The Biological and Medical Effects of Radiation
The Biological and Medical
Effects of Radiation
By
James Waris
Rene Alonso
Atomic Bomb in Hiroshima
• Video
Types of Radiation
• There are many types of radiation.
• Different wavelengths across electromagnetic
spectrum
• Thermal, residual, ionizing
• Ionizing radiation is what is dangerous to living
cells.
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What is Ionizing Radiation?
• High energy radiation
• Can penetrate matter
• Ejects electrons from atomic orbits
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Types of Ionizing Radiation
• Gamma Rays
• X-Rays
• Alpha Particles
• Beta Particles
• Neutrons
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ation.gif
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ch?v=K_zc1WKT0CA
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Effects of Radiation on Cells
• Living tissues are injured due to the
transfer of energy to the molecules in the
cellular structure.
• These molecules become excited and the
following can result:
• Production of free radicals
• Breakage of chemical bonds
• Damage to molecules that regulate
essential processes (ie. DNA and RNA)
Effects of Ionizing Radiation
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m/watch?v=uN82GLQ
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Effects on Different tissues
• Cells with a high rate of
division are most
vulnerable to damage by
radiation
• Blood-forming organs and
reproductive organs are
most vulnerable.
• Skin, bone and teeth, and
muscle intermediate
• Nervous system is the
least vulnerable
• Developing embryos most
sensitive
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Background Radiation
We are constantly surrounded and exposed to low
levels of radiation on a daily basis. In the US, we
receive a dose of around 100 mrem of radiation from
the environment each year. (Although this can very
greatly depending on where you live.) This comes from
a variety of sources:
•Cosmic Rays from Space
~44mrem
•Gamma radiation from external
radioactivity ~40 mrem
•Internal radiation ~18 mrem
Medical Radiation
• In addition to the radiation we receive from
the environment, we also receive an
annual dose of around 50 mrem from
medical sources.
• This includes techniques such as x-rays
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Danger of Low Dose Radiation
• Low dose radiation sustained over a long
period of time may increase risk of cancer.
• Difficult to determine effects, because
levels l so similar il to background levels.
l
• If risks exist they are minimal
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Putting Danger into Perspective
• The following all have a
one in a million chance of
death.
• Exposure to 10 mrem
dose of radiation
• Smoking 1.4 cigarettes in
a lifetime (lung cancer)
• Spending two days in New
York City (air pollution)
• Driving 40 miles in a car
(accident)
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Putting Risk into Perspective
• A 1991 NRC draft guide attempted to place an estimate
on the loss of life expectancy from exposure to 300mrem
of radiation (average occupational exposure).
• Dose of 300 mrem/year – 15 days
• Smoking 20 cigarettes a day – 6 years
• Overweight by 15% - 2 years
• All accidents – 207 days
• Alcohol (US average) – 1 year
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High Dose Exposure
• Acute Whole-body exposure to high doses
of radiation results in irreversible damage
to cells. The exact consequences depend
on the amount and length of exposure.
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Acute Effects of Whole Body
Exposure
Dose
(Rem)
5-20
Effect
20 Possible Chromosome damage
Goldman, 1982
20-100
100 Temporary Reduction in Leukocytes
>50 = temporary sterility in men
100- Mild Radiation sickness (vomiting, diarrhea,
200 fatigue, reduced d immune)
200- Serious Radiation sickness (above plus bone
300 marrow sickness and hemorrhage h LD 10-35/30)
Dose
(Rem)
300-400
400
1000
Acute Effects of Whole Body
Exposure
Effect
400 Serious Radiation Sickness plus bone-marrow and
intestine destruction. Sterility in women.
LD 50-70/30
400- Acute illness, early death; LD 60-95/30
1000
5000
>5000
1000- Acute illness, death in days. LD 100/10
>5000 Acute illness, death in hours-days; central nervous
syndrome. LD 100/2
Goldman, 1982
Lethal Doses
• Mammals LD 50 =350-800 rem
• Bacteria LD 50 ~5000 rem
• Lethal dose for insects shows a lot of
variability. As high as 100-500 kilorems
for some species.
• Plants: LD 50 is in the kilorads
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Atomic Blast
(Hiroshima/Nagasaki)
• Types of Radioactive
Exposure:
• Thermal Burns (infrared
heat radiation)
• Beta Burns (ionizing
radiation on fallout
particles)
• Gamma Burns (highly
penetrating)
Different Stages
– Initial Stage
• First 1-2 weeks.
• Greatest number of deaths.
• 90% due to thermal burns/ blast effects
• 10% due to superlethal radiation exposure
• Blast Effects- pressure over .8 bar
destroys most buildings.
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Different Stages
– Intermediate
• Deaths occurring after 3-8 weeks
• Deaths due to ionizing radiation in median
lethal range
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Different stages - Late
• Period 8-20 weeks after blast
• Characterized by improvement in survivors
conditions
Different Stages - Delayed
• 20+ weeks after blast.
• Complications from wounds
• Infertility
• Blood Disorders
• Genetic effects
• Birth Defects
• Cancer
• Cataracts
t
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p p
Levels at Hiroshima/Nagasaki
1 Sievert =
100 Rem
A-bomb Survivors
• Almost half of all leukemia cases in A-
bomb survivors were attributable to
radiation from the blast.
• As of 1990, 4,565 solid cancer deaths.
8% attributable to radiation.
• As much as 70% of cancers from A-bomb
radiation are expected to appear in the
next 20 years.
Famous Survivors
• Sadako Sasaki
• 2 years old in 1945
• Exposed to Hiroshima
Radiation
• 1954- red/purple spots
appear (symptoms of
Leukemia)
• 1000 paper cranes
• Dies 1955
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Chernobyl – 1986 Ukraine
• Plutonium, noble
gases, and fission
products released into
environment
• Iodine and strontium
most dangerous (food
chain)
• 56 direct deaths.
• According to WHO
estimates, as many as
4,000 extra cancer
deaths caused by
radiation.
• Hundreds of times
more radioactivity
released than
Hiroshima bomb
• Radioactivity longer
lived
• Thousands of years
before accident site
will be completely
safe.
• ~200 years before it
will be safe to resume
agriculture in the
surrounding area.
Chernobyl
Biological Effects
• Radioactive Reaction products released
(included I-131, Cs-137, Sr-90)
• Most dangerous accumulate in food chain
• I-131 accumulates in Thyroid gland
• Thyroid- endocrine gland, controls how fast body
uses energy, rate of protein production, and how
sensitive body is to other hormones
• Hyperthyroidism
• Thyroid Cancer
Questions
• Should the US government pay for medical
treatment costs of Hiroshima and Nagasaki
survivors?
• What should the future of nuclear power be?
Should we expand the industry even though
there have been accidents in the past?
• Reactor accidents have the potential to affect
those in other countries? Do you think that
nuclear power should be under international
regulation and inspection or should it be left up
to the individual country?
Radiation Poisoning
• Illness and symptoms resulting from
excessive exposure to radiation.
Exposure may be accidental or intentional.
• Due to two types of radiation
• Ionizing: produces immediate chemical effects
on human tissue (rays, gamma rays, and
particle bombardment). Can be used for
medical testing and treatment, industrial and
manufacturing purposes, weapons and
weapons development, etc.
Continued
• Nonionizing: radiation from light, radio waves,
microwaves and radar. Usually no harm to tissue.
• Radiation exposure:
• Acute:
• single large exposure
• Usually associated with radiation sickness
• Chronic:
• A series of small exposures spread over time
• Associated with delayed medical problems such as cancer
and premature aging.
Acute
• Mild exposure (1-2 Gy) doses of
radiation
• Moderate exposure (2-3.5 Gy) doses
of radiation
• Severe exposure (3.5-5.5 5.5 Gy) doses
of radiation
• Very severe (5.5-8 5 Gy) doses of radiation
• X-rays or Gamma Rays
• 1 Gy causes radiation sickness
• 4 Gy causes radiation sickness and death in half of
individuals.
• Without medical treatment almost all exposed will die within 30
days.
• 1000 Gy immediate unconsciousness and death within an
hour.
Symptoms
• Appear sooner with higher doses of exposure.
• Become more serious as the dosage of radiation
increases.
• Main symptoms are nausea and vomiting.
• 24-4848 hours in mild exposure.
• 12-2424 hours in moderate exposure
• Less than 1 hour in severe exposure
• Less than 30 minutes in very severe exposure.
Symptoms by severity
• Mild
• Nausea and vomiting, headaches, fatigue, and weakness
• Moderate
• All symptoms of mild, fever, hair loss, infections, bloody vomit
and stools, poor wound healing.
• Severe
• All symptoms of lower levels, diarrhea, high fever
• Very Severe
• All symptoms of lower levels, dizziness, disorientation, low blood
pressure
• Fatal about 50% of the time.
Syndromes
• Prodromal Syndrome
• 15G
1.5 Gy
• causes gastrointestinal distress such as anorexia, nausea, fatique, and
diarrhea
• Bone Marrow Death
• 2 to 10 Gy
• Production of red and white blood cells and platelets is stopped by
division of precursor stem cells.
• Loss of platelets greatly increases the chance of fatal hemorrhage.
• Gastrointestinal Death
• 1 to 5 Gy
• Causes damage to epithelial cells lining gastrointestinal tract
• Death in 7-14 days from loss of water and electrolytes
• Central Nervous System Death
• Main cause of death in 24-4848 hours
Short Term Effects (6-8 Wks)
• Skin
• Germinal layer is the principal i site of damage
• Initial response is erythema (reddening)
• Due to blood vessel congestion and edema
• Lungs
• Most radiosensitive organ to radiation
• Radiation pneumonitis
• Leads to pulmonary insufficiency and death in few months
• Ovaries
• Single dose 1-2 Gy will cause temporary sterility. Suppress
menstruation for up to 3 yrs. 4 Gy will cause permanent sterility.
• Testicles
• 0.1 Gy will cause low sperm count for up to a year.
• 2.5 Gy will cause sterility for 2 to 3 years or more.
• 4 Gy will cause permanent sterility.
Long Term Effects
• Cataract Induction
• Average time of development 2 to 3 years.
• 2 Gy of gamma rays cause opacities in few
• 6-7 Gy seriously impair vision and cause cataracts
• Cancer Induction
• Most significant risk of long exposure
• 1 in 80 exposed will die from cancer
• 1 in 40 will develop cancer
• Utero Effects
• 1 Gy dose will cause 0 to 20 extra cases of perinatal mortality per 1000
births.
• .05 Gy will increase death due to cancer 10 times per 1000 births.
• 1 Gy antenatal dose in first trimester causes the risk of fatal cancer to
increase to 100% of cases.
Long term Effects caused by
• Caused by
• Contaminated water
• Untreated sewage
• Crowded living conditions
• Poor standard of living
• Lack of vaccines
• Infectious Diseases caused by blast
• Dysentery
• Infectious hepatitis
• Salmonellosis:
ll • Cholera
• Menigococcal meningitis
• Tuberculosis
• Diphtheria
i
• Whooping Cough
• Polio
• Pneumonia
Nuclear Blast.
Testing and Diagnosis
• Known Exposure
• Details about distance from the source of radiation and duration of exposure
• Vomiting and other symptoms
• Time between radiation exposure and the onset of vomiting
• Shorter onset means higher dose of exposure
• Blood Tests
• Blood tests over several days
• Details drop in white blood cells and abnormal changes in DNA of
blood cells
• Dosimeter
• Indicate degree of bone marrow damage
• Device that can measure the absorbed dose of radiation but only
if it was exposed to radiation at the same time the person was
exposed.
• Survey Meter
• Device that can be used to survey people to determine the body
location of radiactive particles
• Type of radiation
• Provides guide to decisions for treating people with radiation sickness
First Aid to Radiation Exposure
• Only provide medical treatment if appropriate protective
gear is worn
• Check person’s breathing and pulse
• Start CPR, if necessary
• Remove clothing and seal in container
• Vigorously wash body with soap and water
• Dry body and wrap with soft, clean blanket
• Take person to nearest emergency medical facility
• Report Exposure to Emergency official.
• DO NOT
• Remain in area
• Apply ointments to burned areas
• Remain in contaminated clothing
• Refuse to see medical treatment
Treatments and Drugs
• Goals
• To prevent further radioactive contaminations,
ti
treat damaged organs, reduce symptoms, and
manage pain
• Decontamination
• Remove clothing and shoes to eliminate about
90% of external contamination.
• Lowers the risk of internal contamination from
inhalation, ingestion or open wounds.
• Treatment for damaged bone marrow
• Use of protein granulocyte colony-stimulating
factor
• Promotes the growth of white blood cells
• Neupogen and Neulasta
• Blood transfusions for
severe damage
Treatment continued
• Internal contamination
• Potassium Iodide
• Prevents absorption of radioiodine by thyroid.
• Allows for radioiodine to be cleared in urine
• Prussian blue
• Binds to particles of radioactive elements (Cesium and
thallium)
• Allows for excretion of radioactive elements
• Speeds up elimination and reduces the amount of radiation
cells absorb
• DTPA
• Binds to radioactive elements such as plutonium, americium,
curium.
Supportive Treatment
• Additional medications or interventions to treat:
• Bacterial infections
• Headaches
• Fever
• Diarrhea
• Nausea and Vomiting
• Dehydration
• End of life care
• Usually people who have absorbed radiation greater than 8 Gy.
• Control pain
• Nausea and vomiting
• Diarrhea
Benefits of Radiation
Therapy
What is Radiation Therapy?
• Radiation therapy uses high powered x-rays or
radioactive seeds to kill cancer cells.
• Most harmful to cancer cells than normal cells.
• Prevents cancer cells from growing and dividing
• It is used to fight many types of cancer
• Used to shrink tumor before surgery.
• Used to prevent the return of cancer cells after
surgery
• Can be used to provide temporary relief of symptoms
or to treat malignancies that cannot be removed with
surgery
Radiation Therapy
• Three Types
• External beam radiation
• Most common form
• Uses high powered x-rays aimed directly at the tumor from the
outside of the body
• Kilovoltage x-rays
• Megavoltage x-rays
• Internal radiotherapy (Brachytherapy)
• Radiation source placed inside
or next to the area requiring
treatment
• Commonly used in treating cervical, prostate,
breast.
• Unsealed source radiotherapy
• Use of soluble forms of radioactive substances
either by injection or ingestion.
Side Effects of Radiation Therapy
• Depend on the person, dose, and frequency of therapy.
• Hair loss
• Skin pain
• Red burning skin
• Increased skin coloring
• Itching
• Fatigue
• Low blood counts
• Edema
• Erythema
• Anorexia
• Increased susceptibility to infection
• Fetal Damage in pregnant women
Exposure
• Varies depending on the type and stage of cancer being
treated.
• Typical dose for a solid epithelial tumor ranges from 60 to 80 Gy,
• Lymphoma tumors treated with 20 to 40 Gy.
• Doses are spread out over a period of time (Fractions).
• Allows normal cells time to recover
• Allow tumor cells to develop into a radiation sensitive phase of
the cycle before next fraction.
• Typical fractionation schedule for adults is 1.8 to 2 Gy per day,
five days a week.
Effects on Cancer
• Response based on cancers
radiosensitivity.
• Highly radiosensitive cancer are rapidly killed
my modest doses of radiation. (Leukemia,
lymphomas, and germ cell tumors)
• Epithelial l cancers are moderately
radiosensitive.
• Need higher dose (60-70 Gy)
• Melanoma and Renal cell cancer
• Highly radioresistant
Radiation Therapy Accidents
• 1985-19871987 Radiation therapy machine Therac-
25
• Patients given up to 100 times the intended dose
• 2 people killed
• 2005-20102010
• Missouri hospital overexposed 76 patients during 5yr
period.
• Due to incorrect set up of equipment
• 2009 Los Angeles Hospitals
• 200 patients were exposed to dangerous levels of
radiation during brain scans
Discussion
• Should physicians continue to use radiation
therapy knowing the side effects that are known
and new effects which are being discovered in
the survivors of Hiroshima and Nagasaki?
• Passengers on commercial airliners are
exposed to larger amounts of radiation. Should
the government place restrictions on the number
of hours individuals can fly?
• Should higher quality standards be placed
on the radiation i therapy machines that are being
used in hospitals to prevent patients from being
overexposed to radiation?
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