Increases in available computational resources allow today's researchers to use more accurate and more precise simulation tools to design and optimize medical imaging systems <i>in silico</i>. Monte Carlo methods are among the most powerful tools for simulating imaging systems in the computer. The results of Monte Carlo simulations are exact - except for inherent statistical uncertainties - when accurate models of interaction cross-sections are employed. In addition, the conceptual simplicity of the Monte Carlo method and programs allows us to simulate multiple stochastic processes in complex geometries such as detailed and realistic anatomical models, structured phosphor screens, and multiple-layer detector pixel arrays. This course covers state-of-the-art Monte Carlo simulation methods for medical x-ray imaging systems, and is organized in a 4-module lecture (morning session) followed by a separate, optional hands-on workshop (WS815). The released code and accessory programs described during the course will be made available to participants. LECTURE OUTLINE 1) Fundamental Monte Carlo concepts including random number generators, cross-section models, uncertainty estimation, bias and efficiency, and variance reduction methods. 2) Particle transport methods for x-ray and gamma photons, electrons and positrons in PENELOPE, including physics models, and validation results. 3) Physics of MANTIS (a combined x-ray/electron/optical Monte Carlo imaging system simulation) including optical transport methods, statistics and models of scintillation output, and applications to indirect x-ray detectors with columnar phosphors and multi-modality imaging simulation. 4) Introduction to advanced tools for describing objects for Monte Carlo simulations including analytical, voxel, triangular mesh, and hybrid approaches.

Radiography is being performed using digital detectors with high performance. The display performance required to display radiographic images with high-fidelity is reviewed. New methods to test display performance are described and demonstrated during the course. Cathode ray tube (CRT) devices will be reviewed and methods to improve CRT performance will be summarized. New flat panel display technologies will be discussed with respect to their potential for use in medical imaging.

This hands-on workshop follows SC771 Monte Carlo Simulation of Radiation Imaging Systems, and provides tutorial examples describing how to use the open-source software products PENELOPE and MANTIS. The latest versions of the codes will be distributed to the participants with their notes in a CD. Participants must bring a laptop computer to the session. The instructors will demonstrate the concepts and techniques described in SC771, including: • Introduction to the code structure of PENEASY (a structured general-purpose main program for PENELOPE) and MANTIS. • Hands-on examples of MANTIS simulations of scintillation output and phosphor blur in indirect x-ray detectors with columnar phosphors.