NINSIIMA LYNN
RPO, ATOMIC ENERGY COUNCIL
BASICS OF RADIATION, HEALTH EFFECTS AND PRINCIPLES
A presentation to radiation workers
November 11, 2016
Presentation Outline
• Introduction
• Radiation
• Types of Radiation
• Sources of Radiation
• Exposure Situations
• Effects of Ionizing Radiation
• Principles of Radiation Protection
2
Forms of radiation
Any type of electromagnetic radiation that does not carry enough energy per to ionize atoms or molecules—that is, to completely remove an electron from an atom
eg RF, Infra-red, microwave
Forms of radiation (2)
• Ionizing radiation is radiation that has sufficient energy to remove electrons from atoms
• Radiation is invisible and not detectable by human senses
• Ionizing radiation can cause damage to human DNA (human health) and environment
• Radiation can be detected by use of instruments and detectors
AEC currently regulating ionizing radiation,
Intends to regulate non-ionizing radiation
Types of Ionizing Radiation• Alpha
• Beta
• Gamma
• Neutrons
• Energy
• Penetrating power
• distance
Sources of Ionizing Radiation exposure
• Natural SourcesNatural Background
Terrestrial
Cosmic
Cosmogenic
NORMs
• Artificial sourcesMedical
Industrial
Consumer products
Applications of Ionizing Radiation in Uganda
• MedicalRadiologyNuclear MedicineRadiotherapy
• Industrial Non Destructive Tests
Industrial Radiography
Well logging
Nuclear gauging
Level gauges
Fixed gauges
• Agriculture
Tsetse fly irradiation
• Research & Education
Analytical studies
Exposure Situations
1. Planned Exposure Situations
• Occupational exposures
• Medical Exposures
• Public exposures
2. Emergency exposure Situations
• Occupational exposures
• Public exposures
3. Existing exposure situations
• Public exposures
Stochastic Effects
Probability of occurrence is a function of dose
Severity is not a function of dose
No threshold dose
• Cancer
• Hereditary effects
• Leukemia
Deterministic (Non-Stochastic Effects)
Severity of effect varies with dose
a threshold dose exists
usually after large absorbed doses of radiation (~1-2 Gy)
• Erythema (skin reddening)
• Sterility
• Cataracts
• Death
• Hair loss
Principles of Radiation Protection
• The ALARA Principle:
ALARA stands for As Low As Reasonably Achievable. It is the basic principle of radiation protection procedures.
• The three factors influencing radiation dose are:
ALARA - Time• The less time you’re exposed, the less exposure you receive
• Dose = Dose Rate x Time
• Limit your time near the radiation source!
• Operators should not exceed recommended workload.
Measure of radiation output per week (mA-min)
Dose, number of patients, type of practice, time
ALARA - Distance
• The farther away from the source you are, the weaker the
source is to you
• Exposure levels are based upon the Inverse Square Law
• Increase the distance between you and the source!
• Keep the tube away from the working area/ control cubicle
• Utilize the size of the imaging room
profitably.
ALARA - Shielding
• Shielding can reduce or stop radiation from reaching you
• Increase the amount of shielding material
between you and the source!
• You should never work in the primary beam
• Permanent control cubicle must have properly fitted lead glass of appropriate thickness
1. Understand and apply the cardinal principles of radiation control: time, distance and shielding.
2. Do not allow familiarity to result in a false security.
3. Never stand in the primary beam.
4. Always wear protective apparel when not behind a protective barrier.
5. Always wear a radiation monitor and position it outside the protective apron at collar level.
6. Never hold a patient during radiographic examinations. Use mechanical restraining devices when possible. Otherwise, use patients or friends to hold the patient.
Ten Commandments of ALARA
Ten Commandments of ALARA (2)
7. The person holding the patient must wear protective
apron and if possible, gloves.
8. Use gonadal protective on all people of childbearing age
when it will not interfere with the examination.
9. Examinations of the pelvis or lower abdomen of a
pregnant patient should be avoided whenever possible,
especially during the first trimester.
10. Always collimate to the smallest field size appropriate to
the examination.