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Imaging Final
Stack #2672029
| Question | Answer |
|---|---|
| The purpose of the barcode label is to match the image information with the: | Imaging plate |
| Computers operate using a ______ language | Binary |
| PSP Imaging plates are erased by flooding the plate with: | Light |
| Iâm the technology of CR, the latent image is actually | The light from the phosphor following laser excitation of the reader assembly |
| A histogram displays the useful signal by locating | All pixel values |
| The digital detector used in CR Imaging is the | Imaging plate |
| Grossly overexposed digital images will demonstrate | Low contrast |
| The phosphor layer is made of the phosphors from the _____ family | Barium fluorohalide |
| The layer of the imaging plate that traps electrons during exposure is the _____ layer | Active |
| The active element in a storage phosphor is | Barium fluorohalide |
| CR acquires an image through: | The use of a storage phosphor plate |
| In the past, gas lasers such as a helium-neon laser were used, however, current CR readers use solid state laser diodes that emit a red laser beam having wavelengths of about 670-690nm | True |
| The number of trapped electrons is proportional to the | Absorbed radiation |
| Quantum mottle is caused by | Insufficient light |
| Exposure latitude is to conventional radiography as ____ is to DR | Dynamic range |
| An S value of 200 represents an | Exposure to the IP of 1mR |
| Resolution is controlled by ____ size | Pixel |
| When changing exposure technique from 9 mAs to 18mAs using CR, the radiographer should expect | No change |
| âFadingâ occurred after | 8hours with 25% of image lost |
| CR AND DR have a broader range for exposure and wonât affect the image | True |
| Histograms are graphs of the number of pixels in the entire image or part of the image having the same gray levels | True |
| The LUT is used to distinguish all the different contrasts of an image | True |
| 1MR=2000 Ideal EI # is 1700-2300 Increase by 300, double exposure | Exposure index |
| 1MR= 200 Ideal is100-400 Double #, double exposure | S value |
| The emission of a bluish purple light is when | The transition of the electron from a higher energy state goes to a lower energy state (ground state) |
| When the electron is in the F Center it is at this point when the electrons are spatially distributed and create a _____ image | Latent |
| Have thinner layers of phosphor, provide sharper images, used when small detail is critical Slower speed= high resolution | High resolution IPS |
| Have a thick phosphor layer, absorbs more radiation, have faster speeds High speeds= low resolution | Standards resolution IPS |
| Most important layer within the imaging plate | Phosphor layer |
| Halide can be | Chlorine bromine or iodine |
| Image plate phosphor layer contains Europium within matrix but is not active | True |
| Luminescence | Emission of light by a substance not resulting from heat |
| Fluorescence | Immediate emission of light |
| Phosphorescence | Delayed emission of light |
| PSL | Photostimulated luminescence |
| Four primary steps in CR | Image acquisition Image plate scanning and then erasure Image processing Image display |
| A(n) ____ indicator is a numerical parameter used to monitor the radiation exposure to the IP in CR Imaging | Exposure |
| Kilovoltage peak should be chosen: | Penetration |
| CR systems acquire clinical info by | Laser scanning a PSP plate |
| Photostimulable phosphors have the property of creating and storing a _____ when exposed to X-rays | Latent image |
| Computed radiography is also referred to as | PSP |
| DICOM is a standard that allows imaging modalities and PACS to communicate the same language | True |
| For digital imaging systems, the spatial resolution depends on the size of the ____________________ in the matrix. | pixel |
| Which of the following reduces the output image from the scintillator phosphor to the size of the CCD array? | optical system |
| ____ produce(s) lateral spreading of light, which destroys the spatial resolution of the image. | powdered phosphors |
| Which describes the ability of the imaging system to resolve fine details present in an object? | spatial resolution |
| an eight bit word is called a | byte |
| computers operate using a | binary machine language |
| which layer used in the indirect flat panel digital detector is usually either cesium iodide or gadolinium oxysulfide? | xray scintillator |
| DR is characterized by | the use of a reusable receptor |
| in digital imaging the limiting factor in spatial resolution is the | pixel size |
| ______ is a photoconductor that conducts electrons when struck by light or X-ray photons | selenium |
| when matrix size is increased and pixel size goes down, | spatial resolution increases |
| _______ is a complex mathematical function that measures the ability of the detector to transfer its spatial resolution characteristics to the image | modulation transfer function |
| the window level controls | brightness |
| the exposure indicator number is an | indication of radiation absorbed by the imaging plate |
| each binary number is called a | bit |
| the best signal to noise ratio is | more signal then noise |
| while flat panel indirect detectors use a photodiode, direct detectors use | photoconductor |
| computerized digital images consist of a _____ of picture elements, each with a video display value or gray shade | matrix |
| a histogram is | a graphic representation of X-ray exposure |
| ______ will detect the light from the cesium iodide scintillator in the indirect flat panel TFT detector | sensing area |
| a common feature between indirect and direct DR technology is | TFT |
| in all systems, exposure outside the range indicate | both over and under exposure |
| the purpose of a LUT is to | apple a predetermined scale of contrast to digital data sets |
| _______ deals with the efficiency of a detector to convert the radiation signal at its entrance window into useful image signal | DQE |
| with indirect flat panel TFT digital detectors, what is used to first convert X-ray photons into light photons? | scintillator layer |
| the window width controls | image contrast |
| an MTF of ___ represents a perfect transfer of spatial and contrast information | 1 |
| grossly overexposed digital images will demonstrate | a loss of contrast |
| if the digital FOV is 1024 and the display matrix is 256 the pixel size would be | 4 |
| which major technical component of a digital radiography system refers to the collection of X-rays transmitted through the patient | data acquisition |
| what does X-ray exposure of the PSP IP create | latent image |
| the layers of a flat panel indirect capture detector include | scintillator phosphor, photodiode, TFT array |
| the _____ descriptor takes into consideration not only the signal to noise ration but also the system noise, and therefore includes a measure of the amount of noise added | DQE |
| the window width | decreases contrast and increases grays |
| which image quality descriptor of a digital image is related to the size of the pixels in the image matrix | spatial resolution |
| given the negative feedback due to underexposures, what does a predictable and unfortunate use of higher exposures result in | dose creep |
| _____ is the max range of pixel value a computer, display monitor, or other digital device can store | bit depth |
| a digital image can be described with respect to several characteristics or fundamental parameters, including the matrix, pixels, voxels, and bit depth | true |
| computerized digital images consists of a ____ of picture elements, each with a video display value or gray shade | matrix |
| the term ____ as used in this book, refers to projection radiography, whereby computers process data collected from patients using special electronic detectors that have replaced the X-ray film cassette | digital radiography |
| digital images are less sensitive to scattered and background radiation | false |
| while standard IPS have thick phosphor layers and absorb more radiation, high resolution IPs have thinner phosphor layers and provide sharper images compared to thick phosphors | true |
| saturation and ALARA violations are the primary reasons to use appropriate exposure level | true |
| the most intense aspect of an X-ray beam is located on the cathode side | true |
| which of the following is a photoconductor that conducts electrons when struck by light of X-ray photons | selenium |
| Larger matrix= smaller pixels=improved sharpness | true |
| the LUT is selected by the operator when a procedure is entered at the console | true |
| When the quality of a digital detector is inspected for purchase, the preferred detector for purchase would have | DQE of 68% and MTF of .80 |
| increasing the KVP increases the number of X-ray that X-ray tube emits | true |
| doubling your distance from the radiation source cuts your radiation exposure in half | false |
| the percentage of a detector elements area dedicated to photon absorption | fill factor |
| changes in OID can affect the exposure indicator | true |
| a compton scatter interaction takes place between an X-ray and an outer shell electron | true |
| reducing KVP using a grid and increasing collimation all reduce the production of scattered radiation | false |
| a digital image is composed of a series of rows and columns known as a matrix | true |
| CR systems acquire clinical info by | laser scanning a PSP plate |
| The flat-panel TFT digital detector uses complex and sophisticated electronic circuitry to read out the electrical charges produced and stored in the matrix array. | true |
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