Medical Radiation Dosimetry

Accurate radiation dosimetry is a requirement of radiation oncology, diagnostic radiology and nuclear medicine. It is necessary so as to satisfy the needs of patient safety, therapeutic and diagnostic optimisation, and retrospective epidemiological studies of the biological effects resulting from low absorbed doses of ionising radiation. The radiation absorbed dose received by the patient is the ultimate consequence of the transfer of kinetic energy through collisions between energetic charged particles and atoms of the tissue being traversed. Thus, the ability of the medical physicist to both measure and calculate accurately patient dosimetry demands a deep understanding of the physics of charged particle interactions with matter. Interestingly, the physics of charged particle energy loss has an almost exclusively theoretical basis, thus necessitating an advanced theoretical understanding of the subject in order to apply it appropriately to the clinical regime. ​ Each year, about one-third of the world's population is exposed to ionising radiation as a consequence of diagnostic or therapeutic medical practice. The optimisation of the resulting radiation absorbed dose received by the patient and the clinical outcome sought, whether diagnostic or therapeutic, demands accuracy in the evaluation of the radiation absorbed doses resulting from such exposures. This requirement arrises primarily from two broadly-encompassing factors: The requirement in radiation oncology for a 5% or less uncertainty in the calculation and measurement of absorbed dose so as to optimise the therapeutic ratio of the probabilities of tumour control and normal tissue complications; and The establishment and further refinement of dose reference levels used in diagnostic radiology and nuclear medicine to minimise the amount of absorbed dose for a required degree of diagnostic benefit. The radiation absorbed dose is the outcome of energetic charged particles decelerating and transferring their kinetic energy to tissue. The calculation of this energy deposition, characterised by the stopping power, is unique in that it is derived entirely from theoretical principles. This dominant role of the associated theory makes its understanding of fundamental to the calculation of the radiation absorbed dose to the patient. The theoretical development of charged particle energy loss recognised in medical physics textbooks is in general limited to basic derivations based upon classical theory, generally a simplified form of the Bohr theory. More advanced descriptions of, for example, the Bethe-Bloch quantum result usually do not go beyond the simple presentation of the result without full explanation of the theoretical development of the theory and consideration of its limitations, its dependencies upon the Born perturbation theory and the various correction factors needed to correct for the failures of that Born theory at higher orders. This is not appropriate for a full understanding of the theory that its importance deserves. The medical radiation physicist should be aware of the details of the theoretical derivations of charged particle energy loss in order to appreciate the levels of accuracy in tabular data provided in reports and the calculation methodologies used in modern Monte Carlo calculations of radiation dosimetry.

Complexities of the requirements for accurate radiation dosimetry evaluation in both diagnostic and therapeutic nuclear medicine (including PET) have grown over the past decade. This is due primarily to four factors: Growing consideration of accurate patient-specific treatment planning for radionuclide therapy as a means of improving the therapeutic benefit, development of more realistic anthropomorphic phantoms and their use in estimating radiation transport and dosimetry in patients, Design and use of advanced Monte Carlo algorithms in calculating the above-mentioned radiation transport and dosimetry which require the user to have a thorough understanding of the theoretical principles used in such algorithms, their appropriateness and their limitations, increasing regulatory scrutiny of the radiation dose burden borne by nuclear medicine patients in the clinic and in the development of new radiopharmaceuticals, thus requiring more accurate and robust dosimetry evaluations. An element common to all four factors is the need for precise radiation dosimetry in nuclear medicine, which is fundamental to the therapeutic success of a patient undergoing radionuclide therapy and to the safety of the patients undergoing diagnostic nuclear medicine and PET procedures. As the complexity of internal radiation dosimetry applied to diagnostic and therapeutic nuclear medicine increases, this book will provide the theoretical foundations for: enabling the practising nuclear medicine physicist to understand the dosimetry calculations being used and their limitations, allowing the research nuclear medicine physicist to critically examine the internal radiation dosimetry algorithms available and under development; and providing the developers of Monte Carlo codes for the transport of radiation resulting from internal radioactive sources with the only comprehensive and definitive.

A straightforward presentation of the broad concepts underlying radiological physics and radiation dosimetry for the graduate-level student. Covers photon and neutron attenuation, radiation and charged particle equilibrium, interactions of photons and charged particles with matter, radiotherapy dosimetry, as well as photographic, calorimetric, chemical, and thermoluminescence dosimetry. Includes many new derivations, such as Kramers X-ray spectrum, as well as topics that have not been thoroughly analyzed in other texts, such as broad-beam attenuation and geometrics, and the reciprocity theorem. Subjects are layed out in a logical sequence, making the topics easier for students to follow. Supplemented with numerous diagrams and tables.

Over the past few decades, the radiological science community has developed and applied numerous models of the human body for radiation protection, diagnostic imaging, and nuclear medicine therapy. The Handbook of Anatomical Models for Radiation Dosimetry provides a comprehensive review of the development and application of these computational mode

This book provides a comprehensive yet accessible overview of all relevant topics in the field of radiation protection (health physics). The text is organized to introduce the reader to basic principles of radiation emission and propagation, to review current knowledge and historical aspects of the biological effects of radiation, and to cover important operational topics such as radiation shielding and dosimetry. The author’s website contains materials for instructors including PowerPoint slides for lectures and worked-out solutions to end-of-chapter exercises. The book serves as an essential handbook for practicing health physics professionals.

This study guide will be a reliable support and easy-to-use source of information for students in the fields of dosimetry, physics, radiation oncology, and therapy as they progress through the educational levels in preparation for board examinations. The theoretical and practical knowledge gained by students on previous courses or in clinical settings is reinforced by means of almost 1200 questions and accompanying detailed analytical answers. In order to cater for the needs of all students, the questions are arranged according to three levels of difficulty. The level 1 questions are mainly intended for those hoping to pass the Medical Dosimetrist Certification Board (MDCB) exam but will also be beneficial for Medical Physics candidates taking written exams and for Radiation Oncology residents. The level II questions are in general clinically related and will be relevant for any student, while the level III questions are advanced and are especially suitable for American Board of Radiology candidates or those taking equivalent exams elsewhere in the world. The study guide is broken down into different subject areas, with provision of multiple questions and answers on each subject. In addition, the mathematical and physics questions include brief explanations of how the student can solve each problem. At the end of the guide, three practice tests are included with the same number of questions as are found in the MDCB exam. These tests will help students to test their knowledge and improve their test-taking speed.

Fördert nachhaltig das Verständnis von Konzepten zur Strahlendosimetrie: ausführliche Lösungen zu den Übungen im Lehrbuch "Fundamentals of Ionizing Radiation Dosimetry".

This book provides a first comprehensive summary of the basic principles, instrumentation, methods, and clinical applications of three-dimensional dosimetry in modern radiation therapy treatment. The presentation reflects the major growth in the field as a result of the widespread use of more sophisticated radiotherapy approaches such as intensity-modulated radiation therapy and proton therapy, which require new 3D dosimetric techniques to determine very accurately the dose distribution. It is intended as an essential guide for those involved in the design and implementation of new treatment technology and its application in advanced radiation therapy, and will enable these readers to select the most suitable equipment and methods for their application. Chapters include numerical data, examples, and case studies.

Radiation Dosimetry focuses on the advancements, processes, technologies, techniques, and principles involved in radiation dosimetry, including counters and calibration and standardization techniques. The selection first offers information on radiation units and the theory of ionization dosimetry and interaction of radiation with matter. Topics include quantities derivable from roentgens, determination of dose in roentgens, ionization dosimetry of high-energy photons and corpuscular radiations, and heavy charged particles. The text then examines the biological and medical effects of radiation, as well as radiation effects in malignant tissues, levels of radiation, and mechanism of radiation effects on living cells. The publication takes a look at ionization chambers, Geiger-Mueller counters and proportional counters, scintillation detectors, and photographic film dosimetry, Discussions focus on calibration and standardization techniques, scintillating materials and their light yield, scintillation detector dosimetry of neutrons, and the physics of counters. The text also ponders on chemical and colorimetric indicators and survey instruments and pocket dosimeters. The selection is a dependable reference for readers interested in radiation dosimetry.