This document discusses types of ionizing and non-ionizing radiation, their properties and units of measurement used in radiation protection. It describes the different types of ionizing radiation like alpha, beta, gamma rays and X-rays, and their penetrating abilities. It also covers non-ionizing radiations like UV, visible light, infrared and microwaves. The key units discussed are becquerel (Bq) for activity, roentgen (R) for exposure, gray (Gy) and rad for absorbed dose, and sievert (Sv) and rem for dose equivalent. The principles of radiation protection- justification, limitation and optimization are also summarized.

1. RADIATION: TYPES,
UNITS & PROTECTION.
SUFYAN IBRAHIM
4th SEM
KASTURBA MEDICAL COLLEGE, MANIPAL.

3. Ionizing Radiation
• Electromagnetic: X rays, γ rays.
• Corpuscular: α particles, β particles, etc.
• Cosmic rays.
Non-ionizing Radiation
• UV rays.
• Visible light.
• IR rays.
• Microwaves.
• Radio waves.

4. • Ability to penetrate tissues.
• Carry KE>10eV .
• Deposit its energy within
them.
• Ionize atoms, molecules
• Break chemical bonds,
• Very harmful.
Ionizing
Radiations

5. X rays
λ<10-9m
Solar/Manmade
Penetrating ability:
Air- 120-240m
Tissue- 15-30cm
Lead- 0.3mm
γ rays
λ<10-11m
Spontaneous
radioactive decay
Penetrating ability:
Air-400m
Tissue- 50cm
Lead- 40mm

6. α
rays
2He4 nucleus.
10x powerful than X, β, γ rays
but least penetrating power.
Penetrating ability:
Air- 4cm
Tissue- 0.05mm
Lead- 0
Very dangerous if entered into
the body(by inhalation or
wounds)
β
rays
Electrons or Positrons.
More penetrating than α but
less than γ rays.
Penetrating ability:
Air- 6-300cm
Tissue- 0.06-4.0mm
Lead- 0.005-0.3mm
Sometime used in radiotherapy
to treat superficial tumors

7. NON-
IONIZING
RADIATIONS
EM radiations of longer wavelengths but
KE<10eV thus non-ionizing
Sufficient energy to
change the rotational,
vibrational or
electronic valence
configurations of
molecules/atoms
Greater the wavelength, lesser the
energy(E α 1/λ)
Thermal ionization is still possible at
far higher energies
UV Visible Light
IR
Microwaves
Radio waves
Order of Decreasing
Energies

8. UV
Rays
10nm<λ<400nm
Sunlight, electric arcs, Hg-vapour lamps
Uses: Endogenous Vit D
production, Serotonin
productiion
Bad effects: Suntan,
Freckling, Sunburn, Skin
cancer

9. • Becquerel, Curie, Rutherford, Mache-Einheit
Radio-activity
• Roentgen, Rad, Rem
Potency of Radiation
• C/kg, Gray, Sievert
SI units
R
A
D
I
A
T
I
O
N
U
N
I
T
S

10. UNITS FOR ACTIVITY(A)
• The activity of a radioactive material is the number
of nuclear disintegration per unit time
• SI Unit(derived) is becquerel(Bq)
• One becquerel is defined as the activity of a
quantity of radioactive material in which
one nucleus decays per second
• 1Bq=27pCi [1Ci=3.7×1010 Bq]
• 1Rd=2.703 × 10−5Ci [1 million nuclei decay/sec]
• 1ME=3.64×10−10 Ci/L

11. UNITS FOR EXPOSURE(X)
•Roentgen(R) is the measure of the ionization
produced in air by X-rays or γ rays and it is used
because air ionization can be measured directly
•“Amount of radiation absorbed in air at a given
point, i.e., number of ions produced in 1mL of air”
•SI Unit is Coulomb per kilogram(C/kg)
•1R=2.58×10−4 C/kg

12. UNITS FOR ABSORBED DOSE(D)
•Rad: Amount of radioactive energy absorbed
per gram of tissue or any material
•SI Unit is Gray(Gy): Dose of ionizing radiation
that impart 1 joule of energy to 1 kg of
absorbing material
•1rad=0.01Gy

13. UNITS FOR DOSE EQUIVALENT(H)
• Represent the stochastic biological effects of ionizing
radiations per unit of energy absorbed
• Indicates degree of potential danger for health
• H is the product of absorbed dose(D) and quality
factor(Q)
• Q depends upon density of ionization produced in tissue
by the radiation(for X,γ,e-=1, for particle=20)
• So, H=D*Q
• Units: Rem(Roentgen equivalent in man) and Sievert(Sv)
• 1Sv=100rems

14. Radiation
Protection
Radiation
Hygiene
Prepare
Safety
Standards
Codes for
safe
operation of
Nuclear
Power Plants
Peaceful use
of Atomic
Energy
ICRP, IAEA
and WHO

16. PRINCIPLES OF RADIATION
PROTECTION

17. REGULATION OF DOSE UPTAKE
JUSTIFICATION
No unnecessary
use of radiation
is permitted;
The advantages
must outweigh
the
disadvantages.
LIMITATION
Each individual
must be
protected
against risks that
are far too large
through
individual
radiation dose
limits.
OPTIMIZATION
Radiation doses
should all be
kept
ALARA/ALARP