Decontamination of radioisotopes

Contaminations with radioactive material may occur in several situations related to medicine, industry or research. Seriousness of the incident depends mainly on the radioactive element involved; usually there are no major acute health effects, but in the long term can cause malignancies, leukemia, genetic defects and teratogenic anomalies.The most common is superficial contamination, but the radioactive material can get into the body and be retained by the cells of target organs, injuring directly and permanently sensitive elements of the body. Rapid intervention is very important to remove the radioactive material without spreading it. Work must be performed in a specially prepared area and personnel involved should wear special protective clothing. For external decontamination general cleaning techniques are used, usually do not require chemical techniques. For internal decontamination is necessary to use specific agents, according to the causative element, as well physiological interventions to enhance elimination and excretion.     

Radiation safety requirements for cardiovascular brachytherapy

Cardiovascular brachytherapy, the use of high intensity radiation to inhibit the growth of neointimal tissue after coronary revascularization by either balloon angioplasty or other methods is being tested in a number of clinical trials to assess the efficacy of the treatment. This new use of radiation to aleviate the suffering of individuals with coronary artery disease has excited many interventionalists and has caused others to view the new technique with skepticism. There are a number of operational and safety concerns to face in incorporating this treatment modality into the cardiac catheterization laboratory. Delivering the radiation dose to the patient with a minimum of radiation exposure to both patient and operating personnel requires close attention to the physical characteristics of the radiation source as well as the administrative and regulatory requirements imposed on the facility by federal and state regulators. The insertion of the source into the proper artery and location is the task of the cardiologist in collaboration with the radiation oncologist. The determination of the appropriate radiation dose is the responsibility of the medical physicist. The safe handling of the radioisotope source is the responsibility of the radiation safety specialist. State and federal regulations dictate minimum requirements of safety in the handling of radioactive sources used in cardiovascular brachytherapy. These requirements involve close monitoring of the patient and operating personnel to insure that radiation exposures are minimized. They involve the restricted access of nonessential personnel to the cath lab during the treatment. The entrances to the cath lab must be monitored to prevent unauthorized entry. Operating personnel must be closely monitored to maintain radiation exposures as low as reasonably achievable (ALARA). The patient must be monitored to insure that the source is implanted for the prescribed time and the patient's exposure is also ALARA consistent with the medical benefit expected. Public corridors must be monitored to prevent public exposures to the radiation emanating from the patient. The radiation exposure field around the patient during a typical gamma treatment presents what the regulators define as a high radiation area. This means that the exposure levels are in excess of 100 milli-rem (mrem) per hour at 30 cm from the patient. In fact, the exposure levels around the patient for a typical treatment are in the roentgens per hour range. The use of beta particle emitting radionuclides (Sr90/Y90 and P32) presents a much lower safety problem. But the use of radioactive materials in the cath lab still presents new safety concerns such as training, monitoring, record keeping, and public relations among the cath lab technologists.     

Modalités de la contamination d'une chaine trophique marine benthique par l'argent 110 m: 4. Influence du mode de contamination sur l'élimination du radionucléide

The elimination of ^110mAg by Navicula incerta Grunow ex Van Heurck, Navicula biskanteri Hustedt, Scrobicularia plana (da Costa) and Carcinus maenas (L.) depends upon the duration of contamination or the number of intakes of radioactive food. The longer the contamination occurred, the slower will be the climination.The decontamination is slower after (chronic) ingestion of radioactive food than after immersion in contaminated water. The physico-chemical forms of ^110mAg likely play a rôle in elimination kinetics. So, external organs, whose contamination results mainly from adsorption, get rid of ^110mAg faster than the digestive gland in which silver seems to be retained in a hardly exchangeable form.Consequently, the total radiation dose for contaminated organisms will depend greatly upon the way and the duration of the contamination.     

Exposure of persons accompanying patients in nuclear medicine departments.

Patient who receives a radiopharmaceutical remains radioactive for hours or even days and so represents a potential hazard to other individuals. Thus, in nuclear medicine departments, apart from the personnel who are occupationally exposed to ionizing radiation, protection rules must be observed for members of the public, in particular persons accompanying patients. The purpose of this work was to evaluate the absorbed dose levels, which persons accompanying patients are exposed to. Integral dose studies were carried out in three nuclear medicine departments, in Brazil. Dose levels are presented, and issues are discussed with regard to the presence of members of the public in waiting areas of such departments.     

Radiation Hazards Control in Survival Operations in the Event of a Nuclear War

The concepts of radiation protection in survival operations are explained, and procedures devised to control radiation hazards for the protection of the population and maintenance of the operating efficiency of survival operations personnel are presented.Radiation protection is a command function. The medical responsibility is to provide advice on the probable effects of radiation exposure in the light of existing knowledge of these effects in man.The major hazard is that of external exposure to penetrating gamma radiation. Radiation exposure guides indicate that persons may be exposed to not more than 100 r whole body radiation in a six-week period, or 200 r whole body radiation in a period in excess of six weeks, without loss of operational efficiency. Beta radiation from fallout deposited on skin or clothing may produce burns, but these injuries will not be incapacitating and can be controlled by simple procedures.The internal hazard is mainly from ingestion of food or water contaminated with radioactive material. For protection, only canned or packaged foods and water from covered or deep wells are consumed during the early days after a nuclear attack.     

Modifying influence of iodine deficiency on radiation damage to the fetus (review)

It known an oppressing action of radiation, including radioactive iodine isotopes on the reproductive system and fetus development. There are clinical data on a negative influence of iodine deficiency on the course of pregnancy and fetus development resulting from hormonal disfunction of thyroid gland and a mother-fetus system. There are no data about a character and mechanisms of interaction of radiation and iodine endemia at the combined action on the gonads and fetus. The urgency of this problem is caused by the fact that many regions of the country are characterized to some extent by iodine deficiency in local food and water (in Russian Federation such regions make approximately 50% of territories), and the opportunity of radiation accidents at nuclear plants with contamination of the environment with products of nuclear division (significant part of which is radioactive iodine isotopes is an objective reality. The analysis of a few published and own experimental data allows us to conclude that the combined influence of an external gamma-irradiation and iodine deficiency on reproductive function has a synergic character.     

Perspectives of Radioactive Contamination in Nuclear War

The degrees of risk associated with the medical, industrial and military employment of nuclear energy are compared. The nature of radioactive contamination of areas and of persons resulting from the explosion of nuclear weapons, particularly the relationship between the radiation exposure and the amount of physical debris, is examined.Some theoretical examples are compared quantitatively. It is concluded that the amount of radio-activity that may be carried on the contaminated person involves a minor health hazard from gamma radiation, compared to the irradiation arising from contaminated areas.     

Radiological Terrorism

We run the risk that terrorists will decide to detonate an explosive device laced with radioactive materials (a radiological dispersal device, or RDD). If such an attack occurs, it is unlikely that the affected population or emergency responders would be exposed to high levels of external radiation, although airborne radionuclides may present a health risk under some circumstances. However, the effects of radiation and radioactivity are not well known among the general population, emergency responders, or medical personnel. This could lead to unwarranted panic, refusal to respond to the incident, inappropriately delaying or denying treatment to injured victims, and other unfortunate reactions during the emergency phase of any response. During the recovery phase, current regulations may lead to costly and restrictive radiation safety requirements over very large areas, although there have been recent efforts to relax some of these regulations in the first year following a radiological attack. The wide spread of radioactive contamination can also lead to environmental contamination, particularly in low-flow areas and near storm sewer discharge points, but the total radiation dose to the environment should not be excessively high in most locations.     

Case-control study of leukaemia and non-Hodgkin's lymphoma among children aged 0-4 years living in west Berkshire and north Hampshire health districts.

OBJECTIVE--To investigate the relation between parental employment in the nuclear industry and childhood leukaemia and non-Hodgkin''s lymphoma. DESIGN--Case-control study. SETTING-West Berkshire and Basingstoke and North Hampshire District Health Authorities. SUBJECTS--54 children aged 0-4 years who had leukaemia or non-Hodgkin''s lymphoma diagnosed during 1972-89, who were born in the study area and were resident there when cancer was diagnosed. Six controls were selected for each case: four from hospital delivery registers and two from livebirth registers maintained by the NHS central register. Controls were matched for sex, date of birth (within six months), and area of residence at birth and time of diagnosis. MAIN OUTCOME MEASURES--Parents'' employment by the nuclear industry and exposure to ionising radiation at work. RESULTS--Five (9%) of the 54 cases and 14 (4%) of the 324 controls had fathers or mothers, or both, who had been employed by the nuclear industry (relative risk 2.2, 95% confidence interval 0.6 to 6.9). Nuclear industry employees who work in areas where exposure to radiation is possible are given film badges to monitor their exposure to external penetrating ionising radiation. Three fathers of cases and two fathers of controls (and no mothers of either) had been monitored in this way before their child was conceived (relative risk 9.0, 95% confidence interval 1.0 to 107.8). No father (of a case or control) had accumulated a recorded dose of more than 5 mSv before his child was conceived, and no father had been monitored at any time in the four years before his child was conceived. A dose-response relation was not evident among fathers who had been monitored. CONCLUSIONS--These results suggest that the children of fathers who had been monitored for exposure to external penetrating ionising radiation in the nuclear industry may be at increased risk of developing leukaemia before their fifth birthday. The finding is based on small numbers and could be due to chance. If the relationship is real the mechanisms are far from clear, except that the effect is unlikely to be due to external radiation; the possibility that it could be due to internal contamination by radioactive substances or some other exposure at work should be pursued. The above average rates of leukaemia in the study area cannot be accounted for by these findings.     

PROBLEMS ASSOCIATED WITH MEDICAL DISASTER CARE—Preparations in a Large Southern California Area

In the organization for dealing with medical disaster, the region is in an intermediary position, between the State Disaster Office and the operational areas. Regional functions are largely those of coordinating the activities of the areas, and are based upon directives and plans from the state level.The regional medical chief is a member of the staff of the Civil Defense coordinator and must advise him in all matters related to the health of the people, including medical and casualty care, hospitalization, public health, sanitation, preventive medicine and the special problems of biological, chemical and radiation hazards. Coordination with the other Civil Defense services is necessary.The basic medical plan is to give emergency care in the first aid stations and then evacuate casualties to hospitals when and how the situation permits. Regional function is to obtain personnel, supply, equipment and hospitalization support when required.Dispersal of danger zone populations to support areas creates many medical and public health problems among the displaced people and the residents.Survival of the nation requires altered concepts of casualty management. The least injured who have the greatest productive potential should have the highest treatment priority. Short, lifesaving surgical procedures must have precedence over long, complicated operations.No plan is any better than the individual doctors, nurses and other personnel who will put it into operation.     

Modalités de la contamination d'une chaine trophique marine benthique par l'argent 110 m

The distribution of^110mAg was studied in various invertebrates of a marine benthic food chain as a consequence of the immersion in contaminated seawater and/or ingestion of radioactive food. The studies on^110mAg distribution were carried out at the end of the experimental contamination (when equilibrium was reached) and during the slow stage of elimination. After contamination via the surrounding water, uptake of^110mAg occurs mainly in external organs: shells (34%) and mantle (16%) of the bivalveScrobicularia plana, exoskeleton (40%) and gills (38%) of the crabCarcinus maenas. On the contrary, contamination via food is responsible for a considerable accumulation of^110mAg in the digestive glands ofS. plana (75%) andC. maenas (56%). Moulting plays an important role in the decontamination of crabs following immersion in radioactive seawater owing to the strong contamination of the exuviae. The elimination of^110mAg from the different organs of the animals examined depends upon the mode of contamination: it is generally fast in external organs and slow in the digestive gland. Radiation doses for molluscs and crustaceans were calculated following experimental contaminations by water and food. A significant contamination of external organs is responsible for a radiation dose (in the centre of the test animals) weaker than that instigated by the accumulation of^110mAg in the digestive gland. Thus, with regard to contamination, the ambient water is important; but, from the point of view of irradiation, radioactive food is generally more important.     

Mesure de l’exposition externe au cours de la détection peropératoire. Expérience du service de médecine nucléaire de l’hôpital Ibn Sina

Nationally, the department of nuclear medicine, Ibn Sina Hospital is the first service that started with the technique of isotopic labeling for the treatment of osteoid osteoma and identification of sentinel lymph node. However, the operating room is a place where the staff is not familiar with the handling of radioactive substances. The intraoperative detection in these places leads the staff working there to ask some questions related to radiation safety. In this work, we have implemented the radiation protection aspects of these acts by the measurement of external exposure of personnel involved and we confirmed that the dosimetric measurements are negligible.     

Current Measures on Radioactive Contamination in Japan: A Policy Situation Analysis

Background

The Great East Japan Earthquake on 11^th March 2011 and the subsequent Fukushima Dai-ichi nuclear power plant disaster caused radioactive contamination in the surrounding environment. In the immediate aftermath of the accident the Government of Japan placed strict measures on radio-contamination of food, and enhanced radio-contamination monitoring activities. Japan is a pilot country in the WHO Foodborne Disease Burden Epidemiology Reference Group (FERG), and through this initiative has an opportunity to report on policy affecting chemicals and toxins in the food distribution network. Nuclear accidents are extremely rare, and a policy situation analysis of the Japanese government’s response to the Fukushima Dai-ichi nuclear accident is a responsibility of Japanese scientists. This study aims to assess Japan government policies to reduce radio-contamination risk and to identify strategies to strengthen food policies to ensure the best possible response to possible future radiation accidents.

Methods and Findings

We conducted a hand search of all publicly available policy documents issued by the Cabinet Office, the Food Safety Commission, the Ministry of Health, Labor and Welfare (MHLW), the Ministry of Agriculture, Forestry and Fishery (MAFF) and prefectural governments concerning food safety standards and changes to radiation and contamination standards since March 11^th, 2011. We extracted information on food shipment and sales restrictions, allowable radio-contamination limits, monitoring activities and monitoring results. The standard for allowable radioactive cesium (Cs-134 and Cs-137) of 100 Bq/Kg in general food, 50 Bq/Kg in infant formula and all milk products, and 10 Bq/Kg in drinking water was enforced from April 2012 under the Food Sanitation Law, although a provisional standard on radio-contamination had been applied since the nuclear accident. Restrictions on the commercial sale and distribution of specific meat, vegetable and fish products were released for areas at risk of radioactive contamination. Monitoring of radioactive materials in food products in the prefectures has been mainly conducted before shipment to restrict the distribution of radio-contaminated foods. Between March 2011 and March 2012, 133,832 tests of non-commercial and commercial products were conducted, and 1,204 tests (0.9%) were found to violate the provisional standards. Since April 2012, 278,275 tests were conducted, and 2,372 tests (0.9%) were found to violate the revised standards. MHLW assessment of representative market baskets of foodstuffs at 15 locations throughout Japan between February and March 2014 found very low estimated dietary intake of radioactive cesium (0.0007–0.019 mSv/year), as did assessments of the contents of an average day’s food. Monitoring of fisheries products in coastal areas affected by the nuclear accident found very limited and declining radio-contamination of live fish outside of Fukushima prefecture. Fisheries monitoring is of limited geographical scope and covers only certain fishes.

Conclusions

Area-specific bans on production and distribution have been effective in preventing radioactive contamination in the Japanese food market. Currently there is no major concern about radioactive cesium concentrations in retail foodstuffs in Japan, and very low levels of contamination at the production and wholesale stage. However, because the residue limits and food safety policies were revised on an ad hoc, emergency basis after the nuclear accident, the monitoring procedure needs to be reviewed based on objective and scientifically rational criteria. A transparent and objective scientific framework is needed for prioritizing foodstuffs for inspection and revising Prefecture-specific restrictions. Monitoring of fishes and other seafood products in the wild should be regularized and the information made more publicly accessible, and monitoring activities expanded to identify foodstuffs that are no longer a food safety risk. Consultation with producers and consumers should be more formalized to ensure their concerns are incorporated into regular policy reviews in an appropriate and transparent manner. However, despite the limited available knowledge on best practice in food control and enforcement of provisional radio-contamination limits after the accident, current Japanese policy is sufficient to protect the Japanese public from major risk of radio-contamination from the commercial food market.     

Model for inactivation and disposal of infectious human immunodeficiency virus and radioactive waste in a BL3 facility.

A method is described for autoclaving low levels of solid infectious, radioactive waste. The method permits steam penetration to inactivate biologic waste, while any volatile radioactive compounds generated during the autoclave process are absorbed. Inactivation of radiolabeled infectious waste has been problematic because the usual sterilization techniques result in unacceptable radiation handling practices. If autoclaved under the usual conditions, there exists a high probability of volatilization or release of radioisotopes from the waste. This results in the radioactive contamination of the autoclave and the laboratory area where steam is released from the autoclave. Our results provide a practical method to inactivate and dispose of infectious radioactive waste. For our research, Bacillus pumilus spore strips and vaccinia virus were used as more heat-resistant surrogates of the human immunodeficiency virus (HIV). These surrogates were used because HIV is difficult to grow under most conditions and is less heat tolerant than the surrogates. In addition, B. pumilus has defined cell death values, whereas such values have not been established for HIV. Both B. pumilus and vaccinia virus are less hazardous to work with. The autoclave method is time efficient and can be performed by laboratory personnel with minimal handling of the waste. Furthermore, waste site handlers are able to visually inspect the solid waste containers and ascertain that inactivation procedures have been implemented.     

Model for inactivation and disposal of infectious human immunodeficiency virus and radioactive waste in a BL3 facility

A method is described for autoclaving low levels of solid infectious, radioactive waste. The method permits steam penetration to inactivate biologic waste, while any volatile radioactive compounds generated during the autoclave process are absorbed. Inactivation of radiolabeled infectious waste has been problematic because the usual sterilization techniques result in unacceptable radiation handling practices. If autoclaved under the usual conditions, there exists a high probability of volatilization or release of radioisotopes from the waste. This results in the radioactive contamination of the autoclave and the laboratory area where steam is released from the autoclave. Our results provide a practical method to inactivate and dispose of infectious radioactive waste. For our research, Bacillus pumilus spore strips and vaccinia virus were used as more heat-resistant surrogates of the human immunodeficiency virus (HIV). These surrogates were used because HIV is difficult to grow under most conditions and is less heat tolerant than the surrogates. In addition, B. pumilus has defined cell death values, whereas such values have not been established for HIV. Both B. pumilus and vaccinia virus are less hazardous to work with. The autoclave method is time efficient and can be performed by laboratory personnel with minimal handling of the waste. Furthermore, waste site handlers are able to visually inspect the solid waste containers and ascertain that inactivation procedures have been implemented.     

Cytogenetic biomonitoring carried out in a village (Dolon) adjacent to the Semipalatinsk nuclear weapon test site

The Semipalatinsk region (Kazakhstan Republic) has been affected by extensive radioactive contamination due to more than 450 nuclear tests of which almost 100 were exploded in the atmosphere. The present results refer to cytogenetic assessments in a study cohort of the population of Dolon, a settlement located on the NE boundary of the nuclear weapon test site, which was exposed to elevated doses of ionising radiation primarily due to the first Soviet nuclear test in 1949. Conventional cytogenetic analyses were carried out on 21 blood samples from individuals (more than 50 years old) living in Dolon since the very beginning of nuclear testing. A matched control group included 20 individuals living in non-contaminated areas. Higher frequencies of chromosome aberrations were found in the Dolon cohort compared to the control group, even though they remain within the range of the background levels reported for large normal human population studies on elderly individuals. Received: 24 May 2000 / Accepted: 1 November 2000     

Absorption of Radionuclides from the Fukushima Nuclear Accident by a Novel Algal Strain

Large quantities of radionuclides have leaked from the Fukushima Daiichi Nuclear Power Plant into the surrounding environment. Effective prevention of health hazards resulting from radiation exposure will require the development of efficient and economical methods for decontaminating radioactive wastewater and aquatic ecosystems. Here we describe the accumulation of water-soluble radionuclides released by nuclear reactors by a novel strain of alga. The newly discovered green microalgae, Parachlorella sp. binos (Binos) has a thick alginate-containing extracellular matrix and abundant chloroplasts. When this strain was cultured with radioiodine, a light-dependent uptake of radioiodine was observed. In dark conditions, radioiodine uptake was induced by addition of hydrogen superoxide. High-resolution secondary ion mass spectrometry (SIMS) showed a localization of accumulated iodine in the cytosol. This alga also exhibited highly efficient incorporation of the radioactive isotopes strontium and cesium in a light-independent manner. SIMS analysis showed that strontium was distributed in the extracellular matrix of Binos. Finally we also showed the ability of this strain to accumulate radioactive nuclides from water and soil samples collected from a heavily contaminated area in Fukushima. Our results demonstrate that Binos could be applied to the decontamination of iodine, strontium and cesium radioisotopes, which are most commonly encountered after nuclear reactor accidents.     

Radioactivity and radiation safety: basic concepts for laboratory animal technologists and technicians

Laboratory animals treated with radioactive compounds are a radiation-safety concern. It is important for technologists and technicians who work with these animals to understand ionizing radiation and radiation-safety practices. The author discusses licensing, contamination control, and how to deal with radioactive waste.     

A cohort study of thyroid cancer and other thyroid diseases after the Chornobyl accident: objectives, design and methods

The thyroid gland in children is one of the organs that is most sensitive to external exposure to X and gamma rays. However, data on the risk of thyroid cancer in children after exposure to radioactive iodines are sparse. The Chornobyl accident in Ukraine in 1986 led to the exposure of large populations to radioactive iodines, particularly (131)I. This paper describes an ongoing cohort study being conducted in Belarus and Ukraine that includes 25,161 subjects under the age of 18 years in 1986 who are being screened for thyroid diseases every 2 years. Individual thyroid doses are being estimated for all study subjects based on measurement of the radioactivity of the thyroid gland made in 1986 together with a radioecological model and interview data. Approximately 100 histologically confirmed thyroid cancers were detected as a consequence of the first round of screening. The data will enable fitting appropriate dose-response models, which are important in both radiation epidemiology and public health for prediction of risks from exposure to radioactive iodines from medical sources and any future nuclear accidents. Plans are to continue to follow-up the cohort for at least three screening cycles, which will lead to more precise estimates of risk.     

The biological effects of diagnostic cardiac imaging on chronically exposed physicians: the importance of being non-ionizing

Ultrasounds and ionizing radiation are extensively used for diagnostic applications in the cardiology clinical practice. This paper reviewed the available information on occupational risk of the cardiologists who perform, every day, cardiac imaging procedures. At the moment, there are no consistent evidence that exposure to medical ultrasound is capable of inducing genetic effects, and representing a serious health hazard for clinical staff. In contrast, exposure to ionizing radiation may result in adverse health effect on clinical cardiologists. Although the current risk estimates are clouded by approximations and extrapolations, most data from cytogenetic studies have reported a detrimental effect on somatic DNA of professionally exposed personnel to chronic low doses of ionizing radiation. Since interventional cardiologists and electro-physiologists have the highest radiation exposure among health professionals, a major awareness is crucial for improving occupational protection. Furthermore, the use of a biological dosimeter could be a reliable tool for the risk quantification on an individual basis.