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RADT 456 Equip & QC
ARRT Registry Review
Question | Answer |
---|---|
What are the two types of x-ray productions that take place within the x-ray tube? | Bremsstrahlung and Characteristic |
Which type of x-ray production takes place more commonly? | Bremsstrahlung (70-80%) |
Shorter wavelength is accompanied by what other three characteristics? | higher frequency, higher energy, and increased ionizing potential |
Which type of x-ray interaction with matter contributes signifiatly to patient dose and uses all its energy to eject an inner shell electron? | Photoelectric effect |
Which type of x-ray interaction with matter is high energy and ejects an outer shell electron? It also has little radiation hazard to the patient but does contribute to image fog. It causes hazard to personnel. | Compton scatter |
Which type of x-ray interaction with matter is low energy and is completely absorbed by the atom leaving the atom in an excited state? It releases an x-ray of identical wavelength but travels in a different direction that the incident photon. | Coherent (classical) |
This type of transformer increases voltage and decreases amperage. | step-up |
This type of transformer decreases voltage but increases amperage. | step-down |
Step-up and step-down transformers operate on what type of induction? | mutual |
Autotransformers operate on what type of induction? | Self |
What are the charges of the parts of the x-ray tube? | cathode:negative electrode Anode:positive electrode |
The anode is made of what material? | Disk: graphite/ molybdenum Focal track: tungsten |
What is the line focus principle? | The effective focal spot is always smaller than the actual focal spot |
What are three causes of x-ray tube failure? | Vaprized tungsten, pitted anode, and cracked anode |
What are the components of the primary/ low voltage circuit? | Main switch/circuit breaker, autotransformer, KV selector switch, lne voltage compensator, timer, primary coil of HV transformer, and exposure switch |
What are the components of the secondary/high-voltage circuit components? | secondary coil of HV transformer, mA meter, rectifiers, x-ray production |
what is a 2 dimensional picture element? | pixel |
What is a 3 dimensional volume element? | voxel |
What is a number of pixels? | Matrix |
How much of the part/patient is included in the matrix is known as the? | FOV |
Digital image resolution improves with? | smaller pixel size smaller pixel pitch larger image matrix |
What is pitch? | couch movement in and tube rotation plus slice thickness |
What are the parts of the CT Gantry? | x-ray tube, dectector array, high-voltage generator, collimator assembly, slip rings, DAS, and laser beams for positioning |
how do you figure out minification gain? | input screen diamter/ output screen diameter and square the answer |
How do you figure out total brightness gain? | Flux gain x minification gain |
Testing of this QC element includes a Wisconsin test cassette or digital meter and must be accurate to within 5 of this? | Kilovoltage |
Timer accuracy for single phase equipment is evaluated using this equipment?How does it appear? | spinning top dots |
Timer accuracy for 3 phase equipment utilizes this type of equipment and appears how? | Synchronous spinning top and appears as a solid arc |
Timer accuracy must be how accurate? | Within 5% |
Reproducibility must be how accurate? | 5% |
How is focal spot size tested? | Using a pinhole camera, slit camera, or star pattern type resolution device |
A wire mesh is used to evaluate which QC element? | sceen to film contact |