EVOLVE FINAL PRACTICE QUIZ
it will have lower contrast resolution. Bit depth determines the contrast resolution of an imaging system. A lower bit depth will mean a lower contrast resolution, not greater. Adjustments to the spatial resolution will not cause differentiation in characteristics between a 16-bit or 8-bit system.
As compared to a 16-bit system, an 8-bit imaging system will have which characteristic? It will have lower spatial resolution. It will have higher spatial resolution. It will have lower contrast resolution. It will have greater contrast resolution.
contrast Dynamic range is the number of gray shades that an imaging system can produce. The principle descriptor for contrast resolution is grayscale, also called dynamic range. Brightness refers to the image darkness. Annotation is adding characters/markers on to the image. Spatial resolution refers to detail.
Dynamic range is associated with which digital imaging term? contrast Brightness Annotation Spatial resolution
Pixel size decreases Spatial resolution increases As the size of the image matrix increases, pixel size decreases and spatial resolution increases. When the size of the image matrix increases, the FOV and pixel size decrease. Spatial resolution only decreases with reduction in size of image matrix.
In digital imaging, which occur when the size of the image matrix increases? FOV increases Pixel size increases Pixel size decreases Spatial resolution increases Spatial resolution decreases
Cesium iodide The area depicted with the arrow indicates the scintillator, which is made up of cesium iodide. Tungsten alloy embedded in the copper anode is used in stationary anode tubes. Thorium (1% to 2%) is added to the tungsten filament to enhance the efficiency of thermionic emission. Alloying the tungsten with rhenium provides mechanical strength to withstand the stresses of high-speed rotation and the effects of thermal expansion and contraction.
The figure shows an indirect capture digital radiography thin-film transistor array. Which material is used to prepare the part indicated [black arrow] in the figure? Copper Thorium Rhenium Cesium iodide
Decrease pitch and increase density Spatial resolution has an inverse relationship with pixel pitch and a direct relationship with pixel density. Increasing the pixel pitch while decreasing pixel density will not increase spatial resolution. Similarly, decreasing both or increasing both will not increase spatial resolution.
To increase spatial resolution, what would need to happen with pixel pitch and pixel density? Increase pitch and decrease density Decrease pitch and increase density Increase both pixel pitch and density Decrease both pixel pitch and density
Amplified image contrast Window and level adjustment helps amplify the image contrast. This helps increase the grayscale on the digital radiograph and make the grayscale visible, which is otherwise completely undetectable to the eye. The window and level adjustment does not compress the file size. Radiation fog is not removed by window and level adjustment. Spatial resolution is not affected by window and level adjustment.
What effect is observed in a digital radiographic image after window and level adjustment? Amplified image contrast Compressed file size of the image Reduced radiation fog on the image Increased spatial resolution
It is a plot between frequencies of occurrence versus the digital value of each pixel. A histogram is a plot between frequencies of occurrence versus the digital value of each pixel. It is a characteristic feature of each anatomical projection and is very useful in digital radiography. It is not a plot between the digital values of each pixel versus the number of blank pixels. It is not a plot between the number of blank rows and the number of blank columns. It is not a plot between the digital values of each pixel versus the number of blank columns.
What is a histogram? It is a plot between the number of blank rows and the number of blank columns. It is a plot between frequencies of occurrence versus the digital value of each pixel. It is a plot between the digital values of each pixel versus the number of blank pixels. It is a plot between the digital values of each pixel versus the number of blank columns.
Decreased spatial resolution Detector element (DEL) size and spatial resolution have an inverse relationship. An increase in DEL size results in a decrease, not increase, in spatial resolution. Increasing the DEL will not impact the contrast resolution.
What is the effect on image quality when detector element (DEL) size is increased? Increased spatial resolution Decreased spatial resolution Increased contrast resolution Decreased contrast resolution
Absorbing light and converting it into electronic charges The figure represents the indirect capture digital radiography thin-film transistor array. The X depicts the field-effect transistor (FET)/thin-film transistor (TFT) array containing electrons. It absorbs light and converts it into electronic charges. The resolution of digital images is determined by the individual size of each pixel. A scintillator absorbs x-rays and converts them into light. Lightness and darkness of the image is changed by brightness, which is a monitor control function.
What is the function of the area depicted [black arrow] in this indirect capture digital radiography thin-film transistor array? Determining resolution of digital images Absorbing x-rays and converting them into light Changing lightness and darkness of the image Absorbing light and converting it into electronic charges
It captures the energy of the remnant beam. A photostimulable phosphor detector captures the energy of the remnant beam and stores it for a period of time in "electron traps." Photostimulable phosphors have lower spatial resolution than other imaging systems. The thin film transistor converts x-rays to electrical signals. Kilovolt peak controls the penetrating ability of the beam.
What is the function of the photostimulable phosphor detector? It improves spatial resolution. It converts x-rays to electrical signals. It captures the energy of the remnant beam. It controls the penetrating ability of the beam.
Isolating each pixel element Sending electrical charges to the image processor (The thin-film transistor (TFT) array is a special kind of field-effect transistor. The TFT array isolates each pixel element and sends the electrical charges to the image processor. The image receptor captures the image for recording. The individual size of each pixel determines the resolution of digital images. Milliampere-seconds (mAs) control the total quantity of x-ray photons produced.)
What is the function of the thin-film transistor (TFT) array? Select all that apply. Isolating each pixel element Capturing the image for recording Determining resolution of digital images Sending electrical charges to the image processor Controlling the total quantity of x-ray photons produced
Image intensifier tower The image intensifier tower is shown in the image. The image does not indicate the head end of the surgical bed, the x- ray tube, or the adjustable C-arm.
What is the indicated part of the C-arm digital fluoroscopy system? X-ray tube Adjustable C-arm Image intensifier tower Head end of surgical bed
Faulty imaging plate The artifact represented in the computed radiograph is caused by a faulty imaging plate. This can be concluded from the undesired white shapes on the left side of the CR. A dirty imaging plate shows foreign bodies in the CR. Improper collimation causes exposure field recognition errors and results in noisy images. Incomplete erasure of the imaging plate causes ghost images, none of which are evident.
What is the most likely reason for the formation of an artifact shown in the computed radiograph? Dirty imaging plate Faulty imaging plate Improper collimation Incomplete erasure of the imaging plate
The image receptor (IR) receives insufficient exposure. The figure indicates quantum mottle. It occurs due to insufficient emission of light from the phosphors. It is also called quantum noise. An increase in the number of x-ray photons increases the exposure, which results in increased IR exposure. Increasing source-to-image distance and decreasing OID reduces the magnification.
When does the radiographic image appear as shown in the figure? The number of x-ray photons increases. The source-to-image distance (SID) increases. The object-to-image distance (OID) decreases. The image receptor (IR) receives insufficient exposure.
National Electrical Manufacturers Association (NEMA) The National Electrical Manufacturers Association (NEMA) frames a set of standards for digital imaging and communication (DICOM). DICOM facilitates the display of the image on various DICOM-compatible display devices with consistent gray scale appearance. Video Electronics Standard Association (VESA) developed a set of instructions to evaluate the system performance. The National Institute of Standards and Technology (NIST) provides a calibration method for the photometer used for the measurement of luminance. The Society of Motion Picture and Television Engineers (SMPTE) developed a format to measure the resolution parameters of the display device.
Which association provides the guidelines to transfer a radiographic image to various DICOM-compatible display devices without altering its gray scale? Video Electronics Standard Association (VESA) National Electrical Manufacturers Association (NEMA) National Institute of Standards and Technology (NIST) Society of Motion Picture and Television Engineers (SMPTE)
Cesium iodide In indirect capture DR, the capture element is cesium iodide. In CR, the capture element is photostimulable phosphor. Calcium tungstate and amorphous silicon are not capture elements used in indirect DR.
Which capture element is used in indirect digital radiography? Amorphous silicon Calcium tungstate Cesium iodide Photostimulable phosphor
Pixel size decreases Image quality increases Spatial resolution increases Increased matrix size digital display devices have better spatial resolution because they have smaller pixels. This allows magnification of a region of an image to render the smallest detail, thus increasing spatial resolution and image quality. Pixel size does not increase, image quality does not decrease, and spatial resolution does not decrease.
Which changes will occur if field of view (FOV) remains the same and matrix size is increased? Select all that apply. Pixel size increases Pixel size decreases Image quality increases Image quality decreases Spatial resolution increases Spatial resolution decreases
Increase in sampling frequency Decrease in phosphor layer thickness The relationship between spatial resolution and sampling frequency is direct. The relationship between spatial resolution and the thickness of the phosphor layer is inverse. In computed radiography, the pixel bit depth mainly affects contrast resolution.
Which factors increase spatial resolution in computed radiography? Select all that apply. Increase in pixel bit depth Decrease in pixel bit depth Increase in sampling frequency Decrease in sampling frequency Increase in phosphor layer thickness Decrease in phosphor layer thickness
Increased spatial resolution Spatial frequency refers to line pair. As spatial frequency becomes larger, the objects become smaller. Higher spatial frequency indicates increased spatial resolution. Contrast is not affected by spatial frequency.
Which is the result of an imaging system with higher spatial frequency? Increased contrast Decreased contrast Increased spatial resolution Decreased spatial resolution
Selenium Cesium iodide Amorphous silicon Selenium, cesium iodide, and amorphous silicon are materials used in a flat panel detector. A flat panel detector is a type of digital detector that is bonded with a thin-film transistor for digital image creation and amplification. Aluminum is used for filtration in an x-ray tube. Pyrex glass is used in the construction of an x-ray tube.
Which materials are used in a flat panel detector? Select all that apply. Selenium Aluminum Pyrex Glass Cesium iodide Amorphous silicon
straight towards the device Luminous intensity refers to the total amount of light intensity from the source. Luminous intensity is the property of a light source, such as a display device. The luminous intensity will be the highest if the radiologist views the image on the device, straight on. Luminous intensity is reduced if the image on the display is viewed from the sides. If the distance from the display device is increased, luminous intensity and contrast will be decreased.
Which position is suitable for the best viewing of a radiographic image without reduction in the contrast? Far from the device Straight towards the device Towards the left side of the device Towards the right side of the device
Edge enhancement Edge enhancement helps provide better visualization of this fracture, as it accentuates the interface between the two tissues. Pixel shift is used to correct misrepresentation of a subtraction image. Highlighting does not make the fracture prominent. The region of interest does not make the fracture more noticeable.
Which postprocessing technique helps provide the best view of a hairline fracture that is very thin? Pixel shift Highlighting Region of interest Edge enhancement
Image flip Image flip is used to rotate the images horizontally or vertically as desired, for better viewing. Pixel shift does not flip the images. It eliminates the defects caused by patient motion when subtraction images are used. Image inversion inverts the black and white regions of the image. The region of interest helps in quantitative imaging.
Which postprocessing technique is helpful in rotating a digital radiographic image of the wrist, horizontally or vertically, as shown in the image? Pixel shift Image flip Image inversion Region of interest
Image inversion The radiograph represents the inversion of black to white and white to black. This is done through image inversion. Pixel shift is used to eliminate patient motion on subtraction images. Subtraction helps enhance the image contrast. Interpolation helps eliminate the defective pixels in the image, but it does not invert the black to white in the image.
Which postprocessing technique is used to manipulate the radiograph as seen in the image? Pixel shift Subtraction Interpolation Image inversion
Flatfielding Image A clearly represents the heel effect, produced by the exposure of the image receptor to a raw x-ray beam. This can be corrected using flatfielding. Interpolation is used to eliminate defective pixels from the image; it cannot correct the heel effect. Voltage correction is used to eliminate line noise. The application of offset voltage is used to eliminate image lag; it has no effect on the heel effect.
Which preprocessing procedure converts an undesired effect, shown in image A, into a corrected form, as shown in image B? Flatfielding Interpolation Voltage correction Application of offset voltage
Amorphous selenium Direct-capture digital imaging systems have the best spatial resolution. Amorphous selenium is found in direct-capture digital imaging systems. Cesium iodide and amorphous silicon are found in indirect-capture digital imaging systems. Barium fluorohalide is present in computed radiography (CR) systems.
Which substance is found in the system with the best spatial resolution? Cesium iodide Amorphous silicon Barium fluorohalide Amorphous selenium
To lower the patient's dose To improve image resolution Using cesium iodide as a detector material reduces exposure and lowers the patient's dose. It also helps improve image resolution. Avoiding the use of high temperature chemical solutions for image processing prevents chemical fog. A sufficient amount of light emitted from the phosphor crystals prevents quantum mottle. Beam modification during radiography controls the scattering of radiation.
Why is cesium iodide used as a detector material in fluoroscopy? Select all that apply. To prevent chemical fog To reduce quantum mottle To lower the patient's dose To improve image resolution To control scattering of radiation
To control image brightness Window level is the postprocessing option that adjusts the brightness of the image. Window width adjusts the contrast of the image. Magnification is used to magnify all or part of an image. Equalization is used to alter the pixel values across the image.
Why is the window level adjusted during postprocessing of an image? To control image contrast To control image brightness To magnify all the parts of the image To alter the pixel value of the image
Higher; smaller Smaller objects are seen better with a high spatial resolution system. High spatial resolution means high spatial frequency. Lower spatial resolution can be used with larger objects.
____________ spatial frequency indicates better spatial resolution, which is good to show _____________ objects. Higher; smaller Lower; smaller Lower; larger Higher; larger
more light scatter
thicker phosphor=
