Second

Question 1

 Automatic collimators that sense the size of
the image receptor & adjust the collimating
shutters to that size
 It must be evaluated for all possible receptor
sizes
 The x-ray beam must not be larger than the
image receptor

Answer 1

Positive Beam-Limiting Collimators (PBL)

Question 2

 It principally determines the spatial
resolution of a radiographic imaging system

Answer 2

Focal-Spot Size (FSS)

Question 3

Three Tools Used To Measure FSS:
o PSS

Answer 3

Pinhole Camera, Star Pattern & Slit
Camera

Question 4

 It is difficult to use
 It requires excessive exposure time

Answer 4

Pinhole Camera

Question 5

 It is easy to use
 Significant Limitation: focal-spot sizes less
than 3 mm

Answer 5

Star Pattern

Question 6

 The standard for measurement of focal-spot
size

Answer 6

Slit Camera

Question 7

Specification of Focal-Spot Size
 Depends on the ____ of the tube
 Depends on the ___ of the electron
beam

Answer 7

geometry
focusing

Question 8

 An acceptable alternative to focal-spot size
measurement
 It determines limiting spatial frequency

Answer 8

Line-Pair Test Tool

Question 9

 The x-ray generator must be properly
calibrated

Answer 9

kVp Calibration

Question 10

Kvp Calibration Devices used based on filtered __& ___

Answer 10

Ion chamber photodiodes

Question 11

___% Variation in kVp: necessary to affect
image OD & radiographic contrast

Answer 11

4

Question 12

The measured kVp should be within ___% of
the indicated kVp!

Answer 12

10%

Question 13

Exposure Timer Accuracy
 ____: responsible for patient dose
& OD
 Devices Used:
o Based on irradiation time of an ion
chamber
o Based on irradiation time of
photodiode assembly
 Frequency:
o Annually
o More frequently

Answer 13

Exposure Time

Question 14

__% Accuracy: acceptable for exposure
times of 10 ms or less

Answer 14

20

Question 15

Exposure timer accuracy should be within __%
of the indicated time for exposure times
greater than 10 ms!

Answer 15

5

Question 16

 Designed to provide a constant OD
regardless of tissue thickness, composition
or failure of the reciprocity law
 It also must be evaluated
 Evaluate By:
o Exposing an IR through various
thicknesses of aluminum or acrylic
o Regardless of material thickness &
absolute exposure time, OD of the
image must be constant

Answer 16

Automatic Exposure Control (AEC)

Question 17

ability of a radiographic unit to produce
a constant radiation output for various
combination of mA & exposure time

Answer 17

Linearity

Question 18

Exposure linearity must be within __% for
adjacent mA stations!

Answer 18

10

Question 19

ability of a radiographic unit to produce
a precisely the same radiation exposure
when all the techniques are changed &
returned to previous value

Answer 19

Reproducibility

Question 20

Sequential radiation exposure should be
reproducible to within ± __%!

Answer 20

5

Question 21

Film Illuminators
 It should be analyzed photometrically
 Frequency: annually
 Device Used: ___

Answer 21

photometer

Question 22

: measures light intensity at
several areas of the illuminator

Answer 22

Photometer