Imaging Techniques Flashcards
What is the resolution of modern light microscopy?
0.2μm
Explain what immunohistochemistry is
Localization in tissues of a known antigen by means of antibodies, Ab – Ag complex visualised using a marker
Why is there increased optical resolution/contrast in confocal microscopy?
Adding a spatial pinhole placed at the confocal plane of the lens to eliminate out-of-focus light.
What is H+E?
Stain = Haematoxylin (blue, nucleus), eosin (pink, cytoplasm, extracellular matrix)
What is the magnification of modern light microscopy?
1000x
Explain what TEM stands for and what it is
Transmission electron microscopy, Electron beam in vacuum, Short wavelength = higher resolution, Bean passes through tissue: passed through = bright, absorbed or scatted = dark
In scanning EM what receives the electrons reflected back by the sample?
cathode ray tube
How does MRI work?
body mostly H2O, contain H nuclei (protons), aligned by magnetic field, applies very strong magnetic field = aligns protons, switching magnet off, proton returns to original position, gives off radio signals, measured/made into image
What does polarised light microscopy evaluate?
evaluate composition and 3D structure of anisotropic specimens (physical property, diff value when measured in different directions e.g. wood, stronger along grain than across)
What is autoradiography?
Visualise molecules labelled with radioactive marker, Marker injected into live culture, Section coated with emulsion
What is freeze fracture EM?
Tissue frozen -160C, Fractured by hitting with knife edge, Fractures pass through plasma membrane exposing interior that is then imaged
How does NMR spectroscopy work?
Detail info about structure, dynamics, reaction state, chem environment - Intramolecular magnetic field changes the resonant frequency = details of electron structure
How does ultrasound work?
Transducer sends and received echoing waves: • Piezo electric crystals, voltage = expends, removed = contracts = creates ultrasound. Returning sound waves hit the piezo electric crystal = compressed = generates a voltage that corresponds to the intensity of the ultrasound wave that hits it. This transmit and receive cycle is repeated very rapidly. Air will reflect, important for good contact, no bubbles
Explain doppler imaging
When a wave is sent to an object that is moving towards transmitting probe, doppler effect makes frequency of returning wave higher than frequency of wave sent out. Moving object squashes wave. Also happens in reverse for objects moving away. Colour is added to visualise doppler
