source as possible 


C
 
using compression devices to reduce tissue thickness 


D
 
avoiding extreme collimation

Although the stated focal-spot size is measured directly under the actual focal spot, focal-spot size in fact varies along the length of the x-ray beam. At which portion of the x-ray beam is the effective focal spot the largest?



A
 
At its outer edge 


B
 
Along the path of the CR 


C
 
At the cathode end 


D
 
At the anode end

What lies immediately under the phosphor layer of a PSP storage plate?



A
 
Reflective layer 


B
 
Base 


C
 
Antistatic layer 


D
 
Lead foil

Just under the barium fluorohalide layer is a____that helps direct emitted light up toward the CR reader.

Below the reflective layer is the ____, behind that is an ____ layer, and then the lead foilto absorb backscatter. 

Over the top of the barium fluorohalide is a ____ layer.

The batteries in battery-operated mobile x-ray units provide power to

1. the x-ray tube


2. machine locomotion


3. the braking mechanism

 
A
 
1 only 



 
B
 
2 only 



 
C
 
1 and 2 only 

 
D
 
1, 2, and 3

Image quality in digital fluoroscopy is influenced by

1.	pixel size.
2.	contrast.
3.	noise.

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

_______ is degrading to both traditional and digital images. It can result from a number of causes including insufficient mA

Which of the following voltage ripples is (are) produced by single-phase equipment

1.	100% voltage ripple
2.	13% voltage ripple
3.	3.5% voltage ripple

A
 
1 only 


B
 
2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

Three-phase, 6-pulse equipment has a __% voltage ripple, 

a three-phase, 12-pulse equipment has only a ___% ripple.

Three-phase, 12-pulse equipment comes closest to constant potential, as the voltage never falls below ___% of maximum value.

A focal-spot size of 0.3 mm or smaller is essential for which of the following procedures?



A
 
Bone radiography 


B
 
Magnification radiography 


C
 
Tomography 


D
 
Fluoroscopy

Which of the following combinations would pose the least hazard to a particular anode?



A
 
1.2-mm focal spot, 92 kVp, 1.5 mAs 


B
 
0.6-mm focal spot, 80 kVp, 3 mAs 


C
 
1.2-mm focal spot, 70 kVp, 6 mAs 


D
 
0.6-mm focal spot, 60 kVp, 12 mAs

Which of the following field sizes would require the least amount of patient X-ray dosage?



A
 
12 cm field 


B
 
17 cm field 


C
 
25 cm field 


D
 
30 cm field

To maintain image clarity in an image-intensifier system, the path of electron flow from the photocathode to the output phosphor is controlled by



A
 
the accelerating anode 


B
 
electrostatic lenses 


C
 
the vacuum glass envelope 


D
 
the input phosphor

Component parts of a CT imaging system include a(n)

1. high-frequency generator


2. x-ray tube


3. operator console

A
 
1 only 


B
 
1 and 2 only 


C
 
1 and 3 only 


D
 
1, 2, and 3

Which of the following devices is used to control voltage by varying resistance?



A
 
Autotransformer 


B
 
High-voltage transformer 


C
 
Rheostat 


D
 
Fuse

 The________ transformer increases the voltage and decreases the current.

The ____ is a type of variable resistor that is used to change voltage or current values.