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RAD107_Week 5-8
| Question | Answer |
|---|---|
| An increase in mAs causes ______________ in beam quality and ___________ in beam intensity. | no change; an increase |
| Patient dose increases are directly related to increases in | mAs |
| Both beam quality and beam quantity are increased by ______________ | increasing kVp and using a 3-phase generator |
| There is a direct relationship between the quantity of x-rays and the ___________ | milliamperage |
| the 5% rule | An increase of 5% in kVp may be accompanied by a 30% reduction in mAs to produce the same image receptor response at a slightly reduced contrast scale = |
| The small focal spot will provide a _______ | finer detail of image |
| What are the prime exposure factors? | kVp, mAs, and SID |
| Beam penetrability is increased if ________ is/are increased. | kVp |
| Patient thickness should be measured with the ______ | caliper |
| Added filtration has the effect of __________ the beam quality and ________ patient dose. | increasing; reducing |
| Foreshortening is caused by a(n) ____________________ | angled body part when the beam is perpendicular to the image receptor |
| Changes in kVp do not affect the number of | number of electrons boiled off the filament |
| When only the intensity needs to be changed, only the _______ should be adjusted | mAs |
| Beam quantity is improved when the __________ is increased, but __________ has no effect on beam quantity. | kilovoltage; milliamperage |
| Sharpness of detail can be improved by increasing _______ | SID |
| If mAs is increased from 20 mAs to 40 mAs, the patient dose will _______ | e doubled |
| With automatic exposure techniques the exposure is terminated when the optimum _____ is reached | mAs |
| List the following tissues in order from the most radiolucent to the most radiopaque. | Lung, fat, muscle, bone |
| At least a _____% change in mAs is necessary to produce a visible change in the image | 30 |
| Radiographic image quality is improved when the __________ is increased | source image distance |
| The visibility of image detail is best measured by_____ | Contrast resolution |
| A high quality radiographic image should always demonstrate ________ | Structures and Tissues |
| What is the formula for the magnification factor? | MF = SID/SOD |
| Distortion can be reduced by _________________ | placing the object plane perpendicular to the image plane |
| Which of these body parts has the highest subject contrast? | Chest |
| Sharpness of image detail is best measured by _____________ | spatial resolution |
| Patient thickness affects radiographic technique by affecting _________ | mAs and kVp settings |
| Spatial resolution is limited to ____________ | pixel size |
| Which body habitus indicates an average patient? | Sthenic |
| Radiographic technique charts embedded in the operating console are based on hypersthenic patients (T/F) | False |
| The best way to minimize magnification is to use a __________. | long SID and small OID |
| Subject contrast is affected by ________ | Patient Thickness |
| The technologist primarily controls radiographic contrast by varying the ________ | kilovoltage |
| _________ is defined as the ability to image two separate objects and visually detect one from the other. | Resolution |
| Patient factors include ___________ | anatomical thickness and body composition |
| _______of the image is when the anatomical part appears smaller than normal. | Foreshortening |
| Which body habitus indicates a thin, but healthy appearing patient? | Hyposthenic |
| The ability to image small objects that have high subject contrast is known as ______ | spatial resolution |
| Which group of factors includes spatial resolution and distortion? | Image-quality factors |
| ____may be described by identifying three groups of factors: patient factors, image-quality factors, and exposure technique factors | Radiographic technique |
| Which group of factors includes grids, focal-spot size, and filtration? | Exposure technique factors |
| The ability to distinguish between and image similar tissues is known as ______ | contrast resolution |
| To obtain a magnified radiograph, the _______ is increased while the ______ is held constan | OID; SID |
| Distortion is reduced by positioning the anatomical part of interest in a plane _________ to that of the image receptor. | Parallel |
| Which group of factors includes kVp, mAs, and SID? | Exposure technique factors |
| Which group of factors includes anatomical thickness and body composition? | Patient factors |
| The purpose of image subtraction is to enhance | Contrast |
| What is the basic photometric unit? | Lumen |
| _______ improves with the use of higher megapixel digital display devices. | Spatial resolution |
| Reregistering an image to correct for patient motion is done with ____________ | pixel shift |
| A liquid crystal is a material in a ______________________ state. | state between a liquid and a solid |
| Preprocessing the digital image is done _____________, and post-processing is done __________ | automatically; manually |
| The SI unit for luminance is the | nit |
| Almost all digital images in medical imaging are viewed and interpreted on a __________ | digital display device |
| Signal interpolation is performed during | preprocessing |
| Almost all medical flat panel digital display devices are _____________ | monochrome liquid crystal displays (LCDs) |
| Medical flat panel display devices are identified by the _____________ | number of pixels |
| Annotation is performed during | post-processing |
| A digital display monitor is best viewed ________ | straight on |
| The cosine law is used to describe ________________ | luminous intensity of a digital display device |
| __________________ is corrected by the application of an offset voltage | Image lag |
| Which medical information organization is working to make patient radiation dose ALARA? | ACR |
| File size is the matrix multiplied by the _______ | byte depth |
| ______ implements and speeds image processing, viewing, interpretation, storage, and recall | PACS |
| Which three organizations created the document, “Technical Standard for Electronic Practice of Medical Imaging”? | SIIM, ACR, AAPM |
| The national standard for image transmission in teleradiology is the ____________ format. | DICOM |
| What does DICOM stand for? | Digital Imaging and Communications in Medicine |
| PACS stands for ________________ | Picture Archiving and Communication Systems |
| The _________ deals with schedules, protocol descriptors, diagnostic conclusions, and billing. | Radiology Inforamtion Systems (RIS) |
| The process of remote transmission and viewing of medical images is known as __________. | Teleradiology |
| What does EMR stand for | Electronic Medical Record |
| What system became the standard for PACS in order to receive/read images? | DICOM and HL7 |
| The term network is used to describe the ___________ | manner many computers can be connected |
| Text data and email are generated at a _____________________________ workstation in PACS. | Radiology Information System (RIS) |
| The process of matching any worker to the work environment in order to maximize efficiency is | Ergonomics |
| When light arrives at the retina, it is detected by the _____________ | rods and cones |
| When the ROC analysis is completed, the data is evaluated using the metric, _________ | area under the curve (AUC) |
| Digital radiography is superior to analog radiography because of ______________ | Image brightness |
| ________ is a term related to changes we make voluntarily and involuntarily in order to improve our image perception. | Visual accommodation |
| Light incident on the eye must first pass through the ____________ | cornea |
| The special demands of digital imaging are ________________ and _____________. | postprocessing; numerical analysis |
| The ambient light levels in the reading area should be ______________. | near darkness |
| Photopic vision is used for _____________ | daylight vision |
| Receiver operating characteristic curves is a decision matrix used for __________ | decision-making by the radiologist |
| The decreasing luminous intensity with increasing distance from the source of light follows _______________ | the inverse square law |
| All of the following are components of receiver operating characteristic curves, except ______ | sensitivity index |
| Image perception is a scientific term for what we call visual _________ | sensitivity |
| The Task Group Report 18 is a procedure manual for _______________ | testing digital display devices |
| A telescope photometer is used at __________. | 1 meter |
| Most of the quality control testing of digital display devices is performed with the use of _______________ test patterns. | AAPM TG18 |
| Daily quality control testing is done by the | radiologic technologist |
| SMPTE stands for the _____________________ | Society of Motion Picture and Television Engineers |
| Digital display reflections and ambient light conditions are assessed with a(n) ___________ | illuminance meter |
| There are _______ types of photometers commonly used. | two |
| A standard pattern made to measure the resolution of digital display systems is called the ______________ | SMPTE pattern |
| The TG18-LPV/LPH test is used to evaluate ______________ | geometric distortion |
| Medical images are transferred using the ____________ standard. | DICOM |
| The quality control standard for flat panel displays was released by _______ in 1998. | VESA |
| The qualitative evaluation of luminance response is measured with the ________ test tool. | TG18-CT |
| Specular reflection is reduced with the use of ___________ | improved antireflective coating |
| The consistent appearance of DICOM images on any compatible digital display device is achieved through _____________ | perceptual linearization |
| Which of the following is the principal contributor to image noise in radiographic and fluoroscopic imaging procedures? | Quantum mottle |
| Radiographic __________ is random fluctuation of x-ray interaction on the image receptor. | noise |
| Patient thickness affects image quality by affecting ____________. | magnification, radiographic contrast and focal spot blur |
| The best way to minimize magnification is to use a __________. | long SID and small OID |
| Focal-spot blur is small on ______________ side and large on the ___________ side of the image receptor | anode; cathode |
| _________ is defined as the ability to distinguish anatomical structures of similar subject contrast and visually detect one from the other. | Contrast resolution |
| What is the formula for Radiographic contrast? | Image receptor contrast × subject contrast |
| Distortion depends on _______ | object shape |
| Spatial resolution improves with decreased | focal spot size, motion and pixel size. |
| A high-quality medical image should always demonstrate ___________ | structures and tissues |
| The technologist primarily controls radiographic contrast by varying the __________. | kilovoltage |
| Higher speed image receptors generally produce images with ____________________. | increased noise |
| Which of the following will reduce quantum mottle? | High mAs, low kVp, and slower image receptors |
| The three primary geometric factors affecting image quality are ___________ | magnification, distortion, and focal spot blur |
| Distortion depends on ______ position | object |
| What is the formula for the magnification factor? | MF = SID/SOD |
| Focal spot blur can be reduced by using __________. | a small focal spot |
| Radiographic image quality is improved when the __________ is increased. | source image distance |
| Magnification factor = | image size/object size |
| The x-rays that are transmitted through the patient without interaction contribute to _________ | useful information |
| Photoelectric interactions increase when ___________ is decreased. | kVp |
| Lowering kVp ________ patient dose and _________ image contrast. | increases; increases |
| Federal regulations passed in _____ required that positive beam limiting devices be on all manufactured x-ray collimators. | 1974 |
| The positive beam limiting device (PBL) assures that the x-ray beam is collimated to _____________ | the image receptor size |
| Which kVp selection would result in the most scattered x-rays in the image-forming beam? | 90kvp |
| Approximately _______% of the x-ray beam incident on the patient is transmitted through the patient without interaction to become part of the image-forming beam. | 1% |
| Compton scatter contributes to __________ | image noise |
| Contrast resolution is improved by _____________. | tight collimation, lowering kVp and patient compression |
| The use of a compression device will increase __________. | image contrast |
| The three primary factors influencing the intensity of scatter in the image-forming beam are ___________________. | kVp, field size, and patient thickness |
| A fixed aperture diaphragm should leave a _____ cm unexposed border on the film. | 1cm |
| The use of __________ improves contrast and reduces patient dose. | collimation |
| Beam restriction with a(n) ____________ is only accurate at a fixed SID. | aperture diaphragm |
| The most commonly used beam restricting device is the ____________. | variable collimator |
| How can you improve image contrast with a heavy patient without increasing patient dose? | Use tight collimation. |
| Decreasing the kVp will increase ___________. | patient dose |
| The x-ray interaction that contributes to the clear parts of the image is _____________. | photoelectric interaction |
| Image-forming x-rays include those which have been _________________ | transmitted without interaction and scattered through Compton interaction |
| Scatter radiation increases as ___________________ increases. | field size |
| Computed radiography cassettes can sit for ____________ between exposures. | a few days |
| Histogram selection is done _________________ | by the radiographer before each exam |
| The size and number of digital images have to be compressed to permit _______ | transmitting and archiving |
| Lossy compression reduces data files greater than _____ | 10:1 |
| During preprocessing, the digital output of the image receptor may need to be manipulated to correct for ______________ | dead pixels |
| The three classifications of digital imaging artifacts are _______________________. | image receptor, software, and object |
| The software correction that equalizes the response of each pixel to a uniform exposure of x-rays is called ___________ | flatfielding |
| Each anatomical part has an image histogram with a(n) _______________ shape. | characteristic |
| What size is the average CR or DR image file per image? | 20 MB |
| Backscatter radiation artifacts can occur more readily in digital imaging because of the _____________ | highly sensitive receptors |
| A graph of the frequency of occurrence versus digital value intervals is called a(n) ______________ | histogram |
| Which modality produces the largest image files? | Digital mammography |
| Object artifacts in digital imaging can occur from errors in ________________ | x-ray beam collimation, histogram selection, and patient positioning |
| Computer aided diagnosis (CAD) requires the use of ______________________. | uncompressed images |
| The ability to image small objects that have high subject contrast is known as ____________. | spatial resolution |
| Which statement is true regarding medical image quality? | Spatial resolution is limited to pixel size. |
| Of all of the imaging modalities, _______________ is considered to have the best contrast resolution. | MRI |
| As collimation increases, what is the effect on image contrast? | Increases |
| As the x-ray beam field size increases, what is the effect on scatter radiation? | Increases |
| The height of the grid divided by the interspace width is known as the __________________. | grid ratio |
| Bucky factor = | incident remnant x-rays/transmitted image-forming x-rays |
| Contrast improvement factor = | image contrast with a grid/image contrast without a grid. |
| Which type of compression is up to 3:1 and is generally considered acceptable and helpful in digital radiographic image management? | Lossless compression |
| Digital radiographic image receptors have unique artifacts associated with | Pixel failure |
| What is a preprocessing software correction that is performed to equalize the response of each pixel to a uniform x-ray beam? | Flatfielding |
| Which type of compression is greater than 10:1 and supports teleradiology but not CAD? | Lossy compression |
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jetsetjes