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BIOLOGICAL EFFECTS OF RADIATION. WILLIAM CROOKES. Image from: http://www.homeoint.org/books5/clarkehomeo/crookes.jpg. Crookes Tube. Image from: http://www.resonancepub.com/images/Crookes_Tube_.gif. WILHELM CONRAD ROENTGEN. Image from: http://www.xray.hmc.psu.edu/rci/ss1/img0003.JPG.
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WILLIAM CROOKES Image from: http://www.homeoint.org/books5/clarkehomeo/crookes.jpg
Crookes Tube Image from: http://www.resonancepub.com/images/Crookes_Tube_.gif
WILHELM CONRAD ROENTGEN Image from: http://www.xray.hmc.psu.edu/rci/ss1/img0003.JPG
Mrs. Roentgen’s hand Image from: http://www.xray.hmc.psu.edu/rci/ss1/img0008.JPG
Early radiograph Image from: http://www.xray.hmc.psu.edu/rci/ss1/img0027.JPG
Dr. Kassabian in his Philadelphia lab Image from: http://www.xray.hmc.psu.edu/rci/ss1/img0022.JPG
Image from: http://www.xray.hmc.psu.edu/rci/ss1/img0050.JPG Dr. Kassabian’s hands
Thomas Alva Edison Image from: http://www.cedmagic.com/history/edison-with-disc.jpg
Clarence Dally Edison’s assistant Image from: http://home.gwi.net/~dnb/read/edison/edison_xrays.htm
Direct Effects Direct interaction with DNA + Image from: http://www.environmental.usace.army.mil/info/technical/hp/hptraing/hprsst/11
H2O H2O+ + e- H2O+ + H2O H3O+ + OH Hydrolysis of Water • Radiation ionizes a water molecule • The ion reacts with another water molecule to form the highly reactive hydroxyl radical Indirect Effect Image from: http://www.environmental.usace.army.mil/info/technical/hp/hptraing/hprsst/13
DNA “Target Molecule”
POSSIBLE EFFECTS OF RADIATION • Radiation may pass through cell without doing any damage. • Damage may occur, but be repaired. • The damaged cell may reproduce itself in its damaged form. • The cell may die. DAMAGE CAN BE REPAIRED Image from: http://www.xps.org/dna.jpg
The Law of Bergonié and Tribondeau This law states… • Stem cells are radiosensitive; mature cells are radioresistant. • Younger tissues and organs are radiosensitive. • Tissues with high metabolic activity are radiosensitive. • A high growth rate for tissues result in increased radiosensitivity.
The following tissue types are radiosensitive: • Germinal…reproductive cells of the ovary and testis • Hematopoietic (blood forming) tissues…red bone marrow, spleen, lymph nodes and thymus • Intestinal crypt cells – cells on the surface of the intestine
The least radiosensitive would be tissue such as: • Muscle • Nerve
EARLY EFFECTS VS. LATE EFFECTS
EARLY EFFECTS (Prompt Effects) After a high, single radiation exposure in a short period of time ~ 25 Rem or greater Image from: http://kalarte.com/marder/radiation.jpg
Non-Stochastic Health Effects • Acute effects are “Non-stochastic” effects • The effects become more severe as the exposure increases. • In other words, the amount of the dose does not determine the probability of the effect, it determines the severity of the effect.
ACUTE RADIATION SYNDROME Prodromal Stage Latent Period Images from: http://www.mscare.com/s0008/img/fatigue.jpg http://www.public.iastate.edu/~bolson/happywoman.jpg Manifest Illness Stage
ACUTE RADIATION SYNDROMES • Hematologic Syndrome • Gastrointestinal Syndrome • Central Nervous System Syndrome
Hematologic Syndrome 200 – 1,000 Rad • Prodromal Stage: Mild symptoms appear within a few hours and last for several days • Latent Period: May last up to 4 weeks • Manifest Illness: Vomiting, diarrhea, fatigue and fever – Decline in blood cells – Recovery in 2 to 4 weeks…May last up to 6 months • Possible death due to infection, dehydration or hemorrhage
Gastrointestinal Syndrome 1,000 – 5,000 Rad • Prodromal Stage: Vomiting and diarrhea occur within hours and last up to one day • Latent Period: Lasts 3-5 days • Manifest Illness: Nausea, vomiting and diarrhea – Worsens to bloody stools • Death within 4 to 10 days after exposure primarily due to intestinal cell damage – Also damage to blood-forming tissue results in hemorrhaging and dehydration.
Central Nervous System Syndrome Greater than 5,000 Rad • Prodromal Stage: Severe nausea and vomiting within a few minutes – Nervousness, confusion, burning skin, vision loss…possible loss of consciousness • Latent Period: May last up to 12 hours, or not at all • Manifest Illness: Disorientation, loss of muscle control, breathing problems, seizures, coma • Death always within a few days of exposure – due to increased fluid in brain (pressure) – Death occurs before hematologic and gastrointestinal symptoms appear
LD 50/60 • The dose of radiation to the whole body that will result in death within 60 days to 50% of the subjects receiving the dose…if no treatment is given • For humans…approximately 350 rad • People have survived up to 850 rad if treatment is received
OTHER EARLY EFFECTS(Lower doses or localized) • SKIN • GONADS • BLOOD COUNT REDUCTION • CELLULAR CHROMOSOME DAMAGE
SKIN EXPOSURE • ERYTHEMA • Threshold approximately 200 rad • SED50 approximately 600 rad • ULCERATION • At higher doses • EPILATION • Localized hair loss
ANGIOPLASTY EXPOSURE 6-8 WEEKS AFTER 3RD ANGIOPLASTY 5 MONTHS LATER 22 MONTHS LATER Photographs courtesy of Thomas B. Shope, Ph.D. (FDA)
OVARIES AND TESTES EXPOSURE • 200 rad – Temporary sterility • 500 rad – Permanent sterility • 10 rad – Possible genetic mutation (testes) • 25-50 rad – Possible genetic mutation (ovaries)
HEMATOLOGIC EFFECTS • A dose as low as about 25 rad may cause a reduction in blood cell counts Image from: http://www.easi.org/nape/apslides/22_blood.gif
CYTOGENETIC EFFECTS • Doses as low as 5 rad may cause some cellular chromosome aberrations Image from: http://medschool.umaryland.edu/departments/radiationoncology/rorl/images/morganF2.jpg
LATE EFFECTS After an acute exposure or an extended chronic exposure Take months to years to become evident Some risk at any dose Image from: http://kalarte.com/marder/radiation.jpg
Stochastic Health Effects • Late effects are “Stochastic” effects • The effects become more probable as the exposure increases. • In other words, the amount of the dose determines the probability of the effect, it does not determine the severity of the effect.
Late Effects • Cataracts • Cancer (including leukemia) • Mental retardation (fetal doses)
LATE EFFECTSRISK ESTIMATES • Difficult to quantify • Epidemiological studies needed
A-BOMB SURVIVORS Hiroshima Image from: http://www.aip.org/history/lawrence/images/bomb-plane_bomb.jpg
A-BOMB SURVIVORS Image from: http://osulibrary.orst.edu/specialcollections/coll/atomic/atomic-qv04-0309.jpg
Hiroshima & Nagasaki • 300,000 total population • 100,000 killed • 100,000 survivors with significant radiation doses • Increased leukemia occurrence • Increased mental retardation (8-15 weeks gestation) Image from: http://www.ww2guide.com/atomic.jpg
MARSHALL ISLANDS • 1940’s & 1950’s • Nuclear Testing Fallout • Thyroid Cancer data Image from: http://www.amphilsoc.org/library/exhibits/treasures/images/abomb3sm.jpg
EARLY RADIOLOGISTS Increased occurrence of leukemia and other effects Image from: http://www.xray.hmc.psu.edu/rci/ss2/img0009.JPG
ANKYLOSING SPONDYLITIS PATIENTS • 1940’s and 1950”s • Arthritic spine condition • 100 – 4,000 rad • Permanent cure • Increased occurrence of leukemia Image from: http://hcd2.bupa.co.uk/images/factsheets/ankspond.gif
RADIUM DIAL PAINTERS • 1920’s and 1930’s • Dose of up to 50,000 rad to the bone • Increased occurrence of bone cancer Image from: http://www.anl.gov/OPA/frontiers96arch/f96photo/43.gif
URANIUM MINERS • Radon exposure • Increased occurrence of lung cancer Image from: http://www.radiationsafety.ca/picture%20files/mining02.jpg
RISK MODELS Image from: http://bfa.sdsu.edu/ehs/doseresponse.gif
RISK MODELLinear Non-threshold Image from: http://4d.ehrs.upenn.edu:8080/RSXITW/images/slide16.gif
CANCER RISK ESTIMATES ONE MILLION PEOPLE EXPOSED TO 1 RAD 50 to 150 deaths from radiation induced cancer occurring within 25 years 100,000 PEOPLE EXPOSED TO 100mrad/YEAR 19,000 would die from cancer without exposure Increased cancer deaths estimated at about 550
ALARA Assuming linear non-threshold model All radiation exposure poses some risk Image from: http://4d.ehrs.upenn.edu:8080/RSXITW/images/slide16.gif
PREGNANCY RISK • 1st trimester has most risk • Possible effects: • Death • Congenital abnormalities • Cancer induction • Growth impairment • Mental retardation • Genetic effects Image from:http://www.diabetesuffolk.com/Managing Diabetes/Planning a pregnancy.asp
Effects of 10 Rad in Utero Radiologic Science for Technologists, 7th edition, Stewart C. Bushong, (pg. 512)