Clicker Q's Flashcards
Which X-Ray production process occurs when an electron shifts its shell?
Characteristic (5 very specific X-rays that are produced by this process)
Which X-Ray production process occurs when an electron slows down or stops?
Bremmsstrahlung
Which X-Ray production process is responsible for the majority of the x-rays in the beam?
Bremsstrahlung
Which XRay production process requires at least 70 kVp in a tungsten target?
characteristic
Which one is capable of producing HIGHER energies, greater than 70 keV
bremsstrahlung
What is the type of current distributed by power companies?
AC power
What type of current is necessary to produce X-Rays?
DC current
14 X 36 Full spine
anode?
up
AP Thoracic (T1-T12) anode?
up
Lateral Lumbar
anode?
up
Lateral Thoracic
anode?
down
Lateral Cervical
anode?
doesn’t matter
AP Femur
anode?
down
REM =
RAD x QF
20 RAD=
20 REM
QF of X-ray =
1
20mRAD=
20mREM
1000mREM=
1 REM
20 RAD of alpha exposure=
400 REM
Occupational exposure unit —systems international nomenclature =
Sievert (SI)
100 REM =
1 Grey = 1 Sievert
Which will produce the most Radiographically Dense Image?
1) 20 mAs at 40” SID
2) 20 mAs at 72” SID
20 mAs at 40” SID
***because more xrays made it to the film – blacker image
Which will produce the most geometric sharpness?
1) 30mAs, 73kVp, 36” SID
2) 120 mAs, 73kVp, 72” SID
120 mAs, 73kVp, 72” SID
***higher SID creates MORE geometric sharpness
If 30 mAs used at 36” SID versus 120 mAs used at 72” SID
1) More Dense
2) Less Dense
3) No change in density
No change in density
(***only skin exposure reduced, deep tissue X-rays would not be affected
Which interaction causes the white areas in the image?
photoelectric effect
In which of these interactions is an x-ray totally absorbed when ionizing (in diagnosis)
photoelectric
Which interaction causes image contrast to be reduced?
fog == compton scatter
This x-ray interaction is more probable in high atomic number matter
photoelectric absorption
Which of these energy interactions is important in Diagnostic Radiology?
both photoelectric and compton scatter
Which interaction likely to occur at 10-60 keV?
photoelectric
What is the item that controls contrast?
kVp
Exposure factors that effect the sharpness of detail and the amount of of distortion in an image are known as
geometric factors
Occupational Exposure as reported on radiation dosimeters will be expressed in this classical unit of radiation exposure?
mREM or REM
The unit REM differs from RAD because it combines both occupational and personal exposure.
T/F?
false (they are separate and distinct)
The systems international unit that describes the quantity of patient exposure is:
grey
This x-ray interaction with matter produces the whites in the image
photoelectric absorption
This x-ray interaction causes “fog” in the image
compton scatter
This x-ray interaction occurs at high kVp in the diagnostic range
compton scatter
This x-ray interaction decreases image contrast?
compton scatter
When collimating from 14X17 to 10X12 area – what do we do therefore?
increase mAs by 50%
An AP Lumbar spine exam is properly exposed using 40mAs, 73kVp and a 14X17 film. If a 4X4 spot film is needed, what are the exposure factors.
increase by 50% mAs = 60 mAs, 73kVp, and the spot view
What causes severe underexposure?
Backward Focused Grid – I.E it was put in the wrong way in the Bucky…
Height of the Lead Strip divided by Width of the Interspace Strip:
grid ratio
High Frequency Radiographic Grid does this?
decreases the visibility of grid lines
What grid is on useful in Chiropractic??
crosshatch
This will be indicated on a Focused Grid?
tube side
The Ratio Grid adequate for large images (Gonstead)
12:1 or 16:1
When to use a radiographic grid?
Body part is > 10cm
When we are using > 60 kVp
(Radiographic Grid is also referred to as a “Bucky”)
What is the film BASE made of?
Polyester Plastic (Mylar)
What is the film emulsion made of?
Silver Halide crystals suspended in gelatin
The purpose of using intensifying screens is to:
Reduce Patient Exposure
What are intensifying screens made of?
Rare Earth Crystals –Lanthanum, Gadolinium, and Yttrium
You have a 200 speed film-screen system. The technique chart that is posted is posted works well for that system. What do we need to do with a 600 flim screen system??
Use 1/3X mAs Values
Density is correct when using a 20 mAs on a 1200 speed system. What mAs should be used if changing to a 200 speed system?
120 mAs
Density correct when using 60 mAs with a 300 Speed system. What is the mAs when we buy a new 600 speed system?
30 mAs
What does quantum mottle look like in an image?
graininess
Which of these systems will operate with the most quantum mottle?
1200 speed
Which of these system speeds would you use for detailed extremity images?
100 speed
Which of these would be the minimum speed used for spine imaging?
400 speed
Which of these would result in the most radiation exposure to the patient?
100 speed
Which of these speeds is most consistent with the ALARA concept?
1200 speed
What is film latitude?
range of error
How is film contrast related to film latitude?
inversely
What type of safelight is safe for rare earth screen combinations?
GBX (green blue X-ray)
As film speed system speed increases, geometric blur:
increases
The writing on the Safe-light fixture should be placed:
away from the bulb
The gelatin side of the safelight filter is placed away from the bulb so it will:
not melt
Safelight Bulbs should be in terms of watts:
15 Watts or Less
Safelights should be placed at least this far from the work surface?
4 feet
What is the relative humidity to store films at?
40-60% humidity
Dirty screens can cause these types of artifacts?
Sharp White Dots
These should be used to clean the intensifying screens:
Screen Cleaner and Gauze
Define the term “Latent Image”?
The Invisible Image on the Film Before Processing
Define the term “Manifest Image”?
The Visible Image on Film After Processing
What happens when we use film that is out of date?
FOG – also caused by compton scatter
What is the function of the developer?
To convert the latent image into a manifest image
What is the function of the fixer?
To Clear and Harden the Emulsion
Why does the direction of film transport through the processor motor matter?
Chemical Replenishment
When image processed with oxidized developer what would it look like?
too light
An occupationally exposed person’s own, personal exposure is included in the REM unit?
T/F?
false
Which of these is the most likely to cause “fog” in an image?
1) Use of low kVp
2) Use of high kVp – creates a longer “range”, higher kVp goes further into range of Compton Scatter which causes Fog. higher probability of Compton = higher fog
3) High mA and short exposure time
4) Low mA and long exposure time
Use of high kVp – creates a longer “range”, higher kVp goes further into range of Compton Scatter which causes Fog. higher probability of Compton = higher fog
Which of these will reduce Compton Scatter?
1) Using High kVp (low will reduce)
2) Collimating Well
3) Compressing Tissue
4) Using shorted OID possible (longer = reduce compton)
Collimating Well Compressing Tissue
WHich of these grids is designed so that the strips coincide with the divergence of the x-ray beam:
focused
10:1 grid ratio compared to using no grid will require this change in exposure factors:
Use 4X the mAs
Scale of contrast is too long at 30mAs, and 80kVp. What change should be made to produce a shorter scale of contrast.
Key is to go DOWN in kVp and UP in mAs to compensate.
This means 68kVp, and 60mAs
What is the annual whole body MPD for occupationally exposed persons?
5 REM (or 5000 mREM)
What is the MPD for a pregnant worker?
0.5 REM/gestation period
Which of these is not a cardinal priniciple of Radiation Protection?
1) kVp
2) Time
3) Distance
4) Shielding
kVp
Which of these would allow a greater amount of weekly radiation exposure?
1) Controlled Area
2) Uncontrolled Area
Controlled Area
State the cumulative MPD for a 55 year old occupationally exposed man using the NEW Formula (1 X the person’s age):
55 REM
How often must film badges be sent in for processing?
Once every month
What does the “m” mean on a dosimeter report?
That the exposure was so minimal it did not record
Which of these is allowed a greater amount of weekly exposure?
Controlled Area (Has a benefit to outweigh the risk)
