Special Section on Visions of Safety: Perspectives on Radiation Exposure

Calculation of the entrance skin dose distribution for fluoroscopically guided interventions using a pencil beam backscatter model

[+] Author Affiliations
Sarath Vijayan, Zhenyu Xiong

University at Buffalo, Department of Physiology and Biophysics, Buffalo, New York, United States

Toshiba Stroke and Vascular Research Center, Buffalo, New York, United States

Stephen Rudin, Daniel R. Bednarek

University at Buffalo, Department of Physiology and Biophysics, Buffalo, New York, United States

Toshiba Stroke and Vascular Research Center, Buffalo, New York, United States

University at Buffalo, Department of Radiology, Buffalo, New York, United States

J. Med. Imag. 4(3), 031203 (Jun 14, 2017). doi:10.1117/1.JMI.4.3.031203
History: Received December 19, 2016; Accepted May 31, 2017
Text Size: A A A

Abstract.  Radiation backscattered from the patient can contribute substantially to skin dose in fluoroscopically guided interventions (FGIs). The distribution of backscatter is not spatially uniform, and use of a single backscatter factor cannot provide an accurate determination of skin dose. This study evaluates a method to determine the backscatter spatial distribution through convolution of a backscatter-to-primary (BP) point spread function (PSFn). The PSFn is derived for a pencil beam using EGSnrc Monte Carlo software and is convolved with primary distributions using a dose-tracking system. The backscatter distribution calculated using the convolution method is validated with Monte Carlo-derived distributions for three different size “uniform” fields and with XR-QA2 Gafchromic film for nonuniform x-ray fields obtained using region-of-interest (ROI) attenuators and compensation filters, both with homogenous poly-methyl methacrylate and nonhomogenous head phantoms. The BP ratios inside uniform fields were calculated within ±2% of that determined using EGSnrc. For shaped fields, the BP ratio in the unattenuated ROI was calculated within ±3% of that measured with film; in the beam-attenuated periphery, agreement was within ±17%, due to the larger uncertainty of the dose-response curve of the film in the low-dose region. This backscatter PSFn convolution method is much faster than performing full-field Monte Carlo calculations and provides improved accuracy in skin dose distribution determination for FGI procedures.

Figures in this Article
© 2017 Society of Photo-Optical Instrumentation Engineers

Citation

Sarath Vijayan ; Zhenyu Xiong ; Stephen Rudin and Daniel R. Bednarek
"Calculation of the entrance skin dose distribution for fluoroscopically guided interventions using a pencil beam backscatter model", J. Med. Imag. 4(3), 031203 (Jun 14, 2017). ; http://dx.doi.org/10.1117/1.JMI.4.3.031203


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

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.