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
Exam 4 Rad 102
Chapters 11, 13 & 14 - Prime Factors, Minimizing Pt Dose, Vision and Perception
| Question | Answer |
|---|---|
| What are the prime exposure factors? | Distance, mAs, kVp |
| Prime exposure factors are variables controlled by ________________. | the technologist |
| What is the product of tube current and exposure time? | mAs |
| Quantity of the beam is measured in _____________. | Roentgen |
| Which factor controls quantity? | mAs |
| mAs, distance and filtration directly affect ________________. | quantity |
| Which factor control quality? | kVp |
| X-ray quality is numerically represented by ______________. | Half-value layer (HVL) |
| Reducing x-ray beam intensity (Quantity) by half its original value is _________________. | Half-value layer (HVL) |
| Milliamperage (mA) is the measurement of ______________________. | tube current |
| What does X-ray tube current measure? | # of electrons crossing the tube from cathode to anode per second. |
| As mA increase, the number of electrons that are able to cross the tube to reach the x-ray target __________________. | Increase |
| The penetrating ability of the x-ray beam refers to ________________. | quality |
| Which systems provide the highest beam quality and quantity? | High-frequency |
| What are the quantitative factors affecting x-ray emission? (4) | mAs, kV, Distance, filtration |
| What are the qualitative factors affecting x-ray emission? (2) | kV, filtration |
| What is the focal spot size (range) of an x-ray tube? | 0.5 - 1.0 |
| Large focal spot size has a beam of high __________________, but unchanged _______________. | quantity (more x-rays produced) quality (looks the same) |
| Focal spot size is associated with ________ of an x-ray. | detail |
| What is the unit of current? | ampere |
| 1 ampere (A) equals? | 1 coulomb (C)/sec |
| What happens to the number of electrons passing from the cathode to the anode by doubling the mA? | Increase 2 fold |
| Exposure time is directly proportional to _______________________. | intensity of the beam |
| Short exposure times help in reducing _____________________. | motion artifacts |
| What is the shortest time by a single phase system? | 8ms |
| What does mAs control? (5) | Quantity, radiographic film density, patient dose, intensity, x-ray output |
| By doubling the mAs, the dose is ___________. | doubled |
| Increase in mAs causes a(n) ___________________ in beam quantity. | increase |
| What will increasing the kVp on the control panel cause? | an increase in speed and energy of the electrons |
| What does the Reciprocity Law state? | the density on an x-ray film should remain unchanged as long as intensity and duration of x-ray exposure remains unchanged |
| Which factor controls quality? | kVp |
| Change in kVp affects ____________. | contrast |
| As kVp double, the amount of x-ray photos will increase approximately? | 4 times |
| Amount of silver deposited on hard copy film image | density |
| Intensity and density increases as SID __________________. | decreases |
| What does the Inverse Square Law state? | The intensity of radiation at a given distance from a point source is inversely related to the square of the distance between the object and the source. |
| What is the Inverse Square Law formula? | |
| What is the function of the human eye? | Gather light, focus it, convert it to nerve impulses and transmit it to the brain for processing. |
| What are the 2 retinal cells that transform light into a nervous signal? | Rods and Cones |
| What is the aspect of the visual anatomy that transmit nervous signals to the brain? | Optic Nerve |
| What is the primary location of rods in the eye? | Retina cells |
| What is the primary location of cones in the eye? | Fovea centralis |
| What is another name for nearsightedness? | Myopia |
| What is another name for farsightedness? | hyperopia |
| What do rods and cones do when stimulated by light? | emit neurologic impulses |
| Daylight vision, color, processed by cones | photopic vision |
| Which color of light are cones most sensitive to? | yellow |
| Part of the eye that improves contrast perception? | cones |
| Name for night vision which is sensitive to low light levels | Scotopic Vision |
| Term for the visual phenomenon associated with viewing extremely small objects | Threshold Detection |
| What is boundary effect? | Difficulty is perceiving contrast difference at a distance |
| Neurologic basis for boundary effect. Some situations prevent neurological impulses from being transmitted by retina. | Mach Effect |
| When intense light from view box hits the eye directly, bright light scatters inside the eye (compton effect) and decreases contrast perception... | Veil Glare |
| Rule for views to be made in radiography, in order to perceive depth | Must have two (2) 90° opposing views |
| What radiographs produce the highest ESE? | Lumbar spine, pelvis and hip |
| Which radiographs produce the lowest ESE? | Extremities |
| Ways to reduce patient does? | Positioning Communication Technical Factors Filtration Field Size Gonadal Shielding |
| How do we reduce pt dose with technical factors? | high kVp, lowest possible mAs, increase SID and SOD, highest generator efficiency |
| What is entrance skin exposure (ESE)? | Maximun exposure to body |
| What is roentgen (R) in SI units? | air kerma |
| What is rem in SI units? | sievert |
| What is rad is SI unit? | gray |
Created by:
10157762949820556
Popular Radiology sets