Construction of XR unit and misc XR stuff Flashcards
Detail use of tungsten in xray tubes
What is the approximate voltage / current of the filament circuit?
Describe focal spots, including trade offs
Describe the heel effect. What factors are important / can be modified to limit effect?
Describe magnification radiography, including features that contribute to magnification, and how to calculate magnification factors
Detail differences between stationary and rotating anodes
What are standard anode angles in radiography?
Factors managing heat production in the x ray tube
Detail inherent and added beam filtration
Briefly describe mechanisms for mA and kVp regulation
Describe AC and DC current. What is the advantage of AC?
Describe transformers. What is the law of transformers?
Compare and contrast tube and filament circuits
Define rectification
Outline how semiconductors work. What contains a semiconductor in the xray unit? What materials are used?
Describe three phase and capacitor generators
Describe falling load principle
Describe high frequency generators
What is voltage ripple?
Describe different types of exposure timer x 2
How does voltage ripple vary between generator types?
Approximate the different energies of superficial, diagnostic xrays; orthovoltage, megavoltage x rays; and gamma rays.
What are power ratings? Know the appropriate formulae x 2
Describe different collimator types
Define heating units. How are they calculated?
Explain cooling curves. Where is the MAXIMUM HEATING CAPACITY identified on the curve?
What is normal line voltage? What is the role of a compensator?
Give an overview of the flow of energy through an X-ray unit
Comparing cylinders, cones and aperture diaphragms, which device reduces penumbra the most?
Detail the components of the Image Intensifier. Describe the layers of the INPUT SCREEN and their roles.
Describe features of the II output phosphor
Describe 4 types of grid
Detail grid ratio and grid frequency. How are both calculated?
List two ways that grids can influence image
Describe air-gap radiography and effects on image
What are the two types of fluroscopy unit used?
Detail magnification radiography
Detail how CR systems work
Describe the 3 main DR systems: 2 indirect and 1 direct. REMEMBER MATERIALS!!!
Describe TFT
Describe CCD
Know your indirect and direct DR systems! Think about the diagram
Describe effects of pixel, detector and matrix size on image quality
Describe factors affecting spatial resolution in CR and DR systems. How is spatial resolution quantified?
Describe dynamic range
Describe noise
Describe MTF
Define DQE
Describe some of the more common processing / postprocessing techniques. Describe some filters!
Describe Look up tables
Describe characteristic curves, including concepts of film speed and exposure latitude
Describe differences between subject, film and radiographic contrast
Define differences between OPTICAL DENSITY, RADIOGRAPHIC DENSITY, as well as film fog and Base optical density
Describe quantitative measures of spatial resolution. How are full width half max measurements (FWHM) calculated?
BRIEFLY explain Nyqvist frequency -> how is it relevant to detector pitch and spatial resolution?
- SMALLEST STRUCTURE that can be detected is 50% the size of a detector element
Compare mAs and kVp. What is the rule of thumb regarding changes to kVp?
Describe relationships between kVp and mAs with RADIOGRAPHIC AND OPTICAL DENSITY. Also relationship with contrast
REMEMBER -> kV DICTATES CONTRAST!
mA dictates film blackness
