SCOPE OF THE PROBLEM

1
RADIATION ACCIDENTS TERMINOLOGY, SCOPE
OF PROBLEM AND STATISTICS
Module I
Module I - Radiation accidents
2
WHAT is an accident?

• Accident BSS, Glossary, p.295, 1996
• Any unintended event including operating
  errors, equipment failures or other mishaps, the
  consequences or potential consequences of which
  are not negligible from the point of view of
  protection and safety.

Module Medical I - Radiation accidents
3
What is a radiation accident?

• A situation in which there is an unintentional
  exposure to ionizing radiation or radioactive
  contamination
• Exposure may be real or suspected

Module Medical I - Radiation accidents
4
Radiation accidents

• Radiation accidents include
• radiological and
• nuclear accidents
• It is more appropriate and practical to use the
  term nuclear and radiological emergency for
  purposes of planning, preparedness and response

Module Medical I - Radiation accidents
5
Statistics of radiation accidents, 19442001

• Radiation accidents are rare
• In 1944-2001 420 radiation accidents led to
  significant overexposure of at least one person
• Among 3000 overexposed persons, 133 fatalities
  are registered
• However, loss of control over radiation sources
  has recently lead to more severe accidents

6
Main types of radiation accidents involved groups

• Accidents during work - workers
• radiography
• irradiators (sealed sources and accelerators)
• Accidents due to loss of control over radiation
  sources - public exposure
• radiotherapy
• orphan sources
• Accidents in medical applications - patients
• misadministration of radiopharmaceuticals
• miscalculation of the dose for radiotherapy

Module Medical I - Radiation accidents
7
Where do radiation accidents occur?

• Irradiation facilities
• Material testing (sealed sources)
• Material testing (X-ray devices)
• X-ray and radiotherapy devices (medicine,
  research)
• Isotope production facilities
• Unsealed radionuclides (medicine, research)
• Nuclear reactors
• Transportation
• ???

Module Medical I - Radiation accidents
8
Radiation accidents by facility type, 1945-2000
Module Medical I - Radiation accidents
9
Ionizing radiation medical, industrial and
consumer product applications

• Radiography techniques
• Analytical techniques
• Irradiation techniques
• Techniques involving unsealed radioactive
  materials
• Miscellaneous techniques

Module Medical I - Radiation accidents
10
Ionizing radiation medical, industrial and
consumer product applications
Radiography techniques (industrial and medical)

• Industrial gamma and X-ray radiography
  (non-destructive testing)
• Medical diagnostic radiography
• Beta radiography
• Neutron radiography

Module Medical I - Radiation accidents
11
Radiological accidents by source, 1945-2000
Module Medical I - Radiation accidents
12
Ionizing radiation medical, industrial and
consumer product applications
Analytical techniques

• X-ray fluorescence
• Electron capture
• Neutron capture and activation analysis
• Gamma backscatter gauge
• X-ray fluorescence gauge
• Photon switching (level gauge)
• Selective gamma absorption
• Gamma scattering
• Thermalization of neutrons
• Neutron transmission

Module Medical I - Radiation accidents
13
Ionizing radiation medical, industrial and
consumer product applications
Irradiation techniques

• Radiation beam therapy (teletherapy)
• Brachytherapy
• Radiation sterilization and grafting
• Food preservation

Module Medical I - Radiation accidents
14
Ionizing radiation medical, industrial and
consumer product applications
Techniques involving unsealed radioactive material
s

• Radioisotope tracer techniques
• Therapeutic uses of radiopharmaceuticals
• Self-luminous devices
• Enhancement of electrical discharge
• Uses of thorium

Module Medical I - Radiation accidents
15
Ionizing radiation medical, industrial and
consumer product applications
Miscellaneous techniques

• Static elimination
• Smoke detectors
• Lightning warning systems
• Dewpoint meters
• Nuclear batteries

Module Medical I - Radiation accidents
16
Frequency distribution of major radiation
accidents worldwide, 1940-1999
50
Criticalities Radiation devices Radioisotopes
40
30
Number Sum
20
10
0
1940- 1945- 1950- 1955- 1960-
1965- 1970- 1975- 1980- 1985-
1990- 1995- 1944 1949 1954
1959 1964 1969 1974
1979 1984 1989 1994 1999
17
Scale of radiation accidents

• Small scale radiation accidents
• usually involve a small source term and few
  people
• often come to light from observations by primary
  care physicians (mainly GPs)
• Large scale radiation accidents
• usually involve a large source term and many
  people irradiated/contaminated
• require specialist treatment in both primary and
  secondary medical facilities
• can lead to widespread public health action to
  mitigate the effects of contamination.

Module Medical I - Radiation accidents
18
MAJOR RADIATION ACCIDENTS WORLDWIDE HUMAN
EXPERIENCE 1944 - 1999
Number of Persons Significant Total accidents
involved exposures fatalities
417 133 550 3003 127 Source Radiat
ion Emergency Assistance Center/Training
Site Radiation Accident Registries,
ORISE-EHSD-REAC/TS, Oak Ridge, 2000
Module Medical I - Radiation accidents
19
ORPHAN SOURCES

• never subject to regulatory control or
• initially regulated but then
• abandoned
• lost or misplaced
• stolen or removed without authorization
• frequent cause of radiation accidents during the
  last 15 years

20
After September 11th, growing apprehension that
by shrouding a core of conventional explosives
around a radioactive source.
Terrorist use of radioactive material
21
..contamination could be spread over a wide area


and terror created!!
22
Radiation accidents by cause medical
management

• Radiation accidents with unknown origin and late
  recognition (e.g. Goiania, 1987 Estonia,
  1994 Georgia, 1997 2001 Turkey, 1998/99
  Thailand, 2000 Egypt, 2000 )
• Accidents with initially known radiation origin
  (e.g. Iran, 1996 Peru,
  1999 )
• Accidental exposure in medical applications
  (e.g. Spain, 1990 Costa Rica, 1996,
  Panama, 2001)
• Criticality accidents (e.g. Sarov,
  Russia, 1997 Tokaimura, Japan, 1999)
• Major nuclear accident Chernobyl, USSR (1986)

Module Medical I - Radiation accidents
23
Summary Frequent causes and application areas
of radiological accidents

• misuse of gamma sources and X-ray machines in
  industrial radiography and production control
• misuse of gamma sources in sterilization and
  preservation of foodstuffs or for other purposes
• misuse of ionizing radiation or misadministration
  of radioactive substances for diagnostic
  radiology, nuclear medicine and radiotherapy
  (X-ray generating machines and gamma ray sources,
  particle accelerators, and sealed or unsealed
  radionuclide sources)
• negligent or unregulated disposal of radiation
  sources or radioactive waste

Module Medical I - Radiation accidents
24
Lessons identified for prevention of radiation
accidents

• Registration of all radiation sources and their
  control (during all phases of application,
  transport and disposal)
• Safety culture
• Regular training

Module Medical I - Radiation accidents