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62 Cards in this Set
- Front
- Back
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What 3 people played a role in the discovery of x-rays?
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Roentgen, Roentgen's wife and Goodspeed
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Who won the Noble Peace Prize?
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Roentgen
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What 3 things do you need to produce x-rays?
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1. A Source of electrons
2. Something to help accelerate 3. A target |
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What does the cathode do?
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It heats up and produces electrons.
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What does the anode do?
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It shoots electrons down to the patient, it holds the target.
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What are the two types of anodes?
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Stationary - dental, smaller
Rotating - 2-stage switch, smaller target, better x-rays |
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What 3 controls are used on the x-ray machine?
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KVP, MA, Time
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What controls quality?
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KVP
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What controls quantity?
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MA, Time
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What internal component changes one voltage to another?
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Transformers
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What internal component converts alternating current into direct current?
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Rectifier
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What 3 paths can an x-ray take after they enter the patient?
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Absorbed, Scattered, or passed through
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How can you reduce scatter radiation?
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Collimate (smaller beam), lead in tabletop, lead in back of cassette, use grids
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What are the 3 sources of radiation exposure?
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Primary beam, scatter radiation, leakage from the machine/housing
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What are the 3 principles of radiation safety?
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1. Short exposure time
2. Increase distance 3. Wear protective gear |
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What type of badges are used to measure exposure to radiation?
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TLD badge - crystals
Film badges |
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What are the 3 rules of protective equipment maintenance?
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1. Don't fold or bend gowns or gloves
2. Hang gloves 3. X-ray gowns/gloves 1X a year |
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What year were x-rays discovered?, by who?
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1895 - Roentgen
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What is Electromagnetic radiation?
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A method of transporting energy through space distinguished by wavelengths, frequency and energy.
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Do x-rays travel in a straight path?
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Yes
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What is the nucleus made up of?
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Protons (+) and neutrons (no charge)
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What are electrons?
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They have a negative charge and orbit around the nucleus.
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How are x-rays produced?
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When high energy electrons hit atoms
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How much of the electron kinetic energy is produced into heat?
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99%, the other 1% is turned into x-ray energy
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When x-rays collide with the atoms that makeup matter, the following 4 things may occur.
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1. Change in direction - scatter
2. Absorption 3. Excitation - electron pushed into higher orbit 4. Ionization - electrons moved from orbit completely |
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What are x-ray films made up of?
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Calcium tungstate phosphors and rare earth phosphors
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What is the cathode made up of?
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Tungsten filament and focusing cup
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What does the tungsten filament do?
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The filament heats up and releases a cloud of electrons - the hotter it gets, the more electrons produced and the more electrons available to hit the target, the more x-rays produced.
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What does the focusing cup do?
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It's a metal cup which holds the filament and focuses the electrons toward the "target"
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Is the target mounted straight or on an angle?
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On and angle to direct the x-rays produced down and through the window.
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What's the focal spot?
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The area on the target where the electrons hit - the smaller the focal spot, the greater the clarity.
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What type of tube are the cathode and anode housed in?
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Glass, encased in metal. The metal housing contains oil surrounding the glass tube to help remove heat. The glass tube contains a vacuum.
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What is the "window"?
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The small opening on the bottom side of tube where the x-rays exit.
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What is the Collimator?
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It's used to control the size of the x-ray beam directed at the patient, it blocks the unwanted portion of the primary exit beam.
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What is SID (FFD)?
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Source image distance (focal film distance). The distance from the x-ray tube to the film (40 in. is normal on big machines).
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What's the heel effect?
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When the intensity and energy of the primary beam is not uniform - the primary beam is most intense toward the cathode.
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What does it mean when you have a higher MA?
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There are more electrons free from the filament which means more electrons are available to hit the target and then more x-rays are produced.
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What's the KVP?
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The kilovoltage peak. The electrical "potential" or attraction between the cathode and anode. It controls the wavelength of radiation.
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What does the KVP refer to?
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The quality of or penetration of x-rays the patient receives.
The higher KVP = higher electron speed hitting the target = higher energy of x-rays produced = shorter x-ray wavelength = greater x-ray penetration. |
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How does time affect x-rays?
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It controls the amount of time the x-rays are produced. Along with the MA it controls the quantity of x-rays produced.
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What is the MAS?
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MA and time (in seconds) together to produces the term MAS. The MAS also refers to the quantity of radiation.
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What does the transformers do?
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It changes one voltage into another.
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What are the 3 types of transformers?
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Autotransformers, high voltage transformers, low voltage transformers.
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What does the rectifier do?
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It converts 60 cycles per second alternating current (wall current) to direct current.
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What does the line voltage compensator do?
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It compensates for variations of in-coming voltage to autotransformers. It adjusts the incoming line voltage so power to machine remains constant. It's automatic.
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What is the degree of scatter radiation depends on?
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1. the x-rays field size
2. Tissue thickness 3. KVP |
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Who should not be in the x-ray room when energized?
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People under 18 and pregnant women.
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What are some somatic damages (damage to tissues) that can occur from x-ray exposure?
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catarax, sterility, cancers (esp. of lungs, bones, breast, thyroid and leukemia).
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What are some genetic problems that can occur from x-ray exposure?
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Gene mutations - but may not show up for 2-3 generations and physical deformities.
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What dividing cells are the most sensitive to radiation?
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Skin tissue, gonad tissue (reproductive organs), GI tract, bone marrow, lens of the eye, fetal tissue.
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3 sources of possible radiation exposure?
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1. Primary beam
2. Scatter radiation 3. Leakage from x-ray tube housing |
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What are the 3 types of radiation exposure doses?
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Roentgen, RAD (GRAY), REM (SEIVERT)
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How does the Roentgen method measure radiation exposure?
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It measures the ability of radiation to iodized air. It's the exposure dose.
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What is the RAD (GRAY)?
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It's the radiation absorbed dose - the absorbed dose of the patient.
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What is the REM?
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The dose equalivant. The roentgen equalivant in man. The equalivant or occupational dose.
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What is the MPD?
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The maximum permissible dose. It is measured in REM's and is cumulative.
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What is the occupational MPD?
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5 rems per year, 1.25 rems per quarter.
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What are the 3 principles of radiation safety?
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1. Minimize time
2. Maximize distance 3. Maximize shielding |
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What can you do to minimize radiation exposure time?
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Minimize your time exposed or rotate restraint personnel.
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What can you do to maximize radiation distance?
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Increase the distance between the patient and yourself and stand upright when restraining.
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What can you do to maximize shielding from radiation?
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Wear lead gloves, gown and thyroid shield. Stay out of the primary beam.
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What are argosy's radiation safety rules?
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1. always wear lead gloves/apron/thyroid collar 2. no body part in primary beam 3. rotate restraint personnel 4. nonessentail people behind lead walls 5. don't rest arms on table 6. wear dosimeter badges at collar level outside lead apron 7. dosimeter badges don't leave radiology area
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