Particle Therapy Technology for Safe Treatment

Jay Flanz

• Publisher: CRC Press
• Year: 2022
• Print ISBN: 9780367640149
• eBook ISBN: 9781000528060
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Biotechnology in Medicine
• Index: Technology & Engineering

The path from clinical requirements to technical implementation is filtered by the translation of the modality to the technology. An important part of that filter is that the modality be safe. For that to be the case, it is imperative to understand what clinical parameters affect the safety of a treatment and then determine how the technology can affect those parameters.

This book provides a practical introduction to particle therapy. It provides a thorough introduction to the technological tools and their applications and then details the components that are needed to implement them. It explains the foundations of beam production and beam delivery that serve to meet the necessary clinical requirements. It emphasizes the relationship between requirements and implementation, including how safety and quality are considered and implemented in the solution. The reader will learn to better understand what parameters are important to achieve these goals.

Particle Therapy Technology for Safe Treatment will be a useful resource for professionals in the field of particle therapy in addition to biomedical engineers and practitioners in the field of beam physics. It can also be used as a textbook for graduate medical physics and beam physics courses.

Key Features

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• Presents a practical and accessible journey from application requirements to technical solutions

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• Provides a pedagogic treatment of the underlying technology

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• Describes how safety is to be considered in the application of this technology and how safety and quality can be factored into the overall system

Author Bio

After receiving his PhD in nuclear physics, Dr. Jacob Flanz was the Accelerator Physics Group leader and Principal Research Scientist at the Massachusetts Institute of Technology (MIT), USA, where he designed the recirculator and the GeV stretcher/storage ring. He joined Massachusetts General Hospital (MGH) and Harvard and became project and technical director of proton therapy, with responsibility for specifications, integration, and commissioning ensuring safe clinical performance. He invented the universal nozzle and led the design and implementation of beam scanning at MGH in 2008, including quality assurance. Dr. Flanz has been involved in several FDA applications for particle therapy. He developed and taught the US Particle Accelerator School course "Medical Applications of Accelerators and Beams." He was cochair of education and is currently the president of the Particle Therapy Co-Operative Group.

Exercise solutions to accompany this book can be accessed via the 'Instructor Resources' tab on the book webpage.

1Introduction

DOI: 10.1201/9781003123880-1

The path from clinical requirements to technical implementation is filtered by the translation of the modality to the technology. For example, the word ‘safe’ is defined in the context of the application. The appropriate interpretation of that context is essential. It's reasonable for there to be a deterministic flow from requirements to implementation in any application. For particle therapy, it helps to understand what clinical parameters affect the safety of a treatment, and then the filter is constructed when determining how the technology can affect those parameters. Unsafe scenarios are to be deduced or inferred and mitigated. This all begins as it ends by asking if you would feel comfortable having a family member receive treatment.

Particle therapy is a multidisciplinary application that benefits from the insights of experts in these disciplines. It is the intention to weave many of the disciplines together to construct the framework for the application. This includes the context for the meanings and the relevance of the parameters as well as limits imposed by the physics and engineering. Well, in fact, it is difficult to be exhaustive in a book this size, so a sampling of this is offered, based on personal experience. The book builds with a discussion of some tools, an introduction to the application and the technology of the components that are needed. At almost every step the question, what could go wrong, is asked. The statement that the system must be safe is insufficient. A look into the clinical and technological considerations to achieve a realizable set of preconditions that has safety at its core could be a sufficient start. This may not be done explicitly in every section and for every subject, but it is hoped that there will be sufficient clarification for a safety filter to be internalized.

Somewhat underlying the above is the approach of obtaining the necessary information about the application before considering how to create the technical components. The information necessary to learn about the applications to be presented can be acquired from many sources. The corollary to this is that many good sources exist and it is not the author’s intent to reinvent the wheel. Yet, there are many assumptions in these different sources, so it is hoped that fewer assumptions are made herein. Some of the why is included with the what. If the reader finds the topics interesting and needs additional perspective, that information probably exists.

The approach used is one that leads toward the identification of sensitivities and tolerances. The technology is interpreted while applying a filter that includes the clinical application and safety. Much of this filter has to do with considering what the tolerances are and what could go wrong. It is not intended to fully design a system or even identify all the final specifications, but it is hoped there is enough for many back of the envelope estimates. It’s probably best to get a new box of envelopes now.

To accomplish this, it will be necessary to review some of the fundamental principles. It is assumed that the audience for this book could be from various multidisciplinary fields. The times that the author taught the ‘Medical Applications of Accelerators’ course at the US Particle Accelerator School, the class usually included participants from both the medical and accelerator communities. A foundation is offered that includes the clinical application, physical principles related to the interaction of particles with matter, charged particle beam acceleration and transport and even some engineering considerations. These are described at a level sufficient to build on in the text. Almost everything that is introduced is used, although it may not always be obvious. Some of it will be new for some and other topics will be review for others.

Putting all this together in one place at a level to understand how these can be used together is the challenge. Much that is discussed in this book is placed in a context of safety, even if the word ‘safety’ is not used on every page. The word ‘safety’ is used several times in this introduction, to make up for that. Asking questions about how a parameter might affect a treatment and how a component might affect a parameter will help the reader to get what’s intended from what’s been written. In the end, the reader is rewarded with this. Sections entitled ‘what could go wrong’ are not meant to cause concern, but only to heighten the thought process.

Part of the reason this book has been written after the author’s 45+ years in these fields is the wish that a book like this existed when I started. I sincerely hope that you will find this contribution helpful and perhaps enjoy a few smiles along the journey.

2Evolution of Medical Particles

DOI: 10.1201/9781003123880-2

The discovery of particles at the atomic level and smaller and their interactions with matter has been the subject of considerable interest for over 100 years. As the properties of the particles and their interactions became better understood either quantitatively or qualitatively, applications to use these particles were developed. To better study particles and their interactions, accelerators have been constructed and the field of beam physics was developed. It was only recently (in the last few decades) that the study of the physics of beams has become a legitimate field of investigation. Generally, it was justified by the applications it served such as nuclear and high-energy physics. Furthermore, it may be felt by some that nuclear and high-energy physics themselves are only a stepping stone to develop useful applications for humanity. The ultimate application for society may be medicine. The fundamental search for knowledge has always paid off whether it has been the main goal of research or not. The key to applying the results of research is to have in mind an overview of the relevant phenomena. Beginning with an understanding of what is required for a particular application, the requirements can be followed to determine the details of the implementation.

The applications of particles in medicine have been recognized from the earliest time that particles were discovered. The difficulty involves the preparation and delivery of these beams (from naturally occurring beams [e.g. radioisotopes] to accelerator-produced beams). From the time, in 1895, when Roentgen discovered X-rays, and in 1913, when Coolidge developed the vacuum X-ray tube, it has been shown that energetic particles can be useful for medical applications. It is clear that there is a wide range of applications and, therefore, also a wide range of requirements for the particles that must be considered.

Almost in parallel with the discovery of physical phenomena and the development of physical devices, people started using these discoveries for treating those who were ill. Some of these discoveries include:

• Magnetic fields
• High frequencies
• X-rays
• Electrons
• Protons
• Lasers

Most of the accelerators existing today are used for applications in the field of medicine. While accelerators were originally introduced for research, the use of energetic particles for medicine is natural. Medical applications require energetic beams (particles with energies higher than thermal energi...

Table of contents

• Cover Page
• Half Title Page
• Title Page
• Copyright Page
• Dedication Page
• Contents
• Chapter 1 Introduction
• Chapter 2 Evolution of Medical Particles
• Chapter 3 A Personal Historical Perspective
• Chapter 4 Flow of Requirements
• Chapter 5 External Beam Systems
• Chapter 6 How to Damage Unwanted Cells
• Chapter 7 Exponentials
• Chapter 8 Relativistic Dynamics
• Chapter 9 Charged Particle Interactions in Matter
• Chapter 10 Review of Charged Particle Motion
• Chapter 11 Clinical Perspective of Charged Particle Therapy Beams
• Chapter 12 Three-Dimensional Dose Conformation
• Chapter 13 Accelerator Systems
• Chapter 14 Gantries
• Chapter 15 Safety in Radiotherapy
• Chapter 16 Sensitivities and Tolerances: Scattering
• Chapter 17 From Clinical to Technical Tolerances: Scanning
• Chapter 18 Afterword
• Acknowledgments
• Appendix A: Particle Therapy Facilities (as of June 2021)
• Appendix B: Some Useful Constants
• Appendix C: Hazard Topics
• Appendix D: Beam QA Frequency Possibility
• Appendix E: Some Element and Compound Parameters
• Index