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xray
xray fundamentals
| Question | Answer |
|---|---|
| xrays are produced when fast moving _________ slam into metal | electrons |
| Tungsten is used in xray tubes because? | it has higher thermionic emission (melting point is 3410 degrees C) |
| The three major *circuit* sections in an xray system are: | control console, high voltage tube circuit, and filament circuit |
| the three major parts in an xray system (not the circuit) | xray tube, operating console, and high voltage generator |
| ____ _______ reads the electric flow in the control console | line monitor |
| the _______________ controls the voltage coming from the source | autotransformer |
| the autotransformer has a single _______ and supplies a precise voltage to both the filament circuit and and high volt circuit. | winding |
| the ____ _______ ___________ measures the voltage provided to the xray system and adjusts it. | line voltage compensator |
| Line compensator adjusts voltage to ___ Volts | 220 |
| ___ determines the quality of an xray beam | kVp |
| what does ALARA stand for? | As Low As Reasonably Achievable |
| The kVp meter is placed next to the autotransformer so it actually measures ________ | voltage |
| what does kVp stand for? | Kilovolt Peak |
| _____ ___ selector is the main portion of kVp selection | major kVp |
| _____ kVp selector "fine tunes" what's been selected | minor |
| voltage from the mA selector goes to the ________ _______ | filament circuit |
| the number of electrons emitting from the filament is determined by its ___________ | temperature |
| A filament's temperature is controlled by its _______ | current |
| the _____ ______ effect is when a cloud of electrons coming from a filament blocks more electrons from emitting cuz of electrostatic repulsion. | space charge |
| the release of electrons from a heated filament | thermionic emission |
| xray tube current is monitored by a __ _____ placed in the circuit | mA meter |
| the filament transformer is also called a ____ ____ ___________ | step down transformer |
| the step down transformer for the filament knocks the voltage down to __ Volts | 12 |
| in a filament (step down) transformer, the primary winding holds ___ V and ___ A | 150, 0.5-1 |
| in a filament (step down) transformer, the secondary winding holds __ V and ___ A | 12, 5-8 |
| the number of xrays that reach the image receptor (from the tube) depends on the amount of ____ energized and the tube's _______ | time, current |
| In fluoroscopy, there's an ________ or ____________ ____ switch that can stop the process immediately for safety. | exposure, fluoroscopic foot |
| there is a timing circuit on every radiographic exposure called a _____ _____ to make it hard to overexpose a patient | guard switch |
| synchronous motors spin at exactly __rpm and can also be used as ______ | 60, timers |
| synchronous timers cannot be used for ______ exposures | serial |
| xray systems that use synchronous timers have the minimum exposure time set at ____ a second or __ ms. | 1/60, 17 |
| most exposure timers are __________ and are run with a ______________ | electronic, microprocessor |
| an electronic timer's circuitry is based off of? | the time required to charge a capacitor through a variable resistance |
| ___ timers monitor the products of mA and cuts off exposure when the desired mA is attained (this one's on the nose lmao sorry) | mAs |
| mAs timers are typically used in _______ ____ and _________ _________ imaging systems | falling load, capacitor discharge |
| what does AEC stand for | Automatic Exposure Control |
| the AEC uses either an __________ _______ or a __________ ________ ________ | ionization assembly, photodiode detector assembly |
| the ___ is a device that measure the quantity of radiation that reaches the image receptor | AEC |
| the AEC terminates exposure when the _____ _______ gets enough radiation intensity | image receptor |
| in the situation that an AEC is using an ionization chamber, it disengages when the chamber reaches the appropriate ______ (made via ionization) | charge |
| the AEC is often paired with an __________ timer | electronic |
| the high voltage generator for an xray system is made up of three parts: | high voltage transformer, filament transformer, and rectifiers |
| voltage rectification makes sure electrons flow from _______ to _____ only | cathode, anode |
| an electronic device that contains two electrodes | diode |
| three phase power allows for the _______ to remain constant with significantly less ripple than one or two phase power | voltage |
| term for starting an exposure | initiation time |
| term for ending an exposure | extinction time |
| an anode is positive or negative? | positive |
| a cathode is positive or negative? | negative |
| xray tube envelopes are either made of _____ or _____ | glass, metal |
| what type of radiation is an x-ray | ionizing |
| what percent ripple does 3 phase power with 6 pulse have? | 14% |
| what percent ripple does 3 phase power with 12 pulse have? | 4% |
| what percent ripple does high frequency power have? | 1% |
| what are xray tube filaments made out of? | thoriated tungsten |
| filaments are kept inside a ________ ___ which is __________ charged | focusing cup, negatively |
| the focusing cup ________ the electron beam to fit onto the anode | condenses/focuses |
| the spinny metal thing in an xray tube | anode |
| the difference in waveform between the primary and secondary sides of the high voltage transformer is _________ | amplitude |
| the step up transformer increases voltage ___ - ____ times | 500-1000 |
| the operating console contains circuits that are ___ voltage | low |
| the ________ circuit provides electrons for the xray tube current | filament |
| thermionic emission at the filament determines the __________ across the xray tube during exposure | resistance |
| the most accurate timer is the __________ timer | electronic |
| the mAs timer usually gives the _______ mA at the ________ time | highest, shortest |
| a diode allows electrons to flow from _______ to _____ | cathode, anode |
| the high voltage generator contains the ____ _______ ___________, the ________ ___________ and the __________ | high voltage transformer, filament transformer, rectifiers |
| the components for rectification (in modern imaging) are _____ _____ ______________ | solid state semiconductors |
| 3 phase units (full wave rectified) provide an xray beam at ___ pulses per second | 120 |
| most mammography units use ____ _________ generators | high frequency |
| the xray beam generated by the circuit with the ______ voltage ripple has the _______ quantity and quality | lowest, highest |
| disadvantage of three phase equipment? | cost |
| formula for calculating high voltage generator power | power = max mA x 100kVp |
| what unit determines quantity? | kVp |
| what unit determines quality? | mA and/or mass |
| the 4 main components of an xray tube | glass envelope, cathode, anode, and protective housing |
| what does the tube's protective housing protect against? | radiation exposure and electric shock |
| xrays that escape through the protective housing is called _______ ________ | leakage radiation |
| the kinetic energy of electrons is dependent on ___ | kVp |
| the energy of xrays is dependent on the _______ energy of electrons | kinetic |
| for cooling purposes, tube protective housing has either ___ or ______ ____ | oil, cooling fans |
| the open section of the protective housing where the xray beam comes out is called? | window |
| good protective housing has leakage radiation of less than _____/hr at 1m at maximum conditions | 1 mG |
| Two external things protective housing contribute for the tube | protection from rough handling and mechanical support |
| the glass envelope is made out of what type of glass? | pyrex |
| the tube envelope must maintain a _______ to ensure efficient xray production | vacuum |
| metal envelopes maintain a constant ________ _________ between the electrons in the tube current and enclosure | electric potential |
| the cathode has what two main parts? | filament and focusing cup |
| the focusing cup is __________ charged | negatively |
| the anode is a __________ charged electrode | positively |
| which type of anode is used in dental xrays, some portable systems, and any special purpose system where high current and power isn't required? | stationary |
| most commonly used anode? | rotating |
| rotating anodes are powered by an _____________ _________ motor | electromagnetic induction |
| the area of the anode actually hit by electrons | target |
| the area projected onto patient and film | effective focal spot |
| the effective focal spot is affected by the size of the ______ _____ ____ and the _____ ______ _____ | actual focal spot, anode target angle |
| the ____ _____ _________ is used to reduce the effective focal spot | line focus principle |
| the line focus principle provides the detail of a _____ _____ ____ while allowing for a large amount of _____ ___________ | small focal point, heat dissipation |
| the _____ ____ ______ is the consequence of the line focus principle where the anode has less radiation than the cathode | anode heel effect |
| because of the anode heel effect, electrons interact with target atoms at _______ _______ | varying depths |
| a _______ anode angle greatens the heel effect | smaller |
| the very edge of the anode (not made of tungsten!!) is called the ____ | heel |
| The anode heel effect can be used when radiographing anatomical parts with _______ _________ | Unequal thickness |
| All things are either ______ or ______ | matter, energy |
| _________ energy is the ability to do work by virtue of position | potential |
| the energy of motion | kinetic energy |
| Matter that intercepts radiation is considered | irradiated |
| any type of radiation able to remove an orbital electron | ionizing |
| xrays use what type of energy? | electromagnetic |
| energy that is emitted and transferred through space | radiation |
| the three principles of radiation control | time, distance, shielding |
| the exposure switch has how many stages? | 2 |
| what waveform has the least ripple | high frequency |
| the rectifier circuit converts __ to pulsating __ | AC, DC |
| when an xray beam has higher quality , that means it has higher | penetrability |
| The operating console usually gives control of the ____ ___________, ___, __, and ________ ____ | line compensator, kVp, mA, exposure time |
| mAs is __ x ____ | mA x time |
| a lead apron is an example of what ? | shielding or protective apparel |
| ___________ restricts the beam to the part of the body being imaged | collimation |
| RAD stands for | Radiation Absorbed Dose |
| ___ is the amount of radiation absorbed by the patient | RAD |
| REM is the _________ dose | effective |
| moving real time xray is | fluoroscopy |
| the ________ ______ ___ means that the further you are from the source, the less radiation you get | inverse square law |
| xrays are more evil to women in the _____ trimester of pregnancy | first |
| the first death by xrays was in the year ____ | 1904 |
| the energy of ionizing radiation starts between __eV-__eV | 10-33 |
| tungsten has how many energy levels? | 6 |
| tungsten has __ protons and electrons | 74 |
| does a dosimeter alarm for excessive radiation? | no |
| 6 main components of radiation protection | filtration, collimation, intensifying screens, protective apparel, gonadal shielding, and protective barriers |
| __________ ________ is when electrons radiate from heated metal | thermionic emission |
| lower kVp means more or less penetration? | less |
| the first medical xray was published in | 1896 |
Created by:
banditbandit