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Radiation Protection in Cardiology Lecture 3: Radiation effects 2
Educational Objectives
• Effects other than skin injuries
• Their probability in
interventional cardiology
practice
• Special concerns in children,
young & pregnant females
Radiation Protection in Cardiology Lecture 3: Radiation effects 3
What can radiation do?
It can bring a smile on the faces of people of all ages
Radiation Protection in Cardiology Lecture 3: Radiation effects 4
What can radiation do?
Cancer
Genetic effects
Skin injuries
Cataract
Infertility
DeathNon-neoplastic Effects
NB. In this
lecture, we
shall
predominantly
deal with
cancer &
genetic
effects
Radiation Protection in Cardiology Lecture 3: Radiation effects 6
Main Point
Threshold
Dose
Eff
ect
Deterministic effects
Cataract
infertility
erythema
epilation
Cancer
Genetic
Prob dose
500 mSv cataract
150 mSv for sterility (temporary-males)
2500 mSv for ovarian
Preventable
Radiation Protection in Cardiology Lecture 3: Radiation effects 7
Dose
Deterministic effects
Cataract
infertility
erythema
epilation
Stochastic
Radiation Protection in Cardiology Lecture 3: Radiation effects 8
Stochastic and Deterministic Effects
• A stochastic effect is one where the severity of the result is the same but the probability of occurrence increases with radiation dose, e.g., development of cancer. There is no threshold for stochastic effects.
• A deterministic effect is one where the severity depends upon the radiation dose, e.g., skin burns. There is a threshold for deterministic effects.
Radiation Protection in Cardiology Lecture 3: Radiation effects 9
You mean I can get cancer even if I am working with small amount of radiation?
This requires discussion
on how radiation
effects occur
Cardiologist
Radiation Protection in Cardiology Lecture 3: Radiation effects 11
Radiation from Natural Sources
• Normally 1-3 mSv/year
• In areas of high background, 3-13
mSv/year
Radiation Protection in Cardiology Lecture 3: Radiation effects 12
Interventional
Cardiology
CT
Radiography
International Atomic Energy Agency
NucleusDouble membrane surrounding the chromosomes and the
nucleolus. Pores allow specific communication with the
cytoplasm. The nucleolus is a site for synthesis of RNA
making up the ribosome.
Chromosomes
Radiation Protection in Cardiology Lecture 3: Radiation effects 17
radiation
hits a cell
nucleus!
No change
DNA mutation
Radiation Protection in Cardiology Lecture 3: Radiation effects 18
DNA Mutation
p a DCell survives
but mutated
Stoch.eff.
Mutation
repaired
Unviable Cell
Viable Cell
Cell death
Radiation Protection in Cardiology Lecture 3: Radiation effects 19
Deterministic effects caused by cell
death: burns, organ failure, death
Radiation Protection in Cardiology Lecture 3: Radiation effects 20
Normal
process Altered process due to mutated
genes
Radiation Protection in Cardiology Lecture 3: Radiation effects 22
Stochastic effects
Cancerogenesis
Hereditary effects
Effects in the embryo/foetus
Radiation Protection in Cardiology Lecture 3: Radiation effects 25
So now that you have
scared me with this
information, what
should I do?
It is not our intent to scare
you with these facts, but to
educate about potential
long-term risks.
Radiation Protection in Cardiology Lecture 3: Radiation effects 26
OK, Agree that
Radiation can cause
cancer, But how do
I know if I will get
cancer!!!
Radiation Protection in Cardiology Lecture 3: Radiation effects 27
Life Insurance Agent
Malpractice Insurance
Probability
Radiation Protection in Cardiology Lecture 3: Radiation effects 29
Radiosensitivity
• Probability of a cell, tissue, or
organ suffering an effect per
unit dose
• Will be greater if the cell:
• Is highly mitotic
• Is undifferentiated
Radiation Protection in Cardiology Lecture 3: Radiation effects 30
Life Span Study Massachusetts Children in
(LSS) of Ankylosing tuberculosis patients Israel irradiated
Japanese atomic Spondylitis given chest for ringworm UK National Registry
bomb survivors Study (ASS) fluoroscopies of the scalp Radiation Workers
Parameter (Shimizu et al) (Weiss et al) (Boice et al) (Ron et al) (Kendall et al)
Population 86,500 14109 2573 10834 95217
size (with DS86 doses)
Period of 5-55 years Up to over Up to over 50 years Up to 32 years Up to 40 years
follow-up following exposure 50 years
(mean 25.2 (mean 30 years) (mean 26 years)
years)
Ranges of:
(a) ages at All Virtually all Under 15 to over 40 0-15 years 18-64 years
exposure 15 years
(b) sexes Similar numbers of 83.5% male Female Similar number of 92% male
males and females males and females
© ethnic Japanese Western (UK) Western (N. American) African and Asian Western (UK)
groups
Setting in War Medical: ther- Medical:diagnostic Medical:therapy Occupational
which apy for non- for non-malignant
exposure malignant disease
was received disease
Features of some epidemiological studies of radiation-induced cancer risks
Radiation Protection in Cardiology Lecture 3: Radiation effects 31
Life Span Study Massachusetts Children in
(LSS) of Ankylosing tuberculosis patients Israel irradiated
Japanese atomic Spondylitis given chest for ringworm UK National Registry
bomb survivors Study (ASS) fluoroscopies of the scalp for Radiation Workers
Parameter (Shimizu et al) (Weiss et al) (Boice et al) (Ron et al) (Kendall et al)
Range of All All (but Mainly breast & lung mainly brain, All
organs mainly those bone marrow,
irradiated in proximity thyroid, skin
to spine and breast
Availability Organ doses: Mean organ Organ doses: Brain, thyroid & Individual whole-body
of dose individual basis doses: indiv. Individual basis skin doses: external doses
estimates only for red individual basis
bone marrow
at present
Range dose Mainly 0-4 Gy Mainly 0-20 Gy Mainly 0-3 Gy Brain: 0-6 Gy Mainly 0-0.5 Sv
(mean 1.5 Gy) (mean 0.034 Sv)
Thyroid:0-0.5 Gy
(mean 0.09 Gy)
Dose rate High High High, but highly High Low
fractionated
Radiation Mainly low-LET Low-LET Low-LET Low-LET Mainly low-LET
Quality
Features of some epidemiological studies of radiation-induced cancer risks
Radiation Protection in Cardiology Lecture 3: Radiation effects 32
LIFE SPAN STUDYExcess absolute risk for solid cancer mortality
30 40 50 60 70 80 900
10
20
30
40
50
AGE (years)
EX
CE
SS
CA
SE
S P
ER
10
,00
0 P
Y A
T 1
Sv
Age at exposure: 10, 30, 50 years
Males
5030
10
Females
Radiation Protection in Cardiology Lecture 3: Radiation effects 33
LIFE SPAN STUDY
Atomic Bomb Survivors
Cancer risk estimate:
4–6% per 1000 mSv
(depending on projection method)
! Note: The probability best applies to group of people and is not
suitable for individual case
Radiation Protection in Cardiology Lecture 3: Radiation effects 35
Heritable effects
• Effects to be observed in offspring born
after one or both parents had been
irradiated prior to conception.
Radiation Protection in Cardiology Lecture 3: Radiation effects 36
Hereditary effects
Descendents of Hiroshima and Nagasaki
survivors were studied
but no statistical
abnormalities were detected.
Radiation Protection in Cardiology Lecture 3: Radiation effects 38
A cohort of 31,150 children born to parents who were
within 2 km of the hypocenter at the time of the bombing
was compared with a control cohort of 41,066 children.
No indicator was significantly modified by
parental radiation exposure.
Radiation Protection in Cardiology Lecture 3: Radiation effects 39
In the absence of human data the estimation of hereditary effects is based on animal studies.
Radiation Protection in Cardiology Lecture 3: Radiation effects 40
UNSCEAR 2001 ReportHEREDITARY EFFECTS OF RADIATION
Risks to offspring following
prenatal exposure:
•Total risk = 0.0003 - 0.0005% per mGy
to the first generation
(3000 to 4700 cases per gray
per one million progeny)
•Includes multifactorial diseases
•1/10 the risk of fatal
carcinogenesis
•Constitutes 0.4-0.6% of baseline
frequency
Radiation Protection in Cardiology Lecture 3: Radiation effects 41
…above the prevalent background dose,
an increment in dose
results in a proportional increment in the
probability of hereditary effects of
0.0005% per mSv of dose.
Radiation Protection in Cardiology Lecture 3: Radiation effects 42
OK, Understood that these
radiation effects have a
probability
But, I want to know about ME,
if I will get these
Radiation Protection in Cardiology Lecture 3: Radiation effects 43
Do you worry about?
Not reallyYes
Yes, Very much
Radiation Protection in Cardiology Lecture 3: Radiation effects 45
If you work in such a
manner that you adhere to
prescribed dose limits of 20
mSv per year for whole
working life of 18 to 65
years, your chance of
excess cancer is 1 in 1000.
Note: The probability calculations
are for a group of people and not for
individual case
Radiation Protection in Cardiology Lecture 3: Radiation effects 46
That sounds interesting.
Is it possible to work in such a manner
that I remain within 20 mSv/yr.
It should be possible to achieve
conditions so that you do not exceed ≈
3 mSv/yr.
Just wait for Topic No. 7 in this course
Radiation Protection in Cardiology Lecture 3: Radiation effects 48
Are there reports of increased
cancer incidence among
Cardiologists ?
One, Last Question!!!
Radiation Protection in Cardiology Lecture 3: Radiation effects 49
Let us look into the data for
other professional groups like
radiologists…
(Because cardiologists have traditionally not interacted
with safety and radiation effects professionals)
Radiation Protection in Cardiology Lecture 3: Radiation effects 50
Radiologists & radiological personnel:
Eight cohorts
1. 3 from US (radiologists, Army X ray Technologists,
radiological technologists
2. 1 each from China, Canada, Denmark, Japan & UK
Variety of data pertaining to cancer incidence for
different sites, mortality data (cancer), now also to
other diseases such as cardiovascular
Variation from Healthy worker effect to small increase
Radiation Protection in Cardiology Lecture 3: Radiation effects 51
UK Radiologists
Around 2700 male radiologists, registered from
1897- 1979.
Standardized mortality ratio (SMR)
Annual exposure, 0.1 Sv before 1950, 0.05 Sv in
early 1950’s
Compared mortality rates and death from
Circulatory disease: Observed number of
deaths were generally close to or lower
than expected.
Radiation Protection in Cardiology Lecture 3: Radiation effects 52
US Radiological Technologists
•Over 146,000, predominantly females, 73%
•Total cancer death rates were lower than
expected in general population
•Risks higher for those <1950
•Relative risk of mortality from circulatory
disease higher for those starting work in
earlier years [<1940=1.22, 1940’s=1.00,
1960+=1.00]
Radiation Protection in Cardiology Lecture 3: Radiation effects 53
US Radiologists Study
1920-1939: Cohort with highest exposure, 15%
higher mortality from cardiovascular disease than
other physicians., after age 55. No information
about smoking and other risk factors.
Radiation Protection in Cardiology Lecture 3: Radiation effects 56
May involve small children, young
females and pregnant patients
Radiation Protection in Cardiology Lecture 3: Radiation effects 57
Radiosensitivity In Children
and Young Patients
• Age is a primary determinant of radiosensitivity– the younger the patient, the higher the radiosensitivity
• Breast of 15 year old is 15 times more sensitive to radiocarcinogenesis than the breast of 45 year old
Radiation Protection in Cardiology Lecture 3: Radiation effects 58
Z Kardiol. 2003 Aug;92(8):682-5.
Radiation-induced coronary artery disease.
Mert M, Arat-Ozkan A, Ozkara A, Aydemir NA, Babalik E.
Istanbul University, Institute of Cardiology, Istanbul, Turkey.
mmert@superonline.com
• It was realized that mediastinal radiotherapy due
to Hodgkin's disease at 10-year of age
(causative)
• 36 year man, no coronary artery risk factor. Unstable
angina..1 month.
• Angio-Total occlusion of the left anterior descending
artery and 70% stenosis of the proximal right coronary
artery
Radiation Protection in Cardiology Lecture 3: Radiation effects 59
Such case reports are not
possible for cancer
Risk factors for cardiac- known, ruling
them out helps a lot
(because of long latent period and many others factors in life which
can cause cancer)
Radiation Protection in Cardiology Lecture 3: Radiation effects 62
CONCLUSIONS: This finding is
• compatible with current knowledge about
the carcinogenic effect of low-dose
irradiation
• but differs in the occurrence of an excess
of lymphoma in the absence of an excess
of leukemia,
which has not been reported before.
Pediatrics, 1983 Feb; 71(2): 235-9 [contd.]
Radiation Protection in Cardiology Lecture 3: Radiation effects 63
674 children who underwent cardiac catheterization due
to congenital anomalies, between the years 1950-1970
Expected number of malignancies for all sites was 4.75,
while the observed number was 11.0
Of the 11 cancer cases, 4 lymphomas were observed
(0.63 were expected, SIR = 6.3; 95% CI : 1.7-16.2). One of
these was Hodgkin's Disease. There were also three
cases of melanoma as opposed to 0.62 expected (SIR =
4.9; 95% CI : 1.0-14.2).
Radiation Protection in Cardiology Lecture 3: Radiation effects 64
may potentially cause a small increase in
the lifetime risk of fatal malignancy, with
lung malignancy being most likely
Radiation Protection in Cardiology Lecture 3: Radiation effects 65
Non-neoplastic effects
of Radiation
Risk of Cardiovascular
Diseases
following Radiation
Exposures
Radiation Protection in Cardiology Lecture 3: Radiation effects 66
Does radiation exposure…
• …induce cardiovascular system damage?, e.g.
• congestive heart failure,
• arrhythmia,
• angina pectoris, or
• myocardial infarction…or
• …does it accelerate arteriosclerosis?
Radiation Protection in Cardiology Lecture 3: Radiation effects 67
• Chernobyl workers,
• atomic bomb
survivors, and
• radiotherapy
patients…
Radiation Protection in Cardiology Lecture 3: Radiation effects 68
From Radiotherapy literature: Survivors of Hodgkin’s
disease, non Hodgkin's disease, esophageal
carcinoma, thymoma, lung cancer, breast cancer and
metastatic seminoma
Hodgkin’s:Most data comes from the cohort study of
2232 pediatric and adult patients irradiated during
1960-1990 at Stanford University Medical Centre JAMA
270 (16), 1949-55, 1993.
• Increased relative risk (RR) of cardiovascular
disease demonstrated
Radiation Protection in Cardiology Lecture 3: Radiation effects 71
Who is at risk?
Children or teens who received spinal
radiation, chest radiation (Hodgkin’s, non-
Hodgkin’s lymphoma), left flank (Wilms), or
radiation directly to the heart are possibly
at risk.
Radiation Protection in Cardiology Lecture 3: Radiation effects 73
Circulation 2001 Aug 21; 104(8): 893-7
CONCLUSIONS:
• A typical catheter ablation procedure
results in a very small increase in risk
of harmful effects to the conceptus.
• However, estimation of conceptus dose
from catheter ablation procedures is
always needed to assess the risk to the
individual developing in utero.
Radiation Protection in Cardiology Lecture 3: Radiation effects 74
Exposure before age 20 was associated with higher
ERR(1Sv) compared to exposure at older ages, with
no evidence of consistent variation by exposure age
for ages under 20. ERR(1Sv) was observed to
decline with increasing attained age, with by far the
largest drop around age 35.
Radiation Protection in Cardiology Lecture 3: Radiation effects 75
Breast cancer risk was elevated among women
exposed to medical radiation prior to age 20 years
= 1.4, 95% confidence interval (CI) = 1.2-1.8), This
increased risk was observed only among women
with a history of benign breast disease.
Radiation Protection in Cardiology Lecture 3: Radiation effects 77
Re-Cap
1. What can radiation do?
2. Effect that have threshold
3. No threshold effect- cancer, genetic
4. Effects at the level of Cell, DNA..
5. Probability of Cancer, genetic effects
6. Individual risk
7. Radiologists, Technologists
8. Patients- Children, young & pregnant female
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