Healthcare Technology and Function 25% Flashcards by Jason Davern

Name a commonly used CO2 absorber?

Soda Lime

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What parameter does not affect radiographic contrast?

The level of current used for the exposure

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Which of the following is not a factor determining spatial resolution?

-Acquisition
-Frequency (wavelength)
-Transmit intensity
-Pulse interval

Acquisition

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By selecting an algorithm, the tech selects:

A mathematical formula for processing data

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By selecting an algorithm, the tech selects:
A. The center pixel value in the window width
B. A mathematical formula for processing data
C. The average photon energy of the x-ray beam
D. The shades of gray displayed on the image

B. A mathematical formula for processing data

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Another word used to describe a volume element is:
-Voxel
-Particle
-Pixel
-Interpolated plane

-Voxel

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Which of the following is affected by the slice spacing in the CT study?
-Radiation dose to the patient
-Signal to noise ratio
-Spatial resolution
-Quantum mottle

-Radiation dose to the patient

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Decreasing kV in CT is advantageous because:

-Scan times are reduced
-Tissue contrast improves
-Metal streak artifacts are improved
-X-ray penetration improves

-Tissue contrast improves

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Which of the following numbers reported by the CT scanner best reflects the total amount of radiation delivered to the patient?

-Effective mAs
-CT Dose Index (CTDI)
-Dose-length product (DLP)
-Pitch

-Dose-length product (DLP)

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CT High-pitch techniques are useful for:

-Very small findings (e.g.
nondisplaced fracture)
-Fast scans
-Gated cardiac CT
-Accurate multiplanar
reconstructions

FAST SCANS

Higher pitch=faster scans
Lower pitch=overlapping scans, extra dose but good for moving parts.

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________ is a reconstruction process of spiral/helical CT. It uses a mathematical technique to estimate the unknown value from information on either side.

_Summation
_Convolution
_Interpolation
_Filtering

_Interpolation

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The most commonly used reconstruction technique in Cone-Beam CT is called:

-Iterative Reconstruction.
-Filtered Back Projection.
-Fourier Reconstruction.
-Algebraic Reconstruction.

-Filtered Back Projection.

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Which of the following is not commonly used as a CT scintillation detector?

-Bisumth germanium oxide
-Silver halide
-Rare earth ceramic
-Cadmium tungstate

-Silver halide
(used on film)

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When compared with conventional X-ray, CT produces diagnostic images with improved:

-PT dose
-Minute detail
-Spatial resolution
-Low contrast resolution

-Low contrast resolution

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The factors which most greatly affects x-ray quality is:

Time
kVp
mAs
Distance

kVp

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Spatial resolution is limited by ______________ .

The digital matrix
kVp
Tube current
Compton scatter

The digital matrix

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__________ resolution is a measure of the smallest object that can be resolved by a sensor.

Spatial
Spectral
Temporal
Radiometric

Spatial

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What is inverse square law?

Doubling the distance between you and a radiation source, you increase the exposure by one quarter

Doubling the distance between you and a radiation source, you cut the exposure to one quarter

Doubling the distance between you and a radiation source, you increase the exposure by one half

Doubling the distance between you and a radiation source, you cut the exposure by one half

Doubling the distance between you and a radiation source, you cut the exposure to one quarter

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Of the listed radiographic densities, in terms of what percentage of the x-rays will be absorbed by each, which is the least radiodense:

Mineral
Water
Fat
Bone

Fat
-least radiodense

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All are steps involved in the processing of the film radiograph EXCEPT:

Rinsing
Drying
Printing
Fixing

Printing

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One major advantage of real-time radiography over film is:

Higher image definition

Lower equipment costs

Images can be acquired more rapidly

Higher image contrast sensitivity

Images can be acquired more rapidly

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In comparison with lower-voltage radiographs, high voltage radiographic images have:

Less latitude

Less contrast sensitivity

Greater scatter amounts of radiation relative to primary beam intensity

Greater contrast sensitivity

Less contrast sensitivity

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Radiographic contrast describe:

The average photographic density in a radiograph

The difference in density between two different radiographs

The sharpness of lines in a radiograph

The differences in photographic density in a radiograph

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Which of the following does not affect radiographic contrast?

The wavelength of the radiation used

The amount of scattered radiation

The level of current used for the exposure

Attenuation differences in the component being inspected

The level of current used for the exposure

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Which of the following is true about grids used in radiographic imaging: 1. Use of a grid requires a decrease in exposure technique. 2. Use of a grid decreases image contrast. 3. A grid reduces scatter radiation received by the x-ray tech. 4. Use of a grid requires an increase in exposure technique.

4. Use of a grid requires an increase in exposure technique.

Which of the following materials is commonly used as the target in X-ray tubes for the production of X-rays? a) Copper b) Aluminum c) Lead d) Tungsten e) Titanium

d) Tungsten

The X-ray tube current (mA) influences which ONE of the following parameters: Mean energy (quality) of the X-rays Maximum X-ray energy Number of X-ray photons Patient penetration

Number of X-ray photons

The term photon was coined to apply to: A small wave packet or bundle of electromagnetic radiation. Any electron emitted from the photo-sensitive surface of an image intensifier tube. An accelerated electron (in the diagnostic range). The collimated X-ray beam.

A small wave packet or bundle of electromagnetic radiation.

The proportion of the energy of an electron beam incident on the X-ray tube anode that is converted into X-rays is about: 2.0%. 0.2%. 4.0%. 20%.

0.2%.

As the kV is increased, the contrast between soft and bone tissue seen in a radiographic image: Increases up to 69.5 kV but then remains constant. Decreases regardless of the choice of image receptor. Decreases up to 69.5 kV but thereafter increases due to tungsten K-radiation. Increases above 80 kVp, especially in Computed Radiography.

Decreases regardless of the choice of image receptor.

The intensity of an X-ray beam increases and the subject contrast remains unchanged by: Changing from a single phase generator to a three phase one. Increasing the kVp. Decreasing the filtration in the beam. Increasing the exposure (mAs).

Increasing the exposure (mAs).

The inverse square law relationship between radiation intensity and distance from a point source of radiation is due to: Scatter in air. Divergence of the X-ray beam. Absorption in air. Chance.

Divergence of the X-ray beam.

Increasing filtration reduces the intensity of the X-ray spectrum: Mostly at the lower photon energies Equally at all photon energies. Mostly at the higher photon energies. Only at the lower photon energies.

Mostly at the lower photon energies

The type of X-ray interaction with matter in which all of the energy of the incident photon is expended in dislodging a bound electron is called: Photoelectric effect. Pair. Compton effect. None of the above.

Photoelectric effect.

The X-ray tube current is dictated by: -The filament current. -The filament current and the kilovoltage. -The size of the focal spot. -The anode speed of rotation.

The filament current and the kilovoltage.

Electrons striking the tungsten anode of an X-ray tube with 80 keV energy can produce: -No characteristic X-rays whatsoever. -Bremsstrahlung X-rays of maximum energy 80 keV. -Characteristic X-rays of 80 keV. -Bremsstrahlung X-rays of average energy of 80 keV.

-Bremsstrahlung X-rays of maximum energy 80 keV.

A device used to accelerate charged particles used to produce the isotopes used in PET imaging A. cyclotron B. radioactive molecule C. fluorophores D. confocal imaging

A. cyclotron

Similar to MRI but is a technique that uses the magnetic properties of cell nuclei to gain information about the biochemical qualities of the brain A. MRIs (magnetic resonance imaging) B. fMRIs (functional magnetic resonance imaging) C. MRS (magnetic resonance spectroscopy) D. PET (positron emission tomography) imaging

C. MRS (magnetic resonance spectroscopy)

A device that produces images by reading radioactive substances injected into the body A. gamma camera B. confocal imaging C. digital camera D. pixel

A. gamma camera

What is the purpose of a grid in radiography? A To reduce patient exposure B To improve image contrast C To enhance spatial resolution D To increase image brightness

B To improve image contrast

Which of the following is not a component of a radiographic image receptor system? Collimator Cassette Intensifying Screen Grid

Collimator

Which type of radiation is used in nuclear medicine? X-Rays Gamma Rays Ultraviolet Rays Infrared Rays

GAMMA RAYS

What is the frequency of a pulse Doppler used for blood flow detection in an ICU?

9.1 MHz

What is the pulse Doppler used for?

To detect blood flow, to locate venous clots near the surface, and to detect blood pressures when a stethoscope cannot be used

True of false Tomo is used for vascular studies?

False, tomo is used for long bones or spines

__________ is a reduction of an image's brightness or saturation toward the periphery compared to the image center. -Drop-off -Halo -Moiré -Vignetting

-Vignetting

The indirect Flat Panel Detector uses: -Zinc cadmium sulfide -Cesium iodide (CsI) / Amorphous silicon (a-Si) -Amorphous selenium -Silicon iodide

Cesium iodide (CsI) / Amorphous silicon (a-Si)

In digital subtraction angiography (DSA), video cameras are generally used in the progressive scan mode. This implies: -Scanning the video camera target at appropriate intervals during the X-ray exposure -Scanning adjacent raster lines sequentially after termination of the X-ray exposure -Repeated scanning of the same video image to improve signal-to-noise ratio -Use of a double interlaced vidicon beam

Scanning adjacent raster lines sequentially after termination of the X-ray exposure - (sequential vs interlacing).

A charge-coupled device can be used in digital fluoroscopy: -In lieu of a conventional video camera to look at the output of the image intensifier -As a collimation device -For filtration of the x-ray beam -As a mechanism to reduce scattered radiation

In lieu of a conventional video camera to look at the output of the image intensifier

Fluorography typically: -Results in dose rates which are much less than in fluoroscopy -Refers to a continuous x-ray exposure technique -Uses dose rates 10-50 times greater than in fluoroscopy -Produces images of far inferior quality to fluoroscopy

-Uses dose rates 10-50 times greater than in fluoroscopy (uses fluoro to take images)

Pulsed fluoroscopy is generally used to: -Reduce the effective focal spot size -Increase kVp stabilization -Reduce motion blur -Reduce patient dose

-Reduce patient dose

The magnification mode of an image intensifier is switched from 15 cm to 30 cm. In order to maintain the same image brightness, the exposure at the image intensifier input phosphor must roughly: -Remain the same -Double -Quadruple -Halve

-Quadruple -(Inverse square law.) When the magnification mode of an image intensifier is increased, the exposure required by the image intensifier tube also increases. This is because the field of view decreases with increased magnification.

In an X-ray image intensifier, the overall gain in image brightness is of the order 5000:1 but the gain in brightness due to acceleration of electrons is only about 50:1. The other contribution to brightness gain is the: -Video camera -Conversion efficiency -Minification gain due to the reduction of image size -Preamplifier gain

Minification gain due to the reduction of image size (Size of II output image vs. size of input image)

Which of the following represents a general size of the output phosphor *20 – 40 cm *10 – 20 cm *2.5 – 5 cm *100 – 200 cm

-2.5 – 5 cm

Photoemission is a process of: -Visible light emission following electron stimulation -Electron emission following light stimulation -Electron emission following gas stimulation -X-ray photon emission following electron stimulation

-Electron emission following light stimulation

Which component in an image intensifier is used to minimize S-distortion? Magnetic shielding Focusing electrodes Photo cathode Output phosphor

Magnetic shielding

Which component in an image intensifier is held at the most negative electric potential? Focusing electrodes Output phosphor Photo cathode Input phosphor

Photo cathode

Larger patients require higher tube currents (more radiation, increased air kerma) in order to improve image: Dose Contrast Noise Resolution

Noise (large pts attenuate beam, less electrons at Image receptor)

A _________ cumulative timer is required on all fluoroscopic units to remind the operator audibly of each __________ time interval and to allow the technologist to keep track of the total amount of fluoro time for the exam. 30 minute 20 minute 5 minute 10 minute

5 minute

In a conventional fluoroscopic system images are created and displayed at a rate of: 525 per second 120 per second 1,024 per second 30 per second

30 per second

Visibility of detail in fluoroscopy can generally be improved by using: Low MA Low KV Low exposure rate Small FOV (field of view)

Small FOV (field of view)

While fluoroscoping, the gain of the image intensifier tube can be increased by increasing the: KV Gain control Density control Field of view (mode)

Field of view (mode) - Larger field of view increases minification gain.

The fluoroscopic field of view (mode) is increased from 6 in to 9 in. There will be an increase in: The patient entrance exposure The gain of the image intensifier tube The number of video scan lines The visibility of anatomical detail

The gain of the image intensifier tube

Skin radiation burns are best measured with what metric? Tube voltage (kV) Tube current (mA) Dose-area product (DAP) Tube air kerma (Ka)

Tube air kerma (Ka) -Dose time the area is exposed

A 22 cm multi-mode image intensifier is switched to the 11 cm mode. As a result, the image will be _________ and the automatic brightness control system will _________ the exposure to the image intensifier and the patient. magnified; increase minified; increase magnified; decrease minified; decrease

magnified; increase

Photoemission is a process of: Visible light emission following electron stimulation electron emission following light stimulation electron emission following gas stimulation X-ray photon emission following electron stimulation

electron emission following light stimulation -Photoelectric effect: Light Photons incident on material surface causes emission of electrons.

Which of the following represents a general size of the Image Intensifier output phosphor? 20 – 40 cm 10 – 20 cm 2.5 – 5 cm 100 – 200 cm

2.5 – 5 cm

In an X-ray image intensifier, the overall gain in image brightness is of the order 5000:1 but the gain in brightness due to acceleration of electrons is only about 50:1. The other contribution to brightness gain is the: Video camera Conversion efficiency Minification gain due to the reduction of image size Preamplifier gain

Minification gain due to the reduction of image size

Quadruple -(Inverse square law.)

Fluorography typically: Results in dose rates which are much less than in fluoroscopy Refers to a continuous x-ray exposure technique Uses dose rates 10-50 times greater than in fluoroscopy Produces images of far inferior quality to fluoroscopy

Uses dose rates 10-50 times greater than in fluoroscopy (uses fluoro to take still images)

A charge-coupled device can be used in digital fluoroscopy: In lieu of a conventional video camera to look at the output of the image intensifier As a collimation device For filtration of the x-ray beam As a mechanism to reduce scattered radiation

In lieu of a conventional video camera to look at the output of the image intensifier

Scanning adjacent raster lines sequentially after termination of the X-ray exposure - (technique used for camera: coupled sequential vs interlacing).

_________ is a reduction of an image's brightness or saturation toward the periphery compared to the image center. Drop-off Halo Moiré Vignetting

Vignetting

The indirect Flat Panel Detector uses: Zinc cadmium sulfide Cesium iodide (CsI) / Amorphous silicon (a-Si) Amorphous selenium Silicon iodide

Cesium iodide (CsI) / Amorphous silicon (a-Si)

Pulsed fluoroscopy is generally used to: reduce the effective focal spot size increase kVp stabilization reduce motion blur reduce patient dose

reduce patient dose

In spin echo sequence TE and TR refer to which of the following, respectively a. Echo Time, Repetition Time b. Echo Time, Rephasing Time c. Elapsed Time, Repetition Time d. Elapsed Time, rephrasing Time

a. Echo Time, Repetition Time

Computerized Axial Tomography is used to a. Section tissue along the axis of the nucli b. Determine movement of the electrical axis of structure c. Create a picture of tissues in a selected plane of the body d. Create a picture of a wedge of tissues

c. Create a picture of tissues in a selected plane of the body

Grid Ratio is?

relation of the height of the lead strips to the distance between them

The main clinical role of ultrasound for mammographic procedures is to ? a. Differentiate cysts from solid masses b. Reduce patient discomfort from compression c. Replace routine mammogram screening for asymptomatic patients d. Increase the need for surgical biopsy on suspicious screen film outcomes

a. Differentiate cysts from solid masses

Which of the following results from a partial transfer of energy from an X-Ray photon to an orbital electron? a. Compton effect b. Roentgen effect c. Thornpson effect d. Photoelectric effect

a. Compton effect

Primary purpose of an image intensifier? a. Minification b. Purification c. amplification d. Magnification

c. amplification

An ultrasound piezoelectric transducer converts electrical energy into what type of energy? a. Radiant b. Reflection c. Refraction d. Mechanical

d. Mechanical

Which of the following is used to assess a radiopharmaceutical just prior to administration to a patient? a. Spectrophotometer b. Gamma counter c. Dose calibrator d. Pharmaceutical scale

c. Dose calibrator Used specifically for measuring the activity of radiopharmaceuticals.

What is the typical input dose to a 9” image intensifier in photospot mode? a. 100 uR per frame b. 5,000 uR per frame c. 5 R/minute d. 10 R/minute

Best Answer: a. 100 uR per frame b=too high c/d=fluoro dose

The purpose of a grid on an x-ray bucky is to: a. Stop scatter radiation from going to the film or detector b. Focus the x-ray beam c. Magnify the x-ray beam d. Add lines to the film for measurement purposes

a. Stop scatter radiation from going to the film or detector

Ultrasound Energy for imaging is produced by; a. Piezoelectric Crystal b. Charging Amp c. Feedback oscillator d. Doppler effect

a. Piezoelectric Crystal

Ultrasound is best described as: a. Radiation b. Flow of Sonic Particles c. Electromagnetic Waves d. Acoustic Compressions

d. Acoustic Compressions

Which technique is commonly used to measure the amount of radiation emitted by radionuclides? a) Gamma spectrometry b) X-ray diffraction c) Mass spectrometry d) Infrared spectroscopy

a) Gamma spectrometry

What particle does a SPECT camera detect for diagnosis? A) gamma particles B) beta particles C) x-ray photons D) alpha particles

A) gamma particles

Which is false of single-photon emission computed tomographic (SPECT)? a. can be used to help diagnose bone disorders b. allows provider to see how organs are working c. the scan needs a tracer to be injected d. the patient will be exposed to no radiation from the tracer

d. the patient will be exposed to no radiation from the tracer

Which of the following is the first object that an emitted gamma photon encounters after exiting the body? -Collimator -Photo multiplier tubes -Position logic circuit -Detector crystal

-Collimator

Which of the following is known as a scintillation counter? -Scintillator by itself -Scintillator along with the crystal -Scintillator along with a photo multiplier tube -Scintillator along with position circuitry

-Scintillator along with a photo multiplier tube

Which of the following nuclear medicine instruments forms images resulting from the annihilation of pairs of matter and antimatter particles? -Scintigraphy scanner -Positron emission tomography (PET) scanner -Single-photon emission computed tomography (SPECT) scanner -Multigated acquisition (MUGA) scanner

Positron emission tomography (PET) scanner

Gamma camera uses which of these components to produce a position intensity picture of a radioactive area? -Photo multiplier tubes -Position circuitry -Scintillation detector -Collimator

-Scintillation detector

Beta decay can be in the form of an electron or a: Antiproton Positron Proton Neutron

Positron

Which of these particles are highly penetrating? Alpha particles Gamma particles Beta particles X-ray particles

Gamma particles

Which of the following are highly effective in producing ion pairs when they pass through the matter? X-ray particles Alpha particles Beta particles Gamma particles

Alpha particles

A __________ is a chemical compound in which one or more atoms have been replaced by a radionuclide, so by virtue of its radioactive decay it can be used to explore the mechanism of chemical reactions by tracing the path that the radioisotope follows from reactants to products. Isotope Radio-signal Radiotracer Positron

Radiotracer

The radioactive substances used in nuclear medicine are broadly called: Scintipharmaceuticals Scintigrams Radioscintigrams Radiopharmaceuticals

Radiopharmaceuticals

The first gamma camera is also known by which of the following names? Anger camera Hal camera West cameran Muller camera

Anger camera

An appropriate kV range for mammography would be: 7kV to 15kV 50kV to 75kV 24kV to 32kV 35kV to 50kV

24kV to 32kV

The photon energy spectrum of the x-ray beam is one of the most critical factors in optimizing a procedure with respect to contrast sensitivity and radiation dose. The spectrum depends on the combination of the following factors EXCEPT: The anode material The kV The exposure time The selected filter

The exposure time

Mammography requires the use an x-ray beam that has a spectrum that produces an optimum balance between the requirements for __________ contrast sensitivity and __________ radiation dose. low, high low, low high, high high, low

high, low HIGH contrast sensitivity and LOW radiation dose.

If the x-ray spectrum for mammography is decreased below the optimum energy there will be a (an) __________ in the dose because of the __________ penetration through the breast. decrease, increased decrease, decreased increase, decreased increase, increased

increase, decreased INCREASE in the dose because of the DECREASED penetration through the breast.

When a(an) __________ filter is used with a molybdenum target, it attenuates and blocks much of the bremsstrahlung spectrum above the energy of 20 keV. This results in the spectrum that is most often used in mammography. rhodium aluminum copper molybdenum

molybdenum Mo/Mo combination is most common filter/target combination used in Mammography.

With the __________ filter, the spectrum is shifted to a higher energy (23.22 keV) so that the portion of the bremsstrahlung between 20 keV and 23.22 keV is added to the x-ray beam. This makes the beam more penetrating than when using the other filter and provides some advantage when imaging larger or more dense breast tissue. aluminum copper rhodium molybdenum

rhodium -Filter used for dense breasts, emits higher energy X-ray for better penetration.

Iodine is an effective contrast agent because: -It has a high mass density -It has a high likelihood of photoelectric interaction at diagnostic x-ray energies -It has a high electron density -It has a high likelihood of Compton interaction at diagnostic x-ray energies

It has a high likelihood of photoelectric interaction at diagnostic x-ray energies

Molybdenum was traditionally used as an x-ray anode in mammography because of its: -Intrinsic filtration -Good heat capacity -Characteristic x-rays -Efficient Bremsstrahlung radiation

Characteristic x-rays

magnified; increase

Skin radiation burns are best measured with what metric? Tube voltage (kV) Tube current (mA) Dose-area product (DAP) Dose time the area is exposed Tube air kerma (Ka)

Tube air kerma (Ka)

The fluoroscopic field of view (mode) is increased from 6 in to 9 in. There will be an increase in: -The patient entrance exposure -The gain of the image intensifier tube -The number of video scan lines -The visibility of anatomical detail

-The gain of the image intensifier tube

While fluoroscoping, the gain of the image intensifier tube can be increased by increasing the: KV Gain control Density control Field of view

Field of view (mode) - Larger field of view increases minification gain.

Visibility of detail in fluoroscopy can generally be improved by using: Low MA Low KV Low exposure rate Small FOV (field of view)

Small FOV (field of view)

In a conventional fluoroscopic system images are created and displayed at a rate of: 525 per second 120 per second 1,024 per second 30 per second

30 per second

5 minute

Larger patients require higher tube currents (more radiation, increased air kerma) in order to improve image: Dose Contrast Noise Resolution

Noise (large pts attenuate beam, less electrons at Image receptor)

Which component in an image intensifier is held at the most negative electric potential? Focusing electrodes Output phosphor Photo cathode Input phosphor

Photo cathode

Which component in an image intensifier is used to minimize S-distortion? Magnetic shielding Focusing electrodes Photo cathode Output phosphor

Magnetic shielding

Ultrasound energy, simply known as ultrasound, is a type of __________ energy. Chemical Light Mechanical Electromagnetic

Mechanical

An ultrasound beam is attenuated: By scattering By absorption in tissues By reflection at a tissue interface All are true

All are true

The Doppler effect is a change in echo ______. Frequency Direction Strength Amplitude

Frequency

The propagation speed of sound through soft tissue is: 1650 m/s 1230 m/s 1450 m/s 1540 m/s

1540 m/s *most likely on CRES

Attenuation increases as frequency ______. Increases Decreases

Increases

Attenuation increases as distance _____. Decreases Increases

Increases

The following are all ultrasound frequencies except: 250 KHz 30,000 Hz 15 KHz 0.3 MHz

15 KHz

Which of the following types of tissue would have the lowest mean propagation velocity. Fat Blood Water Air

Air

A piezoelectric crystal may be made of: aluminum calcium tungstate quartz lithium fluoride

quartz

By definition, ultrasound is sound having a frequency greater than __________ cycles per second, that is, sound above the audible range. 40,000 20,000 30,000 10,000

20,000 cycles 20Khz

The basic unit used to describe the energy of a radiation particle is the __________ . Sievert (Sv) Electron volt (eV) Curie (Ci) Becquerel (Bq)

Electron volt (eV)

__________ places an X-ray source and an x-ray detector array between the gamma camera heads. SPECT Bone Scan Hybrid SPECT/CT PET scan

Hybrid SPECT/CT

Which of the following variables does not affect spatial resolution in nuclear medicine imaging systems? Energy of the gamma rays being counted Byte vs. word acquisition mode Computer matrix pixel size Material of which the collimator is constructed

Byte vs. word acquisition mode

Scintillation detector is a large flat crystal of which of the following materials? Sodium carbonate Sodium iodide Sodium chloride Sodium sulphate

Sodium iodide

__________ collimator is used for thyroid work in the medical field. Fanbeam Straight bore Pinhole Low Energy All-Purpose (LEAP)

Pinhole

__________ imaging measures the gamma events created by the collision between an electron and a positron. PET Hybrid SPECT/CT Gamma camera SPECT

PET

Which of the following components adds all the signals and determines where each scintillation event occurred in the detector? Photo multiplier tubes Position circuitry Collimator Detector crystal

Position circuitry

When the energy of an absorbed gamma photon is released, a flash of light is produced. This is similar to which of the following effects? Compton effect Photoelectric effect Collision effect Pair production

Photoelectric effect

Which of the following is a pattern of holes through gamma ray absorbing material, usually lead or tungsten? Collimator Photo multiplier tubes Position circuitry Detector crystal

Collimator

The axial resolution of a US transducer is primarily determined by: The transducer diameter Spatial pulse length Density The acoustic impedance of tissue

Spatial pulse length

US Lateral resolution can be improved by: Damping Pulsing Reflecting Focusing

Focusing

Which of the following is not a factor determining US spatial resolution? Transmit intensity Pulse interval Frequency (wavelength) Acquisition

Acquisition

______ is defined by the number of elements used (effective transducer width). Aperture Transducer Linear Propagation

Aperture

US Axial resolution can be improved by: Focusing Increasing operating frequency Pulsing Damping

Increasing operating frequency

The lateral resolution of a transducer is primarily determined by: Applied voltage The beam width Spatial pulse length The acoustic impedance of tissue

The beam width

In an ultrasound transducer, the __________ stops vibrations reverberating back into the piezoelectric material, and determines the length of the ultrasound pulse by determining how much it is damped. Acoustic insulator: stops the transducer vibrating in hand. Matching layer Backing material Exterior plastic casing

Backing material

The main mode used in diagnostic ultrasound is: A-mode Doppler B-mode M-mode

B-mode

The most common design configuration for clinical MR scanners is: Open bore superconducting Dipolar electromagnet Open bore permanent Closed bore superconducting

Closed bore superconducting

The highest field strength permitted for adults in routine clinical practice by the United States Food and Drug Administration (FDA) is: 8.0 Tesla 3.0 Tesla 11.7 Tesla 7.0 Tesla

8.0 Tesla

The direction of the main magnetic field (Bo) in a cylindrical closed bore scanner is: -Can be at any angle depending on which gradients are turned on -Vertical (cross-wise to the cylinder and perpendicular to the floor) -Longitudinal (along the main axis) of the cylinder -Horizontal (cross-wise to the cylinder and parallel to the floor)

Longitudinal (along the main axis) of the cylinder

Which of the following is not an advantage of high-field (≥ 1.0 T) MR scanners? -Better detection of calcifications and hemorrhage -Smaller artifacts around metallic implants -Better magnetic field homogeneity -Higher signal-to-noise

-Smaller artifacts around metallic implants

Which scanner would have the largest fringe field? 0.6 T Resistive magnet system 3.0 T Superconductive system 1.5 T Superconductive system 0.35 T Permanent magnet system

3.0 T Superconductive system

The cryostat of a typical superconducting MR scanner contains all of the following except: -Main magnet windings -Liquid nitrogen -Superconducting shim coils -Liquid helium

Liquid nitrogen

The temperature of liquid helium is approximately: a) 0 °K b) −4 °K c) 4 °K d) −400 °C

c) 4 °Kelvin 4.2Kelvin more precise or -296 degrees Celsius or -452 Fahrenheit

How many sets of paired physical gradients are present in an MR scanner? 6 1 2 3

Passive magnetic shielding of the scanner room is typically achieved using sheets or rods made of: Iron Aluminum Copper Lead

Iron

Which of the following statements about the gradient subsystem is true? -The gradient coils are cooled by liquid helium. -The gradient coils are located within the cryostat. -Increasing power supplied to a gradient decreases the slope of the gradient. -Gradient coils generate considerable heat during operation.

-Gradient coils generate considerable heat during operation.

The most common metal used for RF shielding is: Nickel Lead Aluminum Copper

Copper

Where is the master computer located that controls the MR scanner and processes data into images? At least 25 meters distant from the main scanner to avoid interference In the MR scanner control room In the MR scanner room In the nearby MR equipment room

In the MR scanner control room

In the construction of a superconducting MR magnet, which is the correct order of coils from outermost to innermost? -RF coils, shield coils, main magnet windings, gradient coils -Gradient coils, shield coils, main magnet windings, RF coils -Main magnet windings, gradient coils, RF coils, shielding coils -Shielding coils, main magnet windings, gradient coils, RF coils

-Shielding coils, main magnet windings, gradient coils, RF coils

The time for a gradient to ramp from zero to its maximum value is known as its: -Rise time -Duty cycle -Gradient time -Slew rate

-Rise time

Whereas most x-ray tubes use tungsten as the anode material, mammography equipment uses __________ anodes. aluminum copper molybdenum rhodium

-molybdenum

In order to distinguish cancer from glandular tissue, mammography relies on: -Low x-ray energies to increase photoelectric effect -High tube currents (mA) -Low x-ray energies to increase Compton scattering -Intravenous contrast agents -High x-ray energies to increase photoelectric effect

-Low x-ray energies to increase photoelectric effect

Tissue contrast is generated by what type of interaction? -Beam hardening effect -Overall attenuation -Incoherent (Compton) scatter -Photoelectric effect -Coherent (Rayleigh) scatter

-Photoelectric effect

The typical x-ray tube for mammography has two selectable focal spots. The spots are generally __________ than for other x-ray procedures because of the requirements for minimal blurring and good visibility of detail to see the small calcifications. -larger -deeper -smaller -wider

-smaller

Whereas most x-ray tubes use tungsten as the anode material, mammography equipment uses __________ anodes. -aluminum -copper -molybdenum -rhodium

-molybdenum

The process of destroying cancer cells with the help of radiation is known as: uroplasty physiotherapy rehabilitation radiotherapy

radiotherapy

Which of the following pair of scattering is important for therapeutic purposes? Coherent and Pair Production Compton and Photoelectric Photoelectric and Disintegration Pair Production and Disintegration

Pair Production and Disintegration

The direction of the main magnetic field (Bo) in a cylindrical closed bore scanner is: -Longitudinal (along the main axis) of the cylinder -Vertical (cross-wise to the cylinder and perpendicular to the floor) -Horizontal (cross-wise to the cylinder and parallel to the floor) -Can be at any angle depending on which gradients are turned on

-Longitudinal (along the main axis) of the cylinder

The temperature of liquid helium is approximately: −4 °K −400 °C 4 °K 0 °K

4 °K

Magnetic field gradients for imaging are typically measured in units of: Gauss per second (G/s) Tesla (T) Tesla per meter per second (T/m-s) Millitesla per meter (mT/m)

Millitesla per meter (mT/m)

High-pitch techniques are useful for: Fast scans Very small findings (e.g. nondisplaced fracture) Gated cardiac CT Accurate multiplanar reconstructions

Fast scans

In helical CT, pitch is defined as: Patient dose in 360 degrees / beam width Reconstructed slice thickness / beam width Table movement in 360 degrees / beam width Gantry angle with respect to the scan axis

Table movement in 360 degrees / beam width

In helical CT, a single transverse slice represents: A plane through the body perpendicular to the scan axis A plane through the body oblique to the scan axis A reconstruction made from projections averaging the entire scan A reconstruction made from projections at neighboring scan axis positions

A reconstruction made from projections at neighboring scan axis positions

The 'filter' in filtered backprojection refers to: -Altering the projection data before performing the back-projections -Conversion between fan-beam and parallel geometry -Conversion between attenuation and Hounsfield units -Bowtie filter between the beam and patient

-Altering the projection data before performing the back-projections

The CT number (Hounsfield unit) of fat depends on:? mAs Reconstruction algorithm kV Nothing - it is constant

The time for a gradient to ramp from zero to its maximum value is known as its? Duty cycle Gradient time Rise time Slew rate

Rise time

18.Which of the following statements about the gradient subsystem is true? -The gradient coils are located within the cryostat. -Increasing power supplied to a gradient decreases the slope of the gradient. -The gradient coils are cooled by liquid helium. -Gradient coils generate considerable heat during operation.

-Gradient coils generate considerable heat during operation.

Which component of a superconducting MR scanner does not require specialized cooling to maintain function? Gradient amplifiers Gradient coils Main coil windings Radiofrequency coils

Radiofrequency coils

In the construction of a superconducting MR magnet, which is the correct order of coils from outermost to innermost? Gradient coils, shield coils, main magnet windings, RF coils Main magnet windings, gradient coils, RF coils, shielding coils Shielding coils, main magnet windings, gradient coils, RF coils RF coils, shield coils, main magnet windings, gradient coils

Shielding coils, main magnet windings, gradient coils, RF coils

The basic coil configuration used to generate the z-gradient in a cylindrical MR scanner is known as? Fingerprint Golay Maxwell pair Double saddle

Maxwell pair

Magnetic field gradients for imaging are typically measured in units of: Tesla per meter per second (T/m-s) Millitesla per meter (mT/m): Gauss per second (G/s) Tesla (T)

Millitesla per meter (mT/m):

Healthcare Technology and Function 25% Flashcards

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