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Ill Effects of Nuclear Radiations and

Safety Measures

Dr. Sarika Prashar,

Medical Physicist & Radiological Safety Officer PGIMER, Chandigarh

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Nuclear Radiation

Ionizing radiation

X, Beta, Alpha, Gamma,

Neutrons

Non ionizing radiation

Microwaves, Radiofrequency

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Radiation Characteristics

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Photons

Most penetrating

Interaction mechanisms

All produce energetic electrons

Photoelectric absorption

Compton scattering

Pair production

Electrons can produce subsequent ionizations

How to measure radiations?

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Radioactivity

• mCi

• Bq

Exposure

• R

• C/Kg

• Gy

Absorbed dose

• Rem

• Sievert or Gy

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Are these Nuclear

Radiations harmful?

Are we living with these harmful

radiation all the time?

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Radiation is everywhere

We live in a sea of radiation…

Cosmic

Inhaled Radon

Rocks Radioactive Elements

Plants Bodies

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About 70 mrem/yr Medical procedures 53 mrems Consumer products 10 mrems One coast to coast airplane flight 2 mrems Watching color TV 1 mrem Weapons test fallout less that 1 mrem Nuclear industry less than 1 mrem

Normal annual exposure from man-made radiation

Normal annual exposure from natural radiation

About 300 mrem/yr

Radon gas 200 mrem

Human body 40 mrem

Rocks, soil 28 mrem

Cosmic rays 27 mrem

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Natural Exposure India

We are all exposed to radiation from natural source,

from earth, sky and natural radionuclides like K-40,

and C-14 in the body.

About 2-3 mSV of radiation is acquired annually from

natural sources New Delhi 700 mGy Bangalore 825 mGy Bombay 424 mGy Kerala 4000 mGy (in narrow coastal strip)

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ill Effects of Radiation

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Introduction

The human body is made up of

many organs, and each organ of the

body is made up of specialized

cells.

Ionizing radiation can potentially

affect the normal operation of these

cells

CELL STRUCTURE

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Interaction of radiation with cells

2 possibilities

Direct interaction in a cell

Indirect interaction in a cell

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Radiolysis of water

Ionizing radiation+H20H20 + + e-

H20 + H+ + OH (f) cell damage

H20 ++ H20

H3O

+ + OH (f) cell damage

e- + H20 H2O

- OH- + H (f) cell damage

H (f) + Oxygen Hyperoxy free radical

OH- + OH- H2O2 H+ +HO2

-

HO2- + Organic molecule > stable org. peroxide > lacks

essential enzyme > eventual cell death

Significant with low LET radiations: X, Gamma

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EFFECTS OF RADIATION ON CELLS

Biological effect begins with the ionization

of atoms. The mechanism by which

radiation causes damage to human tissue, or

any other material, is by ionization of atoms

in the material

•All cells are not equally sensitive to radiation

damage.

•In general, cells which divide rapidly and/or are

relatively non-specialized tend to show effects at

lower doses of radiation then those which are less

rapidly dividing and more specialized.

Relative Biological Effects

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CELL CYCLE

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How to measure

Biological effects?

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CELL SURVIVAL

Surviving fraction is a function of plating

efficiency in the untreated control cultures

Plating efficiency is the number of colonies

counted as a percentage of the number of cells

plated

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Generation of Survival curves

Cell culture

Cell free

suspension

Use of Agar gel

Clone formation

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Plating efficiency

PE = No. of clones / No. of cells seeded

( say 30/100 = 0.3)

Surviving fraction = (Colonies counted/Cells seeded)*PE

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Cell Survival Curves

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Health Effects

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No-one becomes a spider-man 12/21/2018

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BIOLOGICAL EFFECTS OF

RADIATION

These effects in humans are caused by

damage to individual cells

1. Somatic effects

2. Genetic effects

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Immediate Delayed

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Radiation sickness

Acute Radiation Syndrome

Leukemia

Carcinogenesis

Fetal developmental anomalies

Shortening of life

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Biological Effects Somatic

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Biological Effects

GENETIC/heritable effects appear in the future

generations of the exposed person as a result of

radiation damage to the reproductive cells

1) Chromosome mutations

2) Point mutations

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Other Biological Effects

Non specific life shortening

No specific data

Leukemia and malignancy

Atomic bomb data – no evidence

Safe radiation practices decreased

incidence of short life span

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Other Biological Effects

Early aging

Enhancement of physiological aging

Fibrosis of skin, heart muscle, endocrine

glands

Chronic lung inflammation

Controversial concept

ICRP Estimate

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A number of human population groups exposed to high levels of radiation have been studied to estimate the risk of radiation induced cancer at low levels of exposure.

The current estimate, suggested by the International Commission on Radiological Protection (ICRP-103, 2007), is that there would be 50 excess cases of cancer per million populations if exposed to 1 mSv of radiation dose.

Estimated Days of Life Expectancy Lost From

Various Risk Factors Industry Type or Activity Estimated Days of Life

Expectancy Lost

Smoking 20 cigarettes a day 2370 (6.5 years)

Overweight by 20% 985 (2.7 years)

Mining and Quarrying 328

Construction 302

Agriculture 277

Government 55

Manufacturing 43

Radiation - 340 mrem/yr for 30 years 49

Radiation - 100 mrem/yr for 70 years 34

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Acute and Chronic

Radiation Effects

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Acute radiation injury

Within 60 days of exposure

General effects: Cellular injury

Vascular changes: dose-rate dependent

Endothelial cells

Dilationcell swelling, disruption

thromboses,

Later, intimal hyperplasia and collagenous

hyalinization with media

thickeningnarrowing/obliteration.

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Acute radiation injury

Skin: Pathway of external radiation

Mild erythema:2-3 days

Edema: 2-3 weeks

Epithelial blistering

4-6wks

Chronic radio-dermatitis

months to years

Skin cancer

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Acute radiation injury

Eyes : cataract formation, 200-600 cGy damage lens, latent period 2-35 yrs

Other Organs

Relatively RR

Functional damage

occur at high dose

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Chronic Radiation effects

Stochastic in nature

Chief concern Cancer induction

Non cancerous effects

Cataract formation 500-800 R

Shortening of life span

Leukemia 50-100 cGy

No conclusive evidence of ill

effects in medical field Skin damage

from prolonged

fluoroscopic

exposure

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Factors modifying the biological damge

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• Physical factors

– Dose rate

– Fractionation

– Radiation

quality

– Temperature

• Chemical factors – Radioprotectors

– Radiosensitizers

RADIOPROTECTORS

DRF/DMF= Radiation LD50 in presence of protector

Radiation LD50 in absence of protector with biological end point LD50(30)

Examples :- Thiol protectors (cysteine, cysteamine)

2 mercapto ethylamine (MEA)

mercaptopropionylglycine(MPG)

Nonthiol protectors- cytokines, polysaccharides,

metal compounds,

vitamins, plant products

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RADIOSENSITIZERS

ER= TCD50 in absence of sensitizer

TCD50 in presence of sensitizer

TCD50 is radiation dose to cure 50%of treated tumors.

Examples :-

•Nucleotide analogues- halogenated pyramidines

•Hypoxic cell sensitizers- hyperbaric oxygen

•paranitro aceto phenone PNAP

•nitroimidazole- metronidazole, misonidazole, sanazole

•Bioreactive drugs- mitomycin C

•chemotherapeutic drugs-cisplatin, doxorubicin, vincristine

•antimetabolite glucose analouges- 2-deoxy-D-glucose.

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DO WE NEED

RADIATION

PROTECTION ?

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Radiation Safety Measures

Ionizing radiation needs to be

handled with care rather than

fear and its risks should be kept

in perspective with other risks

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EPIDEMIOLOGICAL DATA FROM: Hiroshima-Nagasaki Patients with ancylosing spondylitis cervical cancer tuberculosis mastitis tinea capitis thymus enlargement thyrotoxicosis hemangiomas and more may come Chernobyl Techa river Semiplatinsk Nevada

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Radiation Safety Measures

Basic radiation safety rule

ALARA

As low as reasonably achievable

Radiation Protection

Principles

1)Time

2)Distance

3) Shielding

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Time Dose is proportional to

the time exposed

Dose = Dose-rate x Time

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Distance Inverse square law (ISL)

distance

do

se-r

ate

Dose-rate 1/(distance)2

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Shielding

incident radiation transmitted

radiation

Barrier thickness

Protection

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International and National

Regulatory Bodies

Nuclear Radiation Safety Program

Administered by the Radiation Safety Coordinator,

supported by the Senior Management and governed by

the Radiation Safety Committee

•Management control over work practices

•Personnel qualification and training

•Control of occupational and public exposure to

radiation

•Ascertain the quantity and concentration of any

nuclear substance released as a result of the licensed

activity

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Occupational Dose Limits

WB 50 mSv

Extremities 500 mSv

Skin 500 mSv

Eye lens 150 mSv

AERB Annual 20 mSv

General Public 1 mSv

Radiation Safety Awareness Precautions

•Recognize radiation warning signs and labels.

•Do not enter radiation areas without permission of the

radiation safety trained laboratory personnel.

•Do not bring food, drink, empty coffee cups or utensils

into the radiation rooms.

•Stay as far away from the radioactive sources as

possible.

•Do not touch or handle any radioactive materials if you

are not trained to work with it.

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Postings

Areas in which

radioisotopes are used or

stored must be

conspicuously posted with

the CAUTION

RADIOACTIVE

MATERIAL sign.

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LABELING

Any container in which radioactive material is

transported, stored, or used must bear a CAUTION

RADIOACTIVE MATERIAL label.

Special items used with radioisotope procedures which

could be contaminated should be labeled

Radioactive work areas should be neatly covered with

vinyl-backed absorbent paper.

The label must

state the type,

quantity, and

amount of

radioactive

material in the

container, the date

of the

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Radiation Shield

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Transportation Of Radionuclides

Carry radioisotopes in a container that will

contain inadvertent spills.

Always enclose radioisotopes in liquid-

tight, unbreakable carrying cases

Adequate shielding

Transfer of Radioactive Material Form

must be completed

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Radiation Safety Equipments

Survey instruments

GM instruments

IC instruments

Scintillation instruments

Semiconductor

Proportional counters

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Radiation Safety Equipment

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Area Survey

Regular survey of exposure and removable contamination levels

At start and end of day

Use portable survey meter

Established action levels

Corrective actions

Area Survey

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Radioactive Waste Disposal

Fundamental radioactive waste management RWM Principles

Protection of Humans

Protection of Environment

Protection beyond National borders

Burden of on future generations

National Legal frameworks

RW generation and management

Safety of Facilities

Classification

According to activity

High activity

Medium activity

Low activity

According to state

Solid waste

Liquid waste

Gaseous waste

Basic Guidelines Dilute and Disperse Low level

radioactive waste

Delay and Decay Short lived isotopes

Concentrate and Contain Intermediate and

high level waste

Disposal limits for Sanitary sewerage system

RN Max. Activity MBq/day

Av. Monthly discharge

MBq/m3

99mTc 3.7 185

99Mo 3.7 185

131 I & 125 I 3.7 22.2

32P 3.7 18.5

14 C 18.5 740

3H 92.5 3700

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Radiation Safety Equipments

Personnel Dosimeters

Photographic film based dosimeters

Thermo luminescent dosimeters

Pocket dosimeters

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Personnel Dosimeter

Radiation Safety Audit

• Regular review of radiation safety program

• Visual checks of personnel safety practices

• Annual review of dept safety polices by

Medical Physicist

• Discussion with radiation safety committee

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RADIATION HORMESIS

Hypothesis predicts that minute

doses of ionizing radiation will

benefit growth, development,

reproduction and resistance to

radiation

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With the knowledge and understanding

Ionizing radiation can be utilized to its

best in the medical field

The radiation industry is no different

than other industries that have threshold

limit values for worker exposure

www.icrp.org

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Effects of mobile phone radiations

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Audiologic disturbances in long-term mobile phone users.

Department of Otolaryngology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.