Please enable JavaScript.
Coggle requires JavaScript to display documents.
3G4 Medical Imaging - Coggle Diagram
3G4 Medical Imaging
Medical Image Acquisition
Computed Tomography
Scanning strategies
(generations)
First gen - single detector
Second gen - fan beam
Third gen - wider fan beam
Projection and the Radon Transform
The projection theorem
Direct Fourier reconstruction
(expensive)
Filtered Backprojection
(cheaper)
Nuclear medical imaging (injecting things)
SPECT (Single Photon Emitter Computed Tomography)
longer half life
ne need to produce isotopes nearby
e.g. Tc99
Uses Gamma camera (collimators, NaI crystal, photomultiplier tubes)
PET (Positron Emission Tomography)
short half life
need to produce isotopes in a nearby cyclotron
e.g. C11, N13, O15, FDG18
Detectors for nuclear medicine
Attenuation of photons
Iterative reconstruction
Algebraic Reconstruction Technique (ART)
Additive ART (AART)
Multiplicative ART (MART)
Maximisation Likelihood Expectation Maximisation (ML-EM)
X-rays
Generation
Attenuation Mechanisms
(beam hardening)
Photoelectric absorbtion
Compton scattering
Detection
2D sensors
screen film detectors
storage phosphorors
1D sensors
scintillation detectors
Gas ionisation detectors
Ultasonic imaging
Scanning modes
2D scans (B-scans)
Doppler imaging
1-D scans (A lines)
Motion mode (M-mode)
repeated A-line scan
3D ultrasound
Sound wave generation
(piezoelectric crystals)
Features in ultrasound images
Specular reflection and refraction
Scattering and speckle
Enhancement artefacts
Attenuation
Resolution - axial, lateral, elevational
Magnetic Resonance Imaging (MRI)
Underlying principles
spinning protons
magnetic precession
RF pulse
T2 and T1 relaxation
Slice selection
Phase and freq encoding
Spin-echo image