Transcript What does PACS stand for?

The long-awaited, much-anticipated X-ray
Quiz #2 from Seattle, WA---March 2001.
You’ll quake in your shoes when you take this one! (48 slides!)
• Brought to you by
Washington State Xray Control, PO Box
47827, Olympia, WA
98504--tel: 360 236
3237--e-mail:
mike.odlaug@doh.
• wa.gov
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What does PACS stand for?
• Posterior Anterior Chest System
• Positive Action Collimation System
• Picture Archiving and Communications
System
• Parts and Charts System
C.
A term commonly used in digital
imaging to describe the system used
for sending, viewing, & storing images
True or False?
• Digital imaging always means lower
exposure to the patient than for
conventional film radiography.
• Digital imaging means that you cannot
produce a hard copy image.
False and false.
Digital does not necessarily guarantee
a lower dose since computer image
manipulation is so forgiving with
respect to dose.
The annual whole body occupational
dose limit is 5 REM. What is the limit
for the eye?
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A. 5 REM
B. 10 REM
C. 15 REM
D. 25 REM
E. 50 REM
E. 15 REM
Skin is 50.
What is the equivalent number of SI
units for 200 millirem?
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20 microSieverts
20 milliSieverts
2 microSieverts
200 milliSieverts
2 milliSieverts
One of those is correct.
These SI units are certainly difficult to
get a hold of, aren’t they? Do a little
research and calculation and figure it
out. (Hint: 100 rem = 1 Sv)
What is the usual range for patient
dose rate during fluoroscopy?
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A.
B.
C.
D.
E.
20 - 40 R/minute
20 – 40 mR/minute
2 – 9 R/minute
1 – 10 mR/minute
2 - 9 R/hour
C. 2 -9 Roentgens
per minute
Of course, it can be lower and higher in
some cases.
FDA and state rules allow a maximum of
10 R/min and HLC can go up to 20 R/min
Switching to magnification
mode in fluoroscopy
• A. uses a smaller portion of the input
phosphor screen.
• B. increases the dose rate to the
patient, if ABC is operating
• C. requires the use of pulsed HLC.
A and B.
Pulsed mode fluoroscopy and High
Level Control are not related to
magnification.
Regarding the differences between
MRI and CT, which of the following is
true?
• A. MRI is used strictly for brain imaging.
• B. MRI provides biochemical info, and
gives better contrast.
• C. MRI is equal in image quality to CT.
• D. MRI uses more radiation to obtain
the same information.
B.
Additional note: the MRI machine is
more expensive than a CT system and
each exam costs more and takes
longer.
True or False:
• A. Magnetic Resonance Imaging uses
no ionizing radiation
• B. MRI uses only magnetic fields and RF
pulses
• C. Lead must not be used in
the walls of an MRI room.
A. True, B. True, C. False
Lead wouldn’t be necessary and
anyway, it is non-ferrous and thus not
subject to magnetic fields.
Skin entrance patient exposures are
higher for low kVp techniques,
because
• A. You have to use more photons to get
through the patient
• B. The energy of the beam is lower and
thus it penetrates less
• C. You have to use a different film
speed.
• D. You have to use more mAs.
A, B and D
Sometimes, facilities use latitude film
and then try to regain contrast by
using lower kVp but then they have to
increase the mAs.
Collimation is:
• A. A common misspelling of the word
“columnation.”
• B. Proper alignment of the column upon
which the X-ray tube is mounted.
• C. of benefit to patient, operator and
interpretation of the resultant film.
• D. Not necessary in dental X-ray exams.
C.
Proper collimation provides a better
radiograph with decreased scatter to
the operator, and of course less area
of the patient exposed.
A high ESE for a lumbar spine exam
could be due to:
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A. Lousy processing
B. Low kVp techniques
C. Slow film/screen speed
D. A preference for dark images by the
film reader
• E. A high ratio grid.
All of the above.
Don’t you just love answers like this?
The unaided human eye can resolve
how many line pairs per millimeter?
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A. 1 lp/mm
B. 5 lp/mm
C. 10 lp/mm
D. 15 lp/mm
E. 20 lp/mm
C. 10 lp/mm
We have sharp eyes, don’t we?
Intensifying screens can resolve
about how many lp/mm?
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A. 1 lp/mm
B. 1-5 lp/mm
C. 7-15 lp/mm
D. 15-20 lp/mm
C. 7-15 lp/mm
The old calcium tungstate par speed
screens are smack in the middle at 10
lp/mm.
Why don’t automatic film processors
have a stop-bath step?
• A. Because the rollers squeeze the
developer out of the film.
• B. Because the fixer already contains
some acetic acid.
• C. Because the transit time is too fast.
• D. Because X-ray film is too sensitive.
A and B are correct.
Besides, the processor would have to
be that much larger to accommodate
another compartment and roller set.
What is the “latent image?”
• A. The “ghostly” penumbra
around the image.
• B. The part of the image
that will never show up on film.
• C. The invisible change induced
in silver halide crystals.
C is correct
I thought “ghostly penumbra” sounds
like a pretty good answer, though!
True or False:
• A. Compton scattering contributes to
film fogging.
• B. The photoelectric effect is a photon
absorption interaction resulting in an
ejected electron.
• C. Pair production cannot occur in
diagnostic X-ray energies.
All are correct.
Compton scattering is the source of
most of the scatter. Pair production, by
the way, is not a dating service.
For extra credit:
• What is the minimum photon energy
that will permit the production of an
electron and a positron (“pair
production”) when an X-ray interacts
with the nucleus of a target atom?
1.02 MeV
True or False:
• The radiation intensity coming from the
cathode side of the X-ray beam field is
higher than that from the anode side
(Heel effect).
True
The anode sort of “self-attenuates” or
blocks the heel portion of the X-rays
generated
True or False
• A.) Dental intra-oral X-ray tubes have
rotating anodes
• B.) Fluoroscopic tubes can operate
continuously because the milliAmperage
is low.
• C.) The oil in an X-ray tube is designed
to lubricate the rotating anode.
No, Yes and No.
Intraoral tubes have stationary anodes.
The oil in a tube housing acts as a
coolant and heat distributor.
“Ripple” in a voltage waveform is:
• A.) the same as fudge in certain ice
creams
• B.) is 100% for single phase power.
• C.) is 1% for high frequency waveforms
• D.) not measurable at all.
B and C are correct.
Although fudge ripple does sound
good.
X-ray milli-amperage is:
• A. The amount of current delivered to
the filament of the X-ray tube cathode
• B. the number of electrons flowing per
second from anode to cathode
• C. the number of electrons flowing per
second from cathode to anode.
C is correct.
Some current is, of course, sent to the
filament to make it glow, but that’s
another story.
Dust, dandruff and cookie crumbs on
an intensifying screen:
• A. will not show up on the resulting
films because they are radiolucent
• B. will show up as black
specks on the film
• C. will show up as white
specks on the film
C.
Other possible artifacts include static,
processor marks and fog from light
leaks.
The grid moves during a radiographic
exposure so that
• A. it can automatically get into position
for the next shot
• B. it “smooshes” the grid lines and
makes them disappear.
• C. it increases the resultant “clean-up”
of scattered X-rays
B.
I just made up the other two.
“Smooshes” is a recognized scientific
term used by President Bush.
What does the German word
Bremsstrahlung mean?
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A. broken straight line
B. breaking radiation
C. literally, “bratwurst inhaled”
D. braking radiation
Ja, wohl, the answer is D.
Braking, meaning slowing down, rather
than breaking, meaning coming apart.
Congratulations. You have earned 1
credit of Continuing Education.
• I would appreciate
corrections and
comments to make this
quiz better. And you
can send your
complaints about
anything else to Gary.
[email protected]