Help
Options
Question
attenuation
click to flip
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't know
Question
contrast
Remaining cards (72)
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
110 Unit 3 Sect B
| Question | Answer |
|---|---|
| attenuation | beam energy reduced when passing through tissue/material |
| contrast | difference between adjacent densities |
| density | degree of darkening of film |
| distortion | misrepresentation of true size of object |
| dynamic | with motion |
| half value layer | filtration needed to reduce beam to half its original value |
| intensifying screen | luminescent crystals inside cassette to expose film |
| Inverse square law | formula desribing relationship betwwen intensity and distance |
| Kilovoltage peak (kVp) | measure of electrical pressure, controls quality/quantity of photons in tube |
| latent image | invisible image after exposure but before processing |
| Milliampere Second (mAs) | milliamperage X seconds, controls quantity of photons produced in tube, exposure and density |
| penetrating ability | beam ability to pass through object, controlled by kVp |
| penumbra | fuzzy border |
| photon | particle of radiant energy |
| Positive Beam Limitation (PBL) | automatic collimation |
| primary radiation | beam before hitting object |
| radiolucent | permitting xray passage with little attenuation |
| radiopaque | not easily penetrable by xrays |
| recorded detail | representaion of objects true borders |
| relative speed | speed of film and intensifying screen, slow film, sharper image and more radiation |
| remnant radiation | radiation after beam exits object |
| resolution | measurement of recorded detail on radiograph, aka sharpness of detail, definition |
| scatter radiation | photon interacts with matter, goes in different direction, radiation produced |
| static | unmoving |
| umbra | true border of object as imaged |
| photographic qualities | density and contrast |
| geometric qualities | recorded detail and distortion |
| mAs formula | mA x time = mAs |
| Exposure/density influencing factors | patient factors, kVp, distance, beam modification, grids, film/screen combinations, processing |
| 15% rule | increase kVp 15% will double exposuredecrease kVp 15% will halve exposure |
| 15% rule with no change in exposure | increase kVp 15% and halve mAsdecrease kVp 15% and double mAs |
| inverse square law definition | intensity of beam is inversely proportional to the square of the distance from the source |
| inverse square law formula | I1/I2=D1squared/D2squared |
| inverse square law tip | halve the distance, X intensity by 4 |
| exposure maintenance formula | mAs1/mAs2 = D1squared/D2squared |
| primary beam modification | modified beam before entering patient |
| scale of contrast | range of gray tones; few is high contrast, short scale and vica versa |
| Influencing factors of contrast | patient factors, mAs, beam modification, film/screen combinations, contrast media, processing |
| factors affecting recorded detail | motion, object unsharpness, focal spot size, SID, OID, and material unsharpness |
| SID | greater SID better recorded detail |
| OID | greater OID, decreased sharpness |
| size distortion | magnification |
| shape distortion | true distortion |
| shape distortion controlling factors | alignment of beam, part and IR |
| spot imaging | flouroscopy unit changes to radiographic mode |
| anode | positive electode, target, method to accelerate |
| cathode | negative electrode, filament |
| rotor exposure switch | device that begins the exposure |
| ALARA | (radiation exposure) as low as reasonably acheivable |
| Classic Coherent scattering | low energy photon absorbed and released with only a change in direction |
| Compton effect scattering | high energy photon strikes end removes electron from shell, remaining energy released as scatter photon, most harmful to RT |
| Curie (Ci), Becquerel (Bq) | measures the rate a radionuclide decays, 1Ci=3.7 x 10(to the tenth)Bq |
| SI Units | metric radiation measurement developed in 1948 |
| Kilelectron Volt (keV) | equal to 1000 electron volts |
| pair production | interaction between matter and photon having 1.02 million electron volts, producing positron and negatron |
| photoelectric effect | photon strikes inner shell electron ejecting it and absorbing photons energy, most harmful to patient |
| vaccuum | tube housing |
| radiation | forms of energy emitted and transferred through matter |
| Radiation Absorbed Dose(rad), Gray(Gy) | units measure amount of energy absorbed 1 Gy=100 rads; Gy is SI units |
| Roentgen (R) | measures ionization in air |
| Radiation equivalent man (rem), Sievert (Sv) | measures biologic response of exposed individuals to same quantity of differing radiations 1Sv=100rem; Sv is SI unit;1rad=1rem |
| Somatic cell | all of body's cells except germ cells |
| xray | electromagnetic radiation traveling at the speed of light with the ability to penetrate matter |
| ionizind radiation | capable of creating ions by removing orbital electrons with which it reacts |
| Natural background radiation | uranium, radon; we get approx. 295 mrem/yr |
| man made radiation | nuclear power, xrays, ect. we get approx. 65mrem/yr |
| properties of xrays | penetrating electromagnetic waves, heterogenous(many energies), polyenergetic, travels in straight lines, can't be focused, electronically neutral, produce scatter, ionize gasses, cause biological change |
| absorbtion | transfers energy |
| transmission | xrays pass through matter with no reaction |
| photodisintegration | occurs in nuclear industry; energy interacts directly with nucleus, causes excitement, emits nuclear fragment |
Created by:
sandonblaise
Popular Radiology sets