Prenatal Radiation Exposure Research Articles

Expression of cell cycle genes among the residents of settlements along the Techa River exposed to ionizing radiation <i>in utero</i>

BACKGROUND: The period of intrauterine development is highly susceptible to the effects of ionizing radiation. While the consequences of radiation exposure during pregnancy are not yet fully understood, it is believed that individuals exposed to ionizing radiation in utero are at a greater risk of long-term health consequences.
 AIM: To analyze the expression of mRNA of cell cycle genes (TP53, MDM2, CDKN1A, ATM) in individuals exposed during intrauterine development to chronic radiation exposure after the Techa River accident.
 MATERIAL AND METHODS: The study was conducted over 60–70 years after the onset of chronic radiation exposure in a group of 170 individuals. Among them, 54 individuals were exposed to radiation during both prenatal and postnatal periods of development, while 80 individuals were exposed to chronic radiation after birth. The comparison group consisted of 36 individuals living in similar socio-economic conditions, with a lifetime cumulative dose of red bone marrow radiation not exceeding 70 mGy.
 RESULTS: Individuals residing in coastal villages along the Techa River, who were exposed to radiation during both the prenatal and postnatal stages of development, experience a reduction in the relative mRNA content of the MDM2 and CDKN1A genes compared to the control group and individuals who were exposed to chronic radiation after birth. The results of the correlation analysis indicate that there is no association between changes in mRNA expression of the studied genes and the accumulated absorbed dose of intrauterine and postnatal exposure of red bone marrow.
 CONCLUSION: The reduced transcriptional activity of the MDM2 and CDKN1A genes in individuals exposed to chronic radiation in utero may play a role in the development of long-term effects of radiation exposure in humans.

Successful ERCP application in pregnant women with cholestasis

We aimed to present successful endoscopic retrograde cholangiopancreatography (ERCP) applications and results in our pregnant cases. A retrospective analysis was performed on the data of 14 successful ERCP procedures performed on our pregnant patients between 2016 and 2022. The ERCP operation was carried out on the patients while they were in the left decubitus position by endoscopists skilled in biliary endoscopy. Methods to lessen prenatal radiation exposure were used during the fluoroscopy procedure. Throughout the process, short-term fluoroscopies were employed. The duration of each fluoroscopy on the patient was noted. 14 pregnant women who presented with cholestasis results had ERCP and sphincterotomy. Two of the procedures were completed on full patients during the appropriate trimesters. Our pregnant women had a mean gestational age of 17.8 weeks and a mean mother age of 24.85.6 (19-38). The fluoroscopy took 0.16 minutes (0-35sec). Ten pregnant women (10 sec) had very little fetal radiation exposure, while four other pregnant women (4 sec to 14 sec) had some. The two women's combined prenatal radiation exposure was reportedly between 30 and 35 seconds. One mild bleeding after sphincterotomy, two hyperamylasemia following ERCP, and one case of acute respiratory distress syndrome were procedure-related complications. Two days after an ERCP, cholecystitis manifested in one pregnant woman. When measures are taken as directed by a multidisciplinary team, ERCP can be used during pregnancy without risk and produce positive outcomes.

Prenatal Radiation Exposure Leads to Higher-Order Telencephalic Dysfunctions in Adult Mice That Coincide with Reduced Synaptic Plasticity and Cerebral Hypersynchrony.

Higher-order telencephalic circuitry has been suggested to be especially vulnerable to irradiation or other developmentally toxic impact. This report details the adult effects of prenatal irradiation at a sensitive time point on clinically relevant brain functions controlled by telencephalic regions, hippocampus (HPC), and prefrontal cortex (PFC). Pregnant C57Bl6/J mice were whole-body irradiated at embryonic day 11 (start of neurogenesis) with X-ray intensities of 0.0, 0.5, or 1.0 Gy. Female offspring completed a broad test battery of HPC-/PFC-controlled tasks that included cognitive performance, fear extinction, exploratory, and depression-like behaviors. We examined neural functions that are mechanistically related to these behavioral and cognitive changes, such as hippocampal field potentials and long-term potentiation, functional brain connectivity (by resting-state functional magnetic resonance imaging), and expression of HPC vesicular neurotransmitter transporters (by immunohistochemical quantification). Prenatally exposed mice displayed several higher-order dysfunctions, such as decreased nychthemeral activity, working memory defects, delayed extinction of threat-evoked response suppression as well as indications of perseverative behavior. Electrophysiological examination indicated impaired hippocampal synaptic plasticity. Prenatal irradiation also induced cerebral hypersynchrony and increased the number of glutamatergic HPC terminals. These changes in brain connectivity and plasticity could mechanistically underlie the irradiation-induced defects in higher telencephalic functions.

Pränatale Strahlenexposition aus nuklearmedizinischer Indikation

Radiation exposure from nuclear medicine procedures during pregnancy may cause uncertainty among patients and medical professionals. In 2019, the German Society of Medical Physics (DGMP) and the German Society of Radiology (DRG) published a fully revised version of the report "Prenatal Radiation Exposure Arising from Medical Indication, Dose Calculation, Conclusions for Physicians and Pregnant Women". This report offers a basis for dose calculation and determination of radiation exposure to the unborn. This review summarizes the most notable general adaptions made in the report's newest version and specifically points out the changes relevant to the field of nuclear medicine.The DGMP report provides physicians and medical physicists with means to estimate prenatal radiation exposure to the unborn conservatively, in a prompt and comprehensible approach. The rapidly evolving field of indications in nuclear medicine and radiology gave rise to the initiative of profoundly revising the previous version of the report from 2002. It now accounts for the extended range of devices, nuclear medicine hybrid imaging and radiotracers recently introduced. The most extensive change is a shift from the former 3-step-concept for the dose calculation to a 2-step-concept. In diagnostic nuclear medicine the first step comprises a conservative approximation of radiation exposure on the basis of current diagnostic reference levels (DRL). If exposure is assessed to be below 20 mSv, risk to the unborn child is sufficiently low, no further approaches are considered necessary. If calculated doses exceed 20 mSv, for diagnostic studies without existing DRL or in case of radionuclide therapies step 2 requires dose calculation based on administered activity and the stage of pregnancy.The DGMP report on prenatal radiation exposure offers valuable guidance for physicians and medical physicists in the field of nuclear medicine. The calculation concept provides an important basis to estimate radiation exposure to the unborn. Its extensive revision in 2019 accounts for recent scientific and technical developments and a reform of the stepwise approach to dose estimation.

Prenatal radiation exposure in diagnostic and interventional radiology.

The exposure of a pregnant woman to X-rays is an event that can cause uncertainty for all concerned. This review provides guidance on how to assess such a situation and how to determine the dose to the unborn child. In general, the use of X-rays in pregnant women in radiology should be avoided. If possible, alternatives should be used, or examinations postponed to a time after the pregnancy. This review gives a summary of the procedure for determining the radiation exposure of a pregnant woman. Based on the previous report of 2002 and the literature on prenatal radiation exposure published thereafter, the DGMP/DRG report on the procedure for the assessment of prenatal radiation exposure was adapted to the current state of science and technology. Typically, only relatively low radiation exposures of less than 20 mSv occur for the unborn child in X-ray diagnostics in the vast majority of cases. At these dose level the additional risk of damage to the embryo or fetus caused by the radiation is low and therefore only a rough conservative estimate using tabulated values are made. Only in a few types of examination (CT and interventional radiology) higher doses values might occur in the uterus. Instead of dose estimates (step 1 in the two-step model) in these cases the calculation of dose (step 2) are required and further action by the physician may be necessary. During the assessment, it is useful to initially use simple conservative estimation procedures to quickly determine whether a case falls into this large group less than 20 mSv, where there is a very low risk to the unborn child. If this is the case, the pregnant woman should be informed immediately by the doctor who performed the examination/treatment. This avoids a psychological burden on the patient. The DGMP/DRG report suggests a relatively simple, clearly structured procedure with advantages for all parties involved (physician, medical physics experts, MTRA and patient). · The DGMP/DRG report on prenatal radiation exposure describes the procedure for calculating radiation exposures and the associated risks for the unborn child.. · Using the two-step model, only a simple assessment based on the first step is necessary for most prenatal radiation exposures.. · With the given tables it is possible to estimate individual risks for the unborn child taking into account the radiation exposure.. · Only in the rare case that the first estimate results in a uterine dose larger 20 mSv a more accurate calculation is necessary.. · Fiebich M, Block A, Borowski M et al. Prenatal radiation exposure in diagnostic and interventional radiology. Fortschr Röntgenstr 2021; 193: 778 - 786.

Dose threshold for radiation induced fetal programming in a mouse model at 4 months of age: Hepatic expression of genes and proteins involved in glucose metabolism and glucose uptake in brown adipose tissue.

Exposure to ionizing radiation contributing to negative health outcomes is a widespread concern. However, the impact of low dose and sub-lethal dose radiation (SLDR) exposures remain contentious, particularly in pregnant women who represent a vulnerable group. The fetal programming hypothesis states that an adverse in utero environment or stress during development of an embryo or fetus can result in permanent physiologic changes often resulting in progressive metabolic dysfunction with age. To assess changes in gene expression profiles of glucose/insulin signaling and lipid metabolism caused by radiation exposure in utero, pregnant C57Bl/6J mice were irradiated using a dose response ranging from low dose to SLDR and compared to a Sham-irradiated group. mRNA expression analysis in 16 week old offspring (n = 84) revealed that genes involved in metabolic function including glucose metabolism, insulin signaling and lipid metabolism were unaffected by prenatal radiation exposures up to 300 mGy. However, female offspring of dams exposed to 1000 mGy had upregulated expression of genes contributing to insulin resistance and gluconeogenesis. In a second cohort of mice, the effects of SLDR on fetal programming of hepatic SOCS3 and PEPCK protein expression were assessed. 4 month old female offspring of dams irradiated at 1000 mGy had: 1) increased liver weights, 2) increased hepatic expression of proteins involved in glucose metabolism and 3) increased 18F-fluorodeoxyglucose (FDG) uptake in interscapular brown adipose tissue (IBAT) measured by positron emission tomography (PET) (n = 25). The results of this study indicate that prenatal radiation exposure does not affect metabolic function up to 300 mGy and 1000 mGy may be a threshold dose for sex-specific alterations in glucose uptake and hepatic gene and protein expression of SOCS3, PEPCK, PPARGC1A and PPARGC1B. These findings suggest that SLDR doses alter glucose uptake in IBAT and hepatic gene and protein expression of offspring and these changes may progress with age.

NEUROENDOCRINE EFFECTS OF PRENATAL IRRADIATION FROM RADIOACTIVE IODINE (review).

Neuroendocrine effects of the prenatal radiation exposure from radioactive iodine in an event of nuclear power reactor accidents are a key issue in the field of radiation medicine and radiation safety because of a dramatic radiosensitivity of the developing organism. Review of contemporary epidemiological, clinical and experimental data on neuroendocrine effects of prenatal exposure to 131I. Search in the PubMed/MEDLINE and Google Scholar abstract databases, along with a manual search for the relevant data sources. Estimated absorbed doses of intrauterine thyroid irradiation from radioactive iodine were obtained based on ICRP Publication 88, both with estimates of effective radiation doses on embryo and fetus, and estimates of the brain equivalent doses upon exposure in utero. The latter ones are subject to updating. The evidence-based data has been presented regarding a radiation-associated reduction of head and chest circumference at birth, as well as a radiation-associated excess of goiter with large thyroid nodules, and possibly of thyroid cancer after a prenatal exposure to 131I radionuclides. Data on intrauterine brain damage are controversial, but most researchers share the view that there are cognitive and emotional-behavioral disorders due to prenatal and postnatal irradiation and psy- chosocial impacts. Incidence increase of non-cancerous endocrine disorders and degenerative vascular disease of retina was noted. An experimental model of intrauterine irradiation from 131I on Wistar rats was for the first time ever created, extrapolating the radioneuroembryological effects in rats to individuals prenatally exposed after the Chornobyl disaster. Late neuropsychiatric and endocrine effects may be resulted from the relatively short-term impact of ionizing radiation at a level previously been considered safe. The necessity of neuropsychiatric and endocrinological monitoring of individuals exposed prenatally to ionizing radiation after the Chornobyl catastrophe throughout their life is substantiated. Experimental animal studies are a key direction in the further research of radiation effects, especially associated with low radiation doses. Further experimental and clinical neuroradiobio- logical studies aimed at exploration of the effect of ionizing radiation on hippocampal neurogenesis are most rele- vant nowadays.

Cancer Incidence after In Utero Exposure to Ionizing Radiation in Techa River Residents.

Health effects of in utero exposure to ionizing radiation, especially among adults, are still unclear. The aim of this study was to analyze cancer risk in a cohort of subjects exposed in utero due to releases of nuclear waste into the Techa River in the Southern Urals, taking into account additional postnatal exposure. Analysis for solid cancer was based on 242 cases among 10,482 cohort members, accumulating 381,948 person-years at risk, with follow-up from 1956-2009, while analysis for hematological malignancies was based on 26 cases among 11,070 persons, with 423,502 person-years at risk, with follow-up from 1953-2009. Mean doses accumulated in soft tissues and in red bone marrow during the prenatal period were 4 mGy and 30 mGy, respectively. Additional respective mean postnatal doses received by cohort members were 11 and 84 mGy. Poisson regression analysis was used to estimate the excess relative risk (ERR) of cancer incidence related to in utero and postnatal doses. No association was observed for in utero exposure with solid cancer risk [ERR per 10 mGy: -0.007; 95% confidence interval (CI): <-0.107; 0.148] or with hematological malignancy risk (ERR/10 mGy: -0.011; 95% CI: <-0.015; 0.099). However, ERR of solid cancer increased significantly with increasing postnatal dose (ERR/10 mGy: 0.11; 95% CI: 0.04; 0.22). The very wide confidence intervals in these ERR results are similar to those of studies performed on the LSS cohort and the offspring of the Mayak Female Worker Cohort, as well as case-control studies of effects after in utero medical exposure. There were limitations of this study, with decreased statistical power, due to the low prenatal doses received by most of the cohort members, the small number of cancer cases and the absence of cohort members over the age of 59 years (living cohort members had reached 49-59 years of age). Further aging of the cohort and extension of the follow-up period will enhance the statistical power of this study in the future. There is a shortage of cohort studies reporting on the effects of prenatal radiation exposure, as well as information on chronic exposure during the prenatal period. Therefore, further research of this unique cohort will be a useful addition to the published literature on this subject, and a valuable means of elucidating the long-term effects of low-dose radiation exposure in the fetus.

Ionizing Radiation Exposure During Pregnancy: Effects on Postnatal Development and Life.

Reliable human data on the effects of prenatal exposure to ionizing radiation are largely based on high-dose exposures. Exposure to low doses may produce effects that are not easily observable at birth, and may persist over the course of the offspring's postnatal life. This is important when considering fetal programing, a phenomenon characterized by changes in offspring phenotype due to a stress experienced in utero. In this review, we briefly summarize the known effects of both high- and low-dose exposure to ionizing radiation during pregnancy in humans. There is a major consensus that the atomic bomb survivors' data shows increased incidence of microcephaly and reductions in IQ of A-bomb survivors, whereas, with diagnostic radiography in utero there is no conclusive evidence of increased cancer risk. Due to the relatively limited data (particularly for low-dose exposures) in humans, animal models have emerged as an important tool to study prenatal effects of radiation. These animal models enable researchers to manipulate various experimental parameters and make it possible to analyze a wider variety of end points. In this review, we discuss the major findings from studies using mouse and rat models to examine prenatal ionizing radiation effects in postnatal development of the offspring. In addition, we broadly categorize trends across studies within three major stages of development: pre-implantation, organogenesis and fetal development. Overall, long-term effects of prenatal radiation exposure (including the possible role on the developmental programing of disease) are important factors to consider when assessing radiation risk, since these effects are of relevance even in the low-dose range.

Neurodevelopment for the first three years following prenatal radio frequency radiation and lead exposure

Introduction: We examined prenatal exposure to RFR in association with children’s neurodevelopment for the first three years, considering prenatal maternal blood lead level. Methods: The Mothers an...

TU‐H‐204‐01: Work of ICRP in relation to activities of medical physicists

Since 1928, the International Commission on Radiological Protection (ICRP) has developed, maintained, and elaborated the International System of Radiological Protection used world‐wide as the common basis for radiological protection standards, legislation, guidelines, programs, and practice. ICRP provides and periodically revises radiation and tissue weighing factors, provides and updates recommended dose limits for occupational and public exposures, recommends dose levels for termination of pregnancy, and estimates threshold doses for tissue reactions (deterministic effects). ICRP developed the dose quantity “effective dose”.NCRP Council Committee 1 (CC‐1) is charged with developing recommendations for revising radiation protection guidance for the United States. Topics to be discussed include a summary of current ICRP guidance, NCRP CC‐1 directions, NRC regulatory changes on the horizon, and potential implications of radiation protection guidance changes on the practice of medicine. The opinions of AAPM members on potential changes are welcomed.NCRP Program Area Committee (PAC) 4 has oversight of activities in radiation protection in medicine, including protection of patients and training of health care workers. Documents have been published recently on diagnostic reference levels and achievable doses, health effects of preconception and prenatal radiation exposure, and administrative policies for quality assurance and peer review of tissue reactions associated with fluoroscopically guided interventions. Additional documents are in preparation. Learning Objectives: To understand the international system of radiation protection and learn about the work of the International Commission on Radiological Protection (ICRP) in relation to activities of medical physicists To understand the ongoing work of NCRP in developing new guidance for radiation protection in the U.S. To understand the ongoing work of NCRP in developing new recommendations for radiation protection in medicine. To learn about other national organizations in US whose work plays a useful role in the activities of medical physicists.M. Rehani, Work done as part of being member of ICRP. ICRP is an independent charity.

TU‐H‐204‐02: Work of NRC, States and of re‐evaluating dose limits by NCRP

Since 1928, the International Commission on Radiological Protection (ICRP) has developed, maintained, and elaborated the International System of Radiological Protection used world‐wide as the common basis for radiological protection standards, legislation, guidelines, programs, and practice. ICRP provides and periodically revises radiation and tissue weighing factors, provides and updates recommended dose limits for occupational and public exposures, recommends dose levels for termination of pregnancy, and estimates threshold doses for tissue reactions (deterministic effects). ICRP developed the dose quantity “effective dose”.NCRP Council Committee 1 (CC‐1) is charged with developing recommendations for revising radiation protection guidance for the United States. Topics to be discussed include a summary of current ICRP guidance, NCRP CC‐1 directions, NRC regulatory changes on the horizon, and potential implications of radiation protection guidance changes on the practice of medicine. The opinions of AAPM members on potential changes are welcomed.NCRP Program Area Committee (PAC) 4 has oversight of activities in radiation protection in medicine, including protection of patients and training of health care workers. Documents have been published recently on diagnostic reference levels and achievable doses, health effects of preconception and prenatal radiation exposure, and administrative policies for quality assurance and peer review of tissue reactions associated with fluoroscopically guided interventions. Additional documents are in preparation. Learning Objectives: To understand the international system of radiation protection and learn about the work of the International Commission on Radiological Protection (ICRP) in relation to activities of medical physicists To understand the ongoing work of NCRP in developing new guidance for radiation protection in the U.S. To understand the ongoing work of NCRP in developing new recommendations for radiation protection in medicine. To learn about other national organizations in US whose work plays a useful role in the activities of medical physicists.M. Rehani, Work done as part of being member of ICRP. ICRP is an independent charity.

TU‐H‐204‐00: Work of ICRP, NCRP and Others and How They Impact On Medical Physicists

Since 1928, the International Commission on Radiological Protection (ICRP) has developed, maintained, and elaborated the International System of Radiological Protection used world‐wide as the common basis for radiological protection standards, legislation, guidelines, programs, and practice. ICRP provides and periodically revises radiation and tissue weighing factors, provides and updates recommended dose limits for occupational and public exposures, recommends dose levels for termination of pregnancy, and estimates threshold doses for tissue reactions (deterministic effects). ICRP developed the dose quantity “effective dose”.NCRP Council Committee 1 (CC‐1) is charged with developing recommendations for revising radiation protection guidance for the United States. Topics to be discussed include a summary of current ICRP guidance, NCRP CC‐1 directions, NRC regulatory changes on the horizon, and potential implications of radiation protection guidance changes on the practice of medicine. The opinions of AAPM members on potential changes are welcomed.NCRP Program Area Committee (PAC) 4 has oversight of activities in radiation protection in medicine, including protection of patients and training of health care workers. Documents have been published recently on diagnostic reference levels and achievable doses, health effects of preconception and prenatal radiation exposure, and administrative policies for quality assurance and peer review of tissue reactions associated with fluoroscopically guided interventions. Additional documents are in preparation. Learning Objectives: To understand the international system of radiation protection and learn about the work of the International Commission on Radiological Protection (ICRP) in relation to activities of medical physicists To understand the ongoing work of NCRP in developing new guidance for radiation protection in the U.S. To understand the ongoing work of NCRP in developing new recommendations for radiation protection in medicine. To learn about other national organizations in US whose work plays a useful role in the activities of medical physicists.M. Rehani, Work done as part of being member of ICRP. ICRP is an independent charity.

TU‐H‐204‐03: NCRP PAC 4 (Radiation Protection in Medicine)

Since 1928, the International Commission on Radiological Protection (ICRP) has developed, maintained, and elaborated the International System of Radiological Protection used world‐wide as the common basis for radiological protection standards, legislation, guidelines, programs, and practice. ICRP provides and periodically revises radiation and tissue weighing factors, provides and updates recommended dose limits for occupational and public exposures, recommends dose levels for termination of pregnancy, and estimates threshold doses for tissue reactions (deterministic effects). ICRP developed the dose quantity “effective dose”.NCRP Council Committee 1 (CC‐1) is charged with developing recommendations for revising radiation protection guidance for the United States. Topics to be discussed include a summary of current ICRP guidance, NCRP CC‐1 directions, NRC regulatory changes on the horizon, and potential implications of radiation protection guidance changes on the practice of medicine. The opinions of AAPM members on potential changes are welcomed.NCRP Program Area Committee (PAC) 4 has oversight of activities in radiation protection in medicine, including protection of patients and training of health care workers. Documents have been published recently on diagnostic reference levels and achievable doses, health effects of preconception and prenatal radiation exposure, and administrative policies for quality assurance and peer review of tissue reactions associated with fluoroscopically guided interventions. Additional documents are in preparation. Learning Objectives: To understand the international system of radiation protection and learn about the work of the International Commission on Radiological Protection (ICRP) in relation to activities of medical physicists To understand the ongoing work of NCRP in developing new guidance for radiation protection in the U.S. To understand the ongoing work of NCRP in developing new recommendations for radiation protection in medicine. To learn about other national organizations in US whose work plays a useful role in the activities of medical physicists.M. Rehani, Work done as part of being member of ICRP. ICRP is an independent charity.

Current Evidence for Developmental, Structural, and Functional Brain Defects following Prenatal Radiation Exposure.

Ionizing radiation is omnipresent. We are continuously exposed to natural (e.g., radon and cosmic) and man-made radiation sources, including those from industry but especially from the medical sector. The increasing use of medical radiation modalities, in particular those employing low-dose radiation such as CT scans, raises concerns regarding the effects of cumulative exposure doses and the inappropriate utilization of these imaging techniques. One of the major goals in the radioprotection field is to better understand the potential health risk posed to the unborn child after radiation exposure to the pregnant mother, of which the first convincing evidence came from epidemiological studies on in utero exposed atomic bomb survivors. In the following years, animal models have proven to be an essential tool to further characterize brain developmental defects and consequent functional deficits. However, the identification of a possible dose threshold is far from complete and a sound link between early defects and persistent anomalies has not yet been established. This review provides an overview of the current knowledge on brain developmental and persistent defects resulting from in utero radiation exposure and addresses the many questions that still remain to be answered.

Prenatal radiation exposure

Pregnant women may be exposed to nonionizing, ionizing radiation and contrast media via diagnostic or therapeutic procedures and workplace exposure. When computed tomography or magnetic resonance imaging is performed on a pregnant woman, the effects of exposure to radiation, high magnetic fields and contrast media, which can be risky for a fetus, should be considered. Nonionizing radiation that is not significantly risky for a fetus includes microwave, ultrasound, radio frequency and electromagnetic waves, while ionizing radiation that can be teratogenic, carcinogenic or mutagenic includes particles and electromagnetic radiation. The effects of radiation are associated with the level of exposure and stage of fetal development. Organogenesis (two to seven weeks after conception) and the early fetal period (eight to fifteen weeks after conception) are the most sensitive stages for a fetus. Noncancerous health effects have not been determined at any stage of gestation with less than 50 mGy (5 rad) exposure dose of ionizing radiation. Higher exposure levels may lead to spontaneous abortion, growth restriction, and mental retardation. The risk of cancer is increased regardless of the dose. Although the use of iodinated contrast media is generally thought to be safe during pregnancy, the risk of fetal hypothyroidism should be considered and it should be used only when necessary. The use of gadolinium-based contrast media during pregnancy is controversial because of the lack of clinical data. The purpose of this article is to review the existing literature regarding the prenatal radiation exposure and to discuss fetal risk of radiation.

Prenatal radiation exposure: dose calculation.

The unborn child requires special protection. In this context, the indication for an X-ray examination is to be checked critically. If thereupon radiation of the lower abdomen including the uterus cannot be avoided, the examination should be postponed until the end of pregnancy or alternative examination techniques should be considered. Under certain circumstances, either accidental or in unavoidable cases after a thorough risk assessment, radiation exposure of the unborn may take place. In some of these cases an expert radiation hygiene consultation may be required. This consultation should comprise the expected risks for the unborn while not perturbing the mother or the involved medical staff. For the risk assessment in case of an in-utero x-ray exposition deterministic damages with a defined threshold dose are distinguished from stochastic damages without a definable threshold dose. The occurrence of deterministic damages depends on the dose and the developmental stage of the unborn at the time of radiation. To calculate the risks of an in-utero radiation exposure a three-stage concept is commonly applied. Depending on the amount of radiation, the radiation dose is either estimated, roughly calculated using standard tables or, in critical cases, accurately calculated based on the individual event. The complexity of the calculation thereby increases from stage to stage. An estimation based on stage one is easily feasible whereas calculations based on stages two and especially three are more complex and often necessitate execution by specialists. This article demonstrates in detail the risks for the unborn child pertaining to its developmental phase and explains the three-stage concept as an evaluation scheme. It should be noted, that all risk estimations are subject to considerable uncertainties. • Radiation exposure of the unborn child can result in both deterministic as well as stochastic damage und hitherto should be avoided or reduced to a minimum.• In case of radiation a suitable hygiene consultation may be necessary.• For risk assessment a three-stage concept is applied, which, depending on the radiation exposure, estimates or calculates the dose for the unborn child.• The radiologist plays a crucial role as a competent advisor and provider of reliable expert information. Citation Format: • Scharwächter C, Röser A, Schwartz CA et al. Prenatal Radiation Exposure: Dose Calculation. Fortschr Röntgenstr 2015; 187: 338 - 346.

Radiation exposure and pregnancy.

Radiological exposure from nuclear power reactor accidents, transportation of nuclear waste accidents, industrial accidents, or terrorist activity may be a remote possibility, but it could happen. Nurses must be prepared to evaluate and treat pregnant women and infants who have been exposed to radiation, and to have an understanding of the health consequences of a nuclear or radiological incident. Pregnant women and infants are a special group of patients who need consideration when exposed to radiation. Initial care requires thorough assessment and decisions regarding immediate care needs. Ongoing care is based on type and extent of radiation exposure. With accurate, comprehensive information and education, nurses will be better prepared to help mitigate the effects of radiation exposure to pregnant women and infants following a radiological incident. Information about radiation, health effects of prenatal radiation exposure, assessment, patient care, and treatment of pregnant women and infants are presented.

TU‐C‐18A‐01: Models of Risk From Low‐Dose Radiation Exposures: What Does the Evidence Say?

At dose levels of (approximately) 500 mSv or more, increased cancer incidence and mortality have been clearly demonstrated. However, at the low doses of radiation used in medical imaging, the relationship between dose and cancer risk is not well established. As such, assumptions about the shape of the dose‐response curve are made. These assumptions, or risk models, are used to estimate potential long term effects. Common models include 1) the linear non‐threshold (LNT) model, 2) threshold models with either a linear or curvilinear dose response above the threshold, and 3) a hormetic model, where the risk is initially decreased below background levels before increasing. The choice of model used when making radiation risk or protection calculations and decisions can have significant implications on public policy and health care decisions. However, the ongoing debate about which risk model best describes the dose‐response relationship at low doses of radiation makes informed decision making difficult. This symposium will review the two fundamental approaches to determining the risk associated with low doses of ionizing radiation, namely radiation epidemiology and radiation biology. The strengths and limitations of each approach will be reviewed, the results of recent studies presented, and the appropriateness of different risk models for various real world scenarios discussed. Examples of well‐designed and poorly‐designed studies will be provided to assist medical physicists in 1) critically evaluating publications in the field and 2) communicating accurate information to medical professionals, patients, and members of the general public. Equipped with the best information that radiation epidemiology and radiation biology can currently provide, and an understanding of the limitations of such information, individuals and organizations will be able to make more informed decisions regarding questions such as 1) how much shielding to install at medical facilities, 2) at what dose level are risk vs. benefit discussions with patients appropriate, 3) at what dose level should we tell a pregnant woman that the baby’s health risk from a prenatal radiation exposure is “significant”, 4) is informed consent needed for patients undergoing medical imaging, and 5) at what dose level is evacuation appropriate after a radiological accident. Examples of the tremendous impact that choosing different risks models can have on the answers to these types of questions will be given.A moderated panel discussion will allow audience members to pose questions to the faculty members, each of whom is an established expert in his respective discipline.Learning Objectives: Understand the fundamental principles, strengths and limitations of radiation epidemiology and radiation biology for determining the risk from exposures to low doses of ionizing radiation Become familiar with common models of risk used to describe the dose‐response relationship at low dose levels Learn to identify strengths and weaknesses in studies designed to measure the effect of low doses of ionizing radiation Understand the implications of different risk models on public policy and health care decisions

Occupational hazards for pregnant or lactating women in the orthopaedic operating room.

Pregnant or lactating staff working in the orthopaedic operating room may be at risk of occupational exposure to several hazards, including blood-borne pathogens, anesthetic gases, methylmethacrylate, physical stress, and radiation. Because the use of proper personal protective equipment is mandatory, the risk of contamination with blood-borne pathogens such as hepatitis B, hepatitis C, and HIV is low. Moreover, effective postexposure prophylactic regimens are available for hepatitis B and HIV. In the 1960s, concerns were raised about occupational exposure to harmful chemicals in the operating room such as anesthetic gases and methylmethacrylate. Guidelines on safe levels of exposure to these chemicals and the use of personal protective equipment have helped to minimize the risks to pregnant or lactating staff. Short periods of moderate physical activity are beneficial for pregnant women, but prolonged strenuous activity can lead to increased pregnancy complications. The risk of prenatal radiation exposure during orthopaedic procedures is of concern, as well. However, proper lead protection and contamination control can minimize the risk of occupational exposure to radiation.