Chapter 10 - DOSE LIMITS FOR EXPOSURE TO IONIZING RADIATION Flashcards
Who set the rules and regulations for dose limiting?
Nuclear Regulatory Commission (NRC)
____ risk associated with exposure to ionizing radiation is the basis for effective dose limiting system
Cancer
What are the organizations that make recommendations or evaluate relationships to dose and biologic effect and formulates risks?
ICRP, NCRP, UNSCEAR, NAS/NRC-BEIR
What is the ICRP?
occupational and public dose limits since 1928
What is the NCRP?
sets goals for Radiation Protection
What is the UNSCEAR?
United Nations Scientific Committee on the Effects of Atomic Radiation, evaluates human and environmental exposure to radiation from many sources
What is the NAS/NRC-BEIR?
studies on early radiation workers, atomic bomb victims of Hiroshima/Nagasaki, evacuees from the Chernobyl nuclear power station disaster, review studies of biologic effects of ionizing radiation and risk assessment
What are the US Regulatory Agencies that enforce standards?
NRC, EPA, FDA, OSHA
What is the NRC?
Nuclear Regulatory Commission - production of radioactive substances, in agreement states the NRC assumes responsibility of entering radiation protection regulations through health departments, in non-agreement states both the state and NRC enforce regulations
What is the EPA?
environment protection agency, protecting health of humans and safeguarding the environment (radon)
What is the FDA?
US food and drug administration, regulate design and manufacturing of electronic products like x-ray equipment
What is OSHA?
Occupational safety and health administration, monitoring agency for employment, enforces employee “right to know”
What is the purpose of the Radiation Safety Program?
delegating operational funds in the budget, overseeing the development of policies and procedures, provide the equipment needed for starting and continuing the program
What are the functions of the Radiation Safety Committee?
provide guidance for the program, facilitates ongoing operation of the program, selects a qualified person to serve as a radiation safety officer
What are the duties of the Radiation Safety Officer?
oversee daily operations of radiation safety program, ensures facility’s radiation practices are adequate, implement and enforce policies of the program, they are to develop the program, protect workers from unnecessary exposure, review and maintain radiation monitoring records, provide counseling for individuals receiving doses in excess of allowable limits
What is the Radiation control for Health and Safety Act of 1968
protect the public from the hazards of unnecessary radiation exposure resulting from electronic products and diagnostic x-ray equipment, act caused CDRH (Center for Devices and Radiologic Health) to be established under the FDA
When did the NCRP establish ALARA?
1954
ALARA is also known as
ORP Optimization of radiation protection
What are the two investigation levels and when are they started?
Level 1 - 10% of maximum
Level 2 - 30% of maximum
What type of relationship does ionizing radiation have with the potential risk?
linear non threshold
What is the FDA White Paper enforcement?
initiative to reduce unnecessary radiation exposure from medical imaging, each patient should get the right imaging examination at the right time with the right radiation dose
What act required that only trained technologists perform diagnostic imaging procedures?
Patient Radiation Health and Safety Act of 1981
What are other terms for tissue reactions?
non-stochastic or deterministic
What are tissue reactions?
biologic somatic changes directly related to dose received
_____ reactions happen with hours or days after high levels of radiation, some examples are erythema, decreased WBC count, epilation, and acute radiation syndromes
early
______ reactions happen within months or years after high levels of radiation and are considered somatic effects, examples are cataracts, fibrosis, organ atrophy, loss of parenchymal cells, reduced fertility, and sterility
late
The shape on a diagram of a non linear threshold dose response is
sigmoidal
Stochastic effects are
cancer or genetic changes, can randomly occur, severity is not dose dependent, can be linear, non-threshold and linear or quadratic, causes damage to reproductive cells
How do you calculate cumulative effective dose?
age in years x mSv
When is an embryo/fetus at greatest risk of radiation exposure
8-15 weeks
What are the most critical organs?
gonads, blood-forming organs, red bone marrow, lung tissue
______ ______ ______ accounts for radio sensitivity differences in risk from one tissue to another
tissue weighting factor
What is the annual occupational effectiveness dose limit
50 mSv
______ ______ _____ is the average effective dose of an individual belonging to the exposed population
collective effective dose
What are the limits for non occupationally exposed invidviduals
Frequent - 1 mSv annually
Infrequent - 5 mSv annually
_____ is the amount of radiation per month that a pregnant radiation worker is allotted and ______ for the entire gestational period
.5 mSv
5 mSv
Excessive dose during pregnancy can cause
small head size and intellectual disability
_____ is the amount of radiation allowed during education and training
1 mSv
_____ is the amount of exposure allowed for the lense of the eye and _____ is allowed for the skin hands and feet both for occupation
150 mSv
500 mSv
Radiation ______ is a concept that there exists a beneficial aspect or result to groups of individuals from continuing exposure to small amounts of radiation
hormesis
How many states have a background radiation levels higher than other states by 1 mSv allowing 15% less cancer deaths per 1,000 individuals than the US average
7 states
