Optimized intensity modulation for a dynamic beam attenuator in x-ray computed tomography

Sascha Manuel Huck; George S. K. Fung; Katia Parodi; Karl Stierstorfer

doi:10.1117/12.2511704

1 March 2019 Optimized intensity modulation for a dynamic beam attenuator in x-ray computed tomography

Sascha Manuel Huck, George S. K. Fung, Katia Parodi, Karl Stierstorfer

Proceedings Volume 10948, Medical Imaging 2019: Physics of Medical Imaging; 1094824 (2019) https://doi.org/10.1117/12.2511704
Event: SPIE Medical Imaging, 2019, San Diego, California, United States

Abstract

In our previous study we successfully built a novel sheet-based dynamic beam attenuator (sbDBA) for fluence field modulation in X-ray computed tomography (CT) and performed a first-time experimental validation. In this work, we focus on the optimization of the DBA transmission properties for a given object. In clinical routine, CT scanners must cope with various attenuation properties differing from patient to patient. Typically, the attenuation of patients is high in the center of the fan beam, decreasing towards the periphery. The attenuation profiles of an object can also change for different X-ray tube positions. These variations cause unfavorable imbalances of image quality in the reconstructed object. Typically, the peripheral region, which is generally of minor diagnostically relevance, has relatively lower noise than the central region because the rays contributing to the peripheral region are less attenuated. This imbalance can be reduced by using beam-shaping prefilters, e.g. bowtie filters, attenuating the propagated intensity towards the periphery in a predefined, static profile. Bowtie filters, however, are not capable of dynamically adapting their attenuation to the attenuation profile of the patient. This can be accomplished by using dynamic beam attenuators (DBA) where the fan beam intensity can dynamically be modulated on a view-by-view basis, reducing noise inhomogeneities and enabling region-of-interest (ROI) imaging. Different scenarios (no attenuator, tube current modulation, conventional bowtie filter, the sbDBA and an ideal DBA) are compared in terms of image quality. The optimized sbDBA with tube current modulation (TCM) not only reduces the total radiation dose but also allows for spatial selection of intensity as required for ROI imaging.

Conference Presentation

Citation Download Citation

Sascha Manuel Huck, George S. K. Fung, Katia Parodi, and Karl Stierstorfer "Optimized intensity modulation for a dynamic beam attenuator in x-ray computed tomography", Proc. SPIE 10948, Medical Imaging 2019: Physics of Medical Imaging, 1094824 (1 March 2019); https://doi.org/10.1117/12.2511704

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