WHAT RADIATION EFFECTS ARE POSSIBLE

IAEA International Atomic Energy Agency What Radiation Effects are Possible? (besides skin injuries) L3 Answer True or False 1. It is accepted that the stochastic effects of radiation have a threshold. 2. For deterministic effects of radiation, the severity increases with dose. 3. Radiation risk in children is 2-3 times lower than people above 45 years. 4. Skin injuries and lens opacities are deterministic effects of radiation. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 2 IAEA Educational Objectives • Effects other than skin injuries • Their probability in interventional cardiology practice • Special concerns in children, young & pregnant females Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 3 IAEA What can radiation do? It can bring a smile on the faces of people of all ages IAEA Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 4 What can radiation do? Cancer Genetic effects Skin injuries Cataract Infertility Death Non-neoplastic Effects Radiation Protection in Cardiology NB. In this lecture, we shall predominantly deal with cancer & genetic effects & cataracts Lecture 3: What Radiation Effects are Possible? 5 IAEA Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 6 IAEA Main Point Deterministic effects Effect Threshold Preventable Cancer Genetic Prob ∝ dose Cataract infertility erythema epilation Dose 500 mSv cataract 150 mSv for sterility (temporary-males) 2500 mSv for ovarian Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 7 IAEA Stochastic Deterministic effects Cataract infertility erythema epilation Dose Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 8 IAEA Stochastic and Deterministic Effects • A stochastic effect is one where the severity of the result is the same but the probability of occurrence increases with radiation dose, e.g., development of cancer. There is no threshold for stochastic effects. • A deterministic effect is one where the severity depends upon the radiation dose, e.g., skin burns. There is a threshold for deterministic effects. Lecture 3: What Radiation Effects are Possible? 9 Radiation Protection in Cardiology IAEA Cardiologist You mean I can get cancer even if I am working with small amount of radiation? This requires discussion on how radiation effects occur Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 10 IAEA Is there RADIATION in this room? Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 11 IAEA Radiation from Natural Sources • Normally 1-3 mSv/year • In areas of high background, 3-13 mSv/year Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 12 IAEA Interventional Cardiology CT Radiography Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 13 IAEA Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 14 IAEA IAEA International Atomic Energy Agency Chromosomes Nucleus Double membrane surrounding the chromosomes and the nucleolus. Pores allow specific communication with the cytoplasm. The nucleolus is a site for synthesis of RNA making up the ribosome. Induction of DNA changes Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 16 IAEA No change DNA mutation radiation hits a cell nucleus! Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 18 IAEA Mutation repaired Viable Cell Cell death Unviable Cell DNA Mutation p≅aD Radiation Protection in Cardiology Stoch.eff. Lecture 3: What Radiation Effects are Possible? Cell survives but mutated 19 IAEA Deterministic effects caused by cell death: burns, organ failure, death Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 20 IAEA Normal process Altered process due to mutated genes Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 21 IAEA Stochastic effects Cancerogenesis Hereditary effects Effects in the embryo/foetus Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 23 IAEA IAEA International Atomic Energy Agency Carcinogenesis Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 25 IAEA So now that you have scared me with this information, what should I do? It is not our intent to scare you with these facts, but to educate about potential long-term risks. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 26 IAEA OK, I agree that radiation can cause cancer, but how do I know if I will get cancer!!! Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 27 IAEA Life Insurance Agent Malpractice Insurance Probability Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 28 IAEA Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 29 IAEA Radiosensitivity • Probability of a cell, tissue, or organ suffering an effect per unit dose • Will be greater if the cell: • Is highly mitotic • Is undifferentiated Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 30 IAEA LIFE SPAN STUDY Atomic Bomb Survivors Cancer risk estimate: 4–6% per 1000 mSv (depending on projection method) ! Note: The probability best applies to a group of people and is not suitable for individual case Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 31 IAEA IAEA International Atomic Energy Agency Hereditary Effects Heritable effects • Effects to be observed in offspring born after one or both parents had been irradiated prior to conception. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 33 IAEA Hereditary effects Descendants of Hiroshima and Nagasaki survivors were studied but no statistical abnormalities were detected. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 34 IAEA A cohort of 31,150 children born to parents who were within 2 km of the hypocenter at the time of the bombing was compared with a control cohort of 41,066 children. children. No indicator was significantly modified by parental radiation exposure. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 35 IAEA In the absence of human data the estimation of hereditary effects is based on animal studies. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 36 IAEA UNSCEAR 2001 Report HEREDITARY EFFECTS OF RADIATION Risks to offspring following prenatal exposure: •Total risk = 0.0003 - 0.0005% per mGy to the first generation (3000 to 4700 cases per gray per one million progeny) •Includes multifactorial diseases •1/10 the risk of fatal carcinogenesis •Constitutes 0.4-0.6% of baseline frequency Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 37 IAEA …above the prevalent background dose, dose, an increment in dose results in a proportional increment in the probability of hereditary effects of ≈ 0.0005% per mSv of dose. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 38 IAEA OK, I understood that these radiation effects have a probability But, I want to know about ME, if I will get these Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 39 IAEA Do you worry about? Yes, Very much Yes Not really Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 40 IAEA Do you worry about? Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 41 IAEA If you work in such a manner that you adhere to prescribed dose limits of 20 mSv per year for whole working life of 18 to 65 years, your chance of excess cancer is 1 in 1000. Note: The probability calculations are for a group of people and not for individual cases Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 42 IAEA That sounds interesting. Is it possible to work in such a manner that I remain within 20 mSv/yr? It should be possible to achieve conditions so that you do not exceed ≈ 3 mSv/yr. Just wait for later information in this course Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 43 IAEA Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 44 IAEA One, Last Question!!! Are there reports of increased cancer incidence among cardiologists ? Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 45 IAEA (Because cardiologists have traditionally not interacted with safety and radiation effects professionals) Let us look into the data for other professional groups like radiologists… Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 46 IAEA Radiologists & radiological personnel: Eight cohorts 1. 3 from US (radiologists, Army X ray technologists, radiological technologists 2. 1 each from China, Canada, Denmark, Japan & UK Variety of data pertaining to cancer incidence for different sites, mortality data (cancer), now also to other diseases such as cardiovascular Variation from healthy worker effect to small increase IAEA Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 47 UK Radiologists Around 2700 male radiologists, registered from 1897 to 1979. Standardized mortality ratio (SMR) Annual exposure 0.1 Sv before 1950, 0.05 Sv in early 1950’s Compared mortality rates and death from circulatory disease: Observed number of deaths were generally close to or lower than expected. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 48 IAEA US Radiological Technologists • Over 146,000, predominantly females, 73% • Total cancer death rates were lower than expected in general population • Risks higher for those <1950 • Relative risk of mortality from circulatory disease higher for those starting work in earlier years [<1940=1.22, 1940’s=1.00, 1960+=1.00] Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 49 IAEA US Radiologists Study 1920-1939: Cohort with highest exposure, 15% higher mortality from cardiovascular disease than other physicians, after age 55. No information about smoking and other risk factors. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 50 IAEA Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 51 IAEA Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 52 IAEA Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 53 IAEA May involve small children, young females and pregnant patients Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 54 IAEA Radiosensitivity In Children and Young Patients • Age is a primary determinant of radiosensitivity– the younger the patient, the higher the radiosensitivity • Breast of 15 year old is 15 times more sensitive to radiocarcinogenesis than the breast of 45 year old Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 55 IAEA Mortality excess per Sv (BEIR VII 2005) 20 % m ortality excess 15 10 5 0 0 10 20 30 40 50 60 70 80 90 Year of exposure Males Females Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 56 IAEA 674 children who underwent cardiac catheterization due to congenital anomalies, between the years 1950-1970 Expected number of malignancies for all sites was 4.75, while the observed number was 11.0 Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 57 IAEA NonNon-neoplastic effects of Radiation Risk of Cardiovascular Diseases following Radiation Exposures Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 58 IAEA ICRP statement in its last 2007 recommendations • The available data on possible excess in non-cancer diseases (e.g., cardiovascular disorders) are judged to be insufficient to inform on risks at low doses. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 59 IAEA DETERMINISTIC LENS THRESHOLD AS QUOTED BY ICRP 0,5 - 2,0 Sv in SINGLE EXPOSURE 5 Sv in FRAC. EXPOS. >0,1 Sv/year CONTIN. ANNUAL RATE OPACITIES THRESHOLD CATARACT 5 Sv SINGLE EXPOS. > 8 Sv FRAC. EXPOS. >0,15 Sv/year CONTIN. ANNUAL RATE 60 Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? IAEA IAEA International Atomic Energy Agency Ref. to Radiation Research paper 2007 Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 62 IAEA Re-Cap Re1. 2. 3. 4. 5. 6. 7. 8. What can radiation do? Effect that have threshold No threshold effect- cancer, genetic Effects at the level of cell, DNA Probability of cancer, genetic effects Individual risk Radiologists, technologists Patients- Children, young & pregnant female Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 63 IAEA Answer True or False 1. ICRP states that radiation induced cataract can be produced if more than 150 mSv is received in the lens as a continuous annual rate. 2. The risk for cancer is 10%/Sv. 3. Women have slightly higher risk (increase in cancer probability per unit effective dose) than men. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 64 IAEA Answer True or False 4. ICRP considers that the available data is insufficient to infer possible non-cancer diseases (e.g., cardiovascular disorders) particularly at low doses. 5. Breast of a 15 year old women is many times more sensitive to radio-carcinogenesis than the breast of a 45 year old women. Radiation Protection in Cardiology Lecture 3: What Radiation Effects are Possible? 65 IAEA