Heath Physics Review Flashcards
International Commision of Radiologic Protection
Is an independent organization founded in 1928 they provide recommendations and guidance on all aspects of protection-against ionizing radiation
-has no power to impose laws
National Council on Radaition Protection Measurement (REVISED in 1964)
NCRP is the United States version of the ICRP- founded in 1929 and it seeks to formulate and widely dispersed information guidance and recommendation on radiation protection and measurement .
-Has no power to impose laws
-Deals with educating the public
Nuclear Regulatory Commission (NCR)
A government agency that protects the public health and safety ,and the environment for effects of radiation from nuclear reactors materials and waste facilities.
-NRC enforces their functions by imposing laws
How The NCR regulates
Has five main components
- Regulations and Guidance
2.Licensing and certifications
3.Oversight - Operational Experience
5.Support for Decisions
Regulations and Guidance
-Develops mandatory rules for:
1.Transportation of materials
2.The use of materials at nuclear facilities,power plants,research reactors ,uranium mills,fuel facilities and waste respostiries
3. The use of materials for medical industrial and academic purposes
4. The NCR provides guidance on how to comply with their regulations to the above.
Licensing and Certification
-NCR will license the following activites:
1.Construction, operation and decommissioning of commercial reactors and fuel cycle facilities
2.Possession,use, processing exporting and certain aspects of transporting nuclear materials and waste.
3.Setting,design,construction,operations and closure of waste disposal sites.
- You must have a license to perform the above activities
NCR will certify certain activities :
Certification is usually temporary or limited action.
One time transportation or possibly a one time action
NCR License
General Domestic License is given for the use of byproduct materials in certain in vitro clinical labs test- Physicians, Veterinarians, Clinical Lab and Hospitals
-Only In-vitro test- No humans or animals
-Basically used for Testing and non-diagnostic purposes
-Total Byproducrs materials should not exceed:
-200uCi of I-125/I-131/Se-75/Fe-59
-10uCi of C-14
-20 unit of H-3
Specific License (Two Categories)
-Manufacturep of Transfer of byproduct for commercial distribution
- Possess, use and transfer for byproduct material
(Maximum limit/A broad license given to hospital)
These licenses can be given by the- NCR or an agreement state
An agreement state- agrees with the NCR to enforce radiation laws through their department of the health.
-An agreement state assumes responsibilities of the NRC to regulate the use of radioactive materials.
-18 NCR states and 32 Agreement states (NC is one of them)
Oversight- NCR conducts inspections to ensure licenses meet NCR’s regulatory requirements.
Three inspection areas are:
-Nuclear Reactors Oversight
-Nuclear Materials Oversight
- Radioactive waste Oversight
-Will inspect for training of personnel who use materials radiation protection programs,Patient dose records, and security of materials.
NCR enforces through violations
Identified through inspections and investigations
- ALL violations are subject to civil enforcement and subject to criminal prosecution.
-Three primary enforcement sanctions
-Notice of Violation-identifies a requirement and how it was violated and requires corrective action
-Civil Penalites- Monetary fine that may be assessed up to $120,000 per violation per day
-Orders- Modify, suspend or revoke licenses or require specific actions
Operational Experience
- NCR is involved with handling and preventing safety concerns:
-Emergency Response:provides consultation, support assistance to state and local safety
-Events Assessment-reviews daily and long term, analysis of accidents and other reports.
-Generic Issues-Will also identify and resolve safety issues that affect more than one license facilty.
Support For Decisons
To support the decisions that the NRC makes they:
Research- performs experiments technical studies and analysis to help them make realistic decisions
Advisory proposal: Reviews and independent assessment of the regulatory proposal by independent advisory bodies.
Adjudication- A full and fair hearing will be provided for all nuclear related matters
Code of Federal Regulations
- All of the regulations can be found in the Code of Federal Regulations
- It will be expressed in
-10CFR20
-10 =Title
-20= chapter of the title 10
-There are 50 titles with several chapters each
Some chapters to recognize …
10CFR19-Notices,instructions, and reports to workers:
Inspection and investigations
10CFR20- Standards for protection against radiation
10CFR35- Medical use of byproduct materials
10CFR71- Packing and transportation of the radioactive material
Food and Drug Administration
FDA regulates Radiation Emitting Products:
Cell phones
-States all radiation emitting devices must be labeled radioactive
Personal Protection
Units of Measurement- Two main units
-Convetional Radaiation Units
-SI units
Roentgen(R)
Is the amount of ionization that is caused from x and gamma rays. It is the unit to measure person exposure( how much a person is being exposed to)
Exposure can be presented as a rate: Exposure/time most common is mR/hr the survey meters are measured in mR/hr
Rad (Radiation Absorbed Dose)
Is the amount of energy deposited per unit mass
1 rad =10^-2 joule/kg
0.01 J of energy are deposited in 1 kg of substance
1 rad= 100 ergs/g
Ergs is another unit of energy
REM (Radiation Equivalent Man)
-REM takes into account the different types of radiation and how their biological effect are different
-To calculate rem:
-REM= rad xRBE
-RBE = THE RELATIVE BIOLOGICAL EFFECTIVENESS
- The biological effect that the radiation has on tissues
-REM=QF X N
-QF is the linear energy transfer- amount of energy deposited per length of the path of radiation.
-N is the modifying factor for different types of radiation
Gray(Gy)
Is a unit used to measure quantity called absorbed does/ one gray is equal to one joule of energy in one kg of a material.
- sounds familiar = 1 Gy=100 rad
Sievert (Sv)
-Is a unit to derive a quantity called equivalent dose
-Relates the abasorbed dose in human tissue to the effective biological damage of the radiation
-Sound familiar 1Sv =100 rems
ALARA
Radaition exposure should be kept “ALARA” As low as reasonable achievable
-NCR started this program for all radaition areas.
-ALARA evaluates:
1. Techniques
2. Equipment
3. Procedures
-Concept is applied to all Dose equivalent Limits
Dose Equivalent Limits
-The radiation dose limits that humans are allowed to obtain.
Background Radiation
Radiation from cosmic sources, naturally occurring(radon) global fall out( testing nuclear devices or past nuclear accidents)
Collective Does
Sum of individual dose received in a given period of time by a specified population from exposure to a specific source of a radiation.
Committed Dose Equivalent-(HT,50)
Dose equivalent to organs of tissues that will be received from an intake of radioactive material by an individual during the 50 year period following intake.
Deep- Dose Equivalent (Hd)
External whole-body exposure to tissue at depth of 1cm
Derived Air Concentration (DAC)
The concentration of a given radionuclide in air.
Dose Equivalent(HT)
The product of the absorbed dose in tissue and quailty factor
Lens Dose Equivalent(LDE)
External exposure to the lens of the eye.
-*Taken as the dose equivalent at a tissue depth or 0.3 cm
Occupational Dose
Dose received by and individual in the course of employment in a radiation area.
Shallow Dose Equivalent (HS)
External exposure of the skin and extremity.
-Taken as the dose equivalent at a tissue depth or 0.007 cm over an area of 1 cm^2
Total Effective Dose Equivalent
Sum of the deep-dose equivalent (for external exposure) and the committed dose equivalent (for internal exposures)
Whole Body
External exposure to head,truck,gonads,arms above the elbow and legs above the knee.
Extremities
Arms(elbow and below) and legs( knee and below)
ALI
Annual limit of intake
Occupational Dose Limits for Adults( adults that work in designated radiation areas)
TEDE= 5 REMS (0.05) Sv/yr
LDE=15 REMS (0.15) Sv/yr
HS= 50 REMS (0.50) Sv/yr
Public Exposure (General Public)
TEDE= 0.1 REMS (1.0 mSV) /yr
Occutional Dosse Limits for Minors
10% of the occupational dose limits for adults
Embryo/Fetus Exposure
TEDE=0.5 REMs (5.0 mSV)/term
Declared Pregnant Women
Remains in effect until the woman withdraws the “ Declared Pregnancy“
To declare pregnancy:
1. Be an occupational Radiation worker
2. Inform her employer in writing that she is pregnant
3. Provide an estimate date of conception
Reducing Radiation Exposure
Time/Distance/Shielding(activity)
Time for Reducing Radiation Exposure
Radiation exposure to an individual is directly proportional to the time of the exposure to the radioactive source.
-Keep your time spent with a radioactive source to a minimum
Distance Reducing Radiation Exposure
-Intensity(I) varies inversely as the square of the distance from the source to the point of exposure
-Two Principles to Distance and Exposure:
- Inverse Square Law- Relates intensity and distance
-Exposure Rate Constant- radiation exposure from and x rays and gamma rays
Distance Reducing Radiation Exposure
As the distance doubles( multiple distance by 2) the Intensity decrease by the square of the distance.
-By doubling the distance you have decreased the exposure rate to one quarter of the original dose rate.
-If the distance is cut in half (divide distance by 2) the Intensity increases by the square of the distance
-By cutting the distance in half you have increased the exposure by 4
Inverse Square Law
I(1)D(1)^2 = I(2)D(2)^2
