The Biological and Medical
Effects of Radiation
Atomic Bomb in Hiroshima
Types of Radiation
• There are many types of radiation.
• Different wavelengths across electromagnetic
• Thermal, residual, ionizing
• Ionizing radiation is what is dangerous to living
What is Ionizing Radiation?
• High energy radiation
• Can penetrate matter
• Ejects electrons from atomic orbits
Types of Ionizing Radiation
• Gamma Rays
• Alpha Particles
• Beta Particles
Effects of Radiation on Cells
• Living tissues are injured due to the
transfer of energy to the molecules in the
• 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
Effects on Different tissues
• Cells with a high rate of
division are most
vulnerable to damage by
• Blood-forming organs and
reproductive organs are
• Skin, bone and teeth, and
• Nervous system is the
• Developing embryos most
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
•Gamma radiation from external
radioactivity ~40 mrem
•Internal radiation ~18 mrem
• In addition to the radiation we receive from
the environment, we also receive an
annual dose of around 50 mrem from
• This includes techniques such as x-rays
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.
• If risks exist they are minimal
Putting Danger into Perspective
• The following all have a
one in a million chance of
• 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
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
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.
Acute Effects of Whole Body
20 Possible Chromosome damage
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)
Acute Effects of Whole Body
400 Serious Radiation Sickness plus bone-marrow and
intestine destruction. Sterility in women.
400- Acute illness, early death; LD 60-95/30
1000- Acute illness, death in days. LD 100/10
>5000 Acute illness, death in hours-days; central nervous
syndrome. LD 100/2
• 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
• Types of Radioactive
• Thermal Burns (infrared
• Beta Burns (ionizing
radiation on fallout
• Gamma Burns (highly
– 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.
• Deaths occurring after 3-8 weeks
• Deaths due to ionizing radiation in median
Different stages - Late
• Period 8-20 weeks after blast
• Characterized by improvement in survivors
Different Stages - Delayed
• 20+ weeks after blast.
• Complications from wounds
• Blood Disorders
• Genetic effects
• Birth Defects
Levels at Hiroshima/Nagasaki
1 Sievert =
• 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.
• Sadako Sasaki
• 2 years old in 1945
• Exposed to Hiroshima
• 1954- red/purple spots
appear (symptoms of
• 1000 paper cranes
• Dies 1955
Chernobyl – 1986 Ukraine
• Plutonium, noble
gases, and fission
products released into
• Iodine and strontium
most dangerous (food
• 56 direct deaths.
• According to WHO
estimates, as many as
4,000 extra cancer
deaths caused by
• Hundreds of times
• Radioactivity longer
• Thousands of years
before accident site
will be completely
• ~200 years before it
will be safe to resume
agriculture in the
• 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
• Thyroid Cancer
• Should the US government pay for medical
treatment costs of Hiroshima and Nagasaki
• 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?
• 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.
• Nonionizing: radiation from light, radio waves,
microwaves and radar. Usually no harm to tissue.
• Radiation exposure:
• single large exposure
• Usually associated with radiation sickness
• A series of small exposures spread over time
• Associated with delayed medical problems such as cancer
and premature aging.
• Mild exposure (1-2 Gy) doses of
• Moderate exposure (2-3.5 Gy) doses
• Severe exposure (3.5-5.5 5.5 Gy) doses
• 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
• Without medical treatment almost all exposed will die within 30
• 1000 Gy immediate unconsciousness and death within an
• Appear sooner with higher doses of exposure.
• Become more serious as the dosage of radiation
• 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
• Nausea and vomiting, headaches, fatigue, and weakness
• All symptoms of mild, fever, hair loss, infections, bloody vomit
and stools, poor wound healing.
• All symptoms of lower levels, diarrhea, high fever
• Very Severe
• All symptoms of lower levels, dizziness, disorientation, low blood
• Fatal about 50% of the time.
• Prodromal Syndrome
• causes gastrointestinal distress such as anorexia, nausea, fatique, and
• 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)
• Germinal layer is the principal i site of damage
• Initial response is erythema (reddening)
• Due to blood vessel congestion and edema
• Most radiosensitive organ to radiation
• Radiation pneumonitis
• Leads to pulmonary insufficiency and death in few months
• Single dose 1-2 Gy will cause temporary sterility. Suppress
menstruation for up to 3 yrs. 4 Gy will cause permanent sterility.
• 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
• .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
• Infectious hepatitis
ll • Cholera
• Menigococcal meningitis
• Whooping Cough
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
• 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
• 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
• To prevent further radioactive contaminations,
treat damaged organs, reduce symptoms, and
• 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
• Promotes the growth of white blood cells
• Neupogen and Neulasta
• Blood transfusions for
• 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
• Allows for excretion of radioactive elements
• Speeds up elimination and reduces the amount of radiation
• Binds to radioactive elements such as plutonium, americium,
• Additional medications or interventions to treat:
• Bacterial infections
• Nausea and Vomiting
• End of life care
• Usually people who have absorbed radiation greater than 8 Gy.
• Control pain
• Nausea and vomiting
Benefits of Radiation
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
• Can be used to provide temporary relief of symptoms
or to treat malignancies that cannot be removed with
• 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
• Commonly used in treating cervical, prostate,
• 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
• Low blood counts
• Increased susceptibility to infection
• Fetal Damage in pregnant women
• Varies depending on the type and stage of cancer being
• 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
• Highly radiosensitive cancer are rapidly killed
my modest doses of radiation. (Leukemia,
lymphomas, and germ cell tumors)
• Epithelial l cancers are moderately
• Need higher dose (60-70 Gy)
• Melanoma and Renal cell cancer
• Highly radioresistant
Radiation Therapy Accidents
• 1985-19871987 Radiation therapy machine Therac-
• Patients given up to 100 times the intended dose
• 2 people killed
• Missouri hospital overexposed 76 patients during 5yr
• Due to incorrect set up of equipment
• 2009 Los Angeles Hospitals
• 200 patients were exposed to dangerous levels of
radiation during brain scans
• 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?