Talk:Abnormal Development - Radiation
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Cite this page: Hill, M.A. (2024, April 27) Embryology Abnormal Development - Radiation. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Abnormal_Development_-_Radiation |
2020
Yoon I & Slesinger TL. (2020). Radiation Exposure In Pregnancy. , , . PMID: 31869154
Radiation Exposure In Pregnancy
Choosing the most appropriate imaging modality for pregnancy patients is a common clinical question encountered daily. The general principle for imaging during pregnancy is similar to imaging for the general population, with the goal of radiation exposure being as low as reasonably achievable (ALARA). What is unique during pregnancy is that fetus radiation exposure is an essential factor in deciding optimal imaging studies. Understanding of consequences of radiation exposure on a fetus, degrees of fetal radiation exposure by each imaging modality, and techniques on reducing fetal radiation exposure is vital in choosing the best diagnostic imaging modality. While it is crucial to minimize fetal radiation exposure as much as possible, it is essential to remember that diagnostic studies should not be avoided for fear of radiation exposure, especially when these studies can dramatically change patient management. This activity will discuss the consequences of radiation exposure on a fetus, degrees of radiation exposure by each modality, and techniques of reducing fetal radiation exposure. Solid understanding of how each imaging modality contributes to fetal radiation dose will significantly help in choosing the most appropriate imaging study that provides the best diagnostic information at the lowest level of radiation exposure. The consequence of radiation exposure in fetuses is mostly based on observations rather than based on scientific research. Ethical issues prohibit researching on the fetus. Therefore, most of the data on the impact of radiation on the fetus derives from observations of patients who suffered Japan’s Hiroshima bombing and the Chernobyl nuclear power plant disaster. Based on the observations made from the victims of the high level of radiation exposure, the consequences of radiation exposure can categorize into four broad groups, including pregnancy loss, malformation, developmental delay or retardation, and carcinogenesis. Pregnancy loss most often happens when radiation exposure happens during early gestation (less than two weeks). Malformations of body parts and developmental delays occur during the organogenesis period (2 weeks to 8 weeks) and are dependent on the radiation dose. Below the threshold level of radiation exposure, there is minimal disruption of organogenesis. Above the threshold, the degree of malformation is related to the dose of the radiation. Lastly, carcinogenesis is considered a stochastic effect. In other words, cancer can develop at any level of radiation exposure. However, the probability of developing cancer increases with the increase in the dose of radiation. In the United States, the background radiation exposure for the whole body per year is estimated to be 3.1 mSv (310 mrem). United States Nuclear Regulation Commission (USNRC) also recommends total fetus exposure during pregnancy to be less than 5.0 mSv (500 mrem). The fetus radiation dose below 50 mGy is considered safe and not cause any harm. According to the Center for Disease Control (CDC), radiation dose between 50 mGy to 100 mGy is regarded inconclusive in terms of impact on the fetus. Doses above 100 mGy, especially doses above 150 mGy, are viewed as the minimum amount of dosage at which negative fetal consequences will occur, based on observation. The majority of the diagnostic studies performed during the pregnancy are below the threshold level. The effect of radiation exposure during pregnancy also depends on the gestational age of the fetus. The embryo/fetus is most susceptible to radiation during organogenesis (2 to 7 weeks gestational age) and in the first trimester. The fetus is more resistant to the radiation during the second and third trimester. Dose between 0.05 to 0.5 Gy is generally considered safe for the fetus during the second and third trimester while it is considered potentially harmful during the 1st-trimester fetus. Even though the fetus is more resistant to the radiation during the second and third trimester, a high dose of radiation (greater than 0.5 Gy or 50 rad) may result in adverse effects including miscarriage, growth reduction, IQ reduction, and severe mental retardation. Therefore, clinicians and radiologists should counsel the pregnant patient regardless of the gestational age. Occupational radiation exposure for a pregnant employee should be monitored to make sure the total amount of radiation exposure is under the regulatory limit. According to the National Council of Radiation Protection and Measurement (NCRP), the total dose equivalent to the embryo/fetus should not exceed 500 mRem during the length of the pregnancy. It should not exceed 50mRem in any month during pregnancy. The practice decision on selecting the most appropriate imaging modality for pregnancy should have their basis in the expert opinions of the treating clinician. Nonetheless, the American College of Radiology does provide recommendations on the appropriateness of imaging modalities in accessing common clinical conditions. Each imaging modality is categories into usually appropriate, may be appropriate, and usually not appropriate. For instance, for a pregnant patient presenting with right lower abdominal pain concerning for appendicitis, ultrasound and MRI are usually appropriate imaging modality. CT abdomen and pelvis with or without contrast is categorized as may be appropriate. Abdominal radiograph, Tc-99m WBC scan, and fluoroscopy contrast enema are considered usually not appropriate. The American College of Radiology appropriateness criteria provides the current practice policies and guidelines in the US regarding imaging in pregnant patients.
2017
Low-dose or low-dose-rate ionizing radiation-induced bioeffects in animal models
J Radiat Res. 2017 Jan 10. doi: 10.1093/jrr/rrw120. [Epub ahead of print]
Tang FR1, Loke WK2, Khoo BC3.
Abstract
Animal experimental studies indicate that acute or chronic low-dose ionizing radiation (LDIR) (≤100 mSv) or low-dose-rate ionizing radiation (LDRIR) (<6 mSv/h) exposures may be harmful. It induces genetic and epigenetic changes and is associated with a range of physiological disturbances that includes altered immune system, abnormal brain development with resultant cognitive impairment, cataractogenesis, abnormal embryonic development, circulatory diseases, weight gain, premature menopause in female animals, tumorigenesis and shortened lifespan. Paternal or prenatal LDIR/LDRIR exposure is associated with reduced fertility and number of live fetuses, and transgenerational genomic aberrations. On the other hand, in some experimental studies, LDIR/LDRIR exposure has also been reported to bring about beneficial effects such as reduction in tumorigenesis, prolonged lifespan and enhanced fertility. The differences in reported effects of LDIR/LDRIR exposure are dependent on animal genetic background (susceptibility), age (prenatal or postnatal days), sex, nature of radiation exposure (i.e. acute, fractionated or chronic radiation exposure), type of radiation, combination of radiation with other toxic agents (such as smoking, pesticides or other chemical toxins) or animal experimental designs. In this review paper, we aimed to update radiation researchers and radiologists on the current progress achieved in understanding the LDIR/LDRIR-induced bionegative and biopositive effects reported in the various animal models. The roles played by a variety of molecules that are implicated in LDIR/LDRIR-induced health effects will be elaborated. The review will help in future investigations of LDIR/LDRIR-induced health effects by providing clues for designing improved animal research models in order to clarify the current controversial/contradictory findings from existing studies. © The Author 2017. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology. KEYWORDS: animal model; bionegative and biopositive effect; low-dose or low-dose-rate irradiation; molecular mechanism
PMID 28077626 DOI: 10.1093/jrr/rrw120
2016
Int J Environ Health Res. 2016 Apr;26(2):131-44. doi: 10.1080/09603123.2015.1061112. Epub 2015 Jul 28.
Dabouis V1, Arvers P1, Debouzy JC1, Sebbah C2, Crouzier D1, Perrin A1.
Abstract
This retrospective cohort study deals with the causes of death among 57,000 military personnel who served in the French Navy surface vessels and were observed over the period 1975-2000. We successively compared the mortality rate and the specific causes of death between two groups differing in their potential exposure levels to radar. Occupational exposure was defined according to the on-board workplace (radar and control groups). The age-adjusted death ratios of the navy personnel were compared. For all causes of death, the results showed that 885 deaths in the radar group and 299 in the control group occurred (RR = 1.00 (95 % CI: 0.88-1.14)). RRs were 0.92 (95 % CI: 0.69-1.24) for neoplasms. For the duration of follow-up, the results did not show an increased health risk for military personnel exposed to higher levels of radio frequencies in the radar group, but the number of deaths was very small for some cancer sites. KEYWORDS: epidemiology; exposure; mortality; occupational hazards; radiofrequency
PMID 26216082
2015
Risk of death among children of atomic bomb survivors after 62 years of follow-up: a cohort study
Lancet Oncol. 2015 Oct;16(13):1316-23. doi: 10.1016/S1470-2045(15)00209-0. Epub 2015 Sep 14.
Grant EJ1, Furukawa K2, Sakata R2, Sugiyama H2, Sadakane A2, Takahashi I2, Utada M2, Shimizu Y2, Ozasa K2.
Abstract
BACKGROUND: No clear epidemiological hereditary effects of radiation exposure in human beings have been reported. However, no previous studies have investigated mortality into middle age in a population whose parents were exposed to substantial amounts of radiation before conception. We assessed mortality in children of the atomic bomb survivors after 62 years of follow-up. METHODS: In this prospective cohort study, we assessed 75 327 singleton children of atomic bomb survivors in Hiroshima and Nagasaki and unexposed controls, born between 1946 and 1984, and followed up to Dec 31, 2009. Parental gonadal doses of radiation from the atomic bombings were the primary exposures. The primary endpoint was death due to cancer or non-cancer disease, based on death certificates. FINDINGS: Median follow-up was 54·3 years (IQR 45·4-59·3). 5183 participants died from disease. The mean age of the 68 689 surviving children at the end of follow-up was 53·1 years (SD 7·9) with 15 623 (23%) older than age 60 years. For parents who were exposed to a non-zero gonadal dose of radiation, the mean dose was 264 mGy (SD 463). We detected no association between maternal gonadal radiation exposure and risk of death caused by cancer (hazard ratio [HR] for 1 Gy change in exposure 0·891 [95% CI 0·693-1·145]; p=0·36) or risk of death caused by non-cancer diseases (0·973 [0·849-1·115]; p=0·69). Likewise, paternal exposure had no effect on deaths caused by cancer (0·815 [0·614-1·083]; p=0·14) or deaths caused by non-cancer disease (1·103 [0·979-1·241]; p=0·12). Age or time between parental exposure and delivery had no effect on risk of death. INTERPRETATION: Late effects of ionising radiation exposure include increased mortality risks, and models of the transgenerational effects of radiation exposure predict more genetic disease in the children of people exposed to radiation. However, children of people exposed to the atomic bombs in Hiroshima and Nagasaki had no indications of deleterious health effects after 62 years. Epidemiological studies complemented by sensitive molecular techniques are needed to understand the overall effects of preconception exposure to ionising radiation on human beings. Copyright © 2015 Elsevier Ltd. All rights reserved. Comment in Should we worry about inherited radiation risks? [Lancet Oncol. 2015] PMID 26384241
Overview of ICRP Committee 1: radiation effects
Ann ICRP. 2015 Dec 3. pii: 0146645315614497. [Epub ahead of print]
Morgan WF1.
Abstract
This paper does not necessarily reflect the views of the International Commission on Radiological Protection. The author passed away on 13 November 2015.Committee 1 of the International Commission on Radiological Protection (ICRP) addresses issues pertinent to tissue reactions, risks of cancer and heritable diseases, radiation dose responses, effects of dose rate, and radiation quality. In addition, it reviews data on the effects of radiation on the embryo/fetus, genetic factors in radiation response, and uncertainties in providing judgements on radiation-induced health effects. Committee 1 advises the Main Commission on the biological basis of radiation-induced health effects, and how epidemiological, experimental, and theoretical data can be combined to make quantitative judgements on health risks to humans. The emphasis is on low radiation doses, in the form of detriment-adjusted nominal risk coefficients, where there are considerable uncertainties in terms of the biology and the epidemiology. Furthermore, Committee 1 reviews data from radiation epidemiology studies and publications on the molecular and cellular effects of ionising radiation relevant to updating the basis of the 2007 Recommendations published in ICRP Publication 103. This paper will provide an overview of the activities of Committee 1, the updated work of the Task Groups and Working Parties, and the future activities being pursued. © The International Society for Prosthetics and Orthotics. KEYWORDS: Committee 1; Low dose radiation; Nominal risk coefficients; Stochastic effects; Tissue reactions
PMID 26635336
Draft Glossary
(based on Australian Standard - NOHSC:3022)
- Absorbed dose - the energy absorbed per unit mass by matter from ionizing radiation which impinges upon it.
- Accident - an unintended event which causes, or has the potential to cause, employees or members of the public to be exposed to radiation from which the individual doses or collective doses received do not lie within the range of variation which is acceptable for normal operation. An accident may result from human error, equipment failure or other mishap; it may require emergency action to save life or to safeguard health, property or the environment; it requires investigation of its causes and consequences and, possibly, corrective action within the program for control of radiation; and it may require remedial action to mitigate its consequences.
- Action level - an intervention level applied to exposure to radiation; when a public exposure action level is consistently exceeded, remedial action to reduce exposure should be considered; when an occupational exposure action level is consistently exceeded within a practice, a program of radiation protection should apply to that practice.
- Activity - the measure of quantity of radioactive materials (see Annex B), except when used in the term ‘human activity’.
- ALARA - an acronym for ‘as low as reasonably achievable’, used in the context of optimization.
- Alpha particle - a charged particle, consisting of two protons and two neutrons, emitted by the nucleus of a radionuclide during radioactive decay (α-decay).
- Annual Limit on Intake - (ALI) that quantity of a radionuclide which, taken into the body during one year, would lead to a committed effective dose equal to the occupational annual limit on effective dose.
- Approval - a written agreement by the appropriate authority that a plan or proposal meets the radiation protection requirements of the Recommendations.
- Beta particle - an electron or positron emitted by the nucleus of a radionuclide during radioactive decay (β-decay).
- Code of practice for radiation protection - a document prescribing specific requirements for radiation protection in a particular application.
- Collective effective dose - a measure of the total radiation exposure of a group of people which is obtained by summing their individual effective doses.
- Collective equivalent dose - a measure of the total radiation exposure of a specific organ type or tissue type in a group of people which is obtained by summing the equivalent doses received by those individual organs or tissues of the people exposed.
- Committed effective dose - the effective dose which a person is committed to receive from an intake of radioactive material.
- Committed equivalent dose - the equivalent dose which an organ or tissue is committed to receive from an intake of radioactive material.
- Controlled area - an area to which access is subject to control and in which employees are required to follow specific procedures aimed at controlling exposure to radiation.
- Critical group - a group of members of the public comprising individuals who are relatively homogeneous with regard to age, diet and those behavioural characteristics that affect the doses received and who receive the highest radiation doses from a particular practice.
- Deterministic effect - an effect, such as partial loss of function of an organ or tissue, caused by radiation and manifest only above some threshold of dose, the severity of the effect depending upon the dose received.
- Detriment - a measure, or measures, of harm caused by exposure to radiation and usually taken to mean health detriment; it has no single definition, but can be taken to be an attribute or a collection of attributes which measure harm, such as attributable probability of death and reduction of life expectancy.
- Dose - a generic term which may mean absorbed dose, equivalent dose or effective dose depending on context.
- Effective dose - a measure of dose which takes into account both the type of radiation involved and the radiological sensitivities of the organs and tissues irradiated (see Annex B).
- Electron - an elementary particle of mass 9.11 x 10-31 kg having a single negative charge.
- Equivalent dose - a measure of dose in organs and tissues which takes into account the type of radiation involved.
- Excluded exposure - in the context of occupational exposure, the component of exposure which arises from natural background radiation, provided that any relevant action level, or levels, for the workplace are not exceeded and that the appropriate authority does not prohibit its exclusion.
- Exposure - either the circumstance of being exposed to radiation, or a defined dosimetric quantity now no longer used for radiation protection purposes. (The context in which the word is used should avoid ambiguity.)
- Gamma ray - ionizing electromagnetic radiation emitted by a radionuclide during radioactive decay or during a nuclear (isomeric) transition.
- Guidance level for medical exposure - a reference level of dose or of administered activity likely to be appropriate for average-sized patients undergoing medical diagnosis or treatment.
- Half life - in relation to radioactive decay, the time required for the quantity of a radionuclide to decrease to one half of its initial value.
- Incident - an event which causes, or has the potential to cause, abnormal exposure of employees or of members of the public and which requires investigation of its causes and consequences and may require corrective action within the program for control of radiation, but which is not of such scale as to be classified as an accident.
- Intervention - action taken to decrease exposures to radiation which arise from existing situations.
- Ion - an atom in a charged state following ionization.
- Ionization - the process by which one or more electrons are removed from, or sometimes added to, an atom leaving the atom in a charged state.
- Ionizing radiation - radiation which is capable of causing ionization, either directly (for example: for radiation in the form of gamma rays and charged particles) or, indirectly (for example: for radiation in the form of neutrons).
- Justification - the notion that human activities which lead to exposure to radiation should be justified, before they are permitted to take place, by showing that they are likely to do more good than harm.
- Licence - a written authorization issued to an operator which allows the operator to carry out an operation legally.
- Limitation - the requirement that radiation doses and risks should not exceed a value regarded as unacceptable.
- Medical exposure - exposure of a person to radiation received as a patient undergoing medical diagnosis or therapy, or as a volunteer in medical research, or non-occupational exposure received as a consequence of assisting an exposed patient.
- Muon - an elementary particle of mass 1.88 x 10-28 kg having some properties similar to the electron; muons form a major component of cosmic radiation.
- Neutron - an elementary particle of mass 1.675 x 10-27 kg having some properties similar to the proton but carrying no charge; neutrons are constituents of all nuclei except for the stable isotope of hydrogen.
- Occupational exposure - exposure of a person to radiation which occurs in the course of that person’s work and which is not excluded exposure.
- Positron - an elementary particle of mass 9.11 x 10-31 kg having a single positive charge; the anti-particle of the electron.
- Practice - a type of human activity; in a radiological context, a human activity which may result in exposure to ionizing radiation and to which a system of radiation protection applies.
- Program of radiation protection - an instance of a system of radiation protection, designed for a particular operation.
- Proton - an elementary particle of mass 1.673 x 10-27 kg having a single positive charge; protons are constituents of all nuclei.
- Public exposure - exposure of a person, or persons, to radiation which is neither occupational nor medical exposure.
- Radiation - electromagnetic waves or quanta, and atomic or sub-atomic particles, propagated through space or through a material medium.
- Radiation weighting factor - a factor which modifies absorbed dose in an organ or tissue to yield equivalent dose and which is determined by the type and energy of the radiation to which the organ or tissue is exposed.
- Radioactive decay - the spontaneous transformation of the nucleus of an atom into another state, accompanied by the emission of radiation; for a quantity of such atoms, the expectation value of the number of atoms present decreases exponentially with time.
- Radioactive material - material which spontaneously emits ionizing radiation as a consequence of radioactive decay.
- Radionuclide - a species of atomic nucleus which undergoes radioactive decay.
- Radon - used generically, all isotopes of the element radon, having atomic number 86, but typically used to refer to the radioactive gas radon-222.
- Radon progeny - the short-lived products of the radioactive decay of radon, namely polonium-218, lead-214, bismuth-214, and polonium-214.
- Risk constraint - a restriction applied to potential exposure (see dose constraint).
- Specific activity - the activity of a radionuclide per unit mass of the element, or the activity of a radioactive material per unit mass of that material.
- Stochastic effect - an effect known to occur sometimes as a consequence of exposure to radiation, but which may or may not be expressed in a particular exposed person, the likelihood of the effect occurring being a function of the dose received.
- Supervised area - an area in which working conditions are kept under review but in which special procedures to control exposure to radiation are not normally necessary.
- System of radiation protection - a generic process of radiation risk management designed to limit the health risks arising from exposure to radiation to acceptable levels in a manner which takes economic and social considerations into account.
- Thoron - the radioactive gas radon-220.
- Thoron progeny - the short-lived products of the radioactive decay of thoron, namely polonium-216, lead-212, bismuth-212, polonium-212, and thallium-208.
- Tissue weighting factor - a factor which modifies equivalent dose in an organ or tissue to yield effective dose and which is the partial contribution from the organ or tissue to the total detriment resulting from uniform irradiation of the whole body.
- X-ray - ionizing electromagnetic radiation emitted during the transition of an atomic electron to a lower energy state or during the rapid deceleration of a charged particle.
