Radiation detectors are fundamental tools for the quantitative characterization of therapeutic fields of ionizing radiation. Dosimetry measurements aim to quantify the amount of energy deposited in the body (dose). Therefore, an ideal detector would respond to radiation the same way the human body does. However, the fact that most radiation detectors are not tissue equivalent poses a major challenge. Organic electronics are attractive candidates for radiation detectors due to their potential to be made flexible, configuration highly customizable, wide selection of materials, and tissue equivalence. In this thesis we investigate a novel detector (stemless plastic scintillation detector - SPSD), which couples an organic photodiode to a plastic scintillator. Plastic scintillation detectors (PSDs) offer characteristics that are ideal for the measurement of small fields (high spatial resolution, real-time measurements, tissue equivalence, etc.). However, PSDs suffer from Cerenkov radiation (created in the optical fiber) contaminating the signal and must be corrected. The SPSD detector eliminates the need for an optical fiber to carry the signal. Such a detector could have the advantages of a PSD, while removing the main drawback. A series of four manuscripts form the basis for this thesis. The first manuscript showed an organic photodiode had potential as a radiation detector directly (linearity with dose rate and output factors agreed with a commercial detector). The second explained and validated a novel method for the correction of an extraneous signal (Compton current) in organic photodiode detectors. The third manuscript investigated a single-element SPSD, which was fabricated by coupling an organic photodiode to an organic scintillator. The SPSD was characterized by measuring various dependencies of the detector including: instantaneous dose rate dependence, energy dependence, directional dependence, and linearity with dose. Furthermore, Cerenkov radiation was shown to be minimal and the directional dependence it caused could be effectively eliminated by using reflective tape. The dependencies were encouraging for use as a detector. The culmination of the work was the fourth manuscript, which presented the fabrication of a 1D array SPSD, which demonstrated the accurate measurement of small field profiles and output factors.

Thèse. Biologie. Médecine. 2023

The Dosimetry of Ionizing Radiation, Volume I focuses on the development in radiation dosimetry, which has its origin in the medical application of ionizing radiation with the discovery of X-rays. This book discusses the irradiation of human beings and the biosphere by ionizing radiation from different sources, which is subjected to increased concern and interest due to its possible health effects. Comprised of six chapters, this volume starts with an overview of the factors determining the conversion of the imparted energy into a detectable signal. This text then explores the theoretical basis of microdosimetry and illustrates the numerical data, experimental techniques, and applications of essential concepts and results. Other chapters consider the application of instruments in dose measurements. This book discusses as well the application of radiotherapy for the treatment of malignant diseases. The final chapter deals with the recommended model parameters for internal dosimetry calculations in occupational radiation protection. Physicists, radiation physicists, scientists, and research institutes will find this book useful.

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.

Radiation dosimetry has made great progress in the last decade, mainly because radiation therapy is much more widely used. Since the first edition, many new developments have been made in the basic methods for dosimetry, i.e. ionization chambers, TLD, chemical dosimeters, and photographic films. Radiation Dosimetry: Instrumentation and Methods, Second Edition brings to the reader these latest developments. Written at a high level for medical physicists, engineers, and advanced dosimetrists, it concentrates only on evolvement during the last decade, relying on the first edition to provide the basics.

This comprehensive book covers the everyday use and underlying principles of radiation dosimeters used in radiation oncology clinics. It provides an up-to-date reference spanning the full range of current modalities with emphasis on practical know-how. The main audience is medical physicists, radiation oncology physics residents, and medical physics graduate students. The reader gains the necessary tools for determining which detector is best for a given application. Dosimetry of cutting edge techniques from radiosurgery to MRI-guided systems to small fields and proton therapy are all addressed. Main topics include fundamentals of radiation dosimeters, brachytherapy and external beam radiation therapy dosimetry, and dosimetry of imaging modalities. Comprised of 30 chapters authored by leading experts in the medical physics community, the book: Covers the basic principles and practical use of radiation dosimeters in radiation oncology clinics across the full range of current modalities. Focuses on providing practical guidance for those using these detectors in the clinic. Explains which detector is more suitable for a particular application. Discusses the state of the art in radiotherapy approaches, from radiosurgery and MR-guided systems to advanced range verification techniques in proton therapy. Gives critical comparisons of dosimeters for photon, electron, and proton therapies.

Although many radiation protection scientists and engineers use dose coefficients, few know the origin of those dose coefficients. This is the first book in over 40 years to address the topic of radiation protection dosimetry in intimate detail. Advanced Radiation Protection Dosimetry covers all methods used in radiation protection dosimetry, including advanced external and internal radiation dosimetry concepts and regulatory applications. This book is an ideal reference for both scientists and practitioners in radiation protection and students in graduate health physics and medical physics courses. Features: A much-needed book filling a gap in the market in a rapidly expanding area Contains the history, evolution, and the most up-to-date computational dosimetry models Authored and edited by internationally recognized authorities and subject area specialists Interrogates both the origins and methodologies of dose coefficient calculation Incorporates the latest international guidance for radiation dosimetry and protection