From imaging algorithms to quantum methods Seminar

Name: From imaging algorithms to quantum methods Seminar
Start: 2025-03-17T10:00:00+01:00
End: 2025-03-17T11:30:00+01:00
Location: Zoom

Monday 17 Mar 2025, 10:00 → 11:30 Europe/Warsaw

https://cern.zoom.us/j/66151941204?pwd=n7upvvZYibexBhbtyn5kvTpy36L0Wo.1 (Zoom)

https://cern.zoom.us/j/66151941204?pwd=n7upvvZYibexBhbtyn5kvTpy36L0Wo.1

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Konrad Klimaszewski (NCBJ), Wojciech Krzemien (NCBJ)

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Zoom link: https://cern.zoom.us/j/66151941204?pwd=n7upvvZYibexBhbtyn5kvTpy36L0Wo.1

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# Title: Simulation of Beam Hardending in CT
# Presenter: Maciej Zajkowski
# Date: 17.03 2025

# Participants:
Wojciech Krzemień (WK)
Konrad Klimaszewski (KK)
Maciej Zajkowski (MZ)
Dominik Strzelecki (DS)
Michał Obara (MO)
Michał Mazurek (MM)
Aleksander Ogonowski (AO)
Michal Mrozowski (MMr)
Arkadiusz Ćwiek (AC)
Lech Raczynski (LR)

# Discussion:

(WK) Is this effect dependent on the shape of the object? I guess it must be, cause if the object just removed the lower energy photons uniformly then it
would not affect the final image.
KK/MZ: The attenuation will depend on the path of the photons through the object. So near the edges more photons would pass.

WK: What does it mean - X different simulations?
MZ: Each simulation with a different energy set. Later it is summed with weights taken from the relative intensity spectrum.
KK: I don't think it is dependent on the material. The energy profile in the discussed paper is obtained by minimization of results from measurements of samples from three materials. The relative intensity weights are obtained by minimising differences between simulated and measured data.
MZ: The beam energy in this study was set rather high as it considered dense metal samples.

WK: Are those metrics defined on profiles?
MZ: Yes

WK: When do you apply the corrections?
MZ: We apply it at the sinogram level before the reconstruction.
KK: Corrected means that we try transforming from multichromatic to mono-energetic case

WK: What is the typical beam spread?
MZ: As in the Figure. From 0-150 keV.

WK: Can this effect be solved by replacing the source beam with a more monochromatic one?
MZ: For economic reasons that would be not feasible.
KK: The synchrotron beam would be a good solution, but of course one needs to have access to the synchrotron.

There are minutes attached to this event. Show them.

- 10:00 → 11:00
  
  Simulation of Beam Hardening Effect in CT 1h
  
  Beam hardening is the phenomenon that occurs when an x-ray beam comprised of polychromatic energies passes through an object, resulting in selective attenuation of lower energy photons. The effect is conceptually similar to a high-pass filter in that only higher energy photons are left to contribute to the beam, and thus, the mean beam energy is increased ("hardened").
  
  In this talk, we will present effects of beam hardening for CT imaging of samples with different materials. We will describe a simulation approach easily applicable to standard pipeline for generation of synthetic CT images. Finally we will discuss Beam Hardening correction methods together with metrics used to quantify the quality of corrections.
  
  Speaker: Maciej Zajkowski (NCBJ)
  
  Simulation of Beam Hardening Effect in CT.odp
- 11:00 → 11:30
  
  Discussion 30m

From imaging algorithms to quantum methods Seminar

https://cern.zoom.us/j/66151941204?pwd=n7upvvZYibexBhbtyn5kvTpy36L0Wo.1

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