Ionizing radiation can cause both deterministic and stochastic effects on the human body. Deterministic effects, such as radiation burns, occur above threshold doses and include skin damage, cataracts, sterility, and growth issues for children. Stochastic effects, like cancer induction, occur probabilistically with no safe threshold. The risk of cancer increases with radiation dose. Radiation protection principles aim to justify medical uses, optimize protection measures, and limit radiation doses. Attention to shielding, distance, equipment positioning, and monitoring can help reduce radiation exposures.

1. RADIATION HAZARDS
Presented by:
Dr. Hassan Hameed Malik
(Resident Radiology)
CMH Abbottabad
SUPERVISOR
Brig. Dr. Saerah Iffat Zafar
FRCR (UK), FCPS, MCPS,MBBS
Classified Radiologist

2. RADIATIONS
Radiation, flow of atomic and subatomic particles
and of waves, such as those that
characterize heat rays, light rays, and X rays.
Radiation may be thought of as energy
in motion either at speeds equal to the speed
of light in free space—approximately
3 × 1010 centimetres (186,000 miles) per second—or
at speeds less than that of light.

3. Three things can happen to a photon as it travels
through matter:
1. Transmission
2. Absorption
3. Scatter
The X-ray image is formed by the transmitted
photons. Those that are absorbed or scattered
are said to have been attenuated
Interaction of high energy
photons with matter

4. Radiations emitted by X-Ray
tube

5. Radiations emitted by X-Ray tube

6. HARMFUL EFFECTS OF RADIATIONS

7. Ionizing Radiation Effects
Absorption of Radiation
Ionization
Chemical Change
Repair or Damage
High Dose Effects
Cell killing
Tissue or organ effects
Whole body effects
Low Dose Effects
Mutations
Cancer
Effects to unborn

8. Outcomes after Cell Exposure

11. What harm radiation can do from
X-rays and CT scan ?

12. Summary of Biological Effects

13. Radiation Causes Ionizations of:
ATOMS
which may affect
MOLECULES
which may affect
CELLS
which may affect
TISSUES
which may affect
ORGANS
which may affect
THE WHOLE BODY

14. X-ray passes straight
through cell

No change to cell
X-ray causes a
chemical reaction in
cell, but no damage
done or damage
repaired by cell

No change to cell
DNA damaged in a
“fatal” way”

Cell killed
DNA damaged,

Cancer?
*using
a
c cell to
*
*

15. Ionizing Radiation Can Cause Chemical
Reactions In The Body’s Cells Which May
 do no harm
 kill the cell
 cause the cell to multiply out of
control (cancer)
 cause the cell to malfunction in some other
way

18. TYPES OF RADIATION
DAMAGE

19. DETERMINISTIC (NON-STOCHASTIC) RADIATION EFFECTS I
Deterministic effects result from
the killing of cells which, if the
dose is large enough, causes
sufficient cell loss to impair the
function
exposure
radiation
of the tissue. i.e.
to high doses of
can damage large
number of cells which produce
deterministic effects .
Severity
Radiation Dose
Threshold

20. Deterministic Health Effects

21. Deterministic Health Effects
Organ or tissue
Dose in less
than 2 days, Gy
Deterministic effects
Type of effect
Time of
occurrence
Whole body (bone
marrow)
1
Acute Radiation
Syndrome (ARS)
1 – 2 months
Skin 3 Erythema 1 – 3 weeks
Thyroid 5 Hypothyroidism 1st – several years
Lens of the eye 2 Cataract
6 months - several
years
Gonads 3 Permanent sterility weeks

22. Damage To The Eye
 Radiation to the lens of the eye can cause cataract.
 The threshold radiation dose for production of
detectable damage to the lens is between 0.5 to 2 Sv,
and for production of visual impairment is about 5 Sv.

23. Radiation Injuries from Interventional Procedures
Cataract in eye of
interventionalist after repeated
use of old x ray systems and
improper working conditions
related to high levels of
scattered radiation. (E. Vano et al
British Journal of Radiology
1998).

24. Acute Radiation syndrome

25.  Chernobyl experience:
 Acute Radiation Syndrome and
Radiation burns

26. SKIN INJURIES AFTER A SINGLE IRRADIATION
EFFECT Threshold (Gy) Onset
Temporary epilation 3 3 wk
Permament epilation 7 3 wk
Transient erythema 2 hours
Main erythema 6 10 days
Dry desquamation 10 4 wk
Dermal necrosis 18 >10 wk

27. Skin injuries (Erythema)
 Radiation effects on the
skin can appear several
weeks after the
irradiation and can be
progressive
 After one coronary
angioplasty and
stent procedure

28. Occupational radiation burn following approximately three weeks of exposure
to radiation emitted from nested voltage electron beam accelerator being tested
to kill bacteria.

33. Radiation Injuries From Interventional Procedures
• Skin injuries (after several PTCA’s) (T. Shope,
Radiographics 1996; 16: 1195-99)

34. Hypothyroidism

35. Hair Loss
 Hair loss is another non-stochastic radiation
effect which may occur after a dose to
the scalp of 3Sv or more.
 Recovery takes place in the months following
the exposure unless the hair follicles have
been exposed to high doses.

36. Sterility

37. Deterministic (Non-stochastic) Effects In Children
 Radiation dose of less than 0.1 Sv may cause mental
and growth retardation in children. The younger
children were more susceptible to these effects than
the older ones.

39. Radiation Induced Cancer I
 The production of cancer is the most important stochastic
effect of radiation.
 Modified somatic cells may subsequently, after a prolonged
delay, develop into a cancer.
 There are repair and defence mechanisms that make this a
very improbable outcome.
 The probability of cancer resulting from radiation increases
with increments of dose, probably with no threshold. The
severity of the cancer is not affected by the dose.

40. Stochastic Effects
 Caused by cell mutation leading to cancer
or hereditary disease
 Current theory says, no threshold
 The bigger the dose, the more likely effect
 So how big is the risk?.

41. Stochastic Effects Of Radiation
The Stochastic effects of radiation are;
 Production of cancer,
 Genetic effects and
 Effect on life span.
Radiation Dose
Risk

42. Radiation Induced Cancer I
 The production of cancer is the most important stochastic
effect of radiation.
 Modified somatic cells may subsequently, after a prolonged
delay, develop into a cancer.
 There are repair and defence mechanisms that make this a
very improbable outcome.
 The probability of cancer resulting from radiation increases
with increments of dose, probably with no threshold. The
severity of the cancer is not affected by the dose.

43. Nominal Risk Of Fatal Cancer
Effect Tissue at risk Cases per million per
m Sv
Male Female
Leukaemia Red bone marrow
Female breast
Lung
Thyroid
Cells on bone
surface
Liver
All other tissues
3 3
Breast cancer - 5
Lung cancer 2 2
Thyroid cancer 1 1
Bone sarcoma 0.5 0.5
Liver cancers 1 1
Other cancers 3 3
Total Whole body 10.5 15.5

44. Cancer Risk
 For adult worker, average risk of inducing fatal cancer is
4% per Sv
 i.e. risk from 0.1 mSv
 = 0.04 x 0.0001
 = 0.000004
 = 1 in 250,000

45. Genetic Or Hereditary Effects
 Genetic or hereditary effects are radiation induced mutations
to an individual’s genes and DNA that can contribute to the
birth of defective descendants.

47. Effect On Life Span
 There have been some suggestions that
exposure to ionizing radiation accelerates the
process of aging and accordingly reduce the
life span.

50. PRINCIPLES OF RADIATION PROTECTION

51. JUSTIFICATION

52. OPTIMIZATION

54. DOSE LIMITATION

56. KEY FACTORS TO REDUCE RADIATIONS
1. ATTENTION TO PROTECTION
2. DOUBLING YOUR DISTANCE FROM THE SOURCE OF
RADIATION.
3. ATTENTION TO C-ARM POSITIONING
4. ATTENTION TO IMAGE ACQUISITION

57. 1. ATTENTION TO PROTECTION

58. 2. DOUBLING YOUR DISTANCE FROM THE
SOURCE OF RADIATION

59. 3.ATTENTION TO C-ARM POSITIONING

60. 4. ATTENTION TO IMAGE ACQUISITION

68. PATIENT WAITING AREA

69. 3.PERSONAL SHIELDING

70. These aprons protects an individuals only
from secondary radiation, not the primary
beam.

72. 4.PATIENT SHIELDING

75. PERSONAL MONITORING

76. 1..POCKET DOSIMETER
2..FILM BADGE