Digital imaging

Which of the following is likley ranges of milliampere values that will be impressed on an xray tube that is used for digital fluoro: a. 200-500 milliamperes b. 20-50 milliamperes c. 2-5 milliamperes d..2-.5 milliamperes

a. 200-500 milliamperes

The process by which a photostibuable luminescent plate is exposed to radiation an converted into a high quality 2D digital image is called a. CR b. IDR c. DDR d. DF

a. CR

With either an amorphous selenium or cesium iodide amorphous silicon digital radiographic imaging that latent image is formed by an electronic signal that is stored by: a. an array of TFTs b. an array of photodidiodes c. a vidicon tv camera tube d. a series of quantum detectors

a. an array of TFTs

During DDR or IDR if the exposure index is above the desired range the exposure should be repeated using exposure settings which employ a: a. higher mAs value b. lower mA value c. lower kVp value d. larger focal spot

a. higher mAs value

The main advantage of an amorphous selenium DDR imaging system compared to a cesium iodide amorphous silicon used in IDR imaging system is its: a. higher spatial resolution b. lower resulting dose to patient c. higher detective quantum efficiency d. increased signal to noise ratio

a. higher spatial resolution

The organized arrangement of a digital image into columns and rows for its display on a cathode ray tube (monitor) is referred to as the: a. image matrix b. signal plate c. noise pattern d. hybrid mode

a. image matrix

Most of the energy subtraction techniques used in digital subtraction angiography imaging techniques are intended to demonstrate difference in the k-absorption edge between: a. iodine and soft tissue b. water and spinal fluid c. oxygen and intestinal gas d. barium and air

a. iodine and soft tissue

A image is obtained using CR imaging system if the sensitivity index is below the derired range the exposure should be repeated using exposure settings which employ a: a. lower mAs value b. higher mA setting c. higher kVp setting d. smaller focal spot

a. lower mAs value

Because DDR and IDR are not cassette based they normally cannot be used for a. mobile applications b. tube angulated techniques c. tomographic applications d. extremity imaging

a. mobile applications

The individual picture elements which contribute to the smallest segment of an image matrix, are termed a. pixels b. bits c. ROMs d. bytes

a. pixels

The release of trapped energy in a meta stable F center of a BaFBr crystals in the PSP of a CR are triggered by the exposure to visible laser light in the: a. red spectrum b. blue violet spectrum c. green spectrum d. ultraviolet spectrum

a. red spectrum

With a CR imaging system the desired exposure level is determined by a value known as the: a. sensitivity index b. exposure index c. digital density index d. compensation index

a. sensitivity index

The intensity of the blue purple fluorescence emitted by the PSP when stimulated by HeNe laser is directly poroptional to: a. slow scan or sub scan direction b. spin rotate spin direction c. interlaced or alternating scan axis d. coordinated detection axis

a. slow scan or sub scan direction

The sensitivity of most modern IDR imaging systems is about the same as a/an: a. 1000 speed film screen combo b. 800 speed film screen combo c. 400 speed film screen combo d. 200 speed film screen combo

b. 800 speed film screen combo

The two principle advantages of the digital fluoroscopy has over image intensified fluoroscopy are: a. A lower low contrast detectability and a reduced noise level b. a higher speed of spot image acquisition and the ability to post process the images c. an improved ability to eliminate patient motion and reduce patient exposures d. images with a long scale contrast and higher spatial resolution

b. a higher speed of spot image acquisition and the ability to post process the images

When a thin layer of amorphous selenium is struck by an xray photon in a direct to digital radiographic imaging system the net result is: a. a pair of negatively charged particles that are detected by a charged plat b. an electron hole pair that is detected by an array of TFT c. a number of low energy secondary photons that are burned onto a laser medium d. visible light that is produced in the phosphor layer

b. an electron hole pair that is detected by an array of TFT

The principle color of light emitted when barium fluorohalide crystals in the PSP of a CR after its stimulation by helium neon laser is a/an: a. yellow green light b. blue violet light c. ultraviolet light d. orange light

b. blue violet light

After a photo stimulated luminescent phosphor (PSP) of a CR has been scanned by the PM tube reader the plate is exposed to a high intensity light to: a. clean the transport system of any leftover positive ions b. clear any of the remaining latent image from the image plate c. realign the low intensity laser mirror to the PM tube d. Amplify the electronic signal from the PM tube before it passed into the CRT

b. clear any of the remaining latent image from the image plate

In a laser or Cr reader the galvanometer or rotating polygon is used to: a. modulate the radio frequency of the laser beam b. deflect the laser beam back and forth c. amplify the signal detected by the light channeling guide d. convert the analog signal from the PM tube

b. deflect the laser beam back and forth

With a digital exam employing energy subtraction the principle difference in appearance of the two images is the result of acquiring images with: a. different milliampere second settings b. different kilovoltage peak settings c. different source to image receptor distances d. different radiographic grids

b. different kilovoltage peak settings

With DDR imaging system or IDR the desired exposure level is determined by a value known as the: a. sensitivity index b. exposure index c. digital density index d. compensation index

b. exposure index

The energy of an xray beam is captured in photstimulable phosphor imaging plate (PSP) of a CR as a series of electrons that are trapped in empty spaces in the crystal lattice called: a. excited luminescence bands b. meta stable F centers c. activated conduction bands d. photomultiplier receptor sites

b. meta stable F centers

A failure to properly align the images during digital subtraction angiography imaging techniques process will result in a/an: a. interrogation artifact b. misregistration artifact c. archiving artifact d. windowing artifact

b. misregistration artifact

The adjustment of the image contrast with a digital or computed radiographic unit is accomplished through the used of the: a. frame integration controls b. window width controls c. mask controls d. time interval controls

b. window width controls

In a computed radiography system having a 1024x1024 pixel matrix what is the pixel size for a 23x23 cm FOV used for imaging of the hand? a. 22 mm b. 2.2 mm c. .22mm d. .44 mm

c. .22mm

Pulse progressive fluoroscopy refers to a technique in which digital fluoroscopy images are obtained using a: a. high frequency rectified xray beam b. a combined xray radionuclide source c. a pulse xray source d. a multiple wave guide pulse generator

c. a pulse xray source

A change in the width of the window of a digital display is most closely related to a change in the: a. size distortion in the image b. noise level of the image c. contrast of the image d. digital density of brightness of the image

c. contrast of the image

A PM tube is an important component of a CR reader that serves to: a. convert the red light of the laser into the blue purple fluorescence b. redirecting the laser beam across the face of the imaging plate c. convert and amplify the photostimulated light into a measurable electronic signal d. filter the raw data from the image to eliminate and unwanted electronic noise

c. convert and amplify the photostimulated light into a measurable electronic signal

A digital technique which eliminates the majority of non vascular structures by enhancement of the vasculare structres is best termed: a. photostimuable subtraction radiography (PSR) b. scanned projection radiography (SPR) c. digitial subtraction angiography (DSA) d. teleradiography (TR)

c. digitial subtraction angiography (DSA)

An increase in the amount of voltage that is applied to the PM tube in the CR reader will be associated with a/an: a. increase in the spatial resolution of the laser camera b. decrease in the amount of quantum noise in the cathode ray display (CRT) display c. improve sensitivity of the signal d. Decrease in the amount of scattered radiation in the BaFBr plate

c. improve sensitivity of the signal

The time it takes for the tube in a digital fluoroscopic unit to be switched on an to reach the selected level of technique is called the: a. dead time b. acquisition time c. integration time d. pulse time

c. integration time

The main disadvantage of an amorphous selenium DDR compared toe cesium iodide amorphous silicon IDR is its a. higher spatial resolution b. lower resulting dose to patient c. lower detective quantum efficiency d. delayed acquisition time

c. lower detective quantum efficiency

The reading of the latent image on a PSP CR imaging system is norammly accomplished by a/an: a. electronically focused PM tube b. light guided spectrometer c. mirror deflected laser beam d. grid controlled magnetic beam

c. mirror deflected laser beam

During the reading or acquisition cycle the direction in which the PSP moves during the scanning phase is called the: a. the amount of quantum mottle presne tin the image plate b. the heat that has been gereated in the exposed tissue c. the amount of the xray energy absorbed in the image plate d. the speed of the image processor

c. the amount of the xray energy absorbed in the image plate

The principle advantage of an area beam used in all digital radiographic and fluoroscopic systems as compared to a fan beam used in computed tomography is that: a. the area beam is associated with less scatter production b. the area beam provides a higher image contrast c. the area beam permits shorter exposure timer setting d. the area beam provides an improved low contrast detectability

c. the area beam permits shorter exposure timer settin

In a 12 bit analog to digital converter each pixel will have how many possible values? a. 128 b. 256 c. 512 d. 1024

d. 1024

Which of the following matrix size will be able to display the highest spatial resolution? a. 128x128 b.256x256 c. 512x512 d. 1024x1024

d. 1024x1024

The sensitivity of most modern CR imaging systems is about the as a/an: a. 1000 speed film screen combo b. 800 speed film screen combo c. 400 speed film screen combo d. 200 speed film screen combo

d. 200 speed film screen combo

the image on a PSP of a CR is not permanent and will fade at a rate of about: a. 10% per hour after the initial exposure b. 25% per hour after the initial exposure c. 10% within 8 hours of the exposure d. 25% within 8 hours of the exposure

d. 25% within 8 hours of the exposure

A change in the window level of a digital display is most closely related to a change in the: a. size distortion in the image b. noise level of the image c. shape distortion of the image d. digital density or brightness of the image

d. digital density or brightness of the image

The axis of the movement of the laser across the PSP of a CR imaging system during the acquisition process known as the: a. beam splitting direction b. plate translation direction c. integrated scan direction d. fast scan direction

d. fast scan direction

Digital imaging in radiography is the general term used to describe the number of techniques that can be used to enable the digital acquisition of the info contained in the radiation beam after it exits the patient. Which of the following terms are NOT used to describe this process: a. direct to digital radiography (DDR) b. Digital fluoroscopy (DF) c. computed radiography (CR) d. indirect electronic radiography (IER)

d. indirect electronic radiography (IER)

Which of the following is NOT an advantage of CCD compared to a TV camera tube a. it has greater sensitivity at lower light levels b. it is generally much smaller c. it is less sensitive to mechanical stresses d. it is associated with a reduced contrast resolution or low contrast detectability

d. it is associated with a reduced contrast resolution or low contrast detectability

The pulsing of an xray tube during digital fluoroscopy is required to reduce the amount of heat that is produced during imaging and: a. reduce the effects of patient motion b. increase the spatial resolution c. increase the acquisition speed d. reduce the exposure to the patient

d. reduce the exposure to the patient

The number of pixels that are found in a matrix is most closley related to the: a. thickness of the amorphous layer b. voltage applied to TFT c. effective atomic number of the amorphous layer d. size an number of TFT

d. size an number of TFT

After the initial acquisition of the image used a CR system, which of the folksinging are NOT a step that is required for the evaluation of the image: a. the identification of the image b. the reading of scanning of the image plate c. the digital processing of the image d. the acceptance testing of the image

d. the acceptance testing of the image

The time it takes for the xray tube in a digital fluoroscopic unit to be switched off is called the: a. the termination time b. the interrorgation time c. the dead time d. the extinction time

d. the extinction time

Photostimualable luminescence refers to the process by which: a. the laser beam is converted into a usable electronic signal b. radiation is absorbed into the lattice of a fluorescent crystal c. the photo multiplier tube converts the electronic signal into a laser image d. the trapped energy of the electronic latent image is released as a visible light

d. the trapped energy of the electronic latent image is released as a visible light