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king 2309 unit 5
comp 3 king 2309 unit 5
| Question | Answer |
|---|---|
| the greatest recorded detail is seen using | radiograpic spot film |
| which system is capable of the highest resolution? | radiographic film |
| the physical components of a computer system are generally described as | hardware |
| the control center of the computer, the central processing unit(cpu), consist of 1. modem2. control unit3. memory unit | control unit & memory unit |
| digital imaging in radiography is the general term used to describe a # of techniques that can be used to enable the digital acquisition of the info contained inthe radiation beam after it exits the pt. | 1)direct-to-digital radiography(ddr)2)digital fluoroscopy(df)3)computed radiography(cr)NOT indirect electronic radiography(ier) |
| the picture arching and communication system(pacs) is best defined as a | computer assisted file and storage system for digital images |
| the process by which a photostimulable luminescent plate is exposed to radiation and converted into a high quality two-dimensional digital image is called | computed radiograpyhy(cr) |
| all of the following are classified as types of a vacuum tubes exceptimage intensifierionization chamberx-ray tubevidicon television camera tube | ionization chamber |
| all of the following will occur when a dual field image intensifier tube with automatic brightness(gain) control is being used in the smaller image mode except | 1)a greater magnification of the tissues on the display 2)an improved contrast in the displayed image 3)a reduction in the amount of noise appearing in the image; NOT a reduction in the exposure to the patient |
| in a modern televised image chain, the device normally associated with the least amount of spatial resolution is (are) | television camera and monitor |
| in order to accomodate human eye integration time, each frame of a television image must be presented in less than | 1/30 second |
| the automatic brightness(gain) control in the fluoroscopic system was developed to help maintain consistant brighness as the | 1)thickness of the pt varies 2)kvp and milliampere values change 3)source-to-image receptor distance changes |
| the cesium iodide layer of an image intensifier which converts x-rays into visible light is one of the principle coatings found on the | input side of the image intensifier tube |
| the electronic image formed on the surface of the photocathode will be converted into_______by the output phosphor of the image intensifier | visible light image |
| the main component of the television monitor is a large gas evacuated glass envelope that has been coated with a fluorescent screen called a | cathode-ray tube |
| the most common material used in the formation of the input phhosphor of a modern image intensifier is | cesium iodide |
| the operating potential required to move the electronic image between the input and output sides fo the image intensifier tube is approximately | 25000 volts |
| the principal advantage of image intensifed fluoroscopic technique compared to routine radiographic imaging is that it allows for | the ability to visualize dynamic motion of the tissues |
| the reduction of brightenss at the periphery of image display of an image intensifed fluoroscope is termed | vignetting |
| the usual range of milliamperage required for image intensified fluoroscopy is about | 1-5 mA |
| the visilble light that impinges upon the target of a television camera tube is converted into a | electronic image |
| to aid the radiologist during fluoroscopy, most modern units will automatically change radiation levels for thicker or thinner body parts. this control is termed | automatic brightness gain |
| zinc cadmium sulfied an output phosphor of modern image intensifiers serves to convert | electrons into visible light |
| pulse-progressive fluoroscopy refers to a technique in which digital fluoroscopy(df) images are obtained using a | pulsed x-ray source |
| the main advantage of a charged-coupled device(ccd) compared to a television camera tube include all the following except | it has greater sensitivity at lower light levelsit is generally much smallerit is less sensitive to mechanical stressesNOT it is associated with a reduced contrast resolution or low contrast detectablility |
| the pulsing of an x-ray tube during digital fluoroscopy(df) is required to reduce the amount of heat that is produced during imaging and | reduced the exposure to the patient |
| the two principle advantages that digital fluoroscopy(DF) has over image intensified fluoroscopy(IIF) are | 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 x-ray photon in a direct-to-digital radiographic(DDR) imaging system, the net result is | an electron-hole pair that is detected by an array of thin-film transistors(TFT's) |
| with either an amorphous selenium or cesium iodide amorphous silicon digital radiographic imaging, the latent image is formed by an electronic signal that is stored by | an array of thin-film transtors(TFT's) |
| which of the following layers are found on the input side of an image intensifier tube? | fluoroscent screen & photocathode; NOT incandescent screen |
| the major factors effecting the amount of brightness gain in an image intensifier are | minification ratio and flux gains |
| the time it takes for the human eye to adjust to the low light levels of conventional fluoroscopy is callled | adaptation time |
| most modern image intensifiers utilize an input fluorescent screen layer which is composed of | cesium iodide |
| the squared ratio of the diameter of the input phosphor to the square of the diameter of the output phosphor in an image intensifier tube is termed | minification ratio(gain) |
| a substantial increase in conventional fluoroscopic brightness levels is accomplished in most modern systems using a(an) | image intensifier |
| the ratio of the luminescencein candelas of the output phosphor to the input exposure rate in milliroentgens per second defines | conversion factor |
| the electronic signal that caries the info generated in the television camera tothe cathode-ray tube(tv monitor) is termed the | video signal |
| during televised image intensified fluoroscopy, permanent static images or spot films can be produced and recorded using | 1)photo-spot imaging 2)cassette-loaded spot imaging 3)video tape recording |
| in order to maintain image clarity, the path of electron flow from photocathode to output phosphor in the image intensification tube is controlled by | electrostatic lenses |
| the part of the image intensifier tube that funcions to cahnge the visibel light image into an electronic images is the | photocathode |
| the phosphor and photocathode layers, which convert the x-rays into electronic images in an image intensifier(ii) tube, are located on the | input side of the II tube |
| the output screen material of most image intensifieres is called zinc cadmium sulfide. this substance serves to convert | electrons into light |
| the improved ability to visualize small objects with image intensifed fluoroscopy results from the human factor of vision associated with | photopic(cone) vision |
| the operating potential in most modern image intensifier tubes is apporoximately | 25kV |
| the output screen in an image intensifer serves to convert the electronic image into | a visible light image |
| the principal advantage of image intensified fluoroscopy compared to conventional(nonintensified) fluoroscopy is that it allows for | increased image brightness |
| when both the direct display of the intensified image and the recording cien spot film(or photospot camera images) are desired | tandem(beam-splitting) mirror device is placed between the II tube & the TV camera |
| The targe or photo-conductive layer of a Vidican television camera tube is most often composed of a material called: | Antimony trisulfide |
| The scanned electronic image on the signal plate of a vidicon television camera tube is converted into a(n): | video signal |
| The vidicon & plumbicon are the most commonly employed ____ for a modern radiography dept. | Television camera tubes |
| The point in the image intensifier (II) where the electrons crossover before reaching the output phosphor is termed the: | Electronic focal spot (point) |
| Most computers operate on a simple # system consisting of only the digits 0 & 1 called: | binary system |
| The function component of a computer involved w/feeding information into the central processing unit is termed an: | Input device |
| The mathematical computations or comparisons that can be made by a computer are performed by the: | Arithmetic/logic unit |
| Thousands of individual circuit elements, which are necessary for the operation of a computer, are incorporated onto a small piece of silicon called a(n): | integrated circuit chip (IC) |
| Information that is processed by a computer is most often displayed on a device called a monitor or: | Cathode ray tube (CRT) |
| Which of the following computer hardware devices may be classified as an output device? | printer |
| In computer terminology, a single binary digit is referred to as a: | bit |
| BASIC, FORTRAN, & COBOL are 3 of the most commonly employed: | computer languages |
| Each character (letter or #) of the keyboard is normally encoded by 8 bits of binary info. This will then constitute the basic unit by which the capacity of a computer is measured called a(n): | byte |
| Permanent instructions (programs) that cannot be modified are stored by the: | Read Only Memory (ROM) |
| The interpretation of the user's instructions & transfer & retrieval to the appropriate location is the primary function of the: 1)Control unit 2)Memory unit 3)Arithmetic unit | Control unit only |
| Invisible portions of a computer consist of languages & programs that are normally referred to as: | Software |
| When information is to be added, deleted or changed by the computer, the info is stored by the: | Random Access Memory |
| When large amounts of info or data are to be stored, a secondary memory device, such as a magnetic ____, may be employed. 1)CD-rom 2)Floppy disk 3)Tape drive | CD-rom & Tape drive |
| Electrical data transmission over conventional phone lines from computer to computer may be accomplished w/the use of a(n): | Modem |
| The most frequently used device for the production of a hard copy image in radiology is a: | laser printer |
| Which of the following imaging modalities are largely dependent upon the computer for its acquistion & display of data? 1)Ultrasonography 2)Computed radiography 3)Magnetic resonance imaging | all of the above |
| The organized arrangement of a digital image into columns & rows for its display on a cathode ray tube (monitor) is referred to as the: | Image matrix |
| The individual picture elements, which contribute to the smallest segment of an image matrix, are termed: | pixels |
| Which of the following matrix size will be able to display the highest spatial resolution? a)128x128 b)256x256 c)512x512 d)1024x1024 | 1024x1024 |
| The adjustment of the image contrast w/a digital or computed radiographic unit is accomplished thru the use of the: | Window width controls |
| A change in the window level of a digital display is most closely related to a change in the: | digital density or brightness of the image |
| The gray scale value in the pixels is closely related to the: | Attenuation properties of the amount & density of tissue in the voxel |
| The principle effect of the use of an insufficient amount of radiation when performing any type of digital radiographic examination is a(n): | Increase in the amount of quantum mottle on the image |
| In order to employ the picture archiving & communications system (PACS) for the storage of conventional radiographic images, will require their: | conversion into a digital image format |
| The technique by which digital images may be transmitted over phone lines for remote viewing is termed: | Teleradiology |
| The sensitivity of most modern indirect-to-digital radiographic (IDR) imaging systems is about the same as a(n): | 800 speed film-screen combo |
| After the initial acquisition of the image using a computed radiographic (CR) sys, all of the following are steps that are required for the evaluation of the image EXCEPT? | a)The id of the image b)The reading or scanning of the image plate c)The digital processing of the image |
| Photostimulable luminescence refers to the process by which: | The trapped energy of the electronic latent image is released as a visible light image |
| The energy of the x-ray beam is captured in photostimulable phosphor imaging plate (PSP) of a CR imaging system as a series of electrons that are trapped in empty spaces in the crystal lattice called: | Meta-stable F centers (Europium electron holes) |
| The release of trapped energy in a meta-stable F center (Europium electron holes) of a BaFBr (Barium flurobromide) crystal in the photostimulable phosphor imaging plate(PSP) of a CR imaging sys are triggered by the exposure to visible(laser) light in the: | Red Spectum |
| After photostimulated luminescent phosphor (PSP) of a CR imaging sys has been scanned by the photomultiplier (PM) tube reader, the plate is exposed to a high intensity light to: | Clear any of the remaining latent image from the image plate |
| The princple color of light emitted when barium-fluorohalide crystals in the photostimulable phosphor imaging plate (PSP) of a CR imaging system after its stimulation by a helium neon (HeNe) laser is a(n): | Blue-violet light |
| The image on a photostimulable phosphor plate (PSP) of a CR imaging system is not permanent & will fade at a rate of about: | 25% w/in 8 hrs of exposure |
| The "reading" of the latent image on a photostimulable phosphor plate (PSP) of a computed radiographic (CR) imaging system is normally accomplished by a(n): | mirror deflected laser beam |
| The intesity of the blue-purple fluorescence emitted by the photostimulable phosphor plate (PSP) of a CR imaging sys when stimulated by a HeNe (helium-neon) laser is directly proportional to: | The amount of the x-ray energy absorbed in the image plate |
| The sensitivity of most computed radiographic (CR) imaging sys is about the same as a(n): | 200 speed film-screen combo |
| The device that receives the image formation radiation exiting the pt converts it into light, & then increases the brightness of that light is the: | imaging intensifier |
| A digital technique which eliminates the majority of non-vascular structures by enhancement of the vascular structures is best termed: | Digital subtraction angiography (DSA) |
| The principal advantage of the smaller field of a dual intensifier (II) is a(n): a)Improvement in quality of the image b)Reduction in amount of magnification appearing in the image c)Reduction in the amount of exposure the pt will receive | Improvement in the quality of the image |
| The total brightness gain for a modern image intensifier fluroscopic image is about ____ greater than conventional fluoroscopic screen image. | 5,000-30,000 times |
| _______ releases electrons when struck by light photons & ________ releases electrons when struck by x-ray photons. | Amorphous silicon, amorphous selenium |
| What is the definition of amorphous? | A noncrystaline state of an otherwise crystaline material |
| Visually, dynamic range refers to which of the following? | The # of shades of gray that can be represented |
| Which of the following is an advantage of digital imaging over conventional imaging? a)less exposure time b)less noise c)more resolution d)more exposure latitude | more exposure latitude |
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