The 42nd Lauriston S. Taylor Lecture: Radiation Dosimetry Research for Medicine and Protection-A European Journey.

The assessment of doses related to exposures to ionizing radiation is an essential part of all applications of ionizing radiation including radiation medicine, radiation protection, radiation biology, radiation epidemiology, and also industrial uses of radiation. Absorbed dose is generally considered to be the fundamental quantity of radiation dosimetry. It is a metrologically sound quantity for which even primary standards exist for some materials, and it is used routinely in practice. However, there is no unique correlation between absorbed dose and the radiation-induced biological effect considered. There are also different objectives of radiation dosimetry for different applications. In radiation protection, quantities are required to set meaningful exposure limits and to implement the principle of optimization. In radiation therapy, the dependence of clinical outcomes on temporal aspects of the irradiations must be accounted for. In radiation diagnostics, quantities are needed to enable and monitor optimization of radiation dose and image quality. In radiation protection and in therapy with high linear-energy-transfer radiations, appropriate methods and parameters are needed to account for differences in radiation quality. These limitations of the quantity absorbed dose have led to the use of a multiplicity of dose quantities and dose modification factors. Radiation dosimetry continues, therefore, to be a field of active research regarding fundamental and conceptual aspects, taking account of advances in technologies, of novel methods in radiation therapy and diagnostics, and of progress in computational dosimetry. Dosimetry of high-energy radiations such as cosmic radiation encountered at flight altitudes and during space missions as well as at high-energy accelerators has become an important issue. In Europe, collaboration and coordination of radiation research in general, and dosimetry research in particular, are playing an important role. Dedicated research programs of the European Commission have been and still are very valuable and include collaborations with institutes in Eastern Europe and non-European countries. Several current and recent research topics in radiation dosimetry are addressed based on research carried out within European research programs, at European research centers including the European Organization for Nuclear Research (known as CERN), in European particle therapy projects, and at national metrological institutes. One focus is the quantification of radiation quality in radiation protection and in high linear-energy-transfer radiation therapy with emphasis on measurements with low-pressure proportional counters. Another focus is dosimetry of high-energy radiations with respect to measurements of cosmic radiation and at CERN's high-energy accelerators.

Twenty five years of the National Academy of Medical Sciences of Ukraine - progress and priorities for future of radiation medicine and biology. / DVADTsIaT' P'IaT' ROKIV NATsIONAL'NOÏ AKADEMIÏ MEDYChNYKh NAUK UKRAÏNY ­ PROGRES TA PRIORYTETY NA MAY̆BUTNIe RADIATsIY̆NOÏ MEDYTsYNY TA RADIOBIOLOGIÏ.

After the creation of the Academy of Medical Sciences of Ukraine in 1993 the Research Center for Radiation Medicine was among the first institutions to join the Academy (fig. 1). Estab lishing the Academy was among the first steps of the independent Ukrainian government and aimed to provide a high level health care for population. It was extremely needed for the minimization of Chornobyl medical consequences. This choice was related to a growing recognition of the scientific research in fulfilling the Сenter's mission - study of the effects of low dose radiation on human body and radiation protection of the exposed population.The Center entered the Academy as a potent insti tution. Director General Dr. Anatoly Romanenko and his first deputy prof. Oles Pyatak were lucky to concentrate in three institutes of the Center a talent ed workforce including director of the Institute of Clinical Radiology prof Volodymyr Bebeshko, director of the Institute of Epidemiology and Prophylaxis of radiation Injuries prof. Volodymyr Buzunov, director of the Institute of Experimental Radiology prof. Mikhail Rudnev. Drs. T. Azaren kova, S. Galkina, V. Boer, T. Treskunova were appointed as scientific secretaries. Dosimetry divi sion was headed by brilliant prof Ilya Likhtarev and his staff Drs. I. Los, V. Korzun, V. Repin, O. Pere voznikov, O. Bondarenko, V. Chumak and others.The Center met creation of the Academy with expe rienced research and clinical staff encountering 1587 members, including 272 research staff, 28 doctors of science and 98 PhDs, modern diagnostic and labo ratory equipment, 300 beds in clinical departments and construction of hospital and out patient hospi tal in Svyatoshin. Scientific staff included experi enced prof. I. Khomaziuk, prof. B. Prevarsky, prof. V. Zamostian, prof. P. Chayalo, prof. M. Omelya nets, prof. A. Prysyazhnyuk. Dr. A. Niagu, Dr. E. Stepanova, Dr. A.Chumak, Dr. V. Klymenko, Dr. D. Komarenko, M. Pilinska, L.Ovsiannikova, O. Pi rogova. were among the first academic supervisors in studies of Chornobyl health effects and got professor certificates in this new area. First PhD theses were successfully passed by Dr. E. Gorbov, and Dr. of Sciences - by Dr. D. Bazyka. Basics of future aca demic research directions were elaborated that time by Drs. O. Kovalenko, Zh. Minchenko, V. Talko, I. Holyavka, D. Belyi, D. Yakimenko, E. Mikhai lovska, V. Malyzhev, V. Sushko, A. Cheban, K. Lo ganovsky, K. Bruslova, I. Dyagil, T. Liubarets, O. Kucher, G. Chobotko, and others. Later the major ity of these studies formed a background for Chornobyl legislation, regulatory directives, pre sented as dissertations.A quarter of century passed. The Center as a part of the National Academy of Medical Sciences resisted the challenges and moved forward, was recognized worldwide and fulfilled its main mission - providing highly qualified health care to radiation exposed. Staff numbers decreased (1,091), but work amount has increased. Since 2000, new premises were installed - a hospital with the biggest in Ukraine outpatient clin ic, new laboratory facilities, the last of which was in troduced in 2013. The Academy became a national one and since 2011 the Center was recognized as a national research institution (NRCRM), staff mem bers received 3 State Awards of Ukraine in the Field of Science and Technology, numerous personal awards.During this period, NRCRM staff conducted and published priority research data on radiation risks and molecular mechanisms of leukemia, including chronic lymphocytic, myelodysplastic syndrome, multiple myeloma, thyroid cancer, breast cancer in Chornobyl accident cleanup workers. Studies of the mechanisms of non tumor pathology - cardio vascular, cerebrovascular, cognitive disorders are in process. Of high importance are studies of possible transgenerational effects of radiation. The devel oped new technologies and protocols for the advanced care of radiation exposed were intro duced to the general health care system, the addi tional departments of oncology and chemotherapy were equipped and started activities, databases of cancer cases in exposed population and separate groups of exposed were introduced, as well as an international database of radiation injuries. The Clinical and Epidemiological registry of the NRCRM is in function and developed. An adapta tion of research directions with a respect to the pathomorphosis of radiation induced diseases in the remote period after irradiation will continue.Performed complex studies of the effects of incorporation of 131I on the fetus and the next gen eration of experimental animals became important for understanding the mechanisms of formation of radiation effects. Introduction of new foodstuffs and supplements with radiation protective proper ties was of positive effect for population protection during the first years.In the area of dosimetry a substantial progress has been achieved in reconstruction of thyroid doses in the Ukrainian population, dosimetric passportisation of settlements, radiochemistry, the creation of new methods for reconstructive dosimetry for cleanup workers - SEAD, RADRUE, and ROCKVILLE. All developments are implemented to practice, tens of thousands of doses have been restored. International recognition has received for the method of in utero doses reconstruction. As editor in chief, I regard it successful to incorporate our bilingual edition «Problems of Radiation Medicine and Radiobiology¼ into the NCBI MedLine, SCOPUS and other data bases, that creates an unique opportunity to widely disseminate results of the Center's research.Strategies for the future. Ukraine belongs to countries with a priority development of nuclear energy. Even with the increase in the production of clean energy, there is no other way than the further deployment of a complete nuclear fuel cycle and energy industrial complex, the expansion of the nuclear technologies to all sectors of the economy.The main potential threats to radiation safety include the aging of the material base of the NPPs with the prolongation of the working life for nuclear reactors with the expired terms of exploitation; the existence of a «nuclear legacy¼ sites of the former USSR in the territories of enterprises for the extrac tion and processing of uranium ores. About 5,000 institutions and enterprises use more than 25,000 sources of ionizing radiation in general. The use of radiological technologies and sources of ionizing radiation in medicine is increasing, in particular the burden on patients and staff in invasive cardiac sur gery. This will require significant efforts from the NRCRM to ensure an adequate radiation protec tion of the population, taking into account the experience collected during the mitigation of health effects of Chornobyl. Radiological threats of malev olent use of nuclear technology hasn't be forgotten.The mission of the NRCRM is to expand basic research of the health effects of ionizing radiation, elaboration and implementation of the care and radiation protection of population. Background for future is paved by a successful implementation of a special program of medical and biophysical control of personnel during transformation of the Shelter object into an environmentally safe sys tem, the State social program of increasing safty, labor hygiene and environment for 2014-2018; many years of successful cooperation with the State Nuclear Regulatory Inspectorate, the Natio nal Commission for Radiation Protection, «Ener goatom¼ company, the relevant departments of the Ministry of Health, international organizations such as WHO, UNSCEAR, IAEA, IARC, the US National Cancer Institute, IRSN, Nagasaki, Hiroshima, Fukushima universities and others.From the editorial board I congratulate the staff of the Center with the twenty fifth anniversary of the Academy. I would like also to wish the National Academy of Medical Sciences of Ukraine new ad vances in medical science and practice, sustainabil ity, unity, development and worldwide recognition.

Neutron Metrology in the United States-Where We've Been, Where We Are Now and What We Need to Do Moving Forward.

Neutron metrology in the United States must be based on traceability to standards maintained by the National Institute of Standards and Technology (NIST). This article reviews the history of NIST's neutron-metrology efforts, the loss of those capabilities, and attempts to restore them. Recommendations are made to ensure that neutron dosimetry performed in the United States meets the requirements set forth by the International Standards Organization and other international and national authorities.

Consequences of the radiation accident at the Mayak production association in 1957 (the 'Kyshtym Accident').

This paper presents an overview of the nuclear accident that occurred at the Mayak Production Association (PA) in the Russian Federation on 29 September 1957, often referred to as 'Kyshtym Accident', when 20 MCi (740 PBq) of radionuclides were released by a chemical explosion in a radioactive waste storage tank. 2 MCi (74 PBq) spread beyond the Mayak PA site to form the East Urals Radioactive Trace (EURT). The paper describes the accident and gives brief characteristics of the efficacy of the implemented protective measures that made it possible to considerably reduce doses to the exposed population. The paper also provides retrospective dosimetry estimates for the members of the EURT Cohort (EURTC) which comprises approximately 21 400 people. During the first two years after the accident a decrease in the group average leukocyte (mainly due to neutrophils and lymphocytes) and thrombocyte count was observed in the population. At later dates an increased excess relative risk of solid cancer incidence and mortality was found in the EURTC.

50 Years of the Radiological Research Accelerator Facility (RARAF).

The Radiological Research Accelerator Facility (RARAF) is in its 50th year of operation. It was commissioned on April 1, 1967 as a collaboration between the Radiological Research Laboratory (RRL) of Columbia University, and members of the Medical Research Center of Brookhaven National Laboratory (BNL). It was initially funded as a user facility for radiobiology and radiological physics, concentrating on monoenergetic neutrons. Facilities for irradiation with MeV light charged particles were developed in the mid-1970s. In 1980 the facility was relocated to the Nevis Laboratories of Columbia University. RARAF now has seven beam lines, each having a dedicated irradiation facility: monoenergetic neutrons, charged particle track segments, two charged particle microbeams (one electrostatically focused to <1 µm, one magnetically focused), a 4.5 keV soft X-ray microbeam, a neutron microbeam, and a facility that produces a neutron spectrum similar to that of the atomic bomb dropped at Hiroshima. Biology facilities are available on site within close proximity to the irradiation facilities, making the RARAF very user friendly.

Twelfth Annual Warren K. Sinclair Keynote Address--the Influence of the NCRP on Radiation Protection in the United States: Guidance and Regulation.

The Warren K. Sinclair Keynote Address for the 2015 Annual Meeting of the National Council on Radiation Protection and Measurements (NCRP) describes the Council's influence in the development of radiation protection guidance in the United States since its founding in 1929 as the U.S. Advisory Committee on X-Ray and Radium Protection. The National Bureau of Standards (NBS) was the coordinating agency for the Advisory Committee, and its reports were published as NBS handbooks. In 1946, the Advisory Committee was renamed the National Committee on Radiation Protection and remained so until NCRP was chartered by the U.S. Congress in 1964. In 1931, the U.S. Advisory Committee on X-Ray and Radium Protection proposed the first formal standard for protecting people from radiation sources as NBS Handbook 15 and issued the first handbook on radium protection, NBS Handbook 18. Revised recommendations for external exposure were issued in 1936 and for radium protection in 1938 and remained in force until 1948. Throughout its 86 y history, the Council and its predecessors have functioned as effective advisors to the nation on radiation protection issues and have provided the fundamental guidance and recommendations necessary for the regulatory basis of the control of radiation exposure, radiation-producing devices, and radioactive materials in the United States.

Experimental microdosimetry: history, applications and recent technical advances.

The invention of tissue-equivalent proportional counters simulating micrometre diameter volumes, intended to measure the linear energy transfer of a radiation field, resulted in a practical demonstration of the stochastic nature of energy deposition in small volumes. Besides contributing to a better understanding of the interactions between ionising radiation and biological systems, these detectors have had a significant impact on applied radiation dosimetry. The initial instruments were elegant but suitable only for laboratory experiments because of their sensitivity to environmental conditions and the complex support systems they required. However, their ability to separate the dose due to neutrons from that delivered by photons motivated detector design modifications that eventually resulted in robust detectors suitable for use as radiation survey instruments. Proportional counters simulating micrometre tissue volumes turned out to be the ideal detectors for monitoring the complex radiation environments, including on the space shuttle and International Space Station, and have served as the primary active dosimeters in space for nearly two decades. The need for more sophisticated measurements has led to further improvements in detector design, and the need for smaller and lighter dosimeters is motivating further developments in both detectors and data processing systems.

38th Lauriston S. Taylor lecture: on the shoulders of giants - radiation protection over 50 years.

Most advances in science, technology, and radiation protection are not truly new ideas but rather build upon a foundation of prior work and achievements by earlier generations of scientists and researchers. This paper summarizes major achievements over the last 50-70 y in the various areas involved in radiation protection as well as giving information about some of those who were, and are, significant contributors.

The development of dose planning.

In the very earliest days, there was no computerized dose-planning system. However, it was not long that the first dose-planning system KULA was developed in the mid-1980s. It soon became apparent that while this was geometrically accurate, it was not as visually attractive as programs used by other technologies. It had been designed in the era prior to computerized imaging and had only limited capacity for dosimetry. It was followed by GammaPlan, which has evolved over the years into a sophisticated multiparameter system with very advanced graphic features.

From the lost radium files: misadventures in the absence of training, regulation, and accountability.

PURPOSE: Radium was the foundation of brachytherapy in the early decades of the 20th century. Despite being a most precious and perilous substance, it was mislaid with surprising frequency. This essay explores how it was lost, the efforts taken to recover it, and measures instituted to prevent mishandling. METHODS AND MATERIALS: Review of contemporary literature, government publications, archives, and lay press. RESULTS: Radium is a particularly dangerous substance because of its long half-life, its gaseous daughter (radon), and the high-energy emissions of its decay products. Despite the hazard, it was unregulated for most of the century. Any physician could obtain and administer it, and protocols for safe handling were generally lacking. Change came with appreciation of the danger, regulation, mandated training, and the institution of a culture of accountability. Unfortunately, careless management of medical radionuclides remains a global hazard. CONCLUSION: Responsible stewardship of radioactive material was not a high priority, for practitioners or the federal government, for much of the 20th century. As a result, large quantities of radium had gone astray, possibly subjecting the general public to continued radiation exposure. Lessons from the radium era remain relevant, as medical radionuclides are still mishandled.

The application of x-rays in radiology: from difficult and dangerous to simple and safe.

OBJECTIVE: This article will provide an assessment of the application of x-rays in the early days of radiology, which is an excellent way to come to value the convenience and safety of modern x-ray systems. CONCLUSION: The gas tubes that were originally applied for x-ray production were very unstable because of variations in the tube's vacuum. In an effort to understand some of the problems of these tubes and the high occupational exposure that was indirectly caused by the tubes' erratic behavior, we measured x-ray output rates as a function of the gas pressure inside the tube. The pressure range for the optimal production of x-rays, using an original Ruhmkorff inductor as a high-voltage generator, was found to be narrow. With the vacuum changing over time, this might explain the many photographs from the first years of radiology with operators watching their unshielded tube, either with bare eyes or with a fluoroscope, and their own hand as a test object. This practice often led to severe damage of the hands and to many early deaths due to cancer. Today, after a century of technologic development of x-ray tubes and associated equipment, the total average effective dose of workers in radiology can be close to natural background levels.

Exerpts from the history of alpha recoils.

Any confined air volume holding radon ((222)Rn) gas bears a memory of past radon concentrations due to (210)Pb (T(1/2) = 22 y) and its progenies entrapped in all solid objects in the volume. The efforts of quantifying past radon exposures by means of the left-behind long-lived radon progenies started in 1987 with this author's unsuccessful trials of removing (214)Po from radon exposed glass objects. In this contribution the history and different techniques of assessing radon exposure to man in retrospect will be overviewed. The main focus will be on the implantation of alpha recoils into glass surfaces, but also potential traps in radon dwellings will be discussed. It is concluded that for a successful retrospective application, three crucial imperatives must be met, i.e. firstly, the object must persistently store a certain fraction of the created (210)Pb atoms, secondly, be resistant over decades towards disturbances from the outside and thirdly, all (210)Pb atoms analysed must originate from airborne radon only. For large-scale radon epidemiological studies, non-destructive and inexpensive measurement techniques are essential. Large-scale studies cannot be based on objects rarely found in dwellings or not available for measurements.