The Radiopaedia Reading Room Podcast 71. CT physics update with Michael Nel
Nov 3, 2025
In this lively conversation, Dr. Michael Nel, a radiology educator and author specializing in CT physics, dives deep into iterative reconstruction and dual energy CT. He explains how these advanced techniques enhance image quality and tackle noise. Listeners will also learn about the promising future of photon-counting CT and its practical applications in clinical settings. Alongside some light-hearted tales, including humorous anecdote on edamame, this chat blends cutting-edge science with fun, making it a must-listen for radiology enthusiasts.
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Clear Ice Project With A Hot-Wire Cutter
- Frank Gaillard described his quest to make clear large ice blocks and a 3D-printed hot-wire cutter.
- He prefers directional freezing and larger cubes to reduce dilution and improve drink aesthetics.
Reconstruction Is Math, Not Magic
- Filtered back projection (FBP) and iterative reconstruction use the same raw data but different math to build images.
- Iterative reconstruction models the scanner and noise, yielding lower noise and enabling dose reduction.
Iterative Methods Exploit Predictable Noise
- Iterative reconstruction reduces noise by modelling predictable Poisson noise in detector readings.
- Comparing forward-projection data to acquired data allows removal of random fluctuations.