CT REGISTRY UPDATED EXAMS SCRIPT QUESTIONS AND
ANSWERS SURE A+
✔✔total effective dose equivalent to public
--also average background radiation - ✔✔1 mSv
✔✔Mild reactions to iodinated intravenous contrast media include - ✔✔nausea,
vomiting, mild urticaria, and a warm flushed sensation
✔✔Moderate reactions? - ✔✔Dyspnea, Hives (urticarial); wheezing (mild
bronchospasm); change in pulse; facial edema; vasovagal response; hypo- or
hypertension
✔✔Severe reactions? - ✔✔Severe bronchospasm; anaphylaxis; Drowsiness; headache;
fever/chills, Shock, pulmonary edema
✔✔Osmolality - ✔✔Concentration of a solution in terms of number of dissolved particles
per unit of water
✔✔Non-ionic intravenous contrast media such as Omnipaque should have an average
osmolality of - ✔✔750 mOsm/kg water
✔✔What drugs are administered for moderate reaction to injection of iodinated contrast
medium - ✔✔Antihistamines
Epinephrine
✔✔Prothrombin measures the amount of time necessary for a person's blood to
coagulate - ✔✔normal limits: between 10 and 14 seconds
✔✔why use an autoclave? - ✔✔The use of an autoclave for sterilization involves heat
and steam under pressure to eliminate microbes.
✔✔1 rem= 1 rad - ✔✔When measuring the radiation dose from x-rays, rads and rems
are equivalent. The units of Sv and rem are used to measure any kind of ionizing
radiation where 1 Sv =100rem. The units of rad and Gy are used to measure specifically
x-ray radiation where 1 Gy = 100 rads.
✔✔When performing a multi-slice CT study, the slice thickness may be ___________ to
cover the region of interest, in order to minimize the dose to the patient. - ✔✔Due to
radiation penumbra, a multiple slice study results in a greater patient dose than the
same number of individual slices. By covering a specific region of interest with fewer
slices (increase in slice thickness) the resulting radiation overlap from adjacent slices is
reduced, reducing the dose to the patient.
,✔✔A given CT exam yields a CTDI of 4.5 rads, with a slice thickness of 10mm, and a
2mm gap between slices, the MSAD for this exam is ________ rads. - ✔✔The MSAD is
equal to the CTDI X the ratio of the slice thickness to the table increment. With a 2mm
gap and a 10mm slice the table increment will be 12mm. The MSAD = (4.5 rads) X
(10mm/12mm)
--3.75 rads
✔✔Calulate the DFOV for an image with a 320 2 matrix and a pixel dimention of .75 x
.75 mm.
A)36cm B)12cm C)24cm D)48cm - ✔✔Answer: C
*The formula for DFOV is pixel dimension x the matrix size. 320 x .75 mm = 240mm or
24 cm DFOV
✔✔The units rad and rem are equivalent when measuring radiation dose used in CT x-
ray radiation.
True or False - ✔✔Answer: True
*When measuring the radiation dose only from x-rays, rads and rems are equivalent.
The units Sv and rem measure any kind of ionizeing radiation (1 Sv = 100 rem). The
units rad and Gy measure specifically x-ray radiation
(1 Gy = 100 rads
✔✔Non-ionic contrast media include - ✔✔iopamidol (Isovue), Iohexol (Omnipaque), and
iopromide (Ultravist)
✔✔What is the normal pulse rate for an adult? - ✔✔70-100 bpm
✔✔What is the average normal adult respirations per minute? - ✔✔12-20
✔✔Which of the following iodinated contrast media may NOT be used for an intrathecal
injection? - ✔✔Iohexol(Omnipaque), metrizamide(Amipaque) and iopamidol(Isovue) are
all non-ionic contrast agents that may be used for intrathecal injection. Meglumine is not
considered safe for an intrathecal injection.
✔✔A patient arrives with a central venous line in place. Which type of central venous
line may be used for a CT examination requiring the administration of iodinated contrast
media with an automatic injector? - ✔✔none.. indwelling catheters or central venous
lines cannot withstand the pressure produced by an automatic injector
,✔✔The total quantity of radiation dose received by the patient from a CT scan series is
termed - ✔✔MSAD(multiple-scan average dose) quantifies the amount of exposure to a
patient from a series of CT scans. MSAD is calculated using a series of equations
based on the CTDI(CT dose index). The radiation quantity per scan is measured using
an ionization chamber.
✔✔Average pulse rate for an infant is - ✔✔100-180 bpm
✔✔General signs of shock include: - ✔✔rapid breathing, tachycardia, hypotension,
weak pulse, pallor, cyanosis, and cold, clammy skin.
✔✔What is the average range for activated partial thromboplastin time? - ✔✔28-34
seconds
✔✔The average radiation dose to the pituitary gland during a CT head is - ✔✔2 rads
✔✔A CT exam is done with a slice thickness of 10mm, and a 2mm gap is between the
slices, the pitch is 1:2 and the total scan time is 5 seconds. What is the table increment
for this exam? - ✔✔*The table increment is determined by adding the slice thickness
with the gap between the slices. 10mm + 2mm = 12mm table increment. The other
information given is just that other information to distract you.
✔✔What is medical asepsis? - ✔✔The reduction in number of infectious agents but not
the complete elimination of all organisms.
✔✔Complete cardiac diastole correspond to which portion of the cardiac cycle on a
electrocardiogram (ECG)? - ✔✔T-wave
✔✔Gas accumulating within a degenerating intervertebral disk is termed - ✔✔vacuum
effect
✔✔Following the intravenous administration of iodinated contrast media, a hepatic
hemangioma may become _________ and may no longer appear on the CT image. -
✔✔isodense -- The diagnosis of hemangioma is confirmed on CT by evaluation of its
pattern of enhancement. Hemangiomas enhance from the periphery inward, until they
become isodense with the surrounding hepatic tissue. Once isodense, the hemangioma
attenuates the beam in the same way as the hepatic tissue. The CT numbers of the
hemangioma and hepatic tissue become equal and the structures may become
impossible to differentiate.
✔✔During CT examination of the larynx, the patient is often instructed to phonate the
letter "E" in order to properly evaluate the - ✔✔vocal chords
, ✔✔The exaggeration of displayed calcification within the coronary arteries during a
cardiac MDCT study is referred to as - ✔✔Blooming- refers to the potential
overestimation of vessel calcification due to partial volume artifact
✔✔What describes a condition in which cerebral ischemia is caused by systematic
hypertension? - ✔✔Vasovagal reaction
✔✔Patients whose posterior descending artery branches from the right coronary artery,
and whose left posterior ventricular braches arise from the left circumflex artery are said
to be - ✔✔codominant - 7% of the population is said to be codominant... which means
the PDA is supplied by the RCA.. and the left posterior ventricular braches arise from
the LCX
✔✔Which of the following window settings would optimally display CT colonography
images? - ✔✔level= -400 width= 1600
CT colonography images are best displayed in wide "lung-type" window setting
✔✔A CT scanner with a limiting resolution of 15 lp/cm can resolve an object as small
as.. - ✔✔0.3 mm
The minimum object size that a CT scanner can resolve may be calculated by taking the
reciprocal value of the scanner's limiting resolution. The reciprocal of 15 lp/cm is 1/15
lp/cm. This is equivalent to 10/15 lp/mm, which equals 0.6 mm/lp. Because a line pair is
equivalent to a line and the space adjacent to it, this value may be divided in half to
provide the minimum object that this scanner can resolve..0.3
✔✔The total length of a CT scan may be calculated by multiplying the scan time by the
aperture size - ✔✔An example: If the scan time is 15 seconds and the aperture
size(slice thickness) is 1.0cm(10mm) the length of the scan will be 150mm.
✔✔An abnormal density of the liver is found to be a fatty infiltrate. The CT number for
this area would most likely be in the range of .. - ✔✔-100 Hounsfield units
✔✔What is the HU of a pulmonary nodule? - ✔✔+200 hu
✔✔The radiologist has requested a CT examination to identify the thymus gland in a
young pre-puberty patient. The thymus gland is located - ✔✔anteriosuperior portion of
the mediastinum
✔✔To best image a possible Schwannoma found within the Schwann cells of the eighth
cranial nerves, CT examinations should include which of the following - ✔✔internal
auditory canal
ANSWERS SURE A+
✔✔total effective dose equivalent to public
--also average background radiation - ✔✔1 mSv
✔✔Mild reactions to iodinated intravenous contrast media include - ✔✔nausea,
vomiting, mild urticaria, and a warm flushed sensation
✔✔Moderate reactions? - ✔✔Dyspnea, Hives (urticarial); wheezing (mild
bronchospasm); change in pulse; facial edema; vasovagal response; hypo- or
hypertension
✔✔Severe reactions? - ✔✔Severe bronchospasm; anaphylaxis; Drowsiness; headache;
fever/chills, Shock, pulmonary edema
✔✔Osmolality - ✔✔Concentration of a solution in terms of number of dissolved particles
per unit of water
✔✔Non-ionic intravenous contrast media such as Omnipaque should have an average
osmolality of - ✔✔750 mOsm/kg water
✔✔What drugs are administered for moderate reaction to injection of iodinated contrast
medium - ✔✔Antihistamines
Epinephrine
✔✔Prothrombin measures the amount of time necessary for a person's blood to
coagulate - ✔✔normal limits: between 10 and 14 seconds
✔✔why use an autoclave? - ✔✔The use of an autoclave for sterilization involves heat
and steam under pressure to eliminate microbes.
✔✔1 rem= 1 rad - ✔✔When measuring the radiation dose from x-rays, rads and rems
are equivalent. The units of Sv and rem are used to measure any kind of ionizing
radiation where 1 Sv =100rem. The units of rad and Gy are used to measure specifically
x-ray radiation where 1 Gy = 100 rads.
✔✔When performing a multi-slice CT study, the slice thickness may be ___________ to
cover the region of interest, in order to minimize the dose to the patient. - ✔✔Due to
radiation penumbra, a multiple slice study results in a greater patient dose than the
same number of individual slices. By covering a specific region of interest with fewer
slices (increase in slice thickness) the resulting radiation overlap from adjacent slices is
reduced, reducing the dose to the patient.
,✔✔A given CT exam yields a CTDI of 4.5 rads, with a slice thickness of 10mm, and a
2mm gap between slices, the MSAD for this exam is ________ rads. - ✔✔The MSAD is
equal to the CTDI X the ratio of the slice thickness to the table increment. With a 2mm
gap and a 10mm slice the table increment will be 12mm. The MSAD = (4.5 rads) X
(10mm/12mm)
--3.75 rads
✔✔Calulate the DFOV for an image with a 320 2 matrix and a pixel dimention of .75 x
.75 mm.
A)36cm B)12cm C)24cm D)48cm - ✔✔Answer: C
*The formula for DFOV is pixel dimension x the matrix size. 320 x .75 mm = 240mm or
24 cm DFOV
✔✔The units rad and rem are equivalent when measuring radiation dose used in CT x-
ray radiation.
True or False - ✔✔Answer: True
*When measuring the radiation dose only from x-rays, rads and rems are equivalent.
The units Sv and rem measure any kind of ionizeing radiation (1 Sv = 100 rem). The
units rad and Gy measure specifically x-ray radiation
(1 Gy = 100 rads
✔✔Non-ionic contrast media include - ✔✔iopamidol (Isovue), Iohexol (Omnipaque), and
iopromide (Ultravist)
✔✔What is the normal pulse rate for an adult? - ✔✔70-100 bpm
✔✔What is the average normal adult respirations per minute? - ✔✔12-20
✔✔Which of the following iodinated contrast media may NOT be used for an intrathecal
injection? - ✔✔Iohexol(Omnipaque), metrizamide(Amipaque) and iopamidol(Isovue) are
all non-ionic contrast agents that may be used for intrathecal injection. Meglumine is not
considered safe for an intrathecal injection.
✔✔A patient arrives with a central venous line in place. Which type of central venous
line may be used for a CT examination requiring the administration of iodinated contrast
media with an automatic injector? - ✔✔none.. indwelling catheters or central venous
lines cannot withstand the pressure produced by an automatic injector
,✔✔The total quantity of radiation dose received by the patient from a CT scan series is
termed - ✔✔MSAD(multiple-scan average dose) quantifies the amount of exposure to a
patient from a series of CT scans. MSAD is calculated using a series of equations
based on the CTDI(CT dose index). The radiation quantity per scan is measured using
an ionization chamber.
✔✔Average pulse rate for an infant is - ✔✔100-180 bpm
✔✔General signs of shock include: - ✔✔rapid breathing, tachycardia, hypotension,
weak pulse, pallor, cyanosis, and cold, clammy skin.
✔✔What is the average range for activated partial thromboplastin time? - ✔✔28-34
seconds
✔✔The average radiation dose to the pituitary gland during a CT head is - ✔✔2 rads
✔✔A CT exam is done with a slice thickness of 10mm, and a 2mm gap is between the
slices, the pitch is 1:2 and the total scan time is 5 seconds. What is the table increment
for this exam? - ✔✔*The table increment is determined by adding the slice thickness
with the gap between the slices. 10mm + 2mm = 12mm table increment. The other
information given is just that other information to distract you.
✔✔What is medical asepsis? - ✔✔The reduction in number of infectious agents but not
the complete elimination of all organisms.
✔✔Complete cardiac diastole correspond to which portion of the cardiac cycle on a
electrocardiogram (ECG)? - ✔✔T-wave
✔✔Gas accumulating within a degenerating intervertebral disk is termed - ✔✔vacuum
effect
✔✔Following the intravenous administration of iodinated contrast media, a hepatic
hemangioma may become _________ and may no longer appear on the CT image. -
✔✔isodense -- The diagnosis of hemangioma is confirmed on CT by evaluation of its
pattern of enhancement. Hemangiomas enhance from the periphery inward, until they
become isodense with the surrounding hepatic tissue. Once isodense, the hemangioma
attenuates the beam in the same way as the hepatic tissue. The CT numbers of the
hemangioma and hepatic tissue become equal and the structures may become
impossible to differentiate.
✔✔During CT examination of the larynx, the patient is often instructed to phonate the
letter "E" in order to properly evaluate the - ✔✔vocal chords
, ✔✔The exaggeration of displayed calcification within the coronary arteries during a
cardiac MDCT study is referred to as - ✔✔Blooming- refers to the potential
overestimation of vessel calcification due to partial volume artifact
✔✔What describes a condition in which cerebral ischemia is caused by systematic
hypertension? - ✔✔Vasovagal reaction
✔✔Patients whose posterior descending artery branches from the right coronary artery,
and whose left posterior ventricular braches arise from the left circumflex artery are said
to be - ✔✔codominant - 7% of the population is said to be codominant... which means
the PDA is supplied by the RCA.. and the left posterior ventricular braches arise from
the LCX
✔✔Which of the following window settings would optimally display CT colonography
images? - ✔✔level= -400 width= 1600
CT colonography images are best displayed in wide "lung-type" window setting
✔✔A CT scanner with a limiting resolution of 15 lp/cm can resolve an object as small
as.. - ✔✔0.3 mm
The minimum object size that a CT scanner can resolve may be calculated by taking the
reciprocal value of the scanner's limiting resolution. The reciprocal of 15 lp/cm is 1/15
lp/cm. This is equivalent to 10/15 lp/mm, which equals 0.6 mm/lp. Because a line pair is
equivalent to a line and the space adjacent to it, this value may be divided in half to
provide the minimum object that this scanner can resolve..0.3
✔✔The total length of a CT scan may be calculated by multiplying the scan time by the
aperture size - ✔✔An example: If the scan time is 15 seconds and the aperture
size(slice thickness) is 1.0cm(10mm) the length of the scan will be 150mm.
✔✔An abnormal density of the liver is found to be a fatty infiltrate. The CT number for
this area would most likely be in the range of .. - ✔✔-100 Hounsfield units
✔✔What is the HU of a pulmonary nodule? - ✔✔+200 hu
✔✔The radiologist has requested a CT examination to identify the thymus gland in a
young pre-puberty patient. The thymus gland is located - ✔✔anteriosuperior portion of
the mediastinum
✔✔To best image a possible Schwannoma found within the Schwann cells of the eighth
cranial nerves, CT examinations should include which of the following - ✔✔internal
auditory canal
