Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Physics 14-18
| Question | Answer |
|---|---|
| What could be considered 100% contrast? | one black pixel and one white pixel |
| To release the latent image in computed radiograph (CR), which of the following devices is scanned over the phosphor plate? | Focused laser light |
| Spatial resolution is the ability to... | Distinguish two adjacent objects as separate |
| Why can an acceptable image be produced with CR or flat-panel digital radiography (DR) equipment even when the input exposure was underexposed or overexposed? | Wider exposure latitude of the digital detector |
| The portion of the detector that receives the analog information is the.... | dexel |
| What is a matrix? | An array of cells arranged in rows and columns |
| In Direct digital radiography, what is the substance that is both the capture element and the coupling element? | amorphous selenium |
| The binary number system used for computer processing is based on | ones and zeros |
| The x-ray beam is an analog waveform. True or false. | True |
| To alter image brightness (density), the _____ is changed. | window level |
| The basic unit of photometrics (science of measuring light) is? | lumen |
| What type of image is generated from a continuous variable physical quantity? | Analog |
| The number of visible shades of gray per pixel in a digital image is determined by? | bit depth |
| An 8 bit analog-to-digital converter will divide the analog signal into how many parts? | 2^8= 256 |
| Digital imaging techniques are always applied to _____. | All of the above? (CT, MRI, Ultrasound) |
| In digital radiography, spatial resolution is improved with increased ________. | Matrix size |
| The charge coupled device (CCD) is.... | A solid state device that converts visible light photons to electrons. |
| In digital radiography, the brightness of the image is determined by... | pixel values |
| What occurs if the number of pixels in a matrix increases and the field of view remains the same? | Spatial resolution increases |
| Contrast resolution is the ability of an imaging system to: | Distinguish between small objects that attenuate the x-ray beam similarly in a digital image |
| Computed radiography cassettes respond to radiation with... | photostimulable luminescence |
| In digital radiography, an indirect capture method that uses cesium-iodide as a phosphor, photo-detectors, a thin film transistor (TFT). Which best describes TFT's? | An electric component that includes the readout, charge collector, and light sensitive elements. |
| When a digital image is excessively overexposed, what is the result? | saturation |
| When raw digital image data are corrected in the computer, prior to being sent to the monitor for viewing it is known as: | pre-processing |
| What is the photostimulable phosphor used in CR imaging? | barium fluoro-halide |
| What is the pixel size in millimeters of a 256 matrix with a 32 cm field of view? | 320 mm/256 = 1.25 mm pixel |
| If the number of pixels is increased in a matrix, image _____ will be increased | detail |
| What type of response does digital imaging have to exposure? | linear |
| Which of the following matrices will have the greatest spatial resolution? i.e. greatest detail | 2048 x 2048 (biggest one) |
| If a pixel has a bit depth of 6, this means that... | 2^6, it can produce 64 shades of grey |
| What is the primary cause of scatter radiation? | patient size |
| The cosine law is one of two fundamental laws associated with photometry (along with inverse square), what describes cosine law best? | luminous intensity is reduced as the monitor is viewed at an increased angle from perpendicular; luminous intensity is at a maximum when the monitor is viewed straight on (A & B) |
| What resolution will result in the greatest spatial resolution (greatest detail)? lp/mm differences Think before you answer... | 8 lp/mm |
| What is the function of the analog-to-digital converter? | Change a continuous signal into discrete packages of data |
| What is pixel density? | Number of pixels in a given area |
| Spatial resolution is determined by the ratio of ______ to _______ | field of view, matrix size |
| How many lines are in a line pair? | 2 |
| The distance or spacing from the middle of one pixel to the middle of an adjacent pixel is known as what? | pixel pitch |
| What is the result of under-penetration? | inadequate information |
| What adjusts the range of densities displayed on the monitor? | window width |
| What error does digital imaging have the most latitude for? | over-exposure?? |
| What is the term used to describe the steady increase of exposure to patients because of the increased latitude for overexposure errors in digital imaging? | dose creep |
Created by:
Cjenki10