Digital: Ch 4-6

A device that acts like a camera in an indirect conversion detector is know as A. CCD b. field effect transistor c. CMOS d. thin field converters

A. CCD

The purpose of the the barcode label is to match the image formation with the A, Imaging plate b. patient identifier c. technologist d. radiographic room

B. Patient identifier

The PSP cassette is backed by aluminum that A. reflects xrays B. Absorbs backscatter x-rays C. captures the image D. Transmits X-rays

B.Absorbs backscatter X-rays

WOTF (which of the following ) serves to protect against static build-up , dust collection, and mechanical damage to the imaging plate A. Aluminum Backing B. Lightweight plastic C. Felt Material D. Cassette Front

C. Felt material

The indirect conversion detector system that requires optical coupling and image size reduction is known as a a. CCD b. field effect c. CMOS d. thin field

CCD

A detector in which each pixel has its own amplifier is known as a A. CCD B. field effect transistor c. CMOS d. thin field transistor

CMOS

A highly efficient indirect conversion system that takes up less fill space than CCDs is known as a a. analog to digital b. field effect c. CMOS d. thin field transistor

CMOS

WOTF flat-panel detector technologies was developed by NASA a. CCD b. field effect c. CMOS d. thin field

CMOS

A Gd2O2S scintillator is known as what type of phosphor a. turbid b. unstructured c. structured d. both a and b

D. both. Turbid and Unstructured

The components that focus the signal from the scintillators to the CCD are called a. detector elements b. capacitors c. fiber optics d. analog digital converters

Fiber optics

The most popular base material used in integrated circuits is a. selenium b. sulfur c. silicon d. tellurium

Silicon

When specialized pixels in a complementary metal oxide silicon system are struck with X-ray photons a.The X-ray photons are converted into light b.Light photons are stored in capacitors c.Light photons are converted into electrical charge d. all of the above

The X-ray photons are converted into light Light photons are stored in capacitors Light photons are converted into electrical charge

The range of kVp that can be used with PSP systems is a. 45-120 b. 55-130 c. 65-120 d. 75-130

a. 45-120

The optical mirror in the reader A. directs the laser beam to the imaging plate surface b. forms the laser beam into a circle c. cause the laser beam to diverge d. creates the laser beam

a. Directs the laser beam to the imaging plate surface

___ turn semi-conductors into full electrical conductors a. dopants b. amplifiers c. positive transistors d. negative transistors

a. Dopants

The higher the number of pixels in a matrix, the a. the higher the image resolution b. lower the image resolution c. lack of effect on image resolution d. smaller the image

a. Higher the image resolution

Some advantages to CCDs include a. less expensive to manufacture b. module design makes repair and upgrade easy c. demagnification capabilities d. a and c e. all

a. Less expensive to manufacture

PSP imaging plates are erased by flooding the plate with a. light b. radiation c. electrons d. phosphors

a. Light

In a flat-panel detector, specialized silicon integrated circuits control a. line scanning sequence b. readout c. amplification d. analog to digital conversion

a. Line scanning sequence

Detector elements are formed by voltage gates that ___ at readout to ___ the flow of electrons a. close; allow b. open; allow c. close; stop d. open; stop

a. Open; allow

Scintillators are phosphors that a. produce light when absorbing xrays b. produce xrays when absorbing light c. absorb light and produce electrical charges d. absorb xrays and produce electrical charges

a. Produce light when absorbing X-rays

The most common types of noise that affect image quality include all OTF except a. quantum noise b. statistical noise c. dark current noise d. amplification noise

a. Quantum noise

Demagnification is a. reducing the phosphor output image to the size of the active area of the CCD b. reducing the field size of the CCD detector c. reducing the amount of light spread from the scintillator d. none of the above

a. Reducing the phosphor output image to the size of the active area of the CCD

In CsI detectors a. there is very little light spread b. crystalline needles block light from the detector c. xrays are converted into an electrical signal d. light spread causes resolution to decrease

a. There is very little light spread

A device that includes a photosensitive array and small pixels that convert light into electrical charges is known as a a. thin field b. field effect c.thin film d. field energy

a. Thin-film transistor

The number of grid lines per centimeter or lines per inch describes grid a. frequency b. ration c. focus d. size

a.Frequency

The laser scans the imaging plate in a ____ pattern a. raster b. horizontal c. circular d. random

a.Raster pattern

Manufacturers make efforts to maintain a standard of less than ___ defective pixels a. 0.01%-0.02% b. 0.1%-0.2% c. 1%-2% d. none of the above

b. 0.1% to 0.2%

When insufficient light is produced by the imaging plate phosphor, the image will a. not be formed b. be grainy c. be dark d. be detailed

b. Be grainy

During laser beam formation, both ends of the laser reflect energy back and forth so that the atoms a. absorb each other b. bombard each other c. lose energy d. create xray energy

b. Bombard each other

The imaging plate layer that absorbs stimulating light and reflects emitted light is the A. active b. color c. reflective d. backing

b. Color layer

When the imaging plate is irradiated, stimulated electrons enter the _____ layer. a. active b. conductive c. protective d. support

b. Conductive layer

A device that acts like a switch to send electrical charges to the image processor in a direct conversion flat-panel detector is known as a a. thin field b. field effect c. thin film d. field energy

b. Field-effect transistor

WOTF require more critical beam centering a. parallel grids b. focused grids c. low-ration grids d. low-frequency grids

b. Focused grids

The selection of the incorrect body part from the examination menu may result in a. no image b. image misinterpretation c. proper density and contrast d. no difference

b. Image misinterpretation

Grid use for PSP examinations is more critical than in film/screen radiography because CR a. examinations produce more scatter b. imaging plates record more densities c. imaging plates record less scatter d. examinations requires much higher kVp values

b. Imaging plates record more densities

WOTF can be done to decrease the chance of having image lag occur in the next image a. decrease the amount of time between exposures b. increase the amount of time between exposures c. leave collimation open d. acquire the image requiring the highest technical factors first

b. Increase the amount of time between exposures

Which statement best describes a capacitor a. it converts xray photons to light b. it converts light to an electrical charge and stores it c. it converts xrays photons to light and stores it d. it stores light and converts it from analog to a digital signal

b. It converts light to an electrical charge and stores ot

Intermittent extraneous line patterns are _____ artifacts a. imaging plate b. plate reader c. image processing d. printer

b. Plate reader artifacts

WOTF statements is true a. quantum efficiency and detective quantum efficiency are the same b. quantum efficiency will affect detective quantum efficiency c. quantum efficiency has no effect on detective quantum efficiency d. quantum efficiency is the absolute efficency of the amount of light collected

b. Quantum efficiency will affect detective quantum efficiency

Cracks in the imaging plate can be caused by a. excessive kVp b. removing and replacing the place in the reader c. improper erasure d. scatter through the back of the cassette

b. Removing and replacing the plate in the reader

WOTF statements about scintillators is true a. all scintillators absorb the same amount of xray photons b. the amount of xrays absorbed depends on the type of scintillator c. structured phosphors produce more light spread d. unstructured phosphors are more efficient

b. The amount of X-rays absorbs depends on the type of scintillator

Kilovoltage peak (kVp) should be chosen a. to provide the least contrast possible b. to provide penetration c. for the type and amount of contrast desired d. for the type of imaging plate phosphor

b. To provide penetration

Indirect conversion in flat-panel detectors is a a. 1 b. 2 c. 4 d. 3

b. Two step process

WOTF is not considered a scintillator A.Gd2O2S B. a-Se c. CsI d. none of the above

b. a-Se

Clinical applications for CCDs include all OTF except a. digital fluoro b. computed tomography flurorscopy c. digital mammo d. general radiography

b.Computed tomography fluoroscopy

CsI detectors use a. rare earth scintillators b. thin crystalline needles c. miniture cameras d. specialized pixel sensors

b.Thin crystalline needles

A technologist can lend credibility to his or her expertise by a. using a grid b. using personal position markers c. using less collimation d. none of above

b.Using personal position markers

The k-edge of phosphor imaging plates ranges from a. 10-30 b. 20-40 c. 30-50 d. 40-60

c. 30-50 keV

The wavelength of the PSP reader laser is a. 336 b. 636 c. 633 d. 366

c. 633 nm

The layer of the imaging plate that traps electrons during exposure is the A. protective b. reflective c. active d. support

c. Active layer

Quantum efficiency is a measurement of the a. amount of electron hole pairs held by the electrostatic force b. percentage of light that is absorbed c. amount of electrons produced relative to the incident light from the scintillator d. total amount of light that is absorbed

c. Amount of electrons produced by relative to the incident light from the scintillator

The phosphor layer is made of phosphors from the _____ family a. barium sulfate b. halide calcium c. barium fluorohalide d. calcium fluorohalide

c. Barium fluorohalide family

Each light photon is assigned a number during a. amplification b. sampling c. digitization d. laser scanning

c. Digitization

Shuttering is a postexposure image manipulation technique that a. is placed on the patient b. placed on cassette c. added to the screen image d. changes the amount of scatter

c. Is added to the screen image

Amplifiers perform all OTF except a. readout b. amplification c. noise canceling d. analog to digital

c. Noise canceling

Milliampere-seconds (mA-s) is selected for the a. shortest time possible b. longest time possible c. number of electrons needed d. amount of penetration needed

c. Number of electrons needed

Grid ratio describes the a. number of grid lines per centimeter or lines per inch b. angling of the lead strips to coincide with xray beam diversion c.relationship between the height of the lead strips to the interspace d. physical size of the grid to be used for the distance measured

c. Relationship between the height of the lead strips to the interspace

WOTF should be considered when selecting the PSP cassette a. size and speed b. type and speed c. size and type d. none

c. Size and type

Defective pixels can result from all OTF except a. chemical corrosion b. static discharge c. software programs d. age

c. Software programs

The amount of detail present in any image is known as ______ resolution. a. contrast b. density c. spatial d. optical

c. Spatial resolution

All OTF are considered impurities except a. gallium arsenide b. indium antimonide c. tellurium d. most metal oxides

c. Tellurium

Coherent light is formed by the laser because the photons a. are at right angles to each other b. travel in all directions c. travel in the same direction d. are at varying frequencies

c. Travel in the same direction

WOTF is used as a photoconductor A.Gd2O2S B. a-Se c. a-Si:H d. cesium iodide

c. a-Si:H

Which statement best describes a charge-coupled device (CCD) a. it is the oldest direct conversion technology that is still in use today b. it is the oldest direct conversion technology with limited use today c. it is the oldest indirect conversion technology used in a variety if image capture applications d. it is the oldest indirect and no longer used in medical imaging

c.It is the oldest indirect conversion technology used in a variety of image capture applications

Typical cassette throughput is ___ cassettes per ___ A. 5; minute b. 25; minute c. 25; hour d. 50; hour

d. 50; hour

Photoconductors are materials that a. produce light when absorbing X-rays b. produce X-rays when absorbing light c. absorb light and produce electric charges d. absorb X-rays and produce electrical charges

d. Absorb X-Rays and produce electrical changes

The type of flat-panel detector that uses thin films of silicon integrated with arrays of photodiodes is known as an a. CsI detector b. charge coupled device c. CMOS d. amorphous silicon detector

d. Amorphous silicon detector

When compared with a CMOS, a CCDs A. less sensitive b. are more susceptible to noise c. use more than 100 times the power d. inexpensive to manufacture

d. Are inexpensive to manufacture

All OTF statements are true execpt a. as detector ages, the number of dead pixels increase b. software programs identify and isolate dead pixels c. interpolation uses information from the surrounding pixels to "fill in " missing information d. dead pixels at the edge of the detector are easily identified

d. Dead pixels at the edge of the detector are easily identified

Collimation to a smaller area a. increases scatter b. increases amount of tissue irradiated c. decreases resolution d. decreases compton interactions

d. Decreases Compton interactions

WOTF does not determine PSP resolution a. phosphor layer thickness b. pixel size c. the number of pixels d. laser scan speed

d. Laser scan speed

The exposure indicator number is a. accurate measure of patient dose b. an indication of radiation absorbed by the imaging plate c. both a and b d. neither a or b

d. Neither an accurate measure of patient dose, nor an indication of radiation absorbs by the imaging plate

The reflective layer A. absorbs and reduces static b. gives the imaging sheet strength c. protects the back of the cassette d. sends light in a forward direction

d. Sends light in a forward direction

The readout process requires that ___ and ___ a. electrons flow freely when the gates are open; voltage stays consistant b. the flow of electrons is times; voltage stays consistent c. electrons flow freely when the gates are open; multiple voltage changes occur d. the flow of electrons is timed; multiple voltage changes occur

d. The flow of electrons is timed; multiple voltage changes occur

The process of scanning the moving imaging plate is known as a. transition b. raster scanning c. digitization d. translation

d. Translation

Possible causes of image lag include all but a. rapid succesion images b. overexposure c. lack of beam attention d. underexposure

d. Underexposure

Flat-panel detectors that use indirect conversion technology convert a. electrical signals to light b. light to xrays c. xrays to electrical signals d. xrays to visible light

d. X-Rays to visible light

Detector performance is measured with all OTF execpt a. spatial resolution b. observation of flow contrast objects in a phantom c. DQE d. contrast

d.Contrast

Using an FOV that is much larger than the part being examined will a. increase resolution b. decrease the size of the matrix c. decrease the sampling rate d. decrease resolution

d.Decrease resolution

Quantum mottle is caused by a. excessive mAs b. excessive kVp c. insufficient distance d. insufficient light

d.Insufficient light