The document presents an overview of radiation, focusing on ionizing and non-ionizing radiation, and the importance of radiation protection as defined by various organizations. It discusses historical discoveries in radiation, the measurement of radiation and its biological effects, as well as the regulations and practices concerning radiation safety for individuals and patients. Key radiation units and dosimetry methods, including dosimeters used in personnel monitoring, are also outlined, emphasizing the ongoing need for safety measures and exposure limits.

1. Presented by
MISS KAJAL JHA
BSC.MIT
BPKIHS,DHARAN
Presented to
Dr. ARUN GUPTA
Assistant
Professor
BPKIHS,DHARAN
RADIATION PROTECTION-
01

2. What is radiation?
Radiation is energy that is given off by particular
materials and devices.
• Low-energy radiation is called non-ionizing
radiation.
– Sound waves, visible light, microwaves
• Radiation that can cause specific changes in
molecules is called ionizing radiation (>10ev)
– X-rays, gamma rays and particles (1)

5. Radiation is
OMNIPRESENT

8. Natural vs. artificial
• Here we are-

9. Humans are exposed to ionizing radiation—
about 80% of which is natural—on a regular
basis. Common sources are shown in the
chart below.

11. RADIATION PROTECTION
Radiation protection, also known as
radiological protection, is defined by the
International Atomic Energy Agency (IAEA)
as "The protection of people from harmful
effects of exposure to ionizing radiation,
and the means for achieving this".
Exposure can be from a source of radiation
external to the human body or due to
internal irradiation caused by the ingestion
of radioactive contamination.

12. o For radiation protection and dosimetry
assessment the International Commission on
Radiation Protection (ICRP) and International
Commission on Radiation Units and
Measurements (ICRU) publish
recommendations and data.
o Which is used to calculate the biological effects
on the human body of certain levels of radiation,
and thereby advise acceptable dose uptake limits.

13. What does ionizing radiation do?
-
Too much ionizing radiation may damage tissues

14. How was X-ray discovered?
X-rays were discovered in 1895 by Wilhelm
Conrad Roentgen (1845-1923) who was a
Professor at Wuerzburg University in Germany.
Working with a cathode-ray tube in his laboratory,
Roentgen observed a fluorescent glow of
crystals on a table near his tube.

15. A Second Source of Radiation
Shortly after the discovery of X-rays, another form
of penetrating rays was discovered. In 1896,
French scientist Henri Becquerel discovered
natural radioactivity.
Many scientists of the period were working with
cathode rays, and other scientists were
gathering evidence on the theory that the atom
could be subdivided. Some of the new research
showed that certain types of atoms disintegrate
by themselves

16. Has it ever done any damage?
Given the nearly ubiquitous fascination
of the public with x rays and their immediate
and widespread application to medicine, it
was inevitable that x-ray injuries would soon
appear.
Along with the injuries, came a recognition
of the hazard implicit in the use of x radiation
and of the need for protective measures.

17. The most important provisions for x-ray
protection were elucidated during the first
decade after Roentgen’s discovery .
The story of the development of radiation
protection methods and their applications in
radiology can be told in terms of four
overlapping chronological periods (Table I). (3)

19. THE EVIL ASPECT OF
RADIATION(HISTORY)
 Between1911 and 1914, three review articles
identified 54 cancer deaths and 198 cases of
radiation induced maligancy.
 Thomas Edisions’s assistance, Clarence M.
Dally ,died of cancer making it hr first American
radiation fatality in 1904.

23. Are they always evil?
NO
Has helped to develop the world.
Science
Research
Industry
Medicine
Environment protection
A number of academic and commercial fields
e.t.c.

24. So how do we know if its curse or
boon?
 Radiation dose!!!!
The amount of ionisation produced in a given
mass of matter is proportional to the amount of
energy imparted by ionising radiation in that
mass. The amount of energy deposited per unit
mass of matter can therefore be used to
quantify radiation exposure and this quantity is
called dose.

25. types of dose
• Exposure
 Exposure rate
• Absorbed dose
• Equivalent dose
 Radiation weighting factor
• Effective Dose
 Tissue weighting factor

26. Exposure and Exposure rate
• Exposure is a measure of the amount of
ionizations produced in air by photon radiation.
• Exposure is commonly used to refer to being
around a radiation source, e.g., if you have a
chest x ray, you are exposed to radiation
• Exposure rate is the amount of exposure you
are receiving per unit time (e.g., 1 mR/hour)
• (Dose rate is the amount of dose you are receiving
per unit time (e.g., 1 mrem/hour).

27. Absorbed dose
The fundamental dosimetric quantity in radiation
protection is the absorbed dose.
It is the energy absorbed from radiation per unit
mass of the matter with which the radiation
interacts.
The energy absorbed can be expressed in grays
(Gy), where 1 Gy is one joule per kilogram for
all types of materials.

28. Equivalent dose
 The multiplication of the absorbed dose in
biological tissues by the radiation weighting
factor(ability of a particular radiation to cause
damage) gives a quantity called equivalent
dose, with the unit sievert (Sv), to
distinguish it from the absorbed dose.
 Equation

29. Radiation weighting factor
The radiation weighting factor is a dimensionless
factor
 used to obtain the equivalent dose from the
absorbed dose averaged over a tissue or organ and
is based on the type of radiation absorbed
 This allows comparison of the energy deposition
behavior of all types of radiations with X-rays and
gamma rays defined as having a radiation weighting
factor of one.

32. Tissue weighting factor
• The tissue weighting factor, wT, is
the factor by which the equivalent dose in
a tissue or organ T is weighted to represent
the relative contribution of that tissue or organ
to the total health detriment resulting from
uniform irradiation of the body (ICRP 1991b)

37. Measuring Radiation
 The amount of radiation being given off, or
emitted, by a radioactive material is measured
using the conventional unit curie (Ci), named
for the famed scientist Marie Curie, or the SI
unit becquerel (Bq).
 The radiation dose absorbed by a person (that
is, the amount of energy deposited in human
tissue by radiation) is measured using the
conventional unit rad or the SI unit gray (Gy).
 The biological risk of exposure to radiation is
measured using the conventional unit rem or
the SI unit sievert (Sv).

38. Measuring Emitted Radiation
 A radioactive atom gives off or emits radioactivity
because the nucleus has too many particles, too
much energy, or too much mass to be stable. The
nucleus breaks down, or disintegrates, in an attempt
to reach a nonradioactive (stable) state. As the
nucleus disintegrates, energy is released in the form
of radiation.
 The Ci or Bq is used to express the number of
disintegrations of radioactive atoms in a radioactive
material over a period of time. For example, one Ci
is equal to 37 billion (37 X 109) disintegrations per
second. The Ci is being replaced by the Bq. Since
one Bq is equal to one disintegration per second,
one Ci is equal to 37 billion (37 X 109) Bq.

39. Measuring Radiation Dose
 When a person is exposed to radiation, energy
is deposited in the tissues of the body. The
amount of energy deposited per unit of weight
of human tissue is called the absorbed dose.
Absorbed dose is measured using the
conventional rad or the SI Gy.
 The rad, which stands for radiation absorbed
dose, was the conventional unit of
measurement, but it has been replaced by
the Gy. One Gy is equal to 100 rad.

40. Measuring Biological Risk
 A person’s biological risk (that is, the risk that a
person will suffer health effects from an exposure
to radiation) is measured using the conventional
unit rem or the SI unit Sv.
 The rem has been replaced by the Sv. One Sv is
equal to 100 rem.

41. Conversions and units with
combination
 Conversions from the SI units to older units are as
follows:
 1 Gy = 100 rad
 1 mGy = 100 mrad
 1 Sv = 100 rem
 1 mSv = 100 mrem
• Note 1R=2.58*10^-4 C/Kg
1 Bq=3.73*10dps

43. Radiation Units
 rad or radiation absorbed dose
The amount of radiant energy absorbed in a certain
amount of tissue.
 gray (Gy)
A unit of absorbed radiation equal to the dose of
one joule of energy absorbed per kilogram of
matter, or 100 rad. The unit is named for the British
physician L. Harold Gray (1905-1965), an authority
on the use of radiation in the treatment of cancer.
 milligray (mGy)
A unit of absorbed radiation equal to one
thousandth of a gray, or 0.1 rad.

44.  rem or roentgen-equivalent-man
A unit of measurement that takes into account
different biological responses to different kinds of
radiation. The radiation quantity measured by the
rem is called equivalent dose.
 millirem
One thousandth of a rem, the unit for measuring
equivalent dose.
 roentgen (R, r) (rent-gen, rent-chen)
The international unit of exposure dose for x-rays or
gamma rays. Roentgens are named after Professor
Wilhelm Konrad Roentgen, the man who discovered
x-rays in 1895.

45.  sievert (Sv) (see-vert)
The unit for measuring ionizing radiation
effective dose, which accounts for relative
sensitivities of different tissues and organs
exposed to radiation. The radiation quantity
measured by the sievert is called effective
dose.
 millisievert (mSv) (mill-i-see-vert)
One thousandth of a sievert, the unit for
measuring effective dose.

48. Equipments and patients
effective dose
S/NO EQUIPMENTS PT.EFFECTIVE
DOSE(mSv)
1 General radiography 0.1-1
2 Mammography 0.4
3 CT 2-20
4 Intervantional radiography 1-100
5 Dental radiography 0.005-0.1
6 Dual Emission Xray Absorption/DEXA 0.001

49. Dose limiting recommendation –
(european nuclear society)

50.  The effective dose for members of the public
must not exceed 1 mSv/year. The limit for the
lens of the eye is 15 mSv/year and for the skin
50 mSv/year.

52. Examples of the influence of some
common adjustable CT techniques on
patient radiation dose

53. Who are the regulating
bodies? (via NCBI)
The principal federal agencies with
responsibilities for radiation protection of the
public are
- the Environmental Protection Agency (EPA),
- EPA was created by Reorganization Plan No. 3 of 1970
- the Nuclear Regulatory Commission,
- The Nuclear Regulatory Commission is an independent regulatory
authority created by the Energy Reorganization Act of 1974
-the Department of Energy (DOE).
DOE was created by the Department of Energy Organization Act of 1977.

54. Important national organizations that have
developed recommendations on radiation
protection,
-National Council on Radiation Protection (NCRP)
NCRP is a nonprofit corporation chartered by Congress in 1964
--the Health Physics Society
The Health Physics Society was formed in 1956

55.  The principal international organization
concerned with radiation protection
The International Commission on Radiological
Protection (ICRP)
 ICRP was established in 1928 as the International X-ray and Radium
Protection Committee and was restructured under its present name in
1950.
 International Atomic Energy Agency (IAEA) and
 IAEA is an intergovernmental organization established in 1957 under
the auspices of the United Nations
 the Commission of the European Communities
(CEC).
 CEC is authorized under the Euratom Treaty on Atomic Energy in the
European Communities, which was signed in Rome in 1957.

56. The ICRP Recommendation
 ( ICRP publication 103 – 2007)
 • The Principle of Justification: Any decision that alters the
radiation exposure situation should do more good than harm.
 • The Principle of Optimisation of Protection: The likelihood of
incurring exposure, the number of people exposed, and the
magnitude of their individual doses should all be kept as low
as reasonably achievable, (ALARA) taking into account
economic and societal factors.
 • The Principle of Application of Dose Limits: The total dose to
any individual from regulated sources in planned exposure
situations other than medical exposure of patients should not
exceed the appropriate limits specified by the Commission.

58. Socratic questions for referring
clinicians when considering
imaging procedures

59. Fundamentals of
radiation protection

60. 1. Doses are proportional to the time of exposure
provided the dose rates are the same.
a. Total dose(mSv)=dose rate(mSv/hr) * time
2. Dose rates are inversely proportional to the
distance squared.
a. I=k/d ^2
3. performing portable x-ray exams a tech should
be atleast six feet from the source of the
radiation.

64. 10 day rule
• The “10 day rule” recommended that, in women
of child-bearing potential, non-urgent x ray
examinations that entailed pelvic irradiation
should be restricted to the first 10 days of the
menstrual cycle.

65. What is a Personnel Monitoring
Program?
• A systematic process for monitoring,
recording, evaluating, and reporting the
radiation doses received by
occupationally exposed individuals

66. A dosimeter is a device that measures directly or
indirectly -
• exposure
• KERMA (Kinetic Energy Released per unit Mass of air)
measures the amount of radiation energy in air, unit is J/kg.)
• absorbed dose
• equivalent dose
• or other related quantities.
The dosimeter along with its reader is referred to
as a dosimetry system.

68. Types of dosimeters
• charge collection devices; radiation energy is
converted to electric charge (either directly or
indirectly) and the dosimeter converts this
charge into a signal output
 gas-filled collectors
 scintillation detectors
 solid-state detectors
• other type; devices made of material that
changes on exposure to radiation energy
 photographic film
 thermoluminescent detectors (TLD)
 optically stimulated luminescent detectors

69. • Film dosimeters
 are used to measure radiation exposure to
workers to monitor radiation safety and ensuring
that they receive doses below the appropriate
limit.
 cheapest and most common
 give a permanent record of exposure, i.e. not re-
usable
 their dependence on photon energy, temperature
and chemicals limit their accuracy.

70. Thermoluminescent dosimeter (TLD)
• Thermoluminescent dosimeter (TLD)
 passive radiation detection device
 better accuracy than a film dosimeter (its linearity
of response to dose,its relative energy
independence and its sensitivity to low doses.)
 can measure doses from 0.01 mGy to 10 Gy 3.
 No permanent record or re-readability or
immediate on a job read out is not possible.
 Has our names and random number.
 Non transferable and reusable

71. • Parts
 plastic holder
 nickel-coated aluminum card with TLD discs(d=12mm)
• the discs are made of a thermoluminescent material,
commonly calcium sulphate doped with dysprosium
(CaSO4:Dy) or lithium fluoride (LiF)
• nearly tissue equivalent, although not at all x-ray
energies
• the discs are 0.8 mm thick and have a 1.35 cm diameter
 Three filters against each disc
• top: aluminum and copper (d=1mm , t=1mm))
• middle: perspex (solid transparent plastic made of polymethyl
methacrylate) (d=299mm , t=1.6mm))
• lower: open(d=52.5mm)

72. a. High energy Xray and Gamma doses can be
measured from the disc 1.
b. Low energy , beta and gamma doses can be
measured from disc 2.
c. Low energy beta can be measured from disc 3.

73. Process
1. When a TLD is exposed to ionization radiarion
at ambient temperature,the radiation interacts
with the phosphor crystal and deposits all or
part of the incident energy in that material
2. Some of the atoms in the material that absorbs
that energy becomes ionized producing free
electrons, these electrons get trapped in the
crystal lattice itself

74. How is radiation calculated?
1. Heating (with nitrogen gas up to the temperature 250C )the
crystal causes the crystal lattice to vibrate,
releasing the trapped electrons in the process.
2. As the electrons come back to a ground state,
they release the captured energy from
ionization as light.
3. It is light that is read using photomultiplier
tubes and the photons read is equal to the
radiation stricking the phosphour
(glow curve charts).

76. Optically stimulated
luminescence (OSL)
a methodology that can be employed in
personnel dosimetry to determine the “dose of
record.”
• It is an alternative to thermoluminescent
dosimetry and film dosimetry.
• Materials suitable for OSL are similar to those
used in thermoluminescent dosimetry, i.e., they
are crystalline solids. In many cases, the same
material can be used either as an OSL
dosimeter or a TLD.

77. • Radiation energy deposited in the material
promotes electrons from the valence band to
the conduction band.
• These electrons move to traps in the band gap.
• The greater the radiation energy absorbed
(dose), the greater the number of trapped
electrons.
• • When it is time to assess the dose, the
trapped electrons are freed by exposing the
dosimeter to light.

78. • When the electrons are freed, they fall to a
lower energy level and emit light photons.
• The intensity of the emitted light is measured
and used to calculate the dose.
• Not all the electrons are freed from their traps.
If the light output from the OSL dosimeter is
analyzed over a short period of time, many
electrons will remain trapped. This means that
the dosimeter can be reread many times
without a significant loss of signal.

79. Advantages of OSL Dosimeters
• OSL dosimeters can be read at room temperature. This
simplifies the design of the equipment.
• No need for nitrogen gas.
• The use of OSL powders deposited in thin layers creates a two-
dimensional detector with imaging capabilities much like film.
• No correction factors are needed for individual elements
• Unlike a TLD, OSL dosimeters can be reread multiple times.
• Depending on the illumination conditions, there will be a
decrease of signal of less than one percent in a second reading.
• Used OSL badges are often archived for several years.
• No fading except in extreme temperatures.
• No annealing required.

80. Disadvantages of OSL
Dosimeters
• The OSL system is more expensive to use than
TLDs.
• Workers might wonder why doses are being
reported with OSL dosimeters when no dose
was reported with TL dosimeters.
• Uncertainties in background brings into
question the validity of reporting doses of a few
mrem.

82. By pointing the instrument at a light source, the position of the fiber may
be observed through a system of built-in lenses.The fiber is viewed on a
translucent scale which is graduated in units of exposure.
Typical industrial radiography pocket dosimeters have a full scale reading of
200 milliroentgens but there are designs that will record higher amounts.
Charge leakage, or drift, can also affect the reading of a dosimeter.
Leakage should be no greater than 2 percent of full scale in a 24 hour
period.
The limited range, inability to provide a permanent record, and the
potential for discharging and reading loss due to dropping or bumping are a
few of the main disadvantages of a pocket dosimeter.

83. Scintillator Detectors
• based on scintillation (light emission) are known
as scintillation detectors..
 ● A photomultiplier tube (PMT) is optically
coupled to the scintillator to convert the light
pulse into an electric pulse. Some survey meters
use photodiodes in place of PMTs.

85. Properties of scintillation
detectors
1. Conversion efficiency should be high
2. Decay time of excited state should be short
3. Material should be transparent,rugged and
unaffected by moisture
4. Attenuation cofficient should be high as
conversion efficiency.
5. Scintillating phosphors include solid organic
materials such as anthracene, stilbene and
plastic scintillators as well as thallium activated
and inorganic phosphors such as NaI(Tl) or
CsI(Tl).

86. Ionization chamber
• Simplest of all gass filled detectors
• Works on the principle that charged particles
can ionize gas
• The number of ions paired formed gives the
information of the nature of the incidet particle
(radiation )and its energy

88. Typical locations for
dosimeters are:
• ▪On forehead (prescription point for children)
• ▪Neck (thinnest point)
• ▪Chest: entrance and exit dose to check lung
block thickness
• ▪Umbilicus (prescription point in adults, since it
is typically the thickest part of the body)
• ▪Optional: extremities, especially upper and
lower legs if compensators are used
• ▪Selected protocols require testes boosts for
pediatric male patients

91. 1.Consol of CT should have 2mm Pb Eq
2.The distance from the Xray table to console
should be 2 mm.
3.9 inches brickwall or 7 inches concreat wall is
used for 1.5mm Pb Eq.

94. Recent advances
1) significant research efforts are being made to develop
ultra-thin radiation protection gloves with high radiation
attenuation
1) for use by surgeons performing cardiac catheterisation or similar
interventional radiology procedures where tactile sensitivity is of
paramount importance.
2) The worlds leading manufacturers of radiation
protection gloves are able to offer gloves as thin as
0.20mm thickness containing no lead.
3) State of the art material science research has led to the
development of ultra-light functional core materials with
no lead at all using a combination of bismuth, antimony
and tungsten offering the same level of radiation
attenuation as conventional lead containing material.
4) future holds the promise of new generation imaging
technology that may completely eliminate the use
ionising radiation

95. Where Did the Myth That
Radiation Glows Green Come
From?
By C Stuart Hardwick.
-Probably from radium, which was widely used
in self-luminous paint starting in 1908. When
mixed with phosphorescent copper-doped zinc
sulfide, radium emits a characteristic green
glow

97. REFERENCES
1. Frederic H. Fahey DSc, What You Should Know About Radiation and Nuclear
Medicine,frederic.fahey@childrens.harvard.edu
2. NDT Research Center, History of Radiography, htps://www.nde-
ed.org/EducationResources/CommunityCollege/Radiography/Introduction/history.htm
3. Allen Brodsky, Sc.D. , Department of Radiation Science,Georgetown University,
Washington, D.C . , Ronald 1. Kathren, M.Sc.Department of Radiologic
Sciences,University of Washington, Historical Development of Radiation Safety
Practices in Radiology.
4. Radiation Safety Training Module: Diagnostic Radiology,Radiation Protection in
Diagnostic Radiology.
5. Surendra Maharajan, Radiation Protection ,September-2016,Tokyo University.
6. Radiation protection and the NRC,United States Nuclear Regulatory Comission.
7. General Principles of Radiation Protection in Fields of Diagnostic Medical Exposure
,http://dx.doi.org/10.3346/jkms.2016.31.S1.S6 • J Korean Med Sci 2016; 31: S6-9
8. Protection Against Ionising Radiation Radiation Protection Series F-1 February 2014
9. Christensen’s Physics of Diagnostic Radiology fourth edition.
10. Evaluation of Guidelines for Exposures to Technologically Enhanced Naturally Occurring
Radioactive Materials. htps://www.ncbi.nlm.nih.gov/books/NBK230640.

98. THANK
YOU