Non-stochastic Effects Research Articles

A method to predict space radiation biological effectiveness for non-cancer effects following intense Solar Particle Events

In addition to the continuous exposure to cosmic rays, astronauts in space are occasionally exposed to Solar Particle Events (SPE), which involve less energetic particles but can deliver much higher doses. The latter can exceed several Gy in a few hours for the most intense SPEs, for which non-stochastic effects are thus a major concern. To identify adequate shielding conditions that would allow respecting the dose limits established by the various space agencies, the absorbed dose in the considered organ/tissue must be multiplied by the corresponding Relative Biological Effectiveness (RBE), which is a complex quantity depending on several factors including particle type and energy, considered biological effect, level of effect (and thus absorbed dose), etc.While in several studies only the particle-type dependence of RBE is taken into account, in this work we developed and applied a new approach where, thanks to an interface between the FLUKA Monte Carlo transport code and the BIANCA biophysical model, the RBE dependence on particle energy and absorbed dose was also considered. Furthermore, we included in the considered SPE spectra primary particles heavier than protons, which in many studies are neglected. This approach was then applied to the October 2003 SPE (the most intense SPE of solar cycle 23, also known as “Halloween event”) and the January 2005 event, which was characterized by a lower fluence but a harder spectrum, i.e., with higher-energy particles. The calculation outcomes were then discussed and compared with the current dose limits established for skin and blood forming organs in case of 30-days missions.This work showed that the BIANCA model, if interfaced to a radiation transport code, can be used to calculate the RBE values associated to Solar Particle Events. More generally, this work emphasizes the importance of taking into account the RBE dependence on particle energy and dose when calculating equivalent doses.

A Review of Radiation Protection Standards for Workers in Hospital Radiology: A Narrative Literature Review

One of the goals of radiation protection is to prevent stochastic effects from occurring and to limit the chances of stochastic effects occurring to a limit value that is acceptable to society. This literature review aims to describe radiation protection standards for workers in hospital radiology. To prevent non-stochastic effects, a limit of 0.5 Sv (50 rem) in 1 year was used for all tissues except the lens of the eye. For eyepieces, the recommended annual limit is 0.15 Sv (15 rem). This limit value is used either for radiation reception by a single tissue or for radiation reception by multiple organs. To limit stochastic effects, the annual effective equivalent dose (HE) limit for whole-body radiation reception is 50 mSv (5 rem). The radiation protection equipment that must be available at a radio diagnostic facility is a lead apron, thyroid shield, gonad protectors, gloves, Pb goggles, and lead curtains. In conclusion, radiation protection equipment must be provided by radiology facility operators and used by radiation workers, especially radiologists and other competent doctors. Periodic inspection and standardized maintenance of radiation shields must be carried out for the sake of public safety.

MONITORING EFFECTS OF MEDICAL EXPOSURE ON INTERVENTION AL EXAMINATION PATIENTS IN ADAM MALIK GENERAL HOSPITAL CATHLAB MEDAN: PRELIMINARY STUDY

MONITORING EFFECTS OF MEDICAL EXPOSURE ON INTERVENTION AL EXAMINATION PATIENTS IN ADAM MALIK GENERAL HOSPITAL CATHLAB MEDAN: PRELIMINARY STUDY. Efforts have been made to monitor medical exposure to patients with interventional examinations at the Cathlab to determine the value of medical exposure and the effects of erythema radiation. This initial study was carried out using a retrospective method of total kerma data, fluoro time and type of examination, and dose estimation for Dose Area Product (DAP) patients using X-ray intervention brands GE Medical System and Phillips Allura Xper FD20 for the period 2019 to May 2022, at Adam Malik Hospital. Conduct patient observations after the intervention examination by giving questionnaires to doctors and nurses to monitor intervention actions. Measure the air kerma within 1m from the source, then analyze the data. The results obtained from monitoring patient doses, fluoro time values , and total kerma can cause erythema, which results in stochastic and non-stochastic effects. Hence, it is crucial to record patient doses and monitor them as information to doctors and nurses on the impact. The conclusion is that the Fluoro time and total kerma values are directly at risk according to the reference, which has not been adequately monitored during intervention actions. As a suggestion by the regulation of the Nuclear Energy Supervisory Agency (BAPETEN) and the International Commission Radiological Protection (ICRP) to maintain patient safety by direct monitoring and informing doctors of the total dose of medical exposure in the Cathlab and as reference material for further research. Keywords: Medical Exposure, Interventional Measures, Radiation Safety.

Radiation Injury: Mechanism of Toxicity and Countermeasures

This paper aims to review the basic concept of radiation biology and better understand the mechanism of toxicity when interacting with living tissue. The main content of this review includes the source of radiations, unit and measurement, mechanism of tissue injury and possible effects from that exposure; theoretic dose-response curves and their uses in radiation biology; stochastic versus non-stochastic effects of radiation exposure possible acute and chronic radiation exposure effects. Apart from that, we have also reviewed the recent development and progress available as well as under investigation, potential countermeasures compounds against the radiation-induced injury.

Impact of bone scintigraphy and exposure dose on red blood cells with proposed solutions

Background: Nuclear medicine (NM) technology is as indispensable field, is being widely used in research as well for diagnostic/staging purposes. However, it is also associated with potential hazards of radiation especially among radiation practitioners. Objective: The objective of the study was to determine the effects of NM exposure doses of bone scintigraphy in red blood cells and to propose a recent technology to be incorporated in NM and radiology technologies. Materials and Methods: A retrospective study was carried out among 75 patients who underwent bone scintigraphy between 2014 and 2018. A blood sample of these patients was characterized using transmitted light microscope and obtained data were analyzed using SPSS. Results: There was a decrease in the RBCs% and hemoglobin (HGb) count with the increment of interval time of bone scintigraphy (p=0.3). The average applied radioactive (Methylene Di-phosphate/Technetium-99m) dose of 15±2.9 mCi reduces RBCs and HGb count insignificantly by 3.56% and 3.1%, respectively. With an increased dose of 20±5.8 mCi and after interval time of bone scintigraphy, the histological changes in RBCs such as loss of biconcavity, increased diameter (10±0.4 ?m), developed spikes (anisocytosis and poikilocytosis) were observed. Conclusion: The proposed robotic intelligent system can be utilized partially while performing NM and other radiological examinations under supervision of specialists to prevent stochastic and non-stochastic effects among radiation practitioners.

THE BRONCHOPULMONARY SYSTEM DAMAGE UNDER THE INFLUENCE OF IONIZING RADIATION EXPOSURE AND RADIONUCLIDES INHALATION IN THE CONDITIONS OF THE CHORNOBYL CATASTROPHE (SUMMARIZING OF 35 YEARS RESEARCH EXPERIENCE).

The review is devoted to the summarizing of 35 years of research of ionizing radiation exposure and radionuclidesinhalation influence on the bronchopulmonary system of clean-up workers of the Chornobyl NPP accident. Radiationand hygienic preconditions for the formation of chronic respiratory pathology are considered, taking into accountthe dosimetric data of irradiation of the bronchopulmonary system.The main clinical symptoms, features of disorders of pulmonary ventilation capacity and endoscopic forms of lesionsof the bronchopulmonary system of participants in the liquidation of the accident were determined.On the basis of pathomorphological, microbiological and immunological researches the pathomorphosis of chronicnonspecific lung diseases in the conditions of the Chernobyl catastrophe is proved.It is proved that under combined influence of external irradiation and inhalation of a fragmentary mixture ofradionuclides in the condition of the Chernobyl catastrophe, the bronchopulmonary system has become one of themain «targets»-tissues, of realization of stochastic and nonstochastic effects.

Assessment of individual risk criteria for the disposal of radioactive waste

This article discusses the possibilities of determining the risk to individuals as a result of radiation exposure, which is one of the most common and important characteristics of environmental hazard. Environmental damage with the likelihood of an event contributing to the determination of environmental risk. In this case, the risk itself shows the effect of radiation on the human body. When determining the risk, it is necessary to take into account the power of an individual dose for a certain period of time. The criteria curves considered in the article take into account stochastic and non-stochastic effects. These criteria show compliance of waste disposal methods with requirements related to specific risk levels.

AN ASSESSMENT OF RADIATION EXPOSURE DOSES IN PATIENTS UNDERGOING PRIMARY PERCUTANEOUS CORONARY INTERVENTION BASED ON ANGIOGRAPHIC RECORDS.

The stochastic and non-stochastic (deterministic) effects of radiation dose in patients undergoing primary percutaneous coronary intervention (PPCI) have been investigated using data recorded by an angiographic monitoring system. A total of 132 patients with acute myocardial infarction referred to the angiography department of Vali-Asr hospital, Fasa, Iran, during the second half of 2016 were recruited. Quantities like dose-area product (DAP), total air kerma (Ka,r) and fluoroscopy time (FT) were calculated and converted into effective dose (ED) and peak skin dose (PSD). The values for Ka,r, DAP and FT equaled 80 399.20 ± 63 312 mGy cm2, 1392.80 ± 1155.373 mGy and 524.11 ± 423.057 s, respectively, which were within the ranges reported in previous studies. After considering standard dose thresholds for Ka,r and PSD, it was revealed that only a small portion of patients had reached these thresholds and exceeded them (<3%). Moreover, ED < 20 mSv for the majority of patients was fairly consistent with results from a recent research in eight Belgian hospitals. It was shown that angiographic records are reliable for assessing radiation dose in patients.

Estimation of occupational compensation based on a linear-quadratic methodology for the nuclear industry

Production of nuclear electricity is under scrutiny because of health issues connected with operation of nuclear facilities. National and international regulatory institutions aim to have regulations that ensure that any radiation dose received by the workers are kept as minimal as possible to reduce any risk on human health. Under these circumstances when a controlled nuclear facility is operating in standard conditions the possibility to have direct injuries connected by non-stochastic effects of ionizing radiation will happen only if regulations are violated. In addition, the stochastic effect of radiation may cause cancer. Nuclear power plants calculate the cost of potential health damage caused by ionizing radiation based on the Linear No-Threshold Relationship (LNT) between the dose and cancer risk. However, recent radiological research questions the validity of the LNT relationship for low and very low doses. In this paper, a new methodology based on a linear-quadratic function is proposed for the cost estimation of health risks induced by ionizing radiation, this new methodology results in significantly higher monetary cost for higher doses. At the same time the new methodology also results in lower monetary cost for low exposure levels and even zeros payment for environmental doses because they cannot be avoided. By adopting this new methodology it could provide motivation for nuclear facilities to improve health & safety measures.

Basic Review of Radiation Biology and Terminology.

The purpose of this paper is to review basic radiation biology and associated terminology to impart a better understanding of the importance of basic concepts of ionizing radiation interactions with living tissue. As health care workers in a field that utilizes ionizing radiation, nuclear medicine technologists are concerned about the possible acute and chronic effects of occupational radiation exposure. Technologists should have a clear understanding of what they are exposed to and how their safety could be affected. Furthermore, technologists should be knowledgeable about radiation effects so that they can adequately assuage possible patient fears about undergoing a nuclear medicine procedure. After reading this article, the nuclear medicine technologist will be familiar with basic radiation biology concepts; types of interactions of radiation with living tissue, and possible effects from that exposure; theoretic dose-response curves and how they are used in radiation biology; stochastic versus nonstochastic effects of radiation exposure, and what these terms mean in relation to both high- and low-dose radiation exposure; and possible acute and chronic radiation exposure effects.

SU‐E‐T‐358: Empirical Beam Angle Optimization for Lung Cancer Intensity Modulated Radiation Therapy

Purpose:Creating an improved BAO can decrease the amount of time a dosimetrist spends on making a treatment plan, improve the treatment quality and enhance the tools an inexperienced dosimetrist can use to develop planning techniques.Methods:Using empirical data created by experienced dosimetrists from 69 patients treated for lung cancer, the most frequently used gantry angles were applied to four different regions in each lung to gather an optimal set of fields that could be used to treat future lung cancer patients. This method, given the moniker FAU BAO, is compared in 7 plans created with the Eclipse BAO choosing 5 fields and 9 fields.Results:The results show that the conformality index improved by 30% or 3% when using the 5 and 9 fields. The conformation number was better by 12% from the 5 fields and 9% from the 9 fields. The organs at risk (OAR) were overall more protected to produce fewer nonstochastic effects from the radiation treatment with the FAU BAO.Conclusion:Empirical methods for beam angle optimization is a viable method for IMRT treatment planning techniques.

Minimising intraoperative exposure of ionising radiation to the anaesthesiologist.

Sir, We would like to highlight the dangers of intraoperative exposure to ionising radiation and a novel approach that can be used to reduce such exposure. Ionising radiation (medical exposure) regulations and amendment regulations 2006 and 2011 state radiation protection principles are the responsibility of all healthcare professionals working with radiation in the UK. Recommended occupational exposure should not exceed 100 milli Sievert (mSv) in a consecutive 5 year period and no more than 50 mSv of exposure should occur in any 1-year.[1] Quantities that are measured in Sieverts are intended to represent the stochastic health risk, which is defined as the probability of cancer induction and genetic damage. The Sievert is not used for high levels of radiation, which produce deterministic or non-stochastic effects, which is the severity of acute tissue damage, which is certain to happen. It is estimated that one Sievert carries with it a 5.5% chance of eventually developing cancer from this dose of radiation.[2] Doses >1 Sievert received over a short-time period are likely to cause severe radiation poisoning, possibly leading to death within weeks. A recent study[3] showed that while intraoperative exposure to ionising radiation during both endovascular and interventional radiology procedures were within international safe limits; the median exposure to the anaesthesiologist was as high as 16 μSv per procedure with one single procedure recorded as exposing the anaesthesiologist to 109 μSv. This corresponds to approximately a 0.00003% and 0.0006% chance of eventually developing cancer from this dose of radiation alone. Risk is reduced by limiting the time of exposure, increasing the distance from the source of radiation and by shielding. The layout of operating and radiology procedure rooms should maximise the anaesthesiologists’ distance from the radiation source and allow the use of protective shields.[3] We propose a novel approach of utilising the anaesthesia workstation as a barrier to ionising radiation, further protecting the anaesthesiologist. Commonly the layout of the operating room (OR) is such that the anaesthesiologist sits directly between the X-ray source and the workstation. The workstation is usually orientated such that its rear aspect is close up against and facing the rear wall of the OR, and its front aspect is facing the operating area. In suitable cases, we change the layout, such that the workstation is rotated 180°, with the front of the workstation facing the rear wall, but a short distance away from it, allowing the anaesthesiologist to sit between it and the rear wall. The workstation is thus placed between the X-ray source and the anaesthesiologist. This simple change of layout will result in a shielding effect of the anaesthesia workstation between the X-ray source and the anaesthesiologist and could significantly reduce the X-ray exposure over the working lifetime of anaesthesiologists who commonly work in this environment. This layout has been used successfully for many cases over many years by one of the authors (SR) [Figure 1]. It is feasible that anaesthesia workstation manufacturers may choose to add shielding rear doors designed to be protective against ionising radiation that would further increase the protection offered. Figure 1 Relative positions of anaesthesiologist, machine and surgical table We acknowledge that changing the orientation of the workstation is facilitated by the presence of an overhead gantry for compressed gas pipelines and electrical power and that this layout may not be suitable for all operating areas, cases or for all anaesthetists. We also acknowledge that the actual potential of developing cancer from exposed radiation is very small, however, we believe that the reduction in exposed radiation from utilising our proposed reverse layout is worthy of further study. Furthermore, we also recommend, where feasible, the use of commercially available head and side skirt shields that attach to the head and sides of the operating table and drop down to the floor, reducing X-ray exposure that is reflected and scattered from the floor towards the anaesthesiologist. We also recommend the use of thyroid shields and full body protective lead aprons and the regular use of radiation dosimeters. The provision of leaded eye shields or spectacles can also be considered. Where such equipment is not available, a request can be made to the employing hospital with the support of the radiology department. Further information can be obtained from the Royal College of Radiologists (www.rcr.ac.uk), the Society and College of Radiographers (www.sor.org), the International Commission on Radiological Protection (www.icrp.org) and the International Commission on Radiological Units and Measurements (www.icru.org).

Entrance surface dose in cerebral interventional radiology procedures

During interventional radiology procedures patients receive doses which exceed thresholds for non-stochastic effects on the skin, such as erythema (2 Gy) and epilation (3 Gy), so the entrance surface dose imparted during these proceedings should be monitored. The aim of this work was to determine the entrance surface dose (ESD) in patients who undergo diagnostic or therapeutic procedures at the Instituto Nacional de Neurología y Neurocirugía (INNN). The procedures were performed using two systems for neuroradiology, an Axiom Artis and an Artis Zeego from Siemens. The ESD was measured, for diagnostic and therapeutic procedures, using 15 × 15 cm2 of Gafchromic XR-RV3 film and/or 25 TLD-100 chips that were attached in a holder of 15 × 15 cm2 in the posteroanterior and left and right lateral positions during all the procedures. The results show that the maximum ESD measured was lower than 1 Gy for the nine diagnostic procedures evaluated whereas four of the ten therapeutic procedures were greater than 2 Gy in at least one position. Seven patients were monitored, three of which have presented epilation and one erythema.

Assessment of Radiation Risk in the Families of Reactor Industry Workers

The results of a study of the state of the reproduction function in the families of workers at the Industrial Association Mayak who began work during the startup period (1948–1953) and were subjected to pre- and post-marriage occupational exposure to radiation are presented. The main characteristics of the reproductive cycle, pregnancy outcomes and pre-reproductive mortality of progeny over groups of families as functions of the irradiation conditions are analyzed. It is shown that the main modifier of the selection rate of nonviable genotypes in worker families is external irradiation by γ-rays. No non-stochastic effects of irradiation were found even though workers suffered excessive irradiation at the start of the reproductive period. The stochastic effects of irradiation manifested in the form of a decrease of the average number of children surviving to reproductive age as well as in reliable differences in an unfavorable outcome of pregnancy of irradiated mothers. The increase in the rate of adverse outcomes of pregnancy correlates with the increase in the dose due to external γ-radiation sources.

Dual-age-class population model to assess radiation dose effects on non-human biota populations

In the present paper, a two-age-class group, logistic growth model for generic populations of non-human biota is described in order to assess non-stochastic effects of low linear energy-transfer radiation using three endpoints: repairable radiation damage, impairment of reproductive ability and, at higher radiation dose rates, mortality. This model represents mathematically the exchange between two life stages considering fecundity, growth and mortality. Radiation effects are modeled with a built-in self-recovery pool whereupon individuals can repair themselves. In acute effects mode, the repairing pool becomes depleted due to radiation and the model tends to lethality mode. A base calibration of the model's two free parameters is possible assuming that in acute mode 50% of the individuals die on 30 days when a radiation dose equal to the LD(50/30) is applied during that period. The model, which requires 10 species-dependent life-history parameters, was applied to fish and mammals. Its use in the derivation of dose-rate screening values for the protection of non-human biota from the effects of ionizing radiation is demonstrated through several applications. First, results of model testing with radiation effects data for fish populations from the EPIC project show the predictive capability of the model in a practical case. Secondly, the model was further verified with FREDERICA radiation effects data for mice and voles. Then, consolidated predictions for mouse, rabbit, dog and deer were generated for use in a population model comparison made within the IAEA EMRAS II project. Taken together, model predictions suggest that radiation effects are more harmful for larger organisms that generate lower numbers of offspring. For small mammal and fish populations, dose rates that are below 0.02 Gy day(-1) are not fatal; in contrast, for large mammals, chronic exposure at this level is predicted to be harmful. At low exposure rates similar to the ERICA screening dose rate of 2.4 × 10(-4) Gy day(-1), long-term effects on the survivability of populations are negligible, supporting the appropriateness of this value for radiological assessments to wildlife.

Cancer, fertility and pregnancy: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Cancer, fertility and pregnancy: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Unusual cellular effects of small doses of radiation: a massive, persisting, dose-independent increase in yield of ultrastructural pathology in the rat nephrocyte population

Electron microscopy and optical tests were used to observe the occurrence of damaged cells in the epithelium of renal tubules in white non-breed male rats after being irradiated with gamma rays in doses of 0.25 and 1.5 Gy. The duration of the study was 6 months. The data obtained were analysed from the viewpoint of the phenomenon of 'nonstochastic effects of low doses', which had been discovered earlier in various unicellular organisms and in the studies of postradiation subcellular damage in the capillary endothelium in rats' myocardium. It was shown that even at a dose of 0.25 Gy, there is a sharp increase in the spontaneous death rate of nephrocytes associated with an increase in occurrence of relatively light, predominantly local ultrastructural defects. The effect did not increase with a six-fold increase in dose (up to 1.5 Gy). It was observed at an early stage after the exposure (12 hours) and affected almost all animals. It was persistent during the whole period of observation and was not associated with mitosis. These characteristics do not fit the general concept about the stochastic nature of radiation effects. At the same time, these effects correspond with the phenotype of the studied nonstochastic damage.

An approach to the assessment of risk from chronic radiation to populations of European lobster, Homarus gammarus (L.)

The basic principles underlying a four-discrete age group, logistic, growth model for the European lobster Homarus gammarus are presented and discussed at proof-of-concept level. The model considers reproduction, removal by predation, natural death, fishing, radiation and migration. Non-stochastic effects of chronic low linear energy transfer (LET) radiation are modelled with emphasis on (99)Tc, using three endpoints: repairable radiation damage, impairment of reproductive ability and, at higher dose rates, mortality. An allometric approach for the calculation of LD(50/30) as a function of the mass of each life stage is used in model calibration. The model predicts that at a dose rate of 1 Gy day(-1), lobster population reproduction and survival become severely compromised, leading eventually to population extinction. At 0.01 Gy day(-1), the survival rate of an isolated population is reduced by 10%, mainly through loss of fecundity, comparable to natural migration losses. Fishing is the main ecological stress and only dose rates in the range 0.03-0.1 Gy day(-1) can achieve discernible effects above it. On the balance of radiation and other ecological stresses, a benchmark value of 0.01 Gy day(-1) is proposed for the protection of lobster populations. This value appears consistent with available information on radiation effects in wildlife.

Cancer, fertility and pregnancy: ESMO Clinical Recommendations for diagnosis, treatment and follow-up

Cancer, fertility and pregnancy: ESMO Clinical Recommendations for diagnosis, treatment and follow-up

Nonstochastic heritable cell lethality in the practice of biotesting of man-made pollutants as inducers of aftereffects

A nonstochastic heritable cell lethality effect was for the first time used in the practice of biotesting in a model of Saccharomyces yeasts for predicting the hazard of low mutagen doses. It was demonstrated that the heritable cell lethality might be induced by multicomponent mutagens of a technogenic nature, for example, sewage waters of gas-transferring plants. The possibility of extrapolation of the results to multicellular organisms is discussed.