Ch. 10 Flashcards
Exposure of the general public, patients, and radiation workers to ionizing radiation must be limited in order to
Minimize the risk of harmful biologic effects
Concept of radiation exposure and of the associated risk of radiation induced malignancy
Basis of EfD limiting system
What are the two resources used for revised recommendation
National council on radiation protection and measurements (NCRP)
International Commission on Radiological Protection (ICRP)
Medical imaging professionals must be familiar with previous, existing, and new guidelines for radiation safety because
They share the responsibility for pt safety
The are subject to radiation exposure in their duties
What are the four major organizations responsible for evaluating the relationship between radiation EqD and induced biologic effects.
ICRP, NCRP, UNSCEAR, NAS/NRC-BEIR
What are the 5 U.S. regulatory agencies
NRC, Agreement states, EPA, FDA, OSHA
Facilities providing imaging services shall have an active and detailed radiation safety program to ensure
The safety of patients and radiation workers
The radiation safety program must have the resources necessary for
Delegate operational funds in the budget
Oversee the development of policies and procedures
Provide the equipment needed for starting and continuing the program
The Nuclear Regulatory Commission mandates that a radiation safety committee be established for the facility.
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Who selects the RSO?
RSC (radiation safety committee)
An RSO should
Develop the radiation safety program.
Ensure the facilities radiation practices are adequate
Implement and enforce policies of the program
Review and maintain records
This law is used to protect the public from the hazards of unnecessary radiation exposure resulting from electronic products and diagnostic x-ray equipment
Radiation Control for Health and Safety Act of 1968
Law 90-602 of the Radiation Control for Health and Safety Act of 1968 does not regulate _______.
The diagnostic x-ray user. But it is strictly an equipment performance standard
When did the Code of Standards for Diagnostic X-ray Equipment go into effect
August 1, 1974
When was the ALARA concept put forth and by who?
1954 by the NCRP
What is ALARA also known as
Optimization
In the model for the ALARA concept, the relationship is assumed to be completely _______ and _______
Linear, no threshold
The FDA supports the premise that each patient should get the
Right imaging examination, at the right time, with the right radiation dose
FDA
White paper
This act provides federal legislation requiring the establishment of minimal standards for the accreditation of educational programs for people who perform radiologic procedures and certification of such people.
Consumer-Patient Radiation Health and Safety Act of 1981
What are the two radiation-induced responses
Tissue responses, stochastic effects
What are other names for tissue responses?
Somatic, nonstochastic, deterministic
Biologic somatic effects of ionizing radiation that can be directly related to the dose received. (Has a threshold)
Tissue reactions
Erythema, blood changes, epilation (loss of hair), acute radiation syndrome (hematopoietic, gastrointestinal, and cerebrovascular syndromes)
Early tissue reactions
Cataract formation, fibrosis, organ atrophy, loss of parenchymal cells, reduced fertility, and sterility
Late tissue reactions
Nonthreshold, randomly occurring biologic somatic changes
Stochastic effects
May be demonstrated with the use of both the linear and linear-quadratic dose-response curves
Stochastic effects
These limits may be expressed for whole body, partial body, and individual organ exposure
EfD limiting system
The sum of external and internal whole body exposure is considered for limits
EfD limiting system
The incidence of severe intellectual disability for fetal doses greater than approximately
0.4 Sv
Greatest risk for radiation-induced intellectual disability occurred when the embryo-fetus was exposed _____ weeks after conception
8 to 15
Indicates the ratio of the risk of stochastic effects attributable to irradiation of a given organ or tissue to the total risk when the body is uniformly irradiated
Tissue weighting factor (Wt)
Most sensitive to radiation when discussing Tissue Weighting Factor
Gonads (0.20)
Least sensitive to radiation when discussing Wt
Bone surface and skin (0.01)
A radiation workers lifetime EfD must be limited to his/her age in years times _____mSv
10mSv
Healthcare facilities may establish _____
Action limits
Personnel dosimeter readings should be well below ______ of the maximum EfD limits.
1/10th
The annual upper boundary limits take into account the ____ in all radiation-sensitive organs found in the body
EqD
Because the Wt factors used for calculating EfD are so small for some organs, an organ that is associated with a low Wt factor may receive an unreasonable large dose, whereas the EfD remains within the allowable total limit.
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