Handbook of Anatomical Models for Radiation Dosimetry PDF

Preface

Since the 1960s, the radiological science community has developed and applied more than 90 computational models of the human body—often referred to as "phantoms"—for ionizing radiation dosimetry studies. Each of the models not only defi nes the exterior features of the entire human body, but also includes extensive details on internal organs such as volume, mass, shape, and tissue composition. These computational phantoms are combined with Monte Carlo methods to precisely simulate complex radiation interactions and energy depositions in the human body involving various particles such as photons (x-rays and gamma rays), electrons, neutrons, and protons. Organ dose estimates, often normalized by measurable parameters, have been calculated for different irradiation scenarios found in occupational radiation protection, nuclear medicine, diagnostic imaging, and radiotherapy. Over the years, data derived from these computational phantoms have been adopted into the recommendations of the International Commission on Radiological Protection (ICRP) and other international and national bodies.

Anthropomorphic phantoms of adults and children of various ages, as well as pregnant women, were depicted using increasingly sophisticated solid-geometry modeling techniques over the past 40 years. Early computational phantoms were based on simple quadric equations. Voxelized phantoms, which took advantage of medical imaging advances, started to emerge 20 years ago. These image-based phantoms brought an excitement to the research community because of their anatomical realism. In recent years, phantoms involving advanced geometries, such as the nonuniform rational B-splines (NURBS) and polygonal meshes, were reported with unprecedented capabilities such as deformable anatomy and real-time cardiac and respiratory motion simulations. In addition, a number of computational phantoms have been developed for studies involving nonionizing radiation—radio frequencies such as those emitted by electric power lines and wireless cellular phone technologies. These nonionizing radiation phantoms have similar anatomical features, as well as technical challenges, as those used for ionizing radiation dosimetry. Many such computational phantoms have been used for both fi elds of studies.

For the first time, this book provides a comprehensive review of the historical development and application of a large number of important computational phantoms that have been widely reported in the literature. The history of computational phantoms is clearly in parallel with, and thus offers a unique perspective about, advances in computer technologies and medical imaging such as computed tomography and magnetic resonance imaging. By reading this book, the reader can obtain a unique sense of the scientifi c process in computational phantom development: the conception of an idea, the identifi cation of original anatomical data, solutions of various computing problems, ownership and sharing of results, as well as the satisfaction and frustration associated with any scientifi c endeavor.

This handbook contains 30 chapters and is the result of several years of planning and preparation involving ultimately 64 authors from 13 countries and regions. The idea of this book was fi rst conceived during the Monte Carlo 2005 Topical Meeting in Chattanooga, Tennessee, April 17–21, 2005. A special session on "Tomographic Models for Radiation Protection Dosimetry" was attended by more than a dozen invited speakers worldwide. Recognizing the needs for research collaboration and dissemination, the session attendees strongly suggested two actions. The fi rst was to form the Consortium of Computational Human Phantoms (CCHP) and a portal site for information related to computational human phantoms (www.virtualphantoms.org). The second was to initiate this collaborative book project to document a 40-year history of research and development. Previously, two workshops on "voxelized phantoms" were held: one at the National Board Radiological Protection, U.K., by Peter Dimbylow in 1995 that resulted in a compilation of presentations and the other at the Oak Ridge National Laboratory by Keith Eckerman in 2000. Despite the large number of phantoms that have been developed over the past four decades, information has been scattered and often lacking in detail, and certain data from the early work were diffi cult to locate. In the early 2000s, the ICRP decided to adopt voxelized computational phantoms as standards for radiation protection purposes. As a result, many colleagues had been actively involved for several years in activities associated with the ICRP Reference Computational Phantoms. These experiences accelerated our plan for this book, leading to the acceptance of the proposal by the publisher in 2007. It was clear to us that this book should possess the necessary depth and breadth by considering as broadly as possible phantoms that were historically important. At the same time, this book should also include applications of these phantoms in diverse radiological studies. We are extremely pleased that nearly all major phantom developers around the world accepted our invitation to contribute, except for a few colleagues whose busy schedules prevented them from participating—particularly Peter Dimbylow (for the NORMAN phantom) and George Zubal (for the "Zubal" phantom). It is obvious that we were unable to extend our invitation to many other researchers whose works are included in the tables of Chapter 1. Furthermore, there is a chance that we may have missed a few phantoms despite an exhaustive literature search. If your work is not mentioned anywhere in this book, please contact us so we can update our database that is maintained from the CCHP Web site.

This book is divided into two main parts: the phantoms and their applications. Part I starts with Chapter 1, which provides a review of 40 years of research and development in computational phantoms. This chapter includes a discussion on the classifi cation of phantoms and a comprehensive listing of computational and physical phantoms used for a variety of ionizing and nonionizing radiation applications. Several rare phantoms were included, such as the CAM phantom developed in 1973 for space radiation dosimetry. Chapters 2 through 15 provide detailed accounts for each of the well-known phantoms, such as the MIRD-5, GSF Voxel Family Phantoms, NCAT, the UF Hybrid Pediatric Phantoms, VIP-Man, as well as the latest ICRP Reference Phantoms. Chapter 11, which was contributed by three Chinese groups, details several phantoms, including one that, at the time of writing, has the smallest voxel size (0.2 mm), developed from the Chinese Visible Human Project. Chapter 16 is the fi nal chapter in Part I, and it summarizes physical phantoms for experimental radiation dosimetry.

In Part II, Chapters 17, 18, and 19 cover applications for radiation protection dosimetry involving environmental, nuclear power plant, and internal contamination exposures, respectively. These are followed by medical applications in Chapters 20 through 28, covering topics such as nuclear medicine therapy, CT examinations of pediatric and adult patients, x-ray radiological image optimization, nuclear medicine imaging, external photon and proton treatments, and management of respiration in modern image-guided radiation treatment. Chapters 27 and 28 deal with patient-specifi c phantoms used for radiation treatment planning involving two Monte Carlo code systems: GEANT4 and EGS, respectively. Applications for nonionizing radiation are described in Chapter 29. Finally, Chapter 30 discusses future needs for research and development. To supplement the information in this book, the following related data sets can be downloaded from http://fi les. virtualphantoms.org/public/FreeDownloads: (1) the VIP-Man image data; (2) Monte Carlo N-Particle (MCNP) input fi le for external photon beams source geometry using the VIPMan phantom; and (3) presentation slides.

An ambitious project like this is impossible without the generous support from the leading contributors for each chapter. Their time, effort, and patience are greatly appreciated. The fi eld of computational phantoms has a long and rich history, and the research community is deeply indebted to the visionary work by many pioneers. As editors, we would like to thank Binquan Zhang, Juying Zhang, Matthew Mille, and Paul Booth from Rensselaer Polytechnic Institute, who provided valuable assistance in handling, reviewing, and formatting the electronically submitted manuscripts.