Radiation Protection - Exam 3

Front 1

Digital imaging could only be developed after advances were made in:

a) microprocessors

b) semiconductor memory

c) photostimulable phosphors

d) Both A & C

Back 1

D

Front 2

Computed radiography developed in the 1970s with the use of _______ as the image receptor:

a) phosphor

b) selenium

c) silicon

d) film

Back 2

A

Front 3

The primary limitation of fanned beam radiography is::

a) reduced spatial resolution

b) long scanning time

c) low contrast resolution

d) shortened dynamic range

Back 3

D

Front 4

If a response to radiation is expected no matter how small the dose, then that dose-response is:

a) linear

b) nonlinear

c) nonthreshold

d) threshold

Back 4

C

Front 5

Production of a grainy, reticulated image that cannot be corrected in digital post-processing is the result of:

a) failure to use a high enough mAs setting

b) failure to use a high enough kVp setting

c) failure to use the correct algorithm

d) failure to use the proper SID

Back 5

A

Quantum mottle

Front 6

What is the most recent development in digital radiography image receptors:

a) fanned x-ray beams

b) linear array radiation detectors

c) photostimulable phosphors

d) direct capture solid-state devices

Back 6

D

Front 7

During CR imaging plate processing, the laser frees trapped electrons, allowing them to return to a lower energy state. This process is known as:

a) photostimulated luminescence

b) thermal emission

c) green light phophorescence

d) none of the above

Back 7

A

Front 8

The CR imaging plate is scanned by a(n):

a) helium-neon laser beam

b) ultraviolet light beam

c) infrared heat source

d) all of the above

Back 8

A

Front 9

People who had radiation treatments to their thymus gland as children, later showed excess risk for:

a) bone cancers

b) skin cancers

c) leukemia

d) thyroid cancers

Back 9

D

Front 10

The response of the imaging plate to ionizing radiation is:

a) the characteristic curve similar to the one for film

b) the D log E curve

c) the H and D curves

d) linear

Back 10

D

Front 11

Digital radiography replaces:

a) the reusable detector

b) grids

c) traditional film

d) all of the above

Back 11

C

Front 12

The most radiosensitive cells in the hemopoietic system of the human body are the:

a) granulocytes

b) erythrocytes

c) lymphocytes

d) platelets

Back 12

C

Front 13

The latent image is created by energy transfer during:

a) pair-production

b) coherent scattering

c) photodisintegration

d) photoelectric interactions

Back 13

D

Front 14

Studies of A-bomb indicate that leukkemia has a _______ dose-response relationship:

a) nonlinear, threshold

b) linear, threshold

c) linear, nonthreshold

d) nonlinear, nonthreshold

Back 14

C

Front 15

Silicon and selenium receptors are also known as:

a) flat plate grids

b) flat panel detectors

c) conversion plates

d) conversion grids

Back 15

B

Front 16

Silicon and selenium receptors are also known as:

a) flat plate grids

b) flat panel detectors

c) conversion plates

d) conversion grids

Back 16

B

Front 17

A latent image will lose about 25% of its energy in:

a) 3 seconds

b) 15 minutes

c) 8 hours

d) 24 hours

Back 17

C

Front 18

Scanned projection radiography was developed as a complement to:

a) plain film radiography

b) computerized tomography

c) magnetic resonance imaging

d) nuclear medicine

Back 18

B

Front 19

The latent image is formed on the _______ for digital radiography:

a) radiographic film

b) image matrix

c) radiation detector

d) computer screen

Back 19

C

Front 20

_______ is a late effect of radiation exposure:

a) Erythema

b) Epilation

c) Cancer

d) Nausea

Back 20

C

Front 21

The purpose of a LUT is to:

a) determine the exposure index

b) create the histogram

c) apply a predetermined scale of contrast to the digital data set

d) perform geometric processing in order to reorient the image on display

Back 21

C

Front 22

In digital imaging, the limiting factor in spatial resolution is the:

a) pixel depth

b) pixel size

c) bit depth

d) pixel pitch

Back 22

B

Front 23

What type of system uses a two-part process to convert incoming x-ray photons to an electronic signal?

a) Indirect conversion

b) Inverse conversion

c) Direct conversion

d) Proportional conversion

Back 23

A

Front 24

During the two-part conversion, system a(n) _______ converts light into an electronic digital signal:

a) input phosphor

b) scintilator

c) photodetector

d) output phosphor

Back 24

C

Front 25

Scanned projection radiography differs from conventional radiography in the lack of:

a) patient motion

b) spatial resolution

c) contrast resolution

d) scattered x-rays

Back 25

D

Front 26

A _______ response to radiation is directly proportional to the dose received.

a) linear

b) nonlinear

c) curvilinear

d) nonthreshold

Back 26

A

Front 27

Dose limits are based on a _______ dose-response relationship to radiation.

a) nonlinear, nonthreshold

b) linear, nonthreshold

c) linear, threshold

d) nonlinear, threshold

Back 27

B

Front 28

During the two-part conversion system, a _______ converts x-ray photons to light.

a) photodector

b) scintillator

c) photon attractor

d) cathode

Back 28

B

Front 29

Indirect DR uses _______ as the detector material.

a) DDR

b) amorphous selenium

c) amorphous silicone

d) CCD

Back 29

C

Front 30

Photoemissive materials absorb _______ and _______:

a) x-ray photons, light photons

b) light photons, electrons

c) light photons, x-ray photons

d) x-ray photons, electrons

Back 30

B

Front 31

The capability of an image intensifier to increase the illumination level of the image is called its:

a) flux gain

b) conversion factor

c) brightness gain

d) veiling glare

Back 31

C

Front 32

Indirect DR uses _______ as the detector material:

a) calcium tungstate

b) amorphous selenium

c) amouphous silicon

d) CCD

Back 32

C

Front 33

The _______ in the image intensifier emits electrons when it is stimulated by light photons.

a) input phosphor

b) output phosphor

c) photocathode

d) electron gun

Back 33

C

Front 34

Digitization of the fluoroscopic image permits:

a) input phosphor

b) output phosphor

c) photocathode

d) electron gun

Back 34

C

Front 35

The number of visible shades of gray in a digital image is determined by the:

a) matrix size

b) bit depth

c) widow level

d) patient thickness

Back 35

B

Front 36

The photocathode is composed of _______ metals:

a) lead-based

b) photoabsorptive

c) photoemissive

d) none of the above

Back 36

C

Front 37

The response of the imaging plate to ionizing radiation is:

a) the characteristic curve similar to the one for film

b) The D log E curve

c) the H and D curve

d) linear

Back 37

D

Front 38

The input screen is _______ in shape:

a) oval

b) elliptical

c) concave

d) convex

Back 38

C

Front 39

The number of light photons emitted within the image intensifier is _______ :

a) equal

b) unrelated

c) inversely proportional

d) directly proportional

Back 39

D

Front 40

Fluoroscopy is commonly used for observation of:

a) the heart

b) the GI tract

c) a surgical procedure

d) all of the above

Back 40

D

Front 41

Image intensified fluoroscopy is performed at illumination levels similar to:

a) star gazing

b) darken theaters

c) night driving

d) radiograph viewing

Back 41

D

Front 42

Automatic brightness control (ABC) maintains the brightness of the image by varying:

a) monitor settings

b) kVp & mA

c) monitor bandwith

d) all of the above

Back 42

B

Front 43

Each matrix pixel represents _______ in digital fluoroscopy:

a) interface reflectivity

b) atomic number & mass density

c) proton density and spin relaxation

d) radionuclide uptake

Back 43

B

Front 44

During CR imaging plate processing, the laser frees trapped electrons, allowing them to reduce energy state. This process is known as:

a) photostimulated luminescence

b) thermal emission

c) green light phosphorescence

d) none of the above

Back 44

A

Front 45

An image intensifier tube is identified by the diameter of its:

a) input phosphor

b) glass housing

c) output phosphor

d) focusing lenses

Back 45

A

Front 46

The output screen absorbs _______ end emits_______:

a) electrons, light photons

b) electrons, x-ray photons

c) light photons, electrons

d) light photons, x-ray photons

Back 46

A

Front 47

Silicon and selenium receptors are also known as:

a) flat plate grids

b) flat panel detectors

c) conversion plates

d) conversion grids

Back 47

B

Front 48

During fluoroscopic image intensification, the primary x-ray beam exits the patient and strikes the _______ of the image intensifier :

a) input screen

b) electrostatic lenses

c) photocathode

d) output screen

Back 48

A

Front 49

Fluoroscopy is a _______ radiographic examination:

a) dynamic

b) static

c) diagnostic

d) more than one of the above

Back 49

D

Front 50

The output phosphor of the image intensifier is composed of:

a) cesium iodide

b) antimony

c) zinc cadmium sulfide

d) graphite

Back 50

C

Front 51

A subject would not experience _______ following a dose high enough to cause CNS syndrome:

a) hematologic syndrome

b) gastrointestinal syndrome

c) prodromal syndrome

d) Both A & B

Back 51

D

Front 52

The photocathode absorbes _______ and emits _______.

a) x-ray photons, light photons

b) light photons, electrons,

c) light photons, x-ray photons

d) electrons, light photons

Back 52

B

Front 53

Gonadal responses to radiation have been observed at doses as low as _______ rads:

a) 100

b) 50

c) 20

d) 10

Back 53

D

Front 54

X-rays that exit the patient and enter the image intensifier first interact with the:

a) output phosphor

b) input phosphor

c) photocathode

d) anode

Back 54

B

Front 55

The time it takes to turn on the digital fluoroscpy x-ray tube and reach the selected mA and kV is called the _______ time.

a) interrogation

b) extinction

c) radiographic

d) acquisition

Back 55

A

Front 56

Spatial resolution is determined by the ration of _______ to ______:

a) matrix size, field of view

b) field of view, matrix size

c) bit depth, field of view

d) field of view, dynamic range

Back 56

B

Front 57

The input phosphor converts _______ to _______:

a) x-rays, electrons

b) light, electrons

c) electrons, light

d) x-rays, light

Back 57

D

Front 58

Brightness gain is typically in the range of:

a) 50-75

b) 100-1000

c) 3000-4000

d) 5000-30000

Back 58

D

Front 59

Electrostatic lenses are used to accelerate and focus:

a) light photons

b) x-ray photons

c) electrons

d) non of the above

Back 59

C

Front 60

The input screen absorbs _______ and emits _______:

a) x-ray photons, light photons

b) x-ray photons, electrons

c) light pohotons, x-ray photons

d) electrons, x-ray photons

Back 60

A

Front 61

What is the milliamperage used during fluoroscopy:

a) < 100 mA

b) < 50 mA

c) < 5 mA

d) <1 mA

Back 61

C

Front 62

The ______ is the product of the minification gain and the flux gain.

a) horizontal resolution

b) brightness gain

c) contrast resolution

d) flux gain

Back 62

B

Front 63

A digital fluoroscope with a charge coupled device has lower _______ and higher _______ than a conventional fluoroscope:

a) light sensitivity, patient dose

b) patient dose, light sensitivity

c) detective quantum efficiency, maintenance

d) signal-to-noise ratio, patient dose

Back 63

B

Front 64

During fluoroscopy, the SOD cannot be less than _____ inches.

a) 10

b) 15

c) 20

d) 40

Back 64

B

Front 65

A charged coupled device used in digital fluorosopy provides high:

a) spatial resolution

b) signal-to-noise ratio

c) detective quantum efficiency

d) all of the above

Back 65

D

Front 66

A local dose of _______ rad(s) or more can cause gonadal dysfunction

a) 1

b) 5

c) 10

d) 100

Back 66

C