1
Q
Quality Control Program for Radiographic Units
A
- Visual inspection
- Environmental inspection
- Performance testing
2
Q
It includes checking the main components of the equipment for the proper function, mechanical condition and safety.
A
Visual Inspection
3
Q
Visual Inspection should be performed
A
at least annually using a checklist
4
Q
Visual Inspection should include:
A
- Control panel
- Overhead tube crane
- Radiographic table
- Protective lead apparel
5
Q
Contains all the selectors for the production of X-ray and the various meters.
A
Control Panel
6
Q
Inspection (for control panel) should include:
A
- Tube heat sensor
- Overload protection indicator
- Panel lights, meters and switches
7
Q
Inspection (for control panel) should also ensure the
A
proper view of the exposure room,
correct exposure switch placement and
presence of an up-to-date technique chart.
8
Q
Mounting bracket that holds the x-ray tube over the x-ray table.
A
Overhead Tube Crane
9
Q
Evaluation (for overhead tube crane) should include:
A
- Condition of the high-voltage cable and other wires
- Condition of the cable brackets, clamps, or tie downs
- Stability of the system
- Proper movement
- SID and angulation indicator function
- Lock function
- Bucky center light
- Collimator light
- Interlock system
10
Q
Radiographic table should be kept ___ and ____.
A
clean
safe
11
Q
Items to inspect for radiographic table
A
- Surface condition and cleanliness of table top
- Angulation switches and indicator
- Bucky tray and cassette locks
- Stability
- Condition of footboard and shoulder braces if any.
12
Q
Protective Lead Apparel should be viewed
A
radiographed
or fluoroscopically
13
Q
Protective Lead Apparel should check ____
A
upon acceptance
and every six months
14
Q
Miscellaneous Equipment
A
- Presence of caliper
- Technique Chart
- Cleanliness of positioning devices and accessories
- Integrity of step tools and intravenous stands
15
Q
Involves checking for mechanical and electrical safety.
A
Environmental Inspection
16
Q
Environmental Inspection should be performed
A
annually
17
Q
Environmental Inspection includes evaluation and checking of
A
- the conditions of X-ray tube high tension cables
- the covering on the outside of the cables
- Discoloration of outside insulation
- Mechanical condition of the X-ray tube counterweights and tracks
- Grounding of all equipment
18
Q
Proper lubrication of moving parts should be provided
A
during inspection
19
Q
Evaluates the performance of the x-ray generator and x-ray tube.
A
Performance Testing
20
Q
Much of the data obtained in performance testing includes
A
radiation measurement
21
Q
There are three types of detector used:
A
Ion chamber
Proportional counters
Geiger Mueller counter
22
Q
useful for measuring X-ray
A
Ion chamber
23
Q
measures small quantities of radioactive material
A
Proportional counters
24
Q
often used for contamination control.
A
Geiger Mueller counter
25
The value obtained from the radiation detector is the radiation intensity measured in
Roentgen (R) or
| the SI unit coulomb/kilogram (C/kg)
26
Any x-ray generator should produce the same intensity of radiation each time the same set of technical factors are used to make an exposure.
Reproducibility of Exposure
27
Maximum variability allowed in reproducibility of exposure is
±5%
28
Evaluation of reproducibility variance requires a
dosimeter
29
Similar type of X-ray generators and tube should emit the same amount of radiation per unit of X-ray tube current and time (mAs).
Radiation Output
30
Amount of radiation is measured in
R or C/kg
31
Unit of x-ray tube current and time is
mAs
32
Similar types of x-ray generators should emit
the same mR/mAs value
33
The original mR/mAs value can be obtained
upon acceptance of the unit or
| at the start of the QC program.
34
necessary to remove low-energy photons from the x-ray beam
Proper filtration
35
Filtration check should be performed
upon acceptance
then annually or
whenever service is performed on the collimator or the x-ray tube
36
The best method to determine presence of adequate filtration is
the Half Value Layer (HVL)
37
the thickness of the material at which the intensity of radiation entering it is reduced by one half
half-value thickness
38
HVL should not vary from ______ established during acceptance or at the beginning of quality control program
its original value
39
has a significant effect on image contrast and image density including patient dose
Tube voltage
40
The kVp stated on the control panel should produce an x-ray beam with comparable and consistent amount of energy.
kVp accuracy
41
Variation for kVp accuracy should be within
±5%
42
Instrument used for kVp accuracy
Digital kVp meter or specialized test cassette such as the Wisconsin Test Cassette can be used.
43
Exposure time directly affects the total quantity of radiation emitted from the X-ray tube.
Timer accuracy
44
The variability for timer accuracy allowed is
±5% for exposure times >10ms
| and ±20% for exposures <10ms
45
Timer accuracy should be determined
upon acceptance and annually thereafter
46
Timer accuracy should be measured with the use of
digital X-ray timer,
manual spinning top (for single phase power) or
motor driven spinning top (for three phase or high frequency generator).
47
Waveform when displayed using oscilloscope screen can give considerable information:
- Timer accuracy
- Rectifier malfunction
- Loading characteristics
- Contactor or switching problem
- High voltage cable or connector arching
48
can be hooked up electronically to specific areas of the generator or it can be attached to commercially available X-ray output detector
Oscilloscope
49
The mA selector is used to regulate the tube filament temperature , which along with the exposure time, determines the quantity of x-ray photons.
mA and Exposure Time Linearity and Reciprocity
50
Refers to the same output of the X-ray tube when the same mAs is selected even at different combinations of mA and exposure time as long as the kVp is kept constant
Reciprocity
51
Any variation in reciprocity must be within
±10%
52
Means that the sequential increase in mAs should produce the same sequential increase in the exposure measured.
Linearity
53
Variation in linearity should be kept within
± 10%
54
The area of the anode that is bombarded by projectile electrons.
Focal spot size
55
When focal spot size increases with age, use and with increases in mA station selected this is known as _____
focal spot blooming
56
A ________ can be used to evaluate blooming.
pinhole camera or
| a focal spot test tool
57
Responsible for regulating the size of the x-ray field area
Collimator (Beam Restricting System)
58
Plays a significant role in the reduction of patient dosage.
Beam Restricting System
59
Performance test for beam restricting system should be done
twice a year.
60
Following should be evaluated for beam restricting system
Light field – Radiation field congruence
Image receptor – radiation field alignment
Accuracy of X - Y scale
Illuminator bulb brightness.
61
It measures how well the collimator regulates the field size and if the area illuminated by the positioning light and the area exposed by x-rays are the same.
Light Field – Radiation Field Congruence
62
Congruence must be within ____ of the source-image distance.
±2%
63
Evaluation for Light Field – Radiation Field Congruence can be performed with the use of ______
collimator test tool or the eight penny test
64
This is performed for equipment with positive beam limiting device or automatic collimation
Image Receptor – Radiation Field Alignment
65
Congruence for Image Receptor – Radiation Field Alignment must be within
±3% of the source-image distance.
66
This measures the accuracy of the collimator dials to the size of the X and Y dimensions of the x-ray field during manual collimation
Accuracy of the X-Y Scales
67
The illumination of the light source must be _______
at least 15 ft-c (160 lux) when measured at 100 cm (40 inch) distance.
68
Tool used for the evaluation of Illuminator bulb brightness
photometer
69
The x-ray beam must be mounted properly in its metal housing and aligned to the Bucky tray.
Beam Alignment
70
Items to evaluate for beam alignment in this category include
perpendicularity and
| x-ray beam – Bucky tray alignment
71
beam alignment should be done
upon acceptance and
| then annually with the beam alignment test tool.
72
X-ray beam should be limited to 1 degree of perpendicularity
perpendicularity
73
The center of the Bucky tray and the center of the x-ray beam must be aligned to avoid clipping important anatomy and to avoid grid cutoff.
X-ray Beam – Bucky Tray Alignment or CR Congruency
74
X-ray Beam – Bucky Tray Alignment or CR Congruency must be within
1% of the SID
75
The SID indicator must be installed so that it is accurate within
± 2% of the SID
76
SID indicator must be done upon
acceptance and
| then annually thereafter
QAQC
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