RADIATION PROTECTION
Question outline:
- Introduction
- General information on ionizing radiation
- Definition of X-rays
- Modes of exposure
- Biological effects of ionizing radiation
- Radiation protection
- Definition
- Principle
- Radiation protection standards and DMA
- Protective measures
- Design of premises
- Personal protection
- Patient protection
- Protection of the professional
- Controls
- Medical prevention
- Monitoring of individual exposure
VI) Conclusion
RADIATION PROTECTION
- Introduction :
Rx represents the main cause of human-made irradiation, by the number of people professionally involved and the number of subjects examined (several million per year).
The radiation likely to reach radiologists, technicians and patients has 3 origins:
- Leakage radiation
- Direct radiation
- Scattered radiation
- General information on ionizing radiation (X-ray):
- Definition of X-rays (already seen) diffuse radiation which represents photons which have changed direction by the Compton or Thomson effect.
- Exposure modes:
- Professional
- Medical
- Accidental
- The biological effects of ionizing radiation:
- On the cell: either by lethal effect and cell death, mutation by intranuclear lesions,
- On the most sensitive tissues and organs: bone marrow, skin, ovaries, testicles,
- Radiation protection:
- Definition :
This is the set of measures taken to ensure the protection of man and his environment against the harmful effects of ionizing radiation ==> Keep the doses due to irradiation of artificial origin as low as possible.
- Principle: based on 3 key ideas:
- Justification: for the use of radiation
- Optimization: means of radiation protection
- Limitation: individual doses
- Protective measures:
- Design of premises:
- Specialized design for better protection: thickness and choice of wall materials
- Personal protection:
- Patient protection:
- Large Home-Skin Distance
- Decrease in exposure time
- Reduction in the exposure field (localizer cone, diaphragm, leaded covers, etc.) 🡺 reduction in the irradiated volume and therefore in the diffused radiation.
- Exclude the gonads from the field to be irradiated
- Filter the radiation
- Use high voltages
- Use ER and fast films (to reduce exposure time)
- Limit radiological examinations to the essentials
- Protection of professionals:
- Reduce the exposure time
- Increase Source-User Distance
- Interpose screens between the source and the user
- Wearing appropriate clothing (gloves, coats, gloves, masks, glasses, etc.)
- Protection standards and DMA (Maximum Allowable Dose)
- This is the dose of radiation that does not appear likely to cause appreciable damage to an individual during his or her lifetime.
- We distinguish 4 classes of individuals, who, depending on the degree of exposure, have different DMAs:
- Personnel directly assigned to radiation work:
If whole body exposure, bone marrow, gonads 🡺 < 5 rem/year or 200 rem/life
If partial irradiation 🡺 < 60rem/year
- Personnel not directly assigned to radiation work:
If whole body exposure, bone marrow, gonads 🡺 < 15 rem/year
If partial irradiation 🡺 < 6 rem/year
- Public staff:
If whole body exposure, bone marrow, gonads 🡺 < 0.5 rem/year
If partial irradiation 🡺 < 6 rem/year
- Female staff exposed:
< 1.3 rem / 3 consecutive months with abdominal exposure
If pregnant: declare as soon as possible
- Control :
From the environment and the staff.
- Medical prevention:
Analysis of medical fitness to provide an exposed workstation with optimization of anti-difficulty measures
- Monitoring of individual exposure:
The assessment is carried out by a dosimeter with the results recorded on an exposure sheet.
RADIATION PROTECTION
- Conclusion :
Ionizing radiation has harmful biological effects that are proportional to their dose, even minimal.
Four fundamental rules for optimal radiation protection: (DATE)
- Distance: distance from the source
- Activity: decrease the activity of the source
- Time: Decrease the duration of the exposure
- Screens: protection between the source and the subject
RADIATION PROTECTION
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