IAEA International Atomic Energy Agency RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY L14: Radiation exposure in pregnancy IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology Adapted for Regional Training Course on RP of Patients for Radiographers Accra, Ghana, July 2011

IAEA 14: Radiation exposure in pregnancy2 Topics Introduction Effects and risks of in utero exposure Typical doses Practical implementation

IAEA International Atomic Energy Agency Part 14: Radiation exposure in pregnancy Topic 1: Introduction IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology

IAEA 14: Radiation exposure in pregnancy4 Introduction Thousands of pregnant women are exposed to ionizing radiation each year Lack of knowledge is responsible for much anxiety and possibly unnecessary termination of pregnancies For most patients, the radiation exposure was medically appropriate and the radiation risk was minimal

IAEA 14: Radiation exposure in pregnancy5 Situation analysis Exposure of females of reproductive capacity: Intended medical exposure: Patients needing radiological procedures while pregnant Unintended or accidental medical exposure: Pregnancy not known or not declared Occupational exposure

IAEA 14: Radiation exposure in pregnancy6 Example of justified use of CT on a pregnant female who was in a motor vehicle accident Courtesy: Fred Mettler

IAEA 14: Radiation exposure in pregnancy7 Free blood Kidney ripped off aorta (no contrast in it) Splenic laceration A CT exam performed and then taken to the operating room. The woman and the child survived Courtesy: Fred Mettler

IAEA International Atomic Energy Agency Part 14: Radiation exposure in pregnancy Topic 2: Effects and risks of in utero exposure IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology

IAEA 14: Radiation exposure in pregnancy9 Fetal Radiation Risk There are radiation-related risks throughout pregnancy which are related to the stage of pregnancy and absorbed dose Radiation risks are most significant during organogenesis and in the early fetal period somewhat less in the 2nd trimester and least in the third trimester LessLeast Most risk

IAEA In utero exposures 14: Radiation exposure in pregnancy10 0 Conception Implantation 2 Organogenesis weeks “All or nothing” - lethal effects Threshold (0.1? – 1 Gy) Malformations – gestation- age dependent Threshold ~ 0.1 Gy Severe mental retardation* # 40% risk at 1 Gy Threshold ~ > 0.3 Gy Severe mental retardation, but less risk * Some data show a loss of 25 IQ points per Gy # Spontaneous rate of SMR is about 3% Fatal cancer risk: Childhood: ~ 6 % per Gy Hereditary effects: assumed to be ~ 0.5% per GyGrowth anomalies; e.g. head size

IAEA In utero effects 14: Radiation exposure in pregnancy11 Effect Spontaneous incidence Additional incidence after fetal dose of 25 mGy Lethal effects, pre- implantation > 15 %~ 0 Malformations~ %~ 0 Serious mental retardation ~ 3 %~ 0 Childhood cancer~ 0.2 % Lifetime cancer~ 33 %~ 0.1 % Hereditary effects~ %~ 0

IAEA 14: Radiation exposure in pregnancy12 Probability of bearing healthy children as a function of fetal dose Fetal dose (mGy) Probability of NO malformations % Probability of NO childhood cancer % > 100 Possible malformations Increased probability of childhood cancer

IAEA International Atomic Energy Agency Part 14: Radiation exposure in pregnancy Topic 3: Typical doses IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology

IAEA In utero doses from diagnostic and interventional procedures Magnitude of dose depends on whether fetus is: Not in the beam and beam is distant from uterus Fetal dose typically < 0.01 mGy Not in the beam, but beam is close to the uterus Fetal dose typically < 0.1 mGy In the beam Fetal dose typically in the range 0.1 to 50 mGy Plain film ~ 1 mGy Barium enema ~ 5 mGy CT ~ 10 – 50 mGy 14: Radiation exposure in pregnancy14

IAEA International Atomic Energy Agency Part 14: Radiation exposure in pregnancy Topic 4: Practical implementation IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology

IAEA Diagnostic and Interventional procedures for females of reproductive potential For all procedures: Signs asking female patients to notify staff if they are or might be pregnant Appropriate languages Appropriate placement For procedures that could lead to significant embryo or fetal dose: Radiological medical practitioner Procedures in place to ascertain pregnancy status 14: Radiation exposure in pregnancy16

IAEA Diagnostic and Interventional procedures for females of reproductive potential 4 outcomes to the pregnancy question No possibility of pregnancy Proceed as normally Patient definitely or probably pregnant Pregnancy cannot be excluded low dose procedure high dose procedure 14: Radiation exposure in pregnancy17

IAEA Patient definitely or probably pregnant Review the justification Radiological medical practitioner Referring medical practitioner Decide whether to defer the procedure until after the delivery (or pregnancy is ruled out) Does delaying procedure involve greater risk? Patient needs to be informed of benefits and risks If still justified, then the procedure should be optimized So that the fetal dose is the minimum consistent with the clinical purpose 14: Radiation exposure in pregnancy18

IAEA Pregnancy cannot be excluded: low dose Low dose means fetal dose < ~10 mGy If pregnancy cannot be excluded but menstrual period not overdue Proceed as normal If pregnancy cannot be excluded and menstrual period is overdue Treat patient as probably pregnant Follow advice as in previous slide 14: Radiation exposure in pregnancy19

IAEA Pregnancy cannot be excluded: high dose High dose means fetal dose > ~ 10 mGy For these high dose procedures Either: Apply a “ten day” rule I.e. females of childbearing potential are always booked for these procedures during the first ten days of their menstrual cycle, when conception is unlikely to have occurred Or: Book as any patient, but the procedure is not performed and is re-booked if the attending patient is: In 2 nd -half of their menstrual cycle, and Is of childbearing potential, and Pregnancy cannot be excluded 14: Radiation exposure in pregnancy20

IAEA 14: Radiation exposure in pregnancy21 Inadvertent exposure in pregnancy Can occur in two ways: A pregnant patient is asked whether she is or might be pregnant and denies it Either deliberately or in ignorance of her condition; and Procedure takes place A pregnant patient is NOT asked and the procedure takes place regardless Revised BSS requires the licensee to investigate any inadvertent exposure of the embryo or fetus Dose and risk estimation Patient and referring doctor informed

IAEA 14: Radiation exposure in pregnancy22 Termination of pregnancy Termination of pregnancy for fetal doses of less than 100 mGy is NOT justified based solely upon radiation risk For fetal doses in excess of 100 mGy, there can be fetal damage, the magnitude and type of which is a function of dose and stage of pregnancy In these cases decisions on termination should be based upon individual circumstances

IAEA 14: Radiation exposure in pregnancy23 Occupational Exposure of Pregnant Workers Pregnant medical radiation workers may work in a radiation environment as long as there is reasonable assurance that the fetal dose can be kept below 1 mGy during the pregnancy Typically 3 options for pregnant workers No change in assigned work duties Change to an area where the radiation exposure may be lower Change to a role that has no radiation exposure Discussions are needed Pregnant worker must be informed of potential risks, local policies and the dose limits

IAEA Occupational Exposure of Pregnant Workers From an occupational dose perspective there are few situations in diagnostic and interventional radiology where a pregnant worker would actually need to change their duties “Front line” operators in image guided interventional procedures are a possible exception Need to use previous monitoring history to establish likely levels of exposure Need to be confident that accidents with the potential for occupational exposure are unlikely There will be other concerns of the pregnant worker that will need to be taken into account 14: Radiation exposure in pregnancy24

IAEA 14: Radiation exposure in pregnancy25 Summary The radiation dose to the embryo or fetus from any diagnostic or interventional procedure in current use should present no risk of causing fetal death, malformation, growth retardation or impairment of mental development For the majority of diagnostic procedures, giving fetal doses up to about a milligray, the associated risks of childhood cancer are very low For high fetal dose procedures, systems must be in place to ascertain pregnancy status, with ensuing review of the justification for each patient, and appropriate optimization if the procedure is performed

IAEA 14: Radiation exposure in pregnancy26 Where to Get More Information ICRP Publication 84. Pregnancy and Medical Radiation (1999). ICRP Publication 90. Biological Effects after Prenatal Irradiation (Embryo and Fetus)(2003) ICRP Publication 103. The 2007 Recommendations of the International Commission on Radiological Protection (2007) Protection of Pregnant Patients during Diagnostic Medical Exposures to Ionizing Radiation. Advice from the HPA, RCR and CoR (2009)