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39 Cards in this Set
- Front
- Back
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The enormous heat that builds up in the CT tube is caused by the:
A: intensity of the x-rays emitted from the tube. B: electron beam between the cathode and the anode in the tube C: x-ray filter in the tube which absorbs the lower energy photons before they can enter the patient. D: collision of the electron beam with the tungsten target on the tube anode |
D: collision of the electron beam with the tungsten target on the tube anode
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________________ scanner design was the first to acquire four slices in a single rotation.
A: second - generation b. third-generation c. multi-row detector d. continuous rotation |
c. multi-row detector
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The number of electrons that flow from the cathode to the anode in the tube is controlled by the:
a. anode target b. collimation c. mA d. kV |
c. mA
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The slip ring on continuous rotation CT scanners:
1. prevents the high voltage cable from winding up 2. allows the exam to commence more rapidly 3. eliminates the need for the reversal of gantry frame rotation. a. 1 only b. 2 only c. 3 only d. 1, 2, & 3 |
d. 1, 2, & 3
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Which of the following is NOT a part of the CT tube?
a. tungsten target b. collimator c. rotating anode d. filament |
b. collimator
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Which of the following are NOT commonly used on today's commercially available CT scanners?
1. xenon detectors 2. fourth-generation technology 3. continuous rotation technology a. 1 only b. 1 & 2 c. 2 & 3 d. 1,2, & 3 |
b. 1& 2
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Which system component converts the projection attenuation data into the proper digital form for the array processor?
a. detector b. photodiode c. analog-to-digital converter d. host computer |
c. analog-to-digital converter
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X-ray photons are produced by a fast-moving electron:
1. colliding with an atomic nucleus 2. passing close to an atomic nucleus 3. colliding with an electron within an atom and ejecting it. a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
d. 1, 2 & 3
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Which of the following is TRUE regarding solid state detectors?
1. x-ray photons cause the detectors to generate a flash of light 2. they are the detector type used on most CT scanners today 3. they can be used in both third-generation and fourth-generation CT systems a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
d. 1, 2 & 3
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CT is commonly referred to as all of the following names EXCEPT:
a. computerized axial tomography b. digital subtraction angiography c. CAT-scan d. computed tomography |
b. digital subtraction angiography
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What control does the operator have over the x-rays in a CT exam?
a.the temperature and color of the x-rays can be tuned b. the energy level and the quantity of x-rays can be selected c. the volume and tone of the x-rays can be dialed d. the phase and frequency of the x-rays can be adjusted. |
b. the energy level and the quantity of x-rays can be selected
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Which of the following statements is TRUE?
1. kV is the voltage potential between the tube cathode and anode while mA ultimately controls the filament current and, thus, the temperature of the cathode filament 2. kV controls the energy level of the x-ray photons and mA controls the number of x-ray photons emitted from the tube. 3. although the kV and the mA affect the operation of the CT x-ray tube, the two parameters have no bearing on the image quality. a. 1 only b. 2 only c. 1 & 2 d. 2 & 3 |
c. 1 & 2
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Which of the following does NOT affect the quantity of x-rays that completely penetrates the patient?
1. the distance that the x-ray photons must travel on their course through the patient's body. 2. the molecular composition of the tissues through which the x-ray photons pass. 3. the type of detector material used a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
c. 3 only
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_________________ made helical imaging possible.
a. multi-row detector scanners b. the introduction of second-generation technology c. the introduction of fourth-generation technology d. continuous rotation scanners |
d. continuous rotation scanners
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Which of the following statements is FALSE regarding the collection of CT data?
a. long scan times are more desirable because they average out motion artifacts. b. the reconstruction process used to create the image occurs in the array processor. c. to collect the complete set of CT data, x-rays must be passed through the body at many different angles. d. the detectors measure x-rays which completely penetrate the patient. |
a. long scan times are more desirable because they average out motion artifacts
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Which of the following is a component NOT normally located in the gantry of a modern CT system?
a. pre-patient collimators b. solid-state detectors c. array processor d. x-ray tube |
c. array processor
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X-rays are used in CT because:
a. they are easily produced by the high frequency generator b. they are less harmful than the heating effects of microwave radiation c. they penetrate the body according to specific attenuation characteristics of each tissue d. the FDA imposes no limit on the dose to the patient. |
c. they penetrate the body according to specific attenuation characteristics of each tissue.
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X-rays are produced whenever fast-moving electrons collide with any form of matter because:
1.the electron splits into two x-ray photons of equal energy upon impact with the matter. 2. the electron loses kinetic energy which is converted into the emission of an x-ray photon 3. the electron converts the electron it collides with into an x-ray photon a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
b. 2 only
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Bremsstrahlung radiation does NOT include which type of electron activity?
1. collision between an incoming electron and the nucleus of the target atom. 2. collision between an incoming electron and an electron in an inner shell of the target atom. 3. slowing down of an incoming electron due to the effect of passing close to the positive charge of the nucleus of the target atom. a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
b. 2 only
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the mA determines the:
a. quantity of x-ray photons b. coefficient of attenuation c. slice thickness d. energy level of the x-ray photons |
a. quantity of x-ray photons
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Increased _______________ will increase the likelihood that a given x-ray will penetrate a material.
1. kV 2. mA 3. exposure time a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
a. 1 only
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Collimation:
a. is accomplished by electrically blocking x-rays b. affects the scan time c. limits the low energy x-ray photons and passes the high energy photons d. is accomplished by physically blocking x-rays. |
d. is accomplished by physically blocking x-rays.
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Scatter radiation is caused by:
a. miscalibrated detector b. x-rays generated spontaneously in the ambient atmosphere c. deflections from the original trajectory of an x-ray photons through the patient. d. improper patient positioning |
c. deflections from the original trajectory of an x-ray photons through the patient.
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Which technology do multi-row detector scanners employ?
a. second-generation b. third-generation c. fourth-generation d. first-generation |
b. third-generation
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Which of the following is NOT a function of the PACS system?
a. reconstruction of the image from the raw data. b. long term data storage c. digital distribution of images d. image display for the radiologists |
a. reconstruction of the image from the raw data.
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Which of the following is TRUE regarding multi-row detector CT scanners?
1. the size of the detector arrays along the z-direction may be different. 2. the attenuation information from adjacent detector arrays may be added together to generate thicker slices 3. all of the detector arrays may or may not be used. a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
d. 1, 2 & 3
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Which of the following FALSE regarding CT systems?
1.they are limited to non-oblique transverse scanning 2. they cannot generate a straight coronal or sagittal image. 3. they have no moving parts a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
d. 1, 2 & 3
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Most of the commands from the technologist are received by the:
a. array processor b. operator's console c. host computer d. amplifier |
b. operator's console
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The operator's console may include:
1. monitor 2. keyboard 3. graphic input device a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
d. 1, 2 & 3
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Which of the following CT scanner designs does NOT use an x-ray tube?
a. first-generation CT b. PET/CT c. electron beam CT d. MDCT |
c. electron beam CT
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Tube interscan delay time refers to:
a. the time between the end of one scan and the state of the next scan during which the tube will cool. b. a quality assurance test performed daily by the technologist. c. the time required for the tube to make a complete 360* revolution about the gantry d. the length of time required for the production of photons to begin after applying the voltage to the tube. |
a. the time between the end of one scan and the state of the next scan during which the tube will cool.
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On a single-row detector scanner, collimation:
1. controls the slice thickness 2. minimizes the x-ray dose to the patient. 3. reduces the detection of scatter radiation. a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
d. 1, 2 & 3
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The main purpose of the detector is to:
a. provide additional collimation in order to reduce scatter. b. limit the x-ray dose to the patient c. capture x-ray photons and convert them to a measurable signal d. amplify the measured signal |
c. capture x-ray photons and convert them to a measurable signal
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In order for an x-ray photon to be measured it must:
1. enter the detector chamber 2. be absorbed by the detector material 3. be converted to a measurable event. a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
d. 1, 2 & 3
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The patent table:
a. may move continuously during the scan b. can never be positioned automatically by software due to safety precautions. c. remains stationary throughout the patient exam once it is initially positioned d. only moves after each slice is completed. |
a. may move continuously during the scan
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Which of the following statements is FALSE regarding occurences after an x-ray photon penetrates the detector aperture?
1. the photon can pass through the detector unmeasured. 2. the photon is converted completely into an electron 3. the measured signal is enhanced by an amplifier a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
b. 2 only
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CT images can be directly scanned in planes other than transverse by:
1. orienting the patient's body part so that it is not perpendicular to the x-ray beam 2. tilting the gantry 3. changing the angle that the x-ray beam leaves the tube. a. 1 only b. 1 & 2 c. 2 & 3 d. 1, 2 & 3 |
b. 1 & 2
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The CT x-ray tube rotates around the patient to:
1. keep the tube cool 2. generate projection views at different angles 3. minimize the x-ray dose administered to the patient a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
b. 2 only
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The cathode filament:
a. helps determine the size of the focal spot b. lights up the tube so it can be serviced by an engineer c. releases the x-ray photons d. focuses x-rays onto the anode target |
a. helps determine the size of the focal spot
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