Diagnostic Imaging Questions with Correct Answers
which of these animals does not have a gall bladder? Correct Answer-
horse
Which of following typically appear hyperechoic (bright white) on
ultrasound imaging? Correct Answer-bone and gas
Sound is strongly reflected by mineral and gas, resulting in a
hyperechoic appearance of bone and gas in the gastrointestinal tract or
air in lungs. Fluid such as urine in the bladder typically appears
hypoechoic or anechoic (black), and most soft tissues such as spleen,
liver, and kidney have varying echogenicities in between the two.
In addition to a hyperechoic appearance, mineral and gas also typically
create a shadow that obscures deeper structures because the sound is
unable to penetrate.
In radiation safety, what is the difference between the "rad" and the
"rem"? Correct Answer-rem applies a quality factor to rad
Rad and rem are both old units of types of absorbed dose that can be
applied to either the patient or to personnel. More commonly, rem is
used in radiation safety for personnel, and rad is used in radiation
therapy in dose calculations.
The difference between the two is that rad is the basic unit of absorbed
dose, and rem applies a quality factor depending on the type of radiation.
For x-rays, rad equals rem; but for other types of radiation such as
neutrons and protons, rem may be greater than rad. Rem exposure is of
greater relevance in radiation protection than rad because the biologic
,effects of 10 rad of neutron exposure is far greater than the biologic
effects of 10 rad of x-ray exposure.
The units that should be used currently are the Gray (Gy) and the Sievert
(Sv) for absorbed dose and effective absorbed dose respectively, but
many people still use rad and rem
A 7-year old Saint Bernard dog has a lesion of the left distal radius that
is highly suspicious for a bone tumor (osteosarcoma). Prior to surgery, a
bone scan is ordered and performed. What is the main reason for this
study? Correct Answer-to identify possible additional bone lesions
(other than the distal left radius lesion) that may represent bony
metastases
While the lungs are the most common site of metastasis of bone tumors
in dogs, these tumors can also metastasize to other bony sites. Thoracic
radiographs are generally sufficient to assess gross pulmonary metastasis
but radiography is not typically practical for assessing all of the bones in
the body.
A bone scan is a nuclear medicine test that involves administration of a
bone-seeking radioisotope (Technetium phosphate) that is taken up in
areas of bone turnover. The test does not provide significant anatomic
detail and is not confirmatory of osteosarcoma because it is not specific
for cancer (osteoarthritis or osteomyelitis also are positive on bone
scans). The test is used to identify additional bony sites that should be
evaluated radiographically to assess for metastasis.
Because this ty
,Which of the following is the most common factor that prevents a
diagnostic radiograph in a horse? Correct Answer-motion
motion is problem with any radiograph on any species. however, in
horses, due to their fight or flight nature, getting them to stand still can
be tricky
During which of the following periods is a human embryo or fetus most
sensitive to adverse effects from radiation? Correct Answer-first
trimester
the first 3 months of pregnancy are the most important in terms of
radioation safety because the embryo/fetus is most sensitive at this time.
this heightened sensitivity is due to the organogenesis that occurs during
the first trimester
Linear artifacts on a film are usually due to which of the following?
Correct Answer-grid
Linear artifacts can be normal gridlines or may be due to the beam not
being appropriately centered on the grid. Alternatively, they may occur
if the grid is otherwise out of position, upside-down, or damaged.
Processing machine errors may cause streaks on the film which should
not be confused with linear artifacts. Errors with the other components
listed should not cause linear artifacts.
Your radiograph technique chart indicates that you should use a kVp
setting of 50 and mAs setting of 12.5. Which of the following would be
appropriate? Correct Answer-250 mA, 1/20 sec
, mAs is a measure of the total exposure. It is the product of mA and time
in seconds. Of the choices here, only 250 mA and 1/20 sec yields a
product of 12.5 mAs. Generally, it is also best to maximize the mA and
minimize exposure time to decrease motion artifacts.
The radiograph cassette is usually placed on the tabletop to radiograph
which of the following areas in a medium-sized dog? Correct Answer-
elbow
Tabletop technique is usually used to image structures that are not too
thick (usually <10cm thick) because there is decreased scatter, and a grid
and Bucky are not needed. In this case, the elbow is the only structure on
this list that is not thick enough to warrant the use of a grid and Bucky.
Barium for an upper GI radiograph series should not be given to a
patient with which of the following? Correct Answer-aspiration
pneumonia
Patients with aspiration pneumonia or who are at risk for aspiration
pneumonia should not be given oral barium for an upper GI series due to
the risk of aspiration of the barium. Dehydration and renal failure are
contraindications for other types of contrast such as iodide contrast
agents, which are hyperosmolar and can cause osmotic diuresis and
diarrhea. Barium is commonly given to animals with partial obstructions
and/or diarrhea as part of their diagnostic work-up and is not
contraindicated.
What procedure requires the use of contrast (dye)? Correct Answer-
myelogram
a myelogram involves contrast administration into the subarachnoid
space so that it may be visualized on a radiograph
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