6. Radioactivity
If a nucleus is unstable for any reason,
it will emit and absorb particles. There
are many types of radiation and they
are all pertinent to everyday life and
health as well as nuclear physical
applications.
The electro-magnetic waves vary in their
length and frequency along a very wide
spectrum.
8. Types of Radiation
Radiation is classified into:
1- Ionizing Radiation
- Higher energy electromagnetic waves (gamma) or
heavy particles (beta and alpha).
- High enough energy to pull electron from orbit.
2- Non-ionizing Radiation
- Lower energy electromagnetic waves.
- Not enough energy to pull electron from orbit, but can
excite the electron.
12. Sources of radiations
1. Cosmic rays—Usually of very little concern to
people living over the surface of earth,
2. Terrestrial radiation—Radioactivity is present
everywhere (and has been since the formation of
the earth).
3. Air (radon gas, which is a natural disintegration
product of radium).
14. 4. Internal—Radioactive elements in body.
5. X-rays (0.02-3 rads/film)—Harms the personnel
doing the X-ray more than the patient (the patient
is exposed only once at a time, but for the
operator, its his job).
6. Nuclear fallout, nuclear power plants,
radiotherapy departments.
18. Radiation effects
Acute radiation sickness:
Radiation sickness is generally associated with acute
(a single large) exposure. Nausea and vomiting are
usually the main symptoms. The onset of symptoms is an
indicator of the absorbed dose.
Nausea and vomiting generally occur within 24- 48 hrs after
exposure to mild (1-2 Gy) doses of radiation.
• Moderate (2-3.5 Gy of radiation) exposure is associated
with nausea and vomiting beginning within 12-24 hrs after
exposure, with fever, hair loss, infections, bloody vomit and
stools, and poor wound healing.
20. Radiation effects - cont..
• Nausea and vomiting occur in less than 1 hr after
exposure to severe (3.5-5.5 Gy) doses of
radiation, followed by diarrhea and high fever in
addition to the symptoms of lower levels of
exposure.
• Very severe (5.5-8 Gy of radiation) exposure is
followed by the onset of nausea and vomiting in
less than 30 minutes followed by the appearance
of dizziness, disorientation, and low blood
pressure.
22. Radiation effects - cont..
Acute Somatic Effects:
- Relatively immediate effects to a person
acutely exposed. (Severity depends on dose.)
- Death usually results from damage to bone
marrow or intestinal wall.
- Acute radio-dermatitis is common in
radiotherapy;
- Chronic cases occur mostly in industry.
26. Radiation protection
1. Proper X-ray machines, dose reduction (i.e.
reducing unnecessary X-ray examinations).
2. 0.5 mm lead coat for workers.
3. A film badge/dosimeter shows the
accumulated radiation since the machine was
last charged.
4. Periodic check ups of workers, division of
working hrs.
5. Stop nuclear tests and avoid a nuclear war.
28. Non-ionizing Radiation
- All earth surface system components emit
radiation--- (sun and the earth).
- The sun emits radiation composed of high energy
infrared radiation, visible light, and ultraviolet
radiation collectively known as shortwave
radiation (SW)
- The earth emits radiation composed of lower
energy infrared radiation collectively known as
long-wave radiation (LW)
36. Time: Minimize time of exposure to minimize
total dose. Rotate employees to restrict
individual dose.
Distance: Maximize distance to source to
maximize attenuation in air. The effect of
distance can be estimated from equations.
Shielding: Minimize exposure by placing
absorbing shield between worker and source.
39. Elements of Radiation Protection Program
Monitoring of exposures: Personal, area, and
screening measurements; Medical/biologic
monitoring.
Task-Specific Procedures and Controls: Initial,
periodic, and post-maintenance or other non-
scheduled events.
Engineering (shielding).
PPE administrative controls Including
management and employee
Emergency procedures.
Training and Hazard Communications including
signs, warning lights,, etc. Criteria for need,
design, and information given.
