biological effects of radiation
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BIOLOGICAL BIOLOGICAL EFFECTS EFFECTS
OF OF RADIATIONRADIATION
WILLIAM CROOKES
Image from: http://www.homeoint.org/books5/clarkehomeo/crookes.jpg
Crookes Tube
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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 radiograp
h
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
Dr. Kassabian’s hands
Image from: http://www.xray.hmc.psu.edu/rci/ss1/img0050.JPG
Thomas Alva Edison
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Clarence Dally
Edison’s assistant
Image from: http://home.gwi.net/~dnb/read/edison/edison_xrays.htm
Direct EffectsDirect EffectsDirect EffectsDirect Effects
Direct interaction with DNADirect interaction with DNA
++
Image from: http://www.environmental.usace.army.mil/info/technical/hp/hptraing/hprsst/11
Hydrolysis of WaterHydrolysis of WaterHydrolysis of WaterHydrolysis of Water
Radiation ionizes Radiation ionizes a water moleculea water molecule
The ion reacts The ion reacts with another with another water molecule water molecule to form the to form the highly reactive highly reactive hydroxyl radicalhydroxyl radical
HH22OO HH22OO+ + + e + e--
HH22OO+ + + H+ H22OO HH33OO+ + + OH + OH
Indirect Effect
Image from: http://www.environmental.usace.army.mil/info/technical/hp/hptraing/hprsst/13
DNA
“Target Molecule”
POSSIBLE EFFECTS OF POSSIBLE EFFECTS OF RADIATIONRADIATION
1.Radiation may pass through cell without doing any damage.
2.Damage may occur, but be repaired.
3.The damaged cell may reproduce itself in its damaged form.
4.The cell may die.
DAMAGE CAN BE REPAIRED
Image from: http://www.xps.org/dna.jpg
The Law of Bergonié and The Law of Bergonié and TribondeauTribondeau
This law states…This law states… Stem cells are radiosensitive; Stem cells are radiosensitive;
mature cells are radioresistant.mature cells are radioresistant. Younger tissues and organs are Younger tissues and organs are
radiosensitive.radiosensitive. Tissues with high metabolic Tissues with high metabolic
activity are radiosensitive.activity are radiosensitive. A high growth rate for tissues A high growth rate for tissues
result in increased radiosensitivity.result in increased radiosensitivity.
The following tissue types are The following tissue types are radiosensitive:radiosensitive:
GerminalGerminal…reproductive cells of the ovary …reproductive cells of the ovary and testisand testis
HematopoieticHematopoietic (blood forming) tissues… (blood forming) tissues…red bone marrow, spleen, lymph nodes red bone marrow, spleen, lymph nodes and thymusand thymus
Intestinal crypt cellsIntestinal crypt cells – cells on the – cells on the surface of the intestinesurface of the intestine
The The leastleast radiosensitive radiosensitive would be tissue such as:would be tissue such as:
MuscleMuscle
NerveNerve
EARLY EFFECTSEARLY EFFECTS
VS.VS.
LATE EFFECTSLATE EFFECTS
EARLY EFFECTSEARLY EFFECTS
(Prompt Effects)(Prompt Effects)
After a high, single radiation After a high, single radiation exposure in a short period of exposure in a short period of
timetime
Image from: http://kalarte.com/marder/radiation.jpg
Non-Stochastic Health Non-Stochastic Health EffectsEffects
Acute effects are Acute effects are “Non-stochastic”“Non-stochastic” effects effects
The effects become The effects become more severe as more severe as the exposure increases. the exposure increases.
In other words, In other words, the amount of the the amount of the dosedose does not determine the does not determine the probability of the effect, it probability of the effect, it determines the severity of the determines the severity of the effecteffect..
ACUTE RADIATION ACUTE RADIATION SYNDROMESYNDROME
Prodromal Stage
Latent Period
Manifest Illness Stage
Images from:http://www.mscare.com/s0008/img/fatigue.jpghttp://www.public.iastate.edu/~bolson/happywoman.jpg
ACUTE RADIATION ACUTE RADIATION SYNDROMESSYNDROMES
Hematologic Syndrome
Gastrointestinal Syndrome
Central Nervous System Syndrome
Hematologic SyndromeHematologic Syndrome
200 – 1,000 Rad200 – 1,000 Rad
Prodromal Stage:Prodromal Stage: Mild symptoms appear Mild symptoms appear within a few hours and last for several within a few hours and last for several daysdays
Latent Period: Latent Period: May last up to 4 weeksMay last up to 4 weeks Manifest Illness: Manifest Illness: Vomiting, diarrhea, Vomiting, diarrhea,
fatigue and fever – Decline in blood cells – fatigue and fever – Decline in blood cells – Recovery in 2 to 4 weeks…May last up to Recovery in 2 to 4 weeks…May last up to 6 months 6 months
Possible deathPossible death due to infection, due to infection, dehydration or hemorrhagedehydration or hemorrhage
Gastrointestinal Gastrointestinal SyndromeSyndrome
1,000 – 5,000 Rad1,000 – 5,000 Rad
Prodromal Stage: Prodromal Stage: Vomiting and Vomiting and diarrhea occur within hours and last up diarrhea occur within hours and last up to one dayto one day
Latent Period: Latent Period: Lasts 3-5 daysLasts 3-5 days Manifest Illness: Manifest Illness: Nausea, vomiting Nausea, vomiting
and diarrhea – Worsens to bloody stools and diarrhea – Worsens to bloody stools DeathDeath within 4 to 10 days after within 4 to 10 days after
exposure primarily due to intestinal cell exposure primarily due to intestinal cell damage – Also damage to blood-forming damage – Also damage to blood-forming tissue results in hemorrhaging and tissue results in hemorrhaging and dehydration.dehydration.
Central Nervous System Central Nervous System SyndromeSyndrome
Greater than 5,000 RadGreater than 5,000 Rad
Prodromal Stage: Prodromal Stage: Severe nausea and vomiting Severe nausea and vomiting within a few minutes – Nervousness, confusion, within a few minutes – Nervousness, confusion, burning skin, vision loss…possible loss of burning skin, vision loss…possible loss of consciousnessconsciousness
Latent Period: Latent Period: May last up to 12 hours, or not May last up to 12 hours, or not at allat all
Manifest Illness: Manifest Illness: Disorientation, loss of muscle Disorientation, loss of muscle control, breathing problems, seizures, comacontrol, breathing problems, seizures, coma
DeathDeath always within a few days of exposure – always within a few days of exposure – due to increased fluid in brain (pressure) – due to increased fluid in brain (pressure) – Death occurs before hematologic and Death occurs before hematologic and gastrointestinal symptoms appeargastrointestinal symptoms appear
LD 50/60LD 50/60
The dose of radiation to the The dose of radiation to the whole whole bodybody that will result in death within that will result in death within 60 days60 days to to 50%50% of the subjects of the subjects receiving the dosereceiving the dose…if no treatment …if no treatment is givenis given
For humans…approximately 350 radFor humans…approximately 350 rad People have survived up to 850 rad People have survived up to 850 rad
if treatment is receivedif treatment is received
OTHER OTHER EARLY EFFECTSEARLY EFFECTS
(Lower doses or localized)(Lower doses or localized)
SKIN
GONADS
BLOOD COUNT REDUCTION
CELLULAR CHROMOSOME DAMAGE
SKIN EXPOSURESKIN EXPOSURE
ERYTHEMAERYTHEMA Threshold approximately 200 radThreshold approximately 200 rad SED50 approximately 600 radSED50 approximately 600 rad
ULCERATIONULCERATION At higher dosesAt higher doses
EPILATIONEPILATION Localized hair lossLocalized hair loss
ANGIOPLASTY ANGIOPLASTY EXPOSUREEXPOSURE
Photographs courtesy of Thomas B. Shope, Ph.D. (FDA)
6-8 WEEKS AFTER
3RD ANGIOPLASTY
5 MONTHS LATER 22 MONTHS LATER
OVARIES AND TESTES OVARIES AND TESTES EXPOSUREEXPOSURE
200 rad – Temporary sterility200 rad – Temporary sterility 500 rad – Permanent sterility500 rad – Permanent sterility 10 rad – Possible genetic mutation 10 rad – Possible genetic mutation
(testes)(testes) 25-50 rad – Possible genetic 25-50 rad – Possible genetic
mutation (ovaries)mutation (ovaries)
HEMATOLOGIC HEMATOLOGIC EFFECTSEFFECTS
A dose as low A dose as low as about 25 as about 25 rad may cause rad may cause a reduction in a reduction in blood cell blood cell countscounts
Image from: http://www.easi.org/nape/apslides/22_blood.gif
CYTOGENETIC EFFECTSCYTOGENETIC EFFECTS
Doses as low as 5 rad may cause some Doses as low as 5 rad may cause some cellular chromosome aberrationscellular chromosome aberrations
Image from: http://medschool.umaryland.edu/departments/radiationoncology/rorl/images/morganF2.jpg
LATE EFFECTSLATE EFFECTS
After an acute exposure or an After an acute exposure or an extended chronic exposureextended chronic exposure
Take months to years to Take months to years to become evidentbecome evident
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Stochastic Health EffectsStochastic Health Effects
Late effects are Late effects are “Stochastic”“Stochastic” effects effects The effects become The effects become more probable more probable
as the exposure increases. as the exposure increases. In other words, In other words, the amount of the the amount of the
dose dose determines the determines the probability of probability of the effectthe effect, it does not determine the , it does not determine the severity of the effect.severity of the effect.
Late EffectsLate Effects
CataractsCataracts Cancer (including leukemia)Cancer (including leukemia) Mental retardation (fetal Mental retardation (fetal
doses)doses)
LATE EFFECTSLATE EFFECTSRISK ESTIMATESRISK ESTIMATES
Difficult to quantifyDifficult to quantifyEpidemiological studies Epidemiological studies neededneeded
A-BOMB SURVIVORSA-BOMB SURVIVORS
Hiroshima
Image from: http://www.aip.org/history/lawrence/images/bomb-plane_bomb.jpg
A-BOMB SURVIVORSA-BOMB SURVIVORS
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Hiroshima & NagasakiHiroshima & Nagasaki•300,000 total population300,000 total population
•100,000 killed100,000 killed
•100,000 survivors with 100,000 survivors with significant radiation dosessignificant radiation doses
•Increased leukemia Increased leukemia occurrenceoccurrence
•Increased mental Increased mental retardation (8-15 weeks retardation (8-15 weeks gestation)gestation)
Image from: http://www.ww2guide.com/atomic.jpg
MARSHALL ISLANDSMARSHALL ISLANDS
•1940’s & 1950’s
•Nuclear Testing Fallout
•Thyroid Cancer data
Image from: http://www.amphilsoc.org/library/exhibits/treasures/images/abomb3sm.jpg
EARLY RADIOLOGISTSEARLY RADIOLOGISTS
Increased occurrence of leukemia and other effects
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ANKYLOSING ANKYLOSING SPONDYLITIS PATIENTSSPONDYLITIS PATIENTS
•1940’s and 1950”s
•Arthritic spine condition
•100 – 4,000 rad
•Permanent cure
•Increased occurrence of leukemiaImage from: http://hcd2.bupa.co.uk/images/factsheets/ankspond.gif
RADIUM DIAL RADIUM DIAL PAINTERSPAINTERS
•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 MINERSURANIUM MINERS
•Radon exposure
•Increased occurrence of lung cancer
Image from: http://www.radiationsafety.ca/picture%20files/mining02.jpg
RISK MODELSRISK MODELSImage from: http://bfa.sdsu.edu/ehs/doseresponse.gif
RISK MODELRISK MODELLinear Non-thresholdLinear Non-threshold
Image from: http://4d.ehrs.upenn.edu:8080/RSXITW/images/slide16.gif
CANCER RISK CANCER RISK ESTIMATESESTIMATES
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
ALARAALARA
Assuming linear non-threshold modelAssuming linear non-threshold model
All radiation exposure poses some riskAll radiation exposure poses some risk
Image from: http://4d.ehrs.upenn.edu:8080/RSXITW/images/slide16.gif
PREGNANCY RISKPREGNANCY RISK1st trimester has most
risk
Possible effects:
1.Death
2.Congenital abnormalities
3.Cancer induction
4.Growth impairment
5.Mental retardation
6.Genetic effectsImage from:http://www.diabetesuffolk.com/Managing Diabetes/Planning a pregnancy.asp
Effects of 10 Rad in Effects of 10 Rad in UteroUtero
TimeTime ResponseResponse Nat Nat OccurOccur
Rad Rad ResponseResponse
Up to 2 Up to 2 wkswks
Spont Spont abortionabortion
25%25% 0.1%0.1%
2-10 wks2-10 wks CongenitalCongenital 5%5% 1%1%
2-15 wks2-15 wks Mental ret.Mental ret. 6%6% 0.5%0.5%
Up to 9 Up to 9 mosmos
CancerCancer 8/10,0008/10,000 12/10,00012/10,000
Up to 9 Up to 9 mosmos
Impaired Impaired dev.dev.
1%1% 00
Up to 9 Up to 9 mosmos
Gen Gen MutationMutation
10%10% 00Radiologic Science for Technologists, 7th edition, Stewart C. Bushong, (pg. 512)
REMEMBER…
Radiation does not produce unusual genetic mutations…it can only increase the frequency of mutations normally observed.
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