EARLY NONSTOCHASTIC
EFFECTS/LATE STOCHASTIC EFFECTS
Sherer Chapter 7 and 8
Reference: Bushong, Chapter 36 and 37
Review of Dose response curves
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Threshold
Non threshold
Linear quadratic non threshold curve
Non linear (s-shaped or sigmoid)
Early, Nonstochastic Effects:
• Soon after Rad.
Exposure
• minutes
• hours
• days
• weeks
• “x-ray burns”
ACUTE RADIATION SYNDROMES
• Total body exposure
• acute exposure in a matter of minutes
• 100’s or 1000’s of rads
RADIATION AND MAMMALS
• 200-1000 rads
• Survive a few weeks
• 1000-10,000 rads
• 3-4 days
• 10,000 +
• few minutes
FOUR STAGES
TOTAL BODY IRRADIATION
1) PRODROMAL (NVD SYNDROME)
2)LATENT
3) MANIFEST ILLNESS
4) RECOVERY OR DEATH
1)Prodromal
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Initial
can occur as low as 100 rads
within minutes with exposure to 1000 rads
nausea, vomiting, diarrhea (NVD)
2) Latent period
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Weeks in low dose
Hours in high dose
pt appears symptom free
lethal effects or recovery is beginning
3) Manifest Illness
A) Hematologic
B) Gastrointestinal
C) Cardiovascular
D) Cerebrovascular/
CNS
• Bone Marrow
A) HEMATOLOGIC
• AKA: bone marrow or
hemotopoietic syndrome
• Rad exposure-low
• Stages:
• Prodromal (NVD)
• Latent
Mitotic stem cells are
sterilized
pancytopenia-diminished
supply of blood cells
Death due to dehydration,
electrolyte imbalance
infection
B) GI syndrome
• 600 rads(6 gy)-1000 rads (10 gy)
• prodromal - one day
• latent 3-5 days-deterioration of the lining of
the GI tract has begun
• manifest of illness
• death ( dehydration, anorexia ) 3-4 days
• cannot prevent progression of syndrome
CARDIOVASCULAR
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Not a syndrome
Decreased BP
Increased pulse rate
Acute myocardial insufficiency
C) Cerebrovascular/CNS
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5000 RADS
Prodromal (nausea and vomiting)
latent period 6-12 hours
Death occurs within hours- to several days
GI and Hemopoietic syndrome occurring
simultaneously
L/D
• LD 50/30 (Sherer), LD 50/60 (Bushong)
– used in animals
– humans tend to survive longer (Chernobyl)
– see curve (figure 36-1) on page 519 of Bushong or
LD curve on page 120 Sherer
REPAIR?
• Can occur with sublethal doses but dependent
on cell or organ’s potential for recovery.
• 10% of radiation induced damage - irreparable
LOCAL TISSUE DAMAGE
• High doses
• atrophy of organ
• Skin-many x-ray pioneers suffered x-ray burns
to skin
Skin layers
• Subcutaneous
• middle layer
• outer layer
(epidermis)
• accessory structures
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sensory
hair
sebaceous
sweat
Erythema
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200 rad – within 24-48 hours
Desquamation at a higher dose
Hair loss –epilation-moderate dose
High level fluoroscopy studies-10-2Rmin
A karyotype is
• A) study of the genetics
of cells
• B) a new type of
karaoke machine
• C) a chromosome map
• D) a chromosome
aberration
• Cytogenetic
• Not!!!
• Correct answer. Used
for cytogenetic analysis
• Structural damage
Late Radiation effects
Chapter 8
Months or years after whole or partial ARS
OR
Low doses sustained over a couple of years
DOSE RESPONSE CURVES
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LINEAR NON-THRESHOLD
NON LINEAR NON-THRESHOLD
LINEAR THRESHOLD
NONLINEAR THRESHOLD
DOSE RESPONSE CURVES
WHAT ARE THE THREE MAJOR TYPES
OF LATE SOMATIC EFFECTS?
RISK ESTIMATES
• Low doses (below 10 rem) effect must be
estimated
• Risk still exists –controversial concept
• Absolute risk –specific # of excess cancers will
result due to exposure
• Relative risk - # of excess cancers will increase
as the natural incidence of cancer increases in
the population with age
Carcinogenesis
• Distinguishing radiation induced cancer from low
doses difficult. Why?
• Epidemiologic studies from high doses are used.
Examples include:
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Radium watch dial painters
Uranium miners
Early Radiation workers
Infants treated with radiation for enlarged thymus
Children of Marshall Island
Japanese atomic bomb survivors
Evacuees from Chernobyl
Match the pathology (can use more than
once)
• Radium dial workers
• Uranium miners
• Early Medical radiation
workers
• Infants treated for enlarged
thymus
• Children of Marshall Islands
• Japanese atomic bomb
survivors
• Chernobyl
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Thyroid
Leukemia
Breast cancer
Bone cancer
Skin cancer
Lung cancer
EXTREMITIES
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Amputations
radiodermatitis
shoe fluoroscopy
nuc med. techs
• LIFE SPAN SHORTENING
• CATARCTOGENESIS
• GENETIC EFFECTS
American RT’s
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Ongoing study of 146,000 RT’s
Higher risk of dying?
Higher risk of dying from leukemia?
Higher risk of dying from breast cancer?
When did these risks become less?
GONADS
• Highly sensitive
• can pass on effects to
future generations
• animal
studies/radiotherapy
patients, radiation
accident victims,
convicts
• oogonia
• spermatogonia
TESTES
• 10 rad
effect?
• 200-250 rads
effect?
• 500-600 rads
effect?
OVARIES
• 10 rad
• more sensitive in fetus
/small children
• 200 rad
• 500-625 rads
effect?
why?
effect?
compare this
range with males
why the
difference?
To Be continued
• See power point entitled Chapter 8