what radiation effects are possible

International Atomic Energy Agency

What Radiation Effects are

Possible?

(besides skin injuries)L3

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


What can radiation do?

It can bring a smile on the faces of people of all ages


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


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


Dose

Deterministic effects

Cataract

infertility

erythema

epilation

Stochastic


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.


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


Is there

RADIATION

in this

room?


Radiation from Natural Sources

• Normally 1-3 mSv/year

• In areas of high background, 3-13

mSv/year


Interventional

Cardiology

CT

Radiography


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


Induction of DNA changes


radiation

hits a cell

nucleus!

No change

DNA mutation


DNA Mutation

p a DCell survives

but mutated

Stoch.eff.

Mutation

repaired

Unviable Cell

Viable Cell

Cell death


Deterministic effects caused by cell

death: burns, organ failure, death


Normal

process Altered process due to mutated

genes


Stochastic effects

Cancerogenesis

Hereditary effects

Effects in the embryo/foetus


Carcinogenesis


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.


OK, Agree that

Radiation can cause

cancer, But how do

I know if I will get

cancer!!!


Life Insurance Agent

Malpractice Insurance

Probability


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


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


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


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


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


Hereditary Effects


Heritable effects

• Effects to be observed in offspring born

after one or both parents had been

irradiated prior to conception.


Hereditary effects

Descendents of Hiroshima and Nagasaki

survivors were studied

but no statistical

abnormalities were detected.


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.


In the absence of human data the estimation of hereditary effects is based on animal studies.


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


…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.


OK, Understood that these

radiation effects have a

probability

But, I want to know about ME,

if I will get these


Do you worry about?

Not reallyYes

Yes, Very much


Do you worry about?


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


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


Are there reports of increased

cancer incidence among

Cardiologists ?

One, Last Question!!!


Let us look into the data for

other professional groups like

radiologists…

(Because cardiologists have traditionally not interacted

with safety and radiation effects professionals)


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


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.


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]


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.


May involve small children, young

females and pregnant patients


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


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.

[email protected]

• 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


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)


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.]


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).


may potentially cause a small increase in

the lifetime risk of fatal malignancy, with

lung malignancy being most likely


Non-neoplastic effects

of Radiation

Risk of Cardiovascular

Diseases

following Radiation

Exposures

http://www.heartpoint.com/coronart.html


Does radiation exposure…

• …induce cardiovascular system damage?, e.g.

• congestive heart failure,

• arrhythmia,

• angina pectoris, or

• myocardial infarction…or

• …does it accelerate arteriosclerosis?


• Chernobyl workers,

• atomic bomb

survivors, and

• radiotherapy

patients…


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


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.


Pregnancy


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.


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.


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.


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

what radiation effects are possible

Documents

radiation dose

radiation effectsgenome

death lecture

cell nucleus

development of cancer

mutated geneslecture

cardiologyaltered process

cardiologydna mutation