Surveys Flashcards
(129 cards)
1
Q
Protects XRT from rough handling
A
Protective Tube Housing
2
Q
Lead-lined metal to protect the patient and staff from off-focus radiation
A
Protective Tube Housing
3
Q
Must be constructed so that the leakage radiation measured at a distance of 1m from the x-ray source does not exceed 1 mGya/hr when the tube is operated at its highest voltage at the highest.
A
Protective Tube Housing
4
Q
Off-focus radn
A
Leakage radn
5
Q
Accepted amung of leakage radn from protective tube housing (Give 2 values)
A
<100mR/hr or <1mGya/hr at 1m distance
6
Q
It is where the technical exposure factors such
as milliamperes (mA) and
peak kilovoltage (kVp) are selected and visually displayed.
A
Control Console
7
Q
Control Console is located (1) that has a/n (2) that permits observation of the patient during any procedure.
A
- behind a suitable protective barrier
- radiation-absorbent window
8
Q
Where most of radiographic procedures are performed
A
Radiographic table
9
Q
Must be strong and adequately support the pt
A
Radiographic table
10
Q
Why should the radiographic table be radiolucent as possible?
A
Should be as radiolucent as possible so that it will absorb only a minimal amount of radn, thereby reducing the pt’s radn dose
11
Q
Composition of Radiographic Table
A
Carbon Fiber
12
Q
An equipment that measure the distance from the anode focal spot to the IR to ensure that the correct source-to-image receptor distance (SID) is maintained
A
SID Indicator
13
Q
A tape erasure attached to the collimator or tube housing or lasers
A
SID Indicator
14
Q
SID Indicator Distance and centering indicators must be accurate to within (1) and (2) of the SID respectively
A
- 2%
- 1%
15
Q
The SID Indicator measures the distance from (1) to the (2) to ensure correct (3)
A
- anode focal spot
- IR
- SID
16
Q
Devices that confine the useful, or primary beam before it enters the area of clinical interest
A
XR Beam Limiting Devices
17
Q
XR Beam Limiting Devices reduces the amount of (1) in the tissue and prevents (2) to tissues
A
- scattered radiation
- unnecessary exposure
18
Q
XR Beam Limiting Devices
A
Collimator
Aperture Diaphragm
Cones and Cylinders
19
Q
Collimator aka
A
Light-Localizing Variable-Aperture Rectangular Collimator
20
Q
Light-Localizing Variable-Aperture Rectangular Collimator Consists of these
A
- Two sets of adjustable lead shutters
- Light source
- Mirror
21
Q
Differentiate the 2 sets of adjustable lead shutters
A
- First set/ upper shutters: located as close as possible to the tube window to reduce amount of off-focus radiation
- Second set/ lower shutters: below the level of light source & mirror; further confine beam to area of clinical interest
22
Q
Describe the light source
A
Illuminates XR field and permits it to be centered over area of clinical interest
23
Q
Describe the mirror
A
Deflects light beam towards pt to be radiographed
24
Q
Automatically adjusts activated collimators so the radiation field matches the size of the IR
A
Positive Beam Limitation (PBL)
25
Must be adjusted so that IR size in use at all standard SID must provide an equal XR beam to the IR
Positive Beam Limitation (PBL)
26
Radiation therapy techniques that minimize damage to the skin while effectively targeting tumors beneath the surface
Skin Sparing
27
Skin Sparing
To minimize skin exposure to electrons produced by photon interaction with the collimator, the patient's skin surface should be at least --- the collimator.
15 cm below
28
"spacer bars," which project down from the housing to prevent the collimators from being closer than 15 cm to the patient
Skin Sparing
29
If the luminance of the collimator light source is adequate, the (1) will adequately outline the margins of the (2) on the area of clinical interest on all pts
1. Localizing light beam
2. radiographic beam
30
Luminance is aka
Brightness
31
It is imperative that the (1) and the (2) be correctly aligned with each other.
Every radiographic tube must have a device in place to ensure accurate beam alignment.
1. x-ray beam
2. image receptor
32
This ensures correct alignment of the XR bra and IR
Laser light
33
Simplest beam limitation device
Aperture diaphragm
34
Consists of a flat piece of lead with a hole of designated size and shape cut in its center
Aperture diaphragms
35
Aperture diaphragms are used in
1. Trauma radiographic imaging systems
2. XR units designed specifically for CXR
3. Dental radiographic units
Trauma CD
36
Placed directly below the window of the xray tube to confine the primary radiographic beam dimensions suitable to cover a given size of an image receptor at a specified source-to-image receptor distance.
Aperture Diaphragm
37
Attached to the x-ray tube housing or variable
rectangular collimator to limit the x-ray beam to a predetermined size and shape.
Cones and cylinders
38
Cones and cylinders are used for rad'phic examination of specific areas such as the:
1. Head
2. Vertebral column
3. Chest
CV Head
39
XR Beam Limiting Devices
--- are widely used in dental radiography
Beam-defining cones
40
XR Beam Limiting Devices
Because dental x-ray equipment is usually less bulky than general purpose equipment, a/n --- is convenient.
one-piece beam limitation device
41
XR Beam Limiting Devices
By using (1), dentists reduce the patient’s exposure by eliminating the source of secondary radiation .
1. lead-lined cones
42
Placed between the radiographic image receptor and patient to remove scattered xray photons which improves radiographic
contrast and visibility of detail
Grids
43
Grids are used when thickness of the body part to be radiographed is ---
greater than 10cm
44
Grids increase (1) but/and improves (2)
1. pt dose
2. image quality
45
Pt dose and grid ratio relationship
Direct
46
Grid Surface XR Absorption Formula
( (Width of grid strip)/ (Width of grid strip + width of grid interspace) ) x 100
47
Grid Freq Formula
(10,000 µm/cm) / (T+D µm/ line pair)
48
Contrast Improvement Factor Formula
k= image contrast with grid/ image contrast without grid
49
(1) are more effective than (2) because of the angle of deviation is smaller
1. High-ratio grids
2. low-ratio grids
50
Types of grids
1. Focused
2. Parallel
3. Criss-cross
51
XR Beam is more focused on the center
Parallel grid
52
Grid that minimizes cut-off
Focused
53
Grid that is hard to use especially if pt is bedridden
Criss-cross
54
Misalignment can occur if pt can't be positioned, resulting to cut-off
Criss-cross
55
Sandwiching of 2 parallel grids
Criss-cross
56
For Criss-cross grids, (1) is increased, which also increases (2)
1. kVp
2. pt dose
57
Reduces exposure to the patient's skin and superficial tissue by absorbing lower-energy photons from the beam
Filters
58
Filters increase the (1) or (2) of the XR Beam (3) the beam
1. mean energy
2. quality
3. hardening
59
The absorbed dose to the pt (1) when the correct amount and type of filtration are placed in the path of the radiographic beam.
1. decreases
60
If adequate filtration were not present, very
low energy photons (1) would be almost totally absorbed in the body, thus (2) the pt's radiation dose.
1. 20 keV or lower
2. increasing
61
2 Types of filtration
1. Inherent filtration
2. Added filtration
62
Inherent Filtration consists of:
1. XR window
2. Insulting oil
3. Glass envelope
63
Inherent Filtration thickness
0.25mmAl
64
Added filtration thickness
2mmAl and above
65
Examples are sheets of AL of appropriate thickness
Added filtration
66
Total filtration of (1) for fixed XR units operating at (2) is the regulatory standard
1. 2.5mmAl
2. above 70kVp
67
Stationary (Fixed) Radiographic Equipment
Tube potential minimum total filtration required (kVp) and the minimum total filtration requires
Above 70kVp= 2.5mmAl Eq
50-70kVp= 1.5mmAl Eq
Below 50kVp= 0.5mmAl Eq
68
Aluminum characteristics and its Z
Z=13
- sturdy
- inexpensive
- readily available
69
Mobile diagnostic units and fluoroscopic equipment require a minimum of --- total permanent filtration
2.5mmAl Eq
70
Widely used as filters because it can remove low energy XR photons
Metals (Al)
71
Mammography filters produce photons with ---
17-20keV
72
Molybdenum vs Rhodium as mammo filters
Mo-42
- 0.03mm
- for small or average breast
Rh-45
- 0.025mm
- for large and dense breast
73
Partially attenuate XRs that are directed towards thinner/ less dense area and permits more XRs to strike thee thicker/ dense areas
Compensating filters
74
Clear, wedge filter used for AP Proj of hips, knees, and ankles on a long 51" film
Super tech wedge
75
Aluminum filter with double wedhe used for AP Proj of the thoracic spine
Trough filter
76
Used for AP proj of facial bones and the shoulders
Boomerang Contact filter
77
for AP and PA Oblique scapula y Proj of shoulder
Ferlic collimator mounted filter
78
For lat Proj of cervicothoracic region (aka swimmer's technique) anf axiolat Proj of hip (Danelius Miller)
Ferlic collimator mounted filter
79
For AP Axial Proj of foot
Ferlic collimator mounted filter
80
Enhance action of XRs on the film and thereby convert xr energy into visible light to produce rad'phic density on the film
Intensifying screens
81
Screen-film IRs are --- screens
rare-earth
82
Rare-earth screens are made up of either
gadolinium
lanthanum
yttrium
83
Intensifying screen layers
Low-z front
Contact felt
Base
Phosphor
Emulsion
Base
Emulsion
Phosphor
Base
Contact felt
High-z back
(|CBPE|Base|EPBC|)
84
A singlel XR photon can produce --- light photons which enhances film exposure process and permits radiographic exposure time to be reduced
80 to 95
85
When the speed of screen-film systems doubles , the patient’s radiation exposure is ---
reduced by approximately 50%.
86
SHCs, film speed, and radn relationship
More SHCs= Faster film spees= Less radiation
87
kV, screen speed, and pt dose relationship
High kV= Fast screen speed= Low pt dose
88
Selection of these are two of the most important technical consideration in the amount of pt dose
kVp and screen-film combination
89
The use of carbon fiber as front material in cxt absorb approx (1) as much radn which (2) pt doess
1. half
2. lowers
90
When operating mobile rad'phic units, the radiographed must use a SSD of at least ---
30cm (12")
91
When SSD is small, pt's entrance exposure is significantly --- than exit expoosure
higher
92
This will imit the effect of the inverse square falloff of radn intensity w distance
SSD
93
By ---, the RT maintains a nore uniform distribution of exposure to the pt
decreasing SSD
94
Consistency in output in radiation intensity for identical generator settings from one individual exposure
to subsequent exposures.
Exposure reproducibility
95
XR unit must be able to duplicate certain radiographic exposures in any value of mA, kVp, and time
Exposure reproducibility
96
Makes use of the 15% kVp rule
Exposure reproducibility
97
Consistency in output radiation
intensity at any selected kVp settings when
generator settings are changed from one
mA and time combination
Exposure Linearity
98
Eliminates the need for almost all retakes required as a result of improper technique selection.
Digital Radiography
99
DR
Repeat rates for reasons of --- are NOT lowered
mispositioning
100
Has greater kilovoltage flexibility
CR imaging
101
(1) indicating optimal kVp for all CR projections must be available in the (2) near the (3) for the radiographer
1. Technique charts
2. XR room
3. operating console
102
Routine proactive of overexposing pt's to avoid possible repeat radiographic procedures
Dose creep
103
Fluoroscopic equipment shown in the ppt
1. Image intensification machine/ unit
2. C-arm fluoroscope
104
They produce the greatest pt radiation exposure rate in diagnostic radiology
Fluoroscopic procedures
105
Could lead to adverse somatic and/or genetic effects
Excessive fluoroscopic exam
106
Involves the use of an II ube
Image intensification fluoroscopy
107
Benefits of II
- Increased image brightness
- Saves time for radiologist
- Pt dose reduction
108
Overall brightness of fluoroscopic machine/ image increase --- as conpared to the brightness of a discontinued non-image intensifier fluoroscopic system
10,000x
109
Devices used in evaluating fluoroscopic image then and now
Then: photopic/ cone daylight vision
Now: Stopopic/ rad vision (night vision)
110
Photopic / cone day light vision advantage and disadvantage
adv: improves visual acuity and permits radiologist to discriminate better smaller structures
disadv: requires the use of red goggles for 30mins
111
mA and brightness relationship
inverse
112
Why does the use of II reduce pt dose?
It uses low mA
113
Involves manual or automatic periodic activation of the fluoroscopic tube by the fluoroscopist
Intermittent/ Pulsed Fluoroscopy
114
Intermittent/ Pulsed Fluoroscopy advantages
- Significantly decreases patient dose, especially in long procedures
- Helps extend the life of the tube
115
When fluoroscopic field size is limited, --- decreases substantially.
patient area or integral dose
116
kVp range of fluoroscopy for adults
75-110kVp
117
Select technical exposure factors that will minimize (1) during (2).
1. patient dose
2. manual fluoroscopic procedures
118
Increases in (1) and (2) reduce the patient radiation exposure rate
1. kVp
2. filtration
119
Technical exposure factors for children necessitate a decrease in (1) by as much as (2)
1. kVp
2. 25%
120
kVp and mAs relationship
inverse
121
Limit excessive entrance exposure of the pt by ensuring that the xr SSD is not less than (1) for stationary (fixed) fluoroscopes, and not less than (2)for mobile fluoroscopes.
1. 38 cm (15 inches)
2. 30 cm (12 inches)
122
A resettable device that times the x-ray beam-on time and sounds an audible alarm or temporarily interrupts the
exposure after the fluoroscope has been activated for 5 minutes.
Cumulative Timing Device
123
A Cumulative Timing Device times the (1)
1. XR Beam-on time
124
Should always be taken note off under cumulative Timing device
Fluoroscopic beam-on time
125
A primary protective barrier of --- is required for a fluoroscopic unit.
2mm lead Eq
126
Fluoroscopic Exposure Control Switch must be of the (1): only continuous pressure applied by the operator and can keep them switch activated and the fluoroscopic tube emitting xr
Dead-man type
127
Used for emergency purposes in instances that time should be terminated for the RT to accommodate the pt (ex. pt in heart attack)
Fluoroscopic Exposure Control Switch
128
To reduce pt's entrance dose during C-arm fluoroscopy, the (1) distance should be as short as possible, (2)
1. patient image instensifier
2. 30cm or 12"
129
To reduce scatter radn during C-arm fluoroscopy, position the C-arm so that --- is under the pt whenever possible
XRT
