Spectral analysis of scattered radiation in CT

Klaus J. Engel; Christian Bäumer; Jens Wiegert; Günter Zeitler

doi:10.1117/12.771063

18 March 2008 Spectral analysis of scattered radiation in CT

Klaus J. Engel, Christian Bäumer, Jens Wiegert, Günter Zeitler

Proceedings Volume 6913, Medical Imaging 2008: Physics of Medical Imaging; 69131R (2008) https://doi.org/10.1117/12.771063
Event: Medical Imaging, 2008, San Diego, California, United States

Abstract

In the framework of Spectral Computed Tomography (Spectral CT), scattered X-ray radiation is examined for its spectral composition and spatial distribution by means of Monte Carlo simulations. A reliable material (e.g. bone / contrast agent) separation and quantification requires a precise knowledge of the transmitted X-ray spectrum especially for low energy photons. Unfortunately, for lower energies the primary intensity is increasingly covered by scattered radiation. The detected scattered radiation can be classified into two main categories with respect to their scattering history. The first category contains purely Rayleigh or one-time Compton scattered photons which typically have small scattering angles and an energy spectrum similar to that of the transmitted primary radiation. The second category comprises multiple Compton scattered photons with a spectral composition which is typically softer than that of the transmitted primary photons. In regions of strong beam attenuation (i.e. in the X-ray shadow of a scanned object), the scattered radiation is mainly composed of multiple Compton scattered photons. As a consequence, the spectrally resolved scatter-to-primary ratios strongly increase at low energies. High-quality anti-scatter grids can be used to reduce especially the detection of multiple Compton-scattered photons. A quantitative evaluation of measured photon energies below a certain limit between 30 keV and 50 keV (depending on the phantom geometry and the applied anti-scatter grid) is challenging, since primary photons are superposed by a significantly higher amount of scattered photons.

Citation Download Citation

Klaus J. Engel, Christian Bäumer, Jens Wiegert, and Günter Zeitler "Spectral analysis of scattered radiation in CT", Proc. SPIE 6913, Medical Imaging 2008: Physics of Medical Imaging, 69131R (18 March 2008); https://doi.org/10.1117/12.771063

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available