2014 radiation.

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  • 방사선은 크게 두종류로 나눌수 있습니다.
    이 중 x-ray, r-ray등은 짧은 파장의 고에너지로서 DNA나 조직의 손상을 유발할 수 있는 이온성 방사선으로 분류되고 반면 radiowave, microwave등은 긴파장의 약한 에너지로서 비이온성 방사선으로 분류됩니다.
    Radiation (also known as electromagnetic radiation – EMR) is essentially waves of energy, transmitted at certain frequencies and wavelengths between two objects.
    We can’t see or hear radiation, but we are all exposed to it on an everyday basis. Some radiation is naturally occurring, but we receive much higher levels from man-made sources, such as electrical appliances, cellphones, computers and Wi-Fi devices.
    Scientists divide radiation into two classes:
    Non-ionizing radiation
    Lower-level radiation, including microwaves, radiowaves, infrared and ultraviolet. This is the type of radiation we are all exposed to on a daily basis, from electrical appliances, laptops, cellphones, wireless devices, televisions and power lines.
    Ionizing radiation
    High energy radiation, generated by X-rays and gamma rays. This type of radiation is known to be very dangerous since it is capable of producing molecular changes in body tissue and DNA. It’s the reason why exposure to X-ray machines is limited and why safety procedures for operators are in place.
  • 이온성 방사선은 주위에서도 쉽게 접할 수 있으며 대표적으로 지구의 표면, 대기, 우주상에서, 지구내부에서 일저양의 방사선이 방출되고 있습니다
  • 이온성 방사선은 주위에서도 쉽게 접할 수 있으며 대표적으로 지구의 표면, 대기, 우주상에서, 지구내부에서 일저양의 방사선이 방출되고 있습니다
  • 생후 사망이 의미있게 증가했으며 이의 대부분이 생후 1주 내에 일어난 것으로 이는 태아시기에도 TOXIC할 수 있음 의미
    이들은 THERMAL EFFECT로 생Effects of ionizing radiation(1Gy) prenatal exposure in rodents by gestational
    period
    각되며 1.5도 미만의 온도 상승도 안전하다고는 할 수 없다. Effects of ionizing radiation(1Gy) prenatal exposure in rodents by gestational
    period
  • 이 표는 임신주수에 따른 방사선의 영향을 나타낸 것입니다.
    수정 후 2주 이내라면 배아가 아직 분화를 시작하기 이전이므로 기형유발 보다는 유산을 증가시킬 수 있습니다.
    방사선에 가장 민감한 시기는 수정후 8-15주로 mental retardation, IQ의 감소등의 중추신경계에 영향을 끼치는 시기입니다.
    16-25주에도 유사한 현상이 일어날 수 있지만 8-15주와 비교할 때 같은 영향을 발생시키기 위해서는 훨씬 맣은 양의 노출을 요하는 시기입니다.
    임신 전 시기에 걸쳐 고용량 노출시 소아기의 악성종양발생을 다소 증가시킬 수 있습니다.
  • 노출된 양, 시기, 기형의 양상 등이 이런 상황을 접했을 때 도움이 되는데 이 표가 단서를 제공해주고 있습니다.
    대표적으로 발생할 수 있는 이상은 중추신경계 이상으로 microcephaly, MR, IQ의 감소 등이 있고 이들은 8주에서 15주사이에 그영향이 가장 크며 16주에서 25주 사이에도 발생할 수 있으나 그 정도 가 훨씬 적고 그 이후에는 거의 영향을 끼치지 않습니다.
    또한 3에서 11주 사이에는 eye, skeleton등의 일반적인 기형도 발생할 수 잇으나 이러기 위해서는 20rad이상의 노출이 있어야 합니다 .
    이와 같은 사실 때문에 방금 전과 같은 경우 임신초기의 방사선 촬영으로 인한 기형으로 보기 어려우며 오히려 유전학적 검사를 반드시 시행해야 하는 경우입니다.
  • 이 표는 방사선 노출로 인해 생길 수 있는 또다른 영향, 즉 소아기의 악성종양발생에 관해 보여주는 표입니다.
    일본에 원폭이 투하된후 생존자의 자녀들에 대해 1950년부터 1984년까지 약 30여년에 걸쳐 소아기의 악성종양 발생에 관해 조사했습니다.
    노출된 방사선 양에 따라 4군으로 분류하였고 용량이 증가하면서 그에 따른 relative risk가 점차적으로 증가하는 것을 볼수 있고 이렇듯 자녀의 소아기악성종양발생에 관한 영향은 기형발생에 threshold effect를 보이는 것과는 달리 노출된 양의 많고 적음과 직접적으로 관련이 잇습니다.
  • 이러한 5rad이하의 방사선 노출시 앞에서 언급한 방사선으로 인해 발생할 수 있는 부작용이 더 증가하는 지에 관한 표입니다 .
    유산 기형 지능저하등의 자연발생빈도와 5rad이하의 방사선 노출시 발생빈도를 비교해 볼때 그 위험도가 증가하지 않았으며 소아기의 악성종양과 유전성 질환의 발생에 있어 매우 미미한 정도의 증가를 보였습씁니다.
    즉 대개의 진단적 방사선 촬영은 태아에게 부정적인 영향을 증가시키지 않는다고 볼 수 있으며 필요한 경우 안전하게 쓰일 수 있습니다.
  • 이런 경우는 흔하게 접하는 상황은 아니지만 초회 임신 연령이 늦어지면서 임신중 유방암의 발생빈도가 증가하고 있습니다 .
    유방암은 방사선 치료가 절대적으로 필요한 경우라 딜레마에 빠지게 되는데요, 최근 연구결과로는 골반으로부터 먼 거리에 있는 유방 두경부 등의 종양의 경우 lead shield를한 상태에서 방사선 치료시 총 치료용량 중 극소량이 태아에 전달되기 때문에 안전하게 시행될 수 있다고 보고하고 있습니다.
    그러한 예를 보시겠습니다. ㅣ
  • 이는 1997년 바그너 등이 임신 중 방사선 노출의 경우 임신유지 또는 중절에 관한 권고사항으로 제안 한 것으로
    수정 후 2 주이내 또는 15주 이후에는 에는 노출양과는 무관하게 임신을 유지할 것을 권하며
    수정 2주후부터 15주사이의 기간에는 5rad이상의 노출시에는 다른 위험요인 여부 등을 같이 파악하여 경우에 따라 임신 중절을 고려할 수 도 있다, 특히 8에서 15주 사이에 15rad이상의 노출시에는 방사선 노출로 인해 상당한 영향이 있을 수 있으나 필수적으로 임신중절을 권해야 되는 것은 아니다라고 결론 내리고 있습니다 .
  • 2014 radiation.

    1. 1. RADIATION IN PREGNANCY 2014. 3. 18. 차의과학대학교 강남차병원 산부인과 조 연 경
    2. 2. • Ionizing Radiation IS a Teratogen! • What is a teratogen? • What is ionizing radiation? • What are possible sources of ionizing radiation? • When are the critical periods during pregnancy that ionizing radiation could affect the fetus?
    3. 3. • What are the levels of ionizing radiation that could affect the fetus? • What could result if exposed to a high level of ionizing radiation during pregnancy? • How can I protect myself from ionizing radiation poisoning?
    4. 4. Ionizing & Non-ionizing Radiation
    5. 5. Commonly used measurements for ionizing radiation and their units (Nuclear Wastelands, Makhijani et al., eds., Cambridge: MIT Press, 1995) Units Description equivalent Rem (roentgen equivalent man) A unit of equivalent absorbed dose of radiation with relative biological effectiveness rem = rad x Q Sievert (Sv) A unit of equivalent absorbed dose equal to 100 rem. 1 Sv = 100 rem Sv = Gy x Q Rad (radiation absorbed dose) A unit of absorbed dose of radiation. Rad is a measure of the amount of energy deposited in tissue 1 rad = 100 erg/gram Gray (Gy) A unit of absorbed radiation dose equal to 100 rad. Gray is a measure of deposition of energy in tissue 1 Gy = 100 rad
    6. 6. Health impact of high-dose radiation from a nuclear disaster • Cell death – Alter DNA of normal cells – Uncontrolled cell divisions – Induce cancer • Damage organs – Acute radiation sickness (coagulopathy, immunity disorders) – Diarrhea – Fever, burns, coordination & equilibrium disturbances
    7. 7. Ionizing radiation from Natural source
    8. 8. Ionizing radiation from Natural source (World Nuclear Association)
    9. 9. Effects of Prenatal Radiation Exposure
    10. 10. Effects of radiation in pregnancy • Pregnancy loss • Malformation • Neurobehavioral abnormalities • Fetal growth restriction --- deterministic effect --- Threshold or NOAEL (No-Adverse-Effect Level) • Cancer --- Stochastic effect --- More radiation, greater the chance of the disease --- No defined threshold
    11. 11. Effects of radiation in pregnancy - Deterministic effect • Radiation dose, the trimester of the pregnancy Ex) Pregnancy loss • During the 1st 2 weeks after conception, 100-200mGy (10-20 rad) • Shortly thereafter, 250-500 mGy (25-50 rad) • 18weeks, 5000mGy (500 rad) • At term, 20, 000mGy (2000rad)
    12. 12. Exposure groups Preimplantation Embryo Fetus Spontaneous abortion ++ ± - Congenital malformation - + - Intrauterine growth restriction - + + Mental retardation - + + Effects of Radiation (1Gy) Prenatal Exposure in Rodents (Schull WJ and Otake al. 1999)
    13. 13. Gestational age Weeks after conceptio n Fetal Dose Observed Effect Preimplantation 0-2 5-10 rad Animal data suggest possibility of prenatal death Major organogenesis 1-8 20-25 rad Animal and NBS data suggest that this is the most sensitive stage for growth retardation 2-15 NBS data indicate small head size; those exposed before 8 wk did not display any intellectual deficit even with small head; most sensitive time for induction of childhood cancer Rapid neuron development and migration 8-15 >10 rad Small head size, seizures, decline in IQ points: 25points/100 rad After organogenesis and rapid neuron development 15-term >10 rad Associated with increased frequency of childhood cancer >50 rad Severe mental retardation observed at 16-25wk Effects of Radiation Exposure
    14. 14. Ionizing radiation & CNS malformations Malformations Estimated threshold dose Gestational age at greatest risk Microcephaly >20Gy 8-15 week Mental retardation 0.06-0.31Gy between 8 and 15 wks 0.25-0.28 Gy between 16 and 25 wks >0.5Gy between 8 and 15 wks 8-15 week Reduction of the IQ 0.1Gy 8-15 week Other malformations (skeleton, genitals, eyes) >0.2Gy 3-11 week
    15. 15. Radiation and mental retardation • 8-15 weeks, : Risk of impaired CNS development > 5 times than 16~25 weeks • < 8 weeks, or > 25 weeks – No increased risk of mental retardation
    16. 16. Radiation exposure & Cancer
    17. 17. Cancer incidence (1950-1984) and A-Bomb radiation exposure DS86 maternal uterine dose (Gy) 0 0.01-0.29 0.30-0.59 >0.6 Mean dose (Gy) 0.000 0.087 0.416 1.372 No. at risk 710 682 129 109 Person-Years 21770 21659 4095 3287 Cancer cases 5 7 3 3 Adjusted rate per 100,000 22.4 32.5 77.8 97.0 Esstimated RR 1.00 1.24 2.18 4.78 [1.01-2.10] [1.06-6.32] 1.19-7.93
    18. 18. Risks of leukemia in various groups Group Approximate risk Increased risk over control population occurrence Siblings of leukemic children 1/720 4 To 10 years Gestational exposure 1/2000 1.5 <10 years U.S. white children <15 y.o. 1/2800 1 To 10 years (Brent RL, Teratology, 1986)
    19. 19. Type of risk Spontaneous risk (0 rad exposure) Additional risk from 5 rad Risk of very early pregnancy loss before the first missed period 350,000/106 pregnancies 0 Risk of spontaneous abortion in known pregnant women 150,000/106 pregnancies 0 Risk of major congenital malformation 30,000/106 pregnancies 0 Risk of several mental retardations 5,000/106 pregnancies 0 Risk of childhood leukemia/year 40,000/106 pregnancies/year <?1-3/106 year Risk of early or late-onset genetic disease 110,000/106 pregnancies Very low risk: the risk in the next generation and is not measurably increased with small populations Prematurity 40,000/106 pregnancies 0 Growth retardtaion 30,000/106 pregnancies 0 Stilbirth 20-2,000/106 pregnancies 0 Infertility 7% of couples 0 Spontaneous Risk Vs Additional Risk
    20. 20. Probability of birth with no malformation and no childhood cancer Dose to conceptus (mGy) No malformation (%) No childhood cancer(%) No malformation and No childhood cancer (%) 0 96.00 99.93 95.93 0.5 95.999 99.926 95.928 1.0 95.998 99.921 95.922 2.5 95.995 99.908 95.91 5.0 95.99 99.89 95.88 10.0 95.98 99.84 95.83 50.0 95.90 99.51 95.43 100.0 95.80 99.07 94.91 (Wagner LK et al. 1982)
    21. 21. Health impact of high-dose radiation from a nuclear disaster • ICRP (The International Commission on Radiological Protection) – < 100mGy (10 rad) : Not medical ground for termination • ACOG – Threshold for medical concern ~ 50mGy (5 rad) – > 1000mGy (100 rad) : Serious risk to fetus’ CNS---severe mental retardation – Single diagnostic radiation exposure? –10rad? 5 rad?
    22. 22. Estimated fetal radiation per procedure or event Clinical suspicion Procedure Estimated fetal absorption (mGy) Estimated fetal absorption (rad) pnemonia X-ray chest < 0.01 <0.001 Pulmonary embolism CT scan 0.06-0.96 0.006-0.096 Appendicitis CT scan 8-49 0.85-4.9 Nephrolithiasis Pyelogram 1.7-10 0.17-1 Breast nodule Mammogram 0.07-0.2 0.007-0.02 Colon pathology X-ray abdomen 1-4.2 0.1-0.42 Barium enema 7 0.7 Spine injury X-ray lumbar spine 6 0.6 X-ray skull <0.001 <0.001 (Groen RS et al, 2012)
    23. 23. Estimated fetal radiation per procedure or event Clinical suspicion Procedure Estimated fetal absorption (mGy) Estimated fetal absorption (rad) Pelvic injury X-ray pelvis 1-1.4 0.11-0.4 CT scan pelvis 20-79 2.0-79 Background radiation None 1 mSv 0.1rem Commercial flight Round trip(toronto~frank furt) 0.1mSv 0.01rem 100h of commercial flying 1mSv 0.1rem (Groen RS et al, 2012)
    24. 24. Health impact of high-dose radiation from a nuclear disaster • Radioactive iodine • Fetal thyroid : extremely active from >16 weeks • Begins the uptake of iodine↑ • Hypothyroidism/hyperthyroidisim • Cretinism (esp. 16-25 weeks)
    25. 25. It is estimated that about 3,500 new cases of cancer are diagnosed annually in pregnant women in the U.S., which is equivalent to one case every 1,000 gestations (Pavlidis NA. Coexistence of Pregnancy and Malignancy. Oncologist 2002) Tumor type Incidence Breast cancer 1:3,000-10,000 Cervical cancer 1.2:10,000 Hodgkin’s disease 1:1,000-6,000 Malignant melanoma 2.6:1000 Leukemia 1:75,000- 100,000 Ovarian cancer 1:10,000- 100,000 Colorectal cancer 1:13,000 Site N % Breast 298 26 Cervical 294 26 Leukemia 174 15 Lymphoma 119 10 Melanoma 193 8 Thyroid 45 4 Miscellaneous 111 11 Total 1,134 100
    26. 26. Radiotherapy during pregnancy malignancyNo. Treatment dose (Gy,median) Fetal dose (Gy, median) GA at RT No. of adverse outcomes Brain 7 40.0–54.0(42.0) 0.00270– 0.08000 (0.03000) 18–28 (21) 1 Breast 23 30.0–78.0(41.0 0.03900– 0.16000 (0.15000) 2–24 (17.5) 2 Hodgkin’s lymphoma 58 6.0–44.0(36.0) 0.00100– 10.00000 (0.08500) 1–33 (20) 3 NHL 3 2.0–52.0(26.0) 0.01800– 0.10000 (0.06000) 4–30 (23) 1 (Luis SA et al, J Med Imaging Radat Oncol 2009)
    27. 27. Radiotherapy during pregnancy : Cases with adverse outcomes malignancy Region treated Tx dose (Gy) Fetal dose (Gy) GA at RT No. of adverse outcomes Brain Brain 54.0 0.00270 20 Died in utero Breast chest, axilla Perinatal death Hodgkin’s lymphoma Mediastinum, Supraclavicular fossa 28 Slow learner, spontaneous abortion NHL Mediastinum, chest wall 26 <0.1 30 Fetal distress, short stature, attention deficit, delayed motor development (Luis SA et al, J Med Imaging Radiat Oncol 2009)
    28. 28. Radiation exposure on infants and lactating women • Direct exposure to radiation on breast • Ingestion of radioactive pharmaceuticals • Mammogram ---- breastfeeding (O) • The highest radiation conc. in breast milk – 3-4 hours after adm. of radioactive pharmaceuticals – radiation absorbed by fetus < 3-10% of the total dose absorbed by a woman – But, no negligible dose ! – 1 Gy in infant :thyroid cancer(x10) • CDC: if radioactive iodine ----stop breastfeeding !
    29. 29. Protection of pregnant women and fetuses from radiation exposure • Maintaining a safe distance • Shielding one’s body from exposure • Avoiding ingestion of food and water contaminated with radioactive particles in the air, rain, or soil • In disaster, minimize the exposure • Lead-containing vest • In radioactive pharmaceuticals, hydration + voiding! • If safe protocol, < 1mSv /year
    30. 30. Gestational age Fetal Absorbed Dose <5 rad 5-15 rad >15 rad <2 wk Recommended Recommended Recommended 2-8 wk Recommended Maybe consider termination (in presence of other severe risks) Maybe consider termination (in presence of other risks) 8-15 wk Recommended Maybe consider termination (in presence of other risks) Higher risk conditions exist, but termination is not necessarily recommended 15 wk to term Recommended Recommended Recommended Wagner LK et al : Exposure of the pregnant patient to diagnostic radiations, 1997 Continuing a pregnancy after exposure

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