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_____ determines the fixed spatial resolution characteristic of direct digital systems.
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What controls the subject contrast of the exit/remnant signal in digital imaging?
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RADT 465 Unit 2
Equipment Operation, QA, and Image Acquisition and Evaluation
| Question | Answer |
|---|---|
| _____ determines the fixed spatial resolution characteristic of direct digital systems. | TFT and DEL size pg. 167 |
| What controls the subject contrast of the exit/remnant signal in digital imaging? | Kilovoltage & Photon energy pg. 167 |
| What is an algorithm? | A series of variable instructions pg. 167 |
| 3 components of a detector element (DEL) are | Sensing area, TFT, Capacitor pg. 167 |
| What is geometric sharpness inversely influenced by? | OID pg. 168 |
| If a 12:1 grid ratio exhibits loss of signal at its lateral edges, it's because | SID was too great pg. 169 |
| What is x-ray photons energy inversely related to? | Photon wavelength pg. 170 |
| What are results of a decrease in kilovoltage? | Decrease in photon energy & receptor exposure pg. 171 |
| What is the primary function of x-ray beam filtration? | Reduce patient skin dose pg. 171 |
| Which pathologic condition would require a decrease in exposure factors? Osteomyelitis Osteoporosis Osteosclerosis Osteochondritis | Osteoporosis pg. 167 |
| Which of the following does not affect the exposure rate of the primary beam? mA kV distance field size | Field size pg. 172 |
| Which has the greatest affect on radiographic IR exposure? Aluminum filtration kV SID Scattered radiation | SID pg. 172 |
| What is subject contrast related to? | Differential tissue absorption & atomic number of tissue being traversed pg. 172 |
| Decreasing what will improve spatial resolution/detail sharpness? | OID and patient/part motion pg. 172 |
| What are special considerations/conditions that require an increase from the typical technique factors? Excessive BMI Skeletal sclerosis Osteomalacia | Excessive BMI and skeletal sclerosis pg. 172 |
| Distance from the middle of one pixel to the middle of an adjacent pixel | Pixel pitch pg. 173 |
| What is associated with the term "voxel"? Bit depth Volume element Measure in Z direction Field of view | Volume element & measure in Z direction pg. 173 |
| Spatial resolution will be improved using ___ in the same field of view | A larger matrix pg. 173 |
| To have the same FOV, once the matrix size increases Spatial resolution increases Image quality increases Pixel size decreases | spatial resolution increases, image quality increases, and pixel size decreases pg. 175 |
| How does SID affect sharpness of image details? | Image detail sharpness is directly related to SID pg. 175 |
| How does image resolution improve? Scintillation increases DEL size decreases Fill factor increases | DEL size decreases & fill factor increases pg. 175 |
| What is not true about digital imaging? Window level adjustments are associated with image brightness Brightness is related to IR exposure Image visibility is a function of IR exposure Brightness and density are not interchangeable terms | Brightness is related to IR exposure pg. 175 |
| Kilovoltage selection has an effect on what? Photon energy Penetration Image contrast | Photon energy and penetration pg. 175 |
| What are factors impacting spatial resolution? Focal spot size Subject motion SOD | Focal spot size, subject motion & SOD pg. 175 |
| 512 X 512 matrix with a 20 cm FOV has what pixel size? 0.07 mm/pixel 0.40 mm/pixel 0.04 mm/pixel 4.0 mm/pixel | 0.40 mm/pixel pg. 176 |
| What enables the radiographer to reduce the exposure time required for a particular image? Use of a higher mA Use of a higher kV Use of a higher ratio grid | Use of a higher mA & use of a higher kV pg. 176 |
| What statement is incorrect regarding kilovoltage? Increased kV increases beam intensity Receptor exposure can be doubled or 1/2 by using the 15% rule Increased kV can decrease absorbed dose kV and wavelength are directly proportional | kV and wavelength are directly proportional pg. 176 |
| The image on the input phosphor compared to the image on the output phosphor of the image intensifier is: Magnified Distorted Brighter Dimmer Inverted Minified | Brighter, Inverted, & Minified pg. 217 |
| What statements are true regarding viewing conditions for digital images? Excessive light causes dilation of the pupils of the eyes Low-light level is desirable Too much light causes images to appear dark | Low-light level is desirable & Too much light causes images to appear dark pg. 217 |
| When FOV decreases in image intensification | Output screen image is magnified, mA increases, output screen image has improved resolution pg. 217 |
| Known as equalization, the digital imaging processing function is/does what? | Is a computer software operation, removes densities that veil image details, and compresses the contrast scale pg. 217 |
| Unsharp edges of tiny radiographic details is called what? | Blur pg. 218 |
| When are radiographic equipment collimators required to be checked? | Semiannually pg. 218 |
| What will improve the spatial resolution of image-intensified images? | A very thin input phosphor layer pg. 218 |
| What's the total number of x-ray photons produced at the target depend on? | Tube current, target material & square of the kilovoltage pg. 218 |
| Kilovoltage and HVL relationship | As kilovolatage increases, the HVL increases pg. 219 |
| When window width decreases | Contrast scale decreases pg. 219 |
| What is a circuit device that only allows flow in one direction called? | Solid-state diode rectifiers pg. 219 |
| What is scintillation not associated with? | Amorphous silicon pg. 219 |
| When a high-speed electron slows down as it becomes attracted to a tungsten atom nucleus. | Bremsstrahlung radiation pg. 220 |
| The amount of electric charge flowing per second is called what? | Current pg. 221 |
| Device the directs the light emitted from the image intensifier to different views and imaging apparatus? | Beam splitter pg. 221 |
| What contributes to inherent filtration? | X-ray tube glass envelope & X-ray tube port window pg. 221 |
| The result of digital imaging subject contrast is | Signal differences within the remnant beam pg. 221 |
| What is the product of total brightness gain of an image intensifier? | Flux gain & minification gain pg. 222 |
| As ______ decreases, spatial resolution in compound radiography increases. | PSP crystal size decreases & laser beam size decreases pg. 223 |
| What material is appropriate for IP front material | Magnesium & Bakelite pg. 224 |
| What is the image intensifiers input phosphor made of? | Cesium iodide pg. 224 |
| What can grid interspace be made of? | Aluminum & plastic fiber pg. 224 |
| Changing the size of the actual focal spot will change what? | Detail sharpness, effective focal spot size, and spatial resolution pg. 225 |
| What are required corrections done to "raw" image data that occur because of inherent flaws in the image acquisition system called? | Preprocessing pg. 226 |
| Reference: Saia, D.A. (2022). Image Production: Image Acquisition and Technical Evaluation. In S. Barnes, C. M. Thomas (Eds.), Lange Q & A: Radiography Examination (12th ed., pp. 167-211).Chicago, IL: McGraw-Hill Education. | |
| Reference: Saia, D.A. (2022). Image Production: Equipment Operation and Quality Assurance. In S. Barnes, C. M. Thomas (Eds.), Lange Q & A: Radiography Examination (12th ed., pp. 217-250).Chicago, IL: McGraw-Hill Education. |
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