Rad160 Exam 3

Front 1

Determine the total brightness gain for an image intensification unit if the flux gain is 50 and the minification gain is 121.

a. 2.42

b. 171

c. 6050

d. 17500

Back 1

c. 6050

Front 2

A phosphor commonly used as the input phosphor in the image intensifier is:

a. Calcium tungstate

b. Cesium iodide

c. Lithium flouride

d. Antimony trisulfide

Back 2

c. Cesium Iodide

Front 3

A fluoroscopy units output must be less then:

a. 2.5 mR/second

b. 100 mR/hour

c. 5 R/year

d. 10 r/minute

Back 3

d. 10 r/minute

Front 4

The output phosphor in the image intensifier is made of:

a. Zinc cadmium sulfide

b. Cesium iodide

c. Calcium tungstate

d. Lithium fluoride

Back 4

a. Zinc cadmium sulfide

Front 5

The fluoroscope was invented by:

a. Thomas Edison

b. Wilhelm Roentgen

c. Bell Labs

d. General Electric

Back 5

a. Edison

Front 6

For mobile fluoroscopy equipment, the source to skin distance must not be less then:

a. 40"

b. 24"

c. 15"

d. 12"

Back 6

d. 12"

Front 7

The phosphor and photocathode layers, which convert the x-rays into electron image intensifiers tube, are located on the _____________ of the image intensifying tube.

a. Positive side (anode)

b. Neg side (cathode)

c. Vignette

d. Electrostatic (edges)

Back 7

b. Negative side (cathode)

Front 8

The output phosphor of the image intensifier converts:

a. X-rays into light

b. Electrons into x-rays

c. Electrons into light

d. Light into electrons

Back 8

c. Electrons into light

Front 9

Changing the focal point of an image intensifier will cause a change in:

a. Quantum noise

b. Magnification

c. Flicker

d. Automatic brightness

Back 9

b. Magnification

Front 10

An X-ray tube that operates at 2-3 mA is probably located:

a. Radiation therapy

b. In a dedicated mammography unit

c. Under the x-ray table

d. In the chest unit

Back 10

c. under the x-ray table (fluoro)

Front 11

The device that changes technical factors during a fluoroscopic exam to maintain brightness is called the:

a. AEC

b. Vidicon

c. CCD

d. ABC (ABS)

Back 11

d. ABC (ABS)

Front 12

The undesirable decrease in brightness at the periphery of a fluoroscopic image is called:

a. Size distortion

b. Vignette

c. Concavity

d. Arcing

Back 12

b. Vignetting

Front 13

Calculate the minification gain if an image intensifier has the following dimensions: Input phosphor = 22 cm diameter, and output phosphor = 9 cm diameter.

a. 5.98

b. 167

c. 2.44

d. 0.41

Back 13

a. 5.98

Front 14

The primary purpose of image intensification is to:

a. Lower patient dose by eleiminating quantum mottle

b. Magnify the image by changing the focal point

c. Brighten the image and eliminate the need for scotopic vision

d. Attenuate all of the remnant radiation

Back 14

c. Brighten the image and eliminate the need for scotopic vision

Front 15

Image contrast is often decreased in fluoroscopy due to:

a. Increased SSD

b. Increased OID

c. Increased scatter radiation

d. Increased SID

Back 15

c. Increased scatter

Front 16

The kVp range used for mamm is:

a. 35-38

b. 45-48

c. 25-28

d. 55-58

Back 16

c. 25-28

Front 17

In the order to obtain the greatest sharpness of detail, routine mammography uses focal spot sizes as small as:

a. 11mm

b. 5mm

c. 0.1mm

d. 3mm

Back 17

c. 0.1mm

Front 18

What type of mammography study is done when a patient has a clear pathology?

a. Routine

b. Diagnostic

c. Alternative

d. Contrast

Back 18

b. Diagnostic

Front 19

Compression in mammography is used to:

a. Equalize breast tissue thickness and reduce dose

b. Palpate and magnify breast tissue masses

c. Replace the use of a grid with a smaller breasts

Back 19

a. Equalize breast tissue thickness and reduce dose

Front 20

Which of the following materials is used in the construction of the anode in a mammography x-ray tube?

a. Tungsten

b. Beryllium

c. Molybdenum

d. Aluminum

Back 20

c. Molybdenum

Front 21

To perform magnification views of the breast:

a. OID is increased

b. SID in increased

c. OID is decreased

d. SID is decreased

Back 21

a. OID is increased

Front 22

The function of amorphous selenium in a flat panel detector for mammography is the same as general radiography DR. Its job is to:

a. Detect x-ray photons and convert them into electrons

b. Convert x-rays into light

c. Convert light into electrons

d. trap electrons for readout

Back 22

a. Detect x-ray photons and convert them into electrons

Front 23

The mammography AEC detector is placed __________ in order to _____________.

a. Above the breast; reduce the breast dose

b. After the breast; register correct dose to AEC chamber

c. After the IR; avoid imaging the AEC chambers

d. Inside the IR; terminate the exposure

Back 23

c. After the IR; avoid imaging the AEC chambers

Front 24

MQSA requires mammography to have _______ lp/mm of resolution.

a. 11-13

b. 5-6

c. 20-25

d. 30-35

Back 24

a. 11-13

Front 25

The regulations for the performance of mammography were passed in 1994 as part of:

a. HIPPA
b. ACR

c. DICOM
d. MQSA

Back 25

d. MQSA

Front 26

In mammography, to take advantage of the heel effect:

a. the cathode should be away from the patient

b. the anode should be over the chest wall

c. the cathode should be over the chest wall

d. The tube can be positioned in any manner

Back 26

c. The cathode should be over the chest wall

Front 27

To enhance the resolution of an image obtained using breast magnification:

a. A small 0.1 focal spot size is used

b. OID should be increased

c. The grid should be eliminated

d. A rhodium filter should be used

Back 27

a. A small 0.1 focal spot size is used

Front 28

The first digital mammography units in the US were approved for sale in:

a. 1929

b. 1957

c. 1980

d. 2000

Back 28

d. 2000

Front 29

Lower energy x-ray photons are used in mammography to:

a. produce scatter photons in the glandular region of the breast

b. promote absorbtion of photons and increase image contrast

c. over penetrate masses in the breast

d. ensure that 85% of the beam penetrates the breast tissue

Back 29

b. promote absorbtion of photons and increase image contrast

Front 30

Magnification views of the breast are used:

a. To image the entire breast

b. As part of screening mammograms

c. To visualize suspicious breast tissue

d. When dense breast are imaged

Back 30

c. To visualize suspicious breast tissue

Front 31

The type of CT scanner that allows continuous motion of the xray tube and table through the bore of the gantry is:

a. Translate rotate

b. First generation

c. Spiral/helical

d. Third generation

Back 31

c. spiral/helical

Front 32

The ability to image tissues with similar attenuation properties is a property of which image quality?

a. Contrast resolution

b. Spatial resolution

c. Image brightness

d. Noise

Back 32

a. Contrast resolution

Front 33

The mathematical formulas used by a computer system to interpret and display digital images are called:

a. Voxels

b. Interpolations

c. Translations

d. Algorithms

Back 33

d. Algorithms

Front 34

Modern helical CT scanners use what type of detectors?

a. Scintillation detectors

b. Solid-state detectors

c. Gas filled ionization chambers

d. PM chambers

Back 34

b. Solid-state detectors

Front 35

The ratio of tube movement to section thickness is termed:

a. Translation

b. Indexing

c. Pitch

d. Convolution

Back 35

c. Pitch

Front 36

A scout image that is used to plan the CT study is called:

a. Scanogram

b. Voxel

c. FOV

d. Interpolated image

Back 36

a. Scanogram

Front 37

A structure in a CT image has a CT number (Hounsfield unit) of +1000. Based on that information, the structure must be:

a. muscle

b. air

c. water

d. bone

Back 37

d. bone

Front 38

Which of the following components is responsible for determining slice thickness and improving image contrast during a CT scan?

a. Collimator

b. kVp selection

c. PM tube

d. Gantry angle

Back 38

a. Collimator

Front 39

Seventh-generation CT scanners are able to produce CT images in significantly shorter times primarily due to:

a. Rapidly moving support tables

b. Ability to expose thousands of detectors simultaneously

c. Power injector sync

d. Translate-rotate tech

Back 39

b. Ability to expose thousands of detectors simultaneously

Front 40

Which type of artifact results from data in an entire section thickness being averaged together?

a. Beam hardening

b. Ring artifact

c. Partial volume effect

d. Star artifact

Back 40

c. partial volume effect

Front 41

The average CT dose per CT examination has traditionally been about:

a. 3-5 rad

b. 1-2 rad

c. 20-30 rad

d. 40-50 rad

Back 41

a. 3-5 rad

Front 42

Slip ring technology made what generation of CT scanners possible?

a. First

b. Second/Third

c. Fourth/fifth

d. Sixth/seventh

Back 42

d. Sixth/seventh

Front 43

Modern spiral CT scanners gather information in a corkscrew manner. The image is straightened using:

a. Partial volume averaging

b. Deconvolution

c. Helical interpolation

d. Linearity averaging

Back 43

c. Helical interpolation

Front 44

The CT numbers for water is:

a. -1000

b. 0

c. +1000

d. +5 to 35

Back 44

b. 0

Front 45

The positioning of the CT table is refered to as:

a. Table linearity

b. Table interpolation

c. Scanogram

d. Indexing

Back 45

d. indexing

Front 46

The first step in MRI image acquisition is:

a. Aligning hydrogen protons with an external magnetic field

b. Sending out an RF signal

c. Allowing hydrogen protons to fall out of alignment

d. Detecting external RF signals

Back 46

a. Aligning hydrogen protons with an external magnetic field

Front 47

The function of the dewar in a MRI superconducting magnet is to:

a. Provide an external magnetic field

b. Screen out external RF waves

c. Serve as a vessel for cryogenic agents

d. Limit the magnetic fringe field

Back 47

c. Serve as a vessel for cryogenic agents

Front 48

The lamor frequency of hydrogen is:

a. 32.6 mhz

b. 26.6 mhz

c. 85.2 mhz

d. 42.6 mhz

Back 48

d. 42.6

Front 49

If the RF excitation pulse is not matched to the ______ it will not affect the hydrogen protons.

a. Larmor frequency

b. Presession index

c. Proton density

d. Neutron frequency

Back 49

a. Larmor Frequency

Front 50

The determining factor of MR signal strength is:

a. Larmour frequency

b. Proton density

c. Precession frequency

d. RF-Signal pulse

Back 50

d. RF-Signal pulse

Front 51

The time it takes a proton to precess into alignment refers to:

a. spin lattice time

b. larmor freq

c. T1 relaxation time

d. T2 relaxation time

Back 51

c. T1 relaxation time

Front 52

The paramagnetic contrast agent used in MRI is:

a. Gadolinium

b. Barium sulfate

c. Iodine

d. Gastrografin

Back 52

a. Gadolinium

Front 53

The magnetic field extending outside the bore is called the:

a. Resonance field

b. Faraday field

c. Fringe field

d. RF field

Back 53

c. Fringe field

Front 54

Superconducting MRI units are electrically efficient as a result of:

a. Smaller magnets

b. Cryogens cooling them

c. High freq modern circuits

d. Computer tech/algorithms

Back 54

b. cryogens

Front 55

MRI slice orientation is determined by:

a. Gradient coils

b. Shim coils

c. Dewars

d. Magnet thickness

Back 55

A. Gradient coils

Front 56

__________________ is used to send the RF excitation pulse into the patient, and to detect the RF signal from precessing protons.

a. Shim coils

b. Surface coils

c. Gradient coils

d. Dewars

Back 56

c. Gradient coils

Front 57

External RF signals are prevented from entering the MRI room by a:

a. Surface coil

b. Shim coil

c. Magnetic cage

d. Faraday cage

Back 57

d. Faraday cage

Front 58

Which of the following factors will provide the greatest spatial resolution in MRI?

a. High signal-to-noise ratio

b. Low proton density

c. Short scan times

d. Shorter T1 relaxation times

Back 58

a. High signal-to-noise ratio

Front 59

Which will help to provide the strongest RF signal in MRI?

a. weaker magnetic field

b. Lower proton density

c. Wrong larmor freq

d. High tesla magnet

Back 59

d. high tesla magnet

Front 60

Why is a thorough patient history so important in MRI imaging?

a. To know about metal in the patients body

b. To know about patients fear

c. To explain the study

d. To ask the patient if they have a lot of protons in ther body

Back 60

a. To know about metal in the patients body