Skin dose mapping for non-uniform x-ray fields using a backscatter point spread function

Sarath Vijayan; Zhenyu Xiong; Alok Shankar; Stephen Rudin; Daniel R. Bednarek

doi:10.1117/12.2254257

9 March 2017 Skin dose mapping for non-uniform x-ray fields using a backscatter point spread function

Sarath Vijayan, Zhenyu Xiong, Alok Shankar, Stephen Rudin, Daniel R. Bednarek

Proceedings Volume 10132, Medical Imaging 2017: Physics of Medical Imaging; 101320U (2017) https://doi.org/10.1117/12.2254257
Event: SPIE Medical Imaging, 2017, Orlando, Florida, United States

Abstract

Beam shaping devices like ROI attenuators and compensation filters modulate the intensity distribution of the xray beam incident on the patient. This results in a spatial variation of skin dose due to the variation of primary radiation and also a variation in backscattered radiation from the patient. To determine the backscatter component, backscatter point spread functions (PSF) are generated using EGS Monte-Carlo software. For this study, PSF’s were determined by simulating a 1 mm beam incident on the lateral surface of an anthropomorphic head phantom and a 20 cm thick PMMA block phantom. The backscatter PSF’s for the head phantom and PMMA phantom are curve fit with a Lorentzian function after being normalized to the primary dose intensity (PSF_n). PSF_n is convolved with the primary dose distribution to generate the scatter dose distribution, which is added to the primary to obtain the total dose distribution. The backscatter convolution technique is incorporated in the dose tracking system (DTS), which tracks skin dose during fluoroscopic procedures and provides a color map of the dose distribution on a 3D patient graphic model. A convolution technique is developed for the backscatter dose determination for the nonuniformly spaced graphic-model surface vertices. A Gafchromic film validation was performed for shaped x-ray beams generated with an ROI attenuator and with two compensation filters inserted into the field. The total dose distribution calculated by the backscatter convolution technique closely agreed with that measured with the film.

Conference Presentation

Citation Download Citation

Sarath Vijayan, Zhenyu Xiong, Alok Shankar, Stephen Rudin, and Daniel R. Bednarek "Skin dose mapping for non-uniform x-ray fields using a backscatter point spread function", Proc. SPIE 10132, Medical Imaging 2017: Physics of Medical Imaging, 101320U (9 March 2017); https://doi.org/10.1117/12.2254257

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