Guillem Pratx

Guillem Pratx, PhD

Status

Postdoctoral fellow in Radiation Oncology, Stanford University School of Medicine

Education

BS Engineering, École Centrale Paris, France, 2004

MS Electrical Engineering, Stanford University, 2006

PhD Electrical Engineering, Stanford University, 2010

Thesis: Image Reconstruction in High-Resolution PET: GPU-Accelerated Strategies for Improving Image Quality and Accuracy.

Adviser: Craig S. Levin, PhD

Work and Research Experience

2009-Present, Radiation Oncology, Stanford University School of Medicine, CA

Postdoctoral Fellow. Currently, I am researching novel imaging approaches for guiding cancer radiation therapy and surgery.

Supervisor: Lei Xing, PhD

2005-2009, Molecular Imaging Program, Stanford University, CA

Doctoral Student. Researched and implemented a novel image reconstruction framework for high-resolution positron emission tomography (PET). The framework combines the two following features: ultra fast processing using graphics processing units (GPUs), and high image quality and quantitative accuracy using a precise shift-varying model within the reconstruction, as well as advanced photon positioning. The approach was successfully applied to commercially-available pre-clinical (high-resolution) and clinical (time-of-flight) PET systems. [download dissertation]

Supervisor: Craig S. Levin, PhD

2007-2009, Cancer Center, Stanford University School of Medicine, CA

Research Assistant. Implemented a software package for calibration and real-time operation of a surgical gamma camera prototype. Helped conduct clinical study on the efficacy of the gamma camera for guiding sentinel lymph node biopsy in breast cancer and melanoma (50 patients).

Supervisor: Denise L. Johnson, MD

Summer 2007, University of Manchester, UK

Visiting Researcher. Investigated novel non-linear optimization methods for maximum-likelihood PET image reconstruction based on the conjugate gradient method.

Supervisor: Andrew J. Reader, PhD

Summer 2004, LIAMA, Chinese Academy of Sciences, Beijing, China

Research Intern. Designed and implemented computer-vision algorithms to automatically extract buildings from high-resolution satellite images.

Summer 2001, Kick Start Ventures, London, UK

Market analysis for a company which manages an online marketplace for road freight in the UK. Marketing for British phone operator.

Summer 2000, Thales Alenia Space (formerly Alcatel), Toulouse, France

Computer-aided design (CATIA) and software development.

Honors & Awards

Grants & Fellowships

2010 | Breast Cancer Research Program postdoctoral fellowship, DoD

2010 | Research Seed Grant, AAPM

2010 | Dean's Postdoctoral Fellowship, Stanford University

2006 | BIO-X Predoctoral Fellowship, Stanford University

2006 | NVIDIA Fellowship, NVIDIA Corp.

2006 | Bradley-Alavi Fellow, Society of Nuclear Medicine

Awards

2011 | Travel Award to attend WMIC, San Diego

2010 | Travel Award to attend ARCMP Joint Symposium, Seoul, S. Korea

2010 | Travel Award to attend World Molecular Imaging Congress, Kyoto

2008 | Top Student Paper Award, IEEE Medical Imaging Conference, Dresden

2008 | Soc. Nucl. Med. Travel Award to attend Annual Meeting, Toronto

2008 | IEEE Travel Award to attend IEEE Medical Imaging Conference, Dresden

2007 | Soc. Nucl. Med. Travel Award to attend Annual Meeting, New Orleans

2007 | IEEE Travel Award to attend IEEE Medical Imaging Conference, Honolulu

2007 | Bio-X Travel Grant to attend Fully 3D Meeting, Lindau

2006 | Philips Travel Award to attend IEEE Medical Imaging Conference, San Diego

2001 | Third place, Prologin Coding Contest (1500 participants), Paris

Teaching

Short Course Instructor, IEEE Medical Imaging Conference, 2007

Programming and Medical Applications Using Graphics Hardware

Professional Activities

Service

President, French Stanford Student Association, Stanford University, 2007-2008

Refereeing

IEEE Transactions in Nuclear Science

IEEE Transactions in Medical Imaging

Computer Methods and Programs in Biomedicine

IEEE Transactions on Information Technology in BioMedicine

Medical Physics

Physics in Medicine and Biology

Publications and Conference Presentations

Peer-Reviewed Publications

  1. Cui JY, Pratx G, Prevrhal S & Levin CS, "Fully 3-D list-mode time-of-flight PET image reconstruction on GPUs using CUDA", Med. Phys. 38(12), pp. 6775-6786, Dec. 2011
  2. Meng B, Pratx G & Xing L, "Ultra-fast and scalable cone-beam CT reconstruction using MapReduce in a cloud computing environment", Med. Phys. 38(12) pp. 6603-6609, Dec. 2011
  3. Pratx G & Xing L, "Monte Carlo simulation of photon migration in a cloud computing environment with MapReduce", J. Biomed. Opt. 16(12) pp. 125003, Dec. 2011
  4. Kalantzis G, Vasquez-Quino LA, Zalman T, Pratx G & Lei Y, "Toward IMRT 2D dose modeling using artificial neural networks: A feasibility study", Med. Phys. 38(10), pp. 5807-5817, Oct. 2011
  5. Wang H, Ma Y, Pratx G & Xing L, "Toward real-time Monte Carlo simulation using a commercial cloud computing infrastructure", Phys. Med. Bio. 56(17) pp. 175-181, Aug. 2011
  6. Pratx G & Levin CS, "Online detector response calculations for high-resolution PET image reconstruction", Phys. Med. Bio. 56(13) pp. 4023-4040, Jun. 2011
  7. Sun C, Pratx G, Carpenter CM, Liu HG, Cheng Z, Gambhir SS & Xing L, "Synthesis and radioluminescence of PEGylated Eu3+-doped nanophosphors as bioimaging probes", Adv. Mater., 23(24), pp. H195-H199, Jun. 2011
  8. Carpenter CM, Pratx G, Sun C & Xing L, "Limited-angle x-ray luminescence tomography: Methodology and feasibility study", Phys. Med. Bio. 56(12), pp. 3487-3502, May 2011
  9. Pratx G & Xing L, "GPU computing in medical physics: A review", Med. Phys. 38(5), pp. 2685-2698, May 2011
  10. Pratx G, Carpenter CM, Sun C & Xing L, "X-Ray luminescence computed tomography via selective excitation: A feasibility study", IEEE Trans. Med. Imag. 29(12), pp. 1992-1999, Dec. 2010
  11. Pratx G, Surti S & Levin CS, "Fast list-mode reconstruction for time-of-flight PET using graphics hardware", IEEE Trans. Nucl. Sci. 58(1), pp. 105-109, Nov. 2010
  12. Pratx G, Carpenter CM, Sun C & Xing L, "Tomographic molecular imaging of X-ray-excitable nanoparticles", Opt. Lett. 35(20), pp. 3345-3347, Oct. 2010
  13. Reynolds PD, Olcott PD, Pratx G, Lau FWY & Levin CS, "Convex optimization of coincidence time resolution for a high-resolution PET system", IEEE Trans. Med. Imag. 30(2), pp. 391-400, Sep. 2010
  14. Sun C, Carpenter CM, Pratx G & Xing L, "Facile synthesis of amine functionalized Eu3+-doped La(OH)3 nanophosphors for bioimaging", Nanoscale Res. Lett. 6(1), pp. 24-30, Sep. 2010
  15. Gu Y, Pratx G, Lau FWY & Levin CS, "Effects of multiple-interaction photon events in a high resolution PET system that uses 3-D positioning detectors", Med. Phys. 37(10), pp. 5494-5509, Sep. 2010
  16. Carpenter CM, Sun C, Pratx G, Rao R & Xing L, "Hybrid X-ray/optical luminescence imaging: Characterization of experimental conditions", Med. Phys. 37(8), pp. 4011-4019, Aug. 2010
  17. Pratx G & Levin CS, "Bayesian reconstruction of photon interaction sequences for high-resolution PET detectors", Phys. Med. Bio. 54(17), pp. 5073-5094, Sep. 2009
  18. Pratx G, Chinn G, Olcott PD & Levin CS, "Fast, accurate and shift-varying line projections for iterative reconstruction using the GPU", IEEE Trans. Med. Imag. 28(3), pp. 435-445, Mar. 2009

Book Chapters

  1. Pratx G, Cui JY, Prevrhal S & Levin CS, "3-D tomographic image reconstruction from randomly-ordered lines with CUDA", in GPU Computing Gems Emerald Edition, pp. 679-691, Morgan Kaufmann, Jan 2011

U.S. Patents

  1. Pratx G, Olcott PD & Levin CS, "Method of reconstructing a tomographic image using a graphics processing unit", 11/710,273
  2. Pratx G & Levin CS, "Method and apparatus for imaging using robust Bayesian sequence reconstruction", 12/607,853
  3. Pratx G, Cui JY & Levin CS, "Shift-Varying Line Projection using Graphics Hardware", provisional

Conference Presentations

  1. Carpenter C, Pratx G, Sun C, Liu HG & Xing L, "Toward Molecular Image-guidance for Intraoperative Breast Radiotherapy", ASTRO, 2011
  2. Pratx G, Carpenter C, Sun C, Liu HG & Xing L, "Imaging of Radioluminescent Nanophosphors via Improved X-ray Luminescence Computed Tomography", WMIC, 2011
  3. Sun C, Pratx G, Carpenter C & Xing L, "Multifunctional Nanophosphors for Enhanced Tumor Radiotherapy", WMIC, 2011
  4. Kuang Y, Pratx G, Sun C, Carpenter C & Xing L, "Breast Imaging Using X-ray Stimulated Fluorescence", WMIC, 2011
  5. Meng B, Pratx G & Xing L, "Fast and Reliable Cone-Beam CT Reconstruction Using Cloud Computing", AAPM Annual Meeting, 2011
  6. Wang H, Ma Y, Pratx G & Xing L, "Toward Real-Time Monte Carlo Simulation Using a Commercial Cloud Computing Infrastructure", AAPM Annual Meeting, 2011
  7. Kuang Y, Pratx G, Sun C, Carpenter C & Xing L, "X-Ray Stimulated Fluorescence for Breast Imaging", oral presentation, AAPM Annual Meeting, 2011
  8. Pratx G, Carpenter C, Sun C & Xing L, "Advances in X-Ray Luminescence Computed Tomography: Towards In-Vivo Imaging of Radioluminescent Nanophosphors", oral presentation, AAPM Annual Meeting, 2011
  9. Carpenter C, Pratx G, Sun C & Xing L, "Multiplexed Radio Luminescence Imaging for Radiation Therapy", oral presentation, AAPM Annual Meeting, 2011
  10. Pratx G & Xing L, "Monte-Carlo Simulation in a Cloud Computing Environment with MapReduce", oral presentation, AAPM Annual Meeting, 2011
  11. Cui JY, Pratx G, Prevrhal S, Shao L & Levin CS, "Fully 3-D List-mode Positron Emission Tomography Image Reconstruction on GPU using CUDA", IEEE Medical Imaging Conference, 2010
  12. Xing L, Pratx G, Suh TS & Chang J, "Incorporating Four-Dimensional (4D) PET Information into Treatment Planning of Thoracic Stereotactic Radiosurgery", oral presentation, WMIC, 2010.
  13. Pratx G, Carpenter CM, Sun C, Rao R & Xing L, "Simultaneous Anatomical and Molecular Tomographic Imaging using X-Ray-Excitable Nanoparticles", oral presentation, WMIC, 2010
  14. Carpenter CM, Pratx G, Sun C & Xing L, "Development of X-ray Luminescence Tomography for Intra-operative molecular imaging", WMIC, 2010
  15. Sun C, Carpenter CM, Pratx G & Xing L, "EG-coated BaYF5:Eu3+ Nanophosphors for X-ray Excited Optical Luminescence Molecular Imaging", WMIC, 2010
  16. Pratx G, Carpenter CM, Sun C, Rao R & Xing L, "X-ray Activated Optical Contrast Agents For Simultaneous Anatomical/Functional CT Imaging", ASTRO, 2010
  17. Carpenter CM, Pratx G, Sun C & Xing L, Intraoperative Breast Radiotherapy guided by X-ray Luminescent Nanoparticles", oral presentation, ASTRO, 2010
  18. Sun C, Rao R, Carpenter CM, Pratx G & Xing L, Folate Receptor Targeted Nanophosphors for Enhanced Tumor Radiotherapy", ASTRO, 2010
  19. Sun C, Liu H, Pratx G, Carpenter CM, Xing L & Cheng Z, "Characterization of Cerenkov Optical Irradiation From Radioactive Probes in Phantoms and Living Subjects", oral presentation, AAPM Annual Meeting, 2010
  20. Carpenter CM, Pratx G, Sun C, Xing L & Ravilisetty P, "Development of An X-Ray/Optical Luminescence Imager for Improved X-Ray Contrast Sensitivity", oral presentation, AAPM Annual Meeting, 2010
  21. Pratx G, Carpenter CM, Sun C & Xing L, "X-Ray Luminescence Computed Tomography Via Selective X-Ray Excitation", oral presentation, AAPM Annual Meeting, 2010
  22. Sun C, Liu H, Pratx G, Carpenter CM & Xing L, "Characterization of Cerenkov Optical Irradiation from Radioactive Probes in Phantoms and Living Subjects", oral presentation, AAPM Annual Meeting, 2010
  23. Johnson DL, Olcott PD, Pratx G & Levin CS, "Novel Hand Held Intraoperative Radionuclide Imaging", oral presentation, Soc. Surg. Onc. 63rd Annual Cancer Symposium, 2010
  24. Pratx G, Suh TS, Levin CS & Xing L, "GPU-Accelerated List-Mode Reconstruction for 4-D PET", oral presentation, ICCR, 2010
  25. Carpenter CM, Senadheera L, Pratx G, Sun C, Ravilisetty PR & Xing L, "X-Ray Induced Fluorescence Optical Imaging Enabled by Injectable Nano-Scintillators", oral presentation, Biomed. Opt., 2010
  26. Pratx G, Surti S & Levin CS, "GPU-accelerated list-mode reconstruction for 3-D time-of-flight PET", oral presentation, Soc Nucl Med Annual Meeting, 2009
  27. Olcott PD, Pratx G, Johnson DL, Mansouri MA & Levin CS, "Clinical feasibility of an intra- operative hand-held gamma camera for sentinel lymph node biopsy for the surgical staging of melanoma and breast cancer", oral presentation, Soc Nucl Med Annual Meeting, 2009
  28. Pratx G, Chinn G, Olcott PD & Levin CS, "Fast, accurate and shift-varying line projections for iterative reconstruction using the GPU", IEEE Medical Imaging Conference, 2008
  29. Pratx G, Reader AJ & Levin CS, "Faster maximum-likelihood reconstruction via explicit conjugation of search directions", IEEE Medical Imaging Conference, 2008
  30. Gu Y, Pratx G, Lau FWY & Levin CS, "Effects of photon multiple interactions in a high resolution PET system that uses 3-D positioning detectors", IEEE Medical Imaging Conference, 2008
  31. Reynolds PD, Olcott PD, Pratx G, Lau FWY, Levin CS, "Convex optimization of coincidence time resolution for high-resolution PET systems", IEEE Medical Imaging Conference, 2008
  32. Pratx G & Levin CS, "Maximum a posteriori event positioning in high-resolution PET CZT detectors", oral presentation, Soc Nucl Med Annual Meeting, 2008
  33. Pratx G, Reader AJ & Levin CS, "Fast maximum likelihood image reconstruction via PCG without a line search", oral presentation, Soc Nucl Med Annual Meeting, 2008
  34. Peng H, Olcott PD, Pratx G, Foudray AMK, Chinn G & Levin CS, "Design study of a high-resolution breast-dedicated PET system built from CZT detectors", IEEE Medical Imaging Conference, 2007
  35. Pratx G & Levin CS, "Accurately positioning events in a high-resolution PET system that uses 3D CZT detectors", oral presentation, IEEE Medical Imaging Conference, Honolulu, HI, 2007
  36. Pratx G, Chinn G, Habte F, Olcott PD & Levin CS, "Acceleration of fully 3-D list-mode OSEM with system modeling for high-resolution PET using graphics processing units", oral presentation, International Meeting on Fully 3-D Image Reconstruction in Rad. and Nuclear Medicine, 2007
  37. Pratx G, Chinn G, Habte F, Olcott P & Levin CS, "Fully 3-D list-mode OSEM accelerated by graphics processing units", IEEE Medical Imaging Conference, 2006
  38. Olcott PD, Buss SR, Levin CS, Pratx G & Sramek CK, "GRAY: High energy photon ray tracer for PET applications", IEEE Medical Imaging Conference, 2006
  39. Pratx G, Chinn G, Olcott P & Levin CS, "Accelerated list-mode 3D-OSEM reconstruction for PET on a graphics processing unit", oral presentation, Soc Nucl Med Annual Meeting, 2006
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