Research Papers

Approach to Validate Simulation-Based Distribution Predictions Combining the Gamma-Method and Uncertainty Assessment: Application to Focused Ultrasound

[+] Author and Article Information
Esra Neufeld

Foundation for Research on Information
Technologies in Society (IT'IS),
Zeughausstrasse 43,
Zürich 8004, Switzerland
e-mail: neufeld@itis.ethz.ch

Adamos Kyriacou

Foundation for Research on Information
Technologies in Society (IT'IS),
Zeughausstrasse 43,
Zürich 8004, Switzerland
e-mail: adamos@itis.ethz.ch

Wolfgang Kainz

Division of Physics,
Center for Devices and Radiological Health,
U.S. Food and Drug Administration,
Silver Spring, MD 20993
e-mail: wolfgang.kainz@fda.hhs.gov

Niels Kuster

Foundation for Research on Information
Technologies in Society (IT'IS),
Zeughausstrasse 43,
Zürich 8004, Switzerland;
Swiss Federal Institute of Technology
(ETH) Zürich,
Zürich 8092, Switzerland
e-mail: kuster@itis.ethz.ch

1Corresponding author.

Manuscript received February 9, 2016; final manuscript received July 18, 2016; published online August 9, 2016. Assoc. Editor: Tina Morrison.This work is in part a work of the U.S. Government. ASME disclaims all interest in the U.S. Government's contributions.

J. Verif. Valid. Uncert 1(3), 031006 (Aug 09, 2016) (8 pages) Paper No: VVUQ-16-1002; doi: 10.1115/1.4034323 History: Received February 09, 2016; Revised July 18, 2016

This paper presents a novel approach for simulation validation by combining systematic, National Institute of Standards and Technology-guideline-based uncertainty assessment with the gamma dose distribution comparison method, and applies the approach to simulated and measured complicated pressure distributions in the field of focused ultrasound. Simulations require verification and validation to demonstrate that they correctly implement the underlying model and sufficiently capture the real-world behavior of the system of interest within the context-of-use. Uncertainty assessment is necessary to determine the quality (strength, success, and range) of the validation. The combined approach of systematic uncertainty evaluation and the gamma-method presented herein permits thorough validation with meaningful and reasonable tolerances (expanded uncertainty: 1.04 dB = 12.7%, 1.88 wavelengths), whereas point-wise comparison would have resulted in an unacceptably large uncertainty (>10 dB) due to the impact of distortion. The approach presented also provides a scalar agreement metric and a natural means of visualizing areas of disagreement. Verification is achieved by identifying the critical physical and numerical phenomena and ascertaining correct handling by means of analytical and numerical benchmarks. The generality of the verification and validation approach presented makes it applicable to a wide range of computational models, beyond the highlighted acoustic simulations.

Copyright © 2016 by ASME
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ASME, 2009, “ American Society of Mechanical Engineering Verification and Validation Standard,” American Society of Mechanical Engineering, New York, Standard No. ASME V&V 20-2009.
ASME, 2012, “ American Society of Mechanical Engineering Verification and Validation Guide,” American Society of Mechanical Engineering, New York, Standard No. ASME V&V 10-1-2012.
FDA, 2014, “ Reporting of Computational Modeling Studies in Medical Device Submissions—Draft Guidance for Industry and Food and Drug Administration Staff,” U.S. Food and Drug Administration, Silver Spring, MD.
IEC/IEEE, 2012, “ Recommended Practice for Determining the Spatial-Peak Specific Absorption Rate (SAR) in the Human Body Due to Wireless Communication Devices, 30 MHz – 6 GHz,” International Electrotechnical Commission Technical Committee 106, Geneva Switzerland, Standard No. IEC/IEEE 62704.
Roache, P. J. , 2002, “ Code Verification by the Method of Manufactured Solutions,” ASME J. Fluids Eng., 124(1), pp. 4–10. [CrossRef]
GUM: BIPM, IEC, IFCC, ILAC, IUPAC, IUPAP, ISO, OIML, 2008, “ Evaluation of Measurement Data—Guide for the Expression of Uncertainty in Measurement,” Joint Committee for Guides in Metrology, JCGM 100:2008.
Taylor, B. , and Kuyatt, C. , 1994, “ Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurements Results,” National Institute of Standards and Technology, Washington, DC, USA, Technical Note 1279.
Kuster, N. , and Schoenborn, F. , 2000, “ Recommended Minimal Requirements and Development Guidelines for Exposure Setups of Bio-Experiments Addressing the Health Risk Concern of Wireless Communications,” Bioelectromagnetics, 21(7), pp. 508–514. [CrossRef] [PubMed]
Kuster, N. , Torres, V . B. , Nikoloski, N. , Frauscher, M. , and Kainz, W. , 2006, “ Methodology of Detailed Dosimetry and Treatment of Uncertainty and Variations for In Vivo Studies,” Bioelectromagnetics, 27(5), pp. 378–391. [CrossRef] [PubMed]
Neufeld, E. , Kuehn, S. , Szekely, G. , and Kuster, N. , 2009, “ Measurement, Simulation and Uncertainty Assessment of Implant Heating During MRI,” Phys. Med. Biol., 54(13), pp. 4151–4169. [CrossRef] [PubMed]
Murbach, M. , Neufeld, E. , Capstick, M. , Kainz, W. , Brunner, D. O. , Samaras, T. , Pruessmann, K. P. , and Kuster, N. , 2014, “ Thermal Tissue Damage Model Analyzed for Different Whole-Body SAR and Scan Durations for Standard MR Body Coils,” Magn. Reson. Med., 71(1), pp. 421–431. [CrossRef] [PubMed]
Murbach, M. , Neufeld, E. , Kainz, W. , Pruessmann, K. P. , and Kuster, N. , 2014, “ Whole-Body and Local RF Absorption in Human Models as a Function of Anatomy and Position Within 1.5 T MR Body Coil,” Magn. Reson. Med., 71(2), pp. 839–845. [CrossRef] [PubMed]
Neufeld, E. , Murbach, M. , Kyriakou, A. , Kainz, W. , and Kuster, N. , 2014, “ Uncertainty Assessment and Validation of Multi-Physics In Vivo Simulations: Example EM Exposure Induced Heating and Nerve Stimulation,” Proceedings of the ASME 2014 Verification and Validation Symposium, Las Vegas, NV, May 7–9.
Low, A. , Harms, W. B. , Mutic, S. , and Purdy, J. A. , 1998, “ A Technique for the Quantitative Evaluation of Dose Distributions,” Med. Phys., 25(5), pp. 656–661. [CrossRef] [PubMed]
Low, D. A. , and Low, J. F. , 2003, “ Evaluation of the Gamma Dose Distribution Comparison Method,” Med. Phys., 30(9), pp. 2455–2464. [CrossRef] [PubMed]
Kyriakou, A. , 2015, “ Multi-Physics Computational Modeling of Focused Ultrasound Therapies,” Ph.D. thesis, Swiss Federal Institute of Technology, Zurich, Switzerland.
Zhou, D. , Huang, W. P. , Xu, C. L. , Fang, D. G. , and Chen, B. , 2001, “ The Perfectly Matched Layer Boundary Condition for Scalar Finite-Difference Time-Domain Method,” IEEE Photon. Technol. Lett., 13(5), pp. 454–456. [CrossRef]
Chew, W. C. , and Weedon, W. H. , 1994, “ A 3D Perfectly Matched Medium From Modified Maxwell's Equations With Stretched Coordinates,” Microwave Opt. Tech. Lett., 7(3), pp. 599–604. [CrossRef]
McGough, R. J. , 2013, “ FOCUS: Fast Object-oriented C++ Ultrasound Simulator,” Michigan State University, East Lansing, MI, (last accessed Aug. 4, 2016), http://www.egr.msu.edu/∼fultras-web/
Kyriakou, A. , Neufeld, E. , Werner, B. , Szekely, G. , and Kuster, N. , 2015, “ Full-Wave Acoustic and Thermal Modeling of Transcranial Ultrasound Propagation and Investigation of Skull-Induced Aberration Correction Techniques: A Feasibility Study,” J. Ther. Ultrasound, 3(1), pp. 1–18. [CrossRef] [PubMed]
Roache, P. J. , 1998, Verification and Validation in Computational Science and Engineering, Hermosa Publisher, Socorro, NM.


Grahic Jump Location
Fig. 1

Photos of the setup for in vitro ultrasonic measurements. The side-walls of the water-tank were lined with an acoustic absorber to minimize reflections (a). The entire exposure setup featuring the transducer (b) is shown in (c), and (d) shows the setup next to the robotic measurement arm with the extension on which the hydrophone is mounted.

Grahic Jump Location
Fig. 2

Cross section of the absolute pressure amplitude through the location of the peak for the reference simulation (a). The local maxima named SS, SW, SE, NW, and NE, extracted to ascertain the local distortion effects of the focal region, are marked as white points (b), while the center of the focal region is marked as a black point.

Grahic Jump Location
Fig. 3

Gamma-method for comparison of results with tolerances calculated by uncertainty analysis (see Table 9). The normalized pressure resulting from the measurements (a) and the simulation (b) are plotted on a plane through the maximum, while (c) shows the corresponding γ index distribution. Perfect agreement can be seen for these tolerances as all γ indices lie below a value of 1.0.



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