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Rad Imag. 2
Ch. 12-17
| Question | Answer |
|---|---|
| The two basic components of radiologic film are | base and emulsion |
| The main purpose of the gelatin is to | hold the silver halide crystals |
| Crystals in film emulsion consist of | silver bromide and silver iodide |
| The overcoat on radiographic film is a protective covering of | gelatin |
| Latent imaging formation occurs during the film | exposure |
| A contaminant in the silver halide crystal created the | sensitivity speck |
| The latent image can only be seen after | development |
| Photon interaction in the emulsion occur with exposure to both | xray and light |
| Film is made with double emulsion to enhance film | speed |
| The efficiency of the intensifying screen is improved by the | reflective layer |
| A phosphorescent material emits light for a period of time after | stimulation |
| An intensifying screen is an example of both | luminescence and fluorescence |
| Luminescent material emits light after its outer shell _________ are excited | electrons |
| A screen that emits light after an exposure terminates is exhibiting screen _____ | log |
| The ability of an intensifying screen to absorb xrays is called | detective quantum efficiency |
| The four primary exposure factors are | mA, kVp, time, and SID |
| Changes in kVp affect | optical density, image contrast, and image noise |
| An increase in mAs causes | no change in beam quality and an increase in beam quantity |
| There is a direct relationship between the quantity of xrays and the | milliamperage |
| If mAs is increased from 20mAs to 40 mAs the patient dose will increase | double |
| A 15% increase in kVp has the same effect on density as _____ the mAs | doubling |
| A radiograph with long scale of contrast will also have wide latitude and _____ contrast | low |
| Reducing the kVp 15% and doubling the mAs will increase contrast but maintain the | optical density |
| At least 30% change in mAs is necessary to produce a visible change in | optical density |
| A technique of 55kVp @ 20mAs was used, what technique would double density and produce a longer scale radiograph? | 65kVp @ 20mAs; increase 15%kVp |
| Patient dose increases are directly related to increases in ______ | mAs and distance |
| The small focal spot is used to provide ______ detail when less quantity if xrays is needed. | greater |
| Two effects of added filtration ____ beam quality and ___ patient exposure | increase; reduce |
| Lung is the most ____ tissue in the body, fat is more radiolucent than muscle and bone is the most radiopaque | radiolucent |
| Emphysema makes the lungs ____ radiolucent | more |
| When only optical density needs to be changed only the ___ should be changed | mAs |
| Sharpness of detail can be improved by increasing the ___ and ___ | SID; decreasing OID |
| ____ is caused by an angled body part when the beam is perpendicular to the image. | foreshortening |
| A _____ chart has a set kVp and specific mAs settings either for small, medium, and large or for every 2cm of thickness. | variable mAs technique; fixed kVp technique |
| With ____ the exposure is terminated when the optimum optical density is reached | automatic exposure control |
| The first generation of computers was run with _____ tubes | vacuum |
| Modern day computers use _____ chips to store information | silicon |
| Computer ____ includes any part of the computer that you can see and touch | hardware |
| The mouse is an example of computer input ___ | hardware |
| A tape, diskette, hard disk, or optical density is used to ______ film or archive image | replace |
| The bit represents zero or ____ | one |
| In computer language, 2 bytes is a _____ | word |
| Microprocessors process _____, they do not store data. | data |
| Teleradiology is the practice of transferring patient images, and ___ to remote sites | reports |
| Digital radiography was first introduced by Fuji in ____ | 1981 |
| CR IPs and FS cassettes can be used _____ with any xray imaging system | interchangeably |
| CR screens respond to radiation with | photostimulable luminescence |
| A photostimulable phosphor in a metastable state will emit light ___ when stimulated by xrays, when ___ by light and over time. | immediately; stimulated |
| Europium is the ___ of the photostimulable phosphor | activator |
| The CR cassette is called an ______ | imaging plate |
| The PSP screen is handled in a ____ | reader, scanner |
| The CR reader is made up of ______, _____, and ______ modules. | mechanical, optical, computer |
| The four steps of creating an image with computer radiography are ____, ____, ____, ____. | exposure, stimulate IP, read IP, erase |
| Following the laser stimulation of PSP, the electrons are mostly ____. | relaxed |
| Optical filters are used to filter out the ____ light and allow emitted light to reach the photodetector | stimulating |
| The output signal from the PSP plate is converted from light to digital by the _____ | computer system |
| One of the similarities between CR and SF imaging is that both have ___ | latent images |
| The principle source of noise in CR is _____ | scatter radiation |
| With computed radiography the contrast is constant ___ | regardless of radiation exposure |
| The computed radiography image has ____ exposure latitude and improved ____ resolution | greater/wider; contrast |
| After switching from film screen imaging to CR the step of reloading the ___ is eliminated. | cassette |
| _____ is prevented by flooding the erased plate (screen) with bright light | ghosting |
| Computed radiography images produce ____ gray shades | 10,000 |
| Switching from screen film imaging to computed radiography can reduce patient ______ | exposure dose |
| ______ and contrast resolution are the two principle characteristic of a medical image. | spatial |
| In medical imaging, the quality of spatial resolution is measured by the _________ | spatial frequency |
| A digital imaging system cannot resolve anything smaller than ___ pixel | one |
| A spatial resolution of 4 lp/mm resolves 8 objects per mm, each object being ___ or 0.125mm. | 1/8 |
| As spatial frequency increases the object size decreases and the _____ increases. | spatial resolution |
| In a perfect system the image size would equal the object size and the MTF would be equal to __ | 1 |
| The human visual system distinguish no more than ___ shades of gray | 30 |
| The number of shade of gray that an imaging system can produce is called its ___ | dynamic range |
| Screen film radiography has a dynamic range of ____ | 1,000 |
| The bit capacity of each pixel identifies the ___ range of a digital imaging system | dynamic |
| The mammography digital imaging systems uses the highest ______ | dynamic range, number of shades of gray |
| The portion of the useful image-forming xrays is referred to as the ___ | signal |
| Recent studies have shown that denser breast tissue is best imaged with ____ mammography. | digital |
| As mAs is increased the _______ is increased | signal to noise |
| Image detail is also called ______ | spatial resolution |
| With digital imaging, patient dose can be reduced by using ___ kVp techniques | higher |
| DQE stands for | detective quantum efficiency |
| With digital radiography, problems with overexposure or inadequate brightness or contrast can be corrected during | post processing |
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