Physics of Medical Imaging

Implementing the complete beam hardening effect of the bowtie filter versus scaling beam intensities: effects on dosimetric applications in computed tomography

[+] Author Affiliations
Xochitl Lopez-Rendon

Katholieke Universiteit Leuven, Division of Medical Physics and Quality Assessment, Department of Imaging and Pathology, Herestraat 49 P.O. Box 7003, 3000 Leuven, Belgium

Guozhi Zhang

University Hospitals Leuven, Department of Radiology, Herestraat 49, Leuven 3000, Belgium

Hilde Bosmans, Raymond Oyen

Katholieke Universiteit Leuven, Division of Medical Physics and Quality Assessment, Department of Imaging and Pathology, Herestraat 49 P.O. Box 7003, 3000 Leuven, Belgium

University Hospitals Leuven, Department of Radiology, Herestraat 49, Leuven 3000, Belgium

Federica Zanca

Katholieke Universiteit Leuven, Division of Medical Physics and Quality Assessment, Department of Imaging and Pathology, Herestraat 49 P.O. Box 7003, 3000 Leuven, Belgium

J. Med. Imag. 1(3), 033507 (Dec 30, 2014). doi:10.1117/1.JMI.1.3.033507
History: Received July 24, 2014; Accepted November 25, 2014
Text Size: A A A

Abstract.  The bowtie filter is an essential element of computed tomography scanners. Implementation of this filter in a Monte Carlo dosimetry platform can be based on Turner’s method, which describes how to measure the filter thickness and relate the x-ray beam as a function of bowtie angle to the central beam. In that application, the beam hardening is accounted for by means of weighting factors that are associated to the photons according to their position (fan angle) and energy. We assessed an alternative approximation in which the photon spectrum is given a fan angle-dependent scaling factor. The aim of our investigation was to evaluate the effects on dose accuracy estimation when using the gold standard bowtie filter method versus a beam scaling approximation method. In particular, we wanted to assess the percentage dose differences between the two methods for several water thicknesses representative for different patients of different body mass index. The largest percentage differences were found for the thickest part of the bowtie filter and increased with patient size.

Figures in this Article
© 2014 Society of Photo-Optical Instrumentation Engineers

Citation

Xochitl Lopez-Rendon ; Guozhi Zhang ; Hilde Bosmans ; Raymond Oyen and Federica Zanca
"Implementing the complete beam hardening effect of the bowtie filter versus scaling beam intensities: effects on dosimetric applications in computed tomography", J. Med. Imag. 1(3), 033507 (Dec 30, 2014). ; http://dx.doi.org/10.1117/1.JMI.1.3.033507


Tables

Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Related Book Chapters

Topic Collections

PubMed Articles
Advertisement
  • Don't have an account?
  • Subscribe to the SPIE Digital Library
  • Create a FREE account to sign up for Digital Library content alerts and gain access to institutional subscriptions remotely.
Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).
Access This Proceeding
Sign in or Create a personal account to Buy this article ($15 for members, $18 for non-members).
Access This Chapter

Access to SPIE eBooks is limited to subscribing institutions and is not available as part of a personal subscription. Print or electronic versions of individual SPIE books may be purchased via SPIE.org.