Tungsten is used as the target material on the tube's anode because it has a _____ atomic number and a _______ melting point.
________ scanner design was the first to acquire four slices in a single rotation.
The enormous heat that builds up in the tube is caused by the:
The number of electron that flow from the cathode to the anode in the tube is controlled by the:
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
Which of the following is NOT a part of the CT tube?
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
Which system component coverts the projection attenuation data into the proper digital form for the array processor?
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
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
CT is commonly referred to as all of the following names EXCEPT:
What control does the operator have over the x-rays in a CT exam?
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 nubmer of x-ray photons emitted from the tube
3. althought the kV and the mA affect the operaton of the CT x-ray tube, the two parameters have no bearing on the image quality
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 throught 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
_____ made helical imaging possible.
Which of the following statements is FALSE regarding the collection of CT data?
Which of the following is a component NOT normally located in the gantry of a modern CT system?
X-rays are used in CT because:
X-rays are produced whenever fast-moving electron 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
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 necleus of the target atom
The mA determines the:
Increased _____ will increase the likelihood that a given x-ray will penetrate a material.
3. exposure time
Scatter radiaton is caused by:
Which technology do multi-row detector scanners employ?
Which of the following is NOT a function of a PACS system?
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
Which of the following is 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
Most of the commands from the technologist are received by the:
The operator's console may include:
3. graphic input device
Which of the following CT scanner designs does NOT use an x-ray tube?
Tube interscan delay time refers to:
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
The main purpose of the detector is to:
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
The patient table:
Which of the following statements is FALSE regarding occurrences 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
CT images can be directly scanned in planes other then transverse by:
1. orienting the patient's body part so that is is not perpendicular to the x-ray beam
2. tilting the gantry
3. changing the angle that the x-ray beam leaves the tube
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