chapter 10 EXAM 5 Flashcards
effective dose limiting system
a set of numeric dose limits that are based on calculations of the various risks of cancer and genetic effects to tissues or organs exposed to radiation
What is the effective dose limiting system
the concept of radiation exposure and the associated risk of radiation induced malignancy
what are the 2 reasons medical imaging professionals must be familiar with previous, existing and new guidelines for radiation safety?
- they share the responsibility for patient safety from radiation exposure 2. they are subject to radiation exposure in the performance of their duties
T or F informed radiographers will be more conscious of good radiation safety practices
true
4 major organizations are responsible for evaluating the relationship between radiation EqD and induced biologic effects. those 4 organizations are:
- international comission on Radiological Protection (ICRP) 2. National Council on Radiation Protection and Measurements (NCRP) 3. United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 4. National Academy of Sciences/National Research Council Committee on the Biological Effects of Ionizing Radiation (NAS/NRC-BEIR)
what is the function of the ICRP
it evaluates information on biologic effects of radiation and provides radiation protection guidance through general recommendations on occupational and public dose limits
what is the function of the NCRP
it reviews regulations formed by the ICRP and decides ways to include those recommendations in the US radiation protection criteria
what is the function of UNSCEAR
it evaluates human and environmental ionizing radiation exposure and derives radiation risk assessments from epidemiologic data and research conclusions. It provides info to organizations such as the ICRP for evaluation
what is the function of NAS/NRC-BEIR
it reviews studies of biologic effects on ionizing radiation and risk assessment and provides the info to organizations such as the ICRP for evaluation
what does ICRP stand for
International Commission on radiological protection
what does NCRP stand for
National Council on Radiation Protection and Measurements
what does UNSCEAR stand for
United Nations Scientific Committee on the Effects of Atomic Radiation
what does NAS/NRC-BEIR stand for
National Academy of Sciences/National Research Council Comittee on the Biological Effects of Ionizing Radiation
what are the 5 US regulatory agencies
- Nuclear Regulatory Commission (NRC) 2. Agreement States 3. Environmental Protection Agency (EPA) 4. US Food and Drug Administration (FDA) 5. Occupational Safety and Health Administration (OSHA)
what do the US regulatory agencies do
they enforce the protection standards that have been determined for the protection of the general public, patients, and occupationally exposed personnel
what is the function of the NRC
oversees the nuclear energy industry, enforces radiation protection standards, enters into written agreements with state governments permitting the state to license and regulate the use of radioisotopes and certain other material within that state
what is the function of Agreement states
enforce radiation protection regulations through their respective health departments
what is the function of the EPA
facilitates the development and enforcement of regulations pertaining to the control of radiation in the environment
what is the function of the FDA
conducts an ongoing product radiation control program regulating the design and manufacture of electronic products including xray equipment
what is the function of OSHA
functions as a monitoring agency in places of employment, predominantly in industry
public law 90-602, the radiation control for health and safety act of 1968, the FDA
conducts an ongoing product radiation control program regulating the desing and manufacture of electronic products including diagnostic xray machines
T or F all facilities providing imaging services must have an effective and detailed radiation safety program to ensure adequate safety for pts. and workers
true
to maintain a radiation safety program you must do 3 things
- delegate operational funds in the budget 2. oversee the development of policies and procedures 3. provide the equipment necessary for starting and continuing the program
T or F the NRC mandates a radiation safety committee (RSC)
true
what is a radiation safety committee (RSC)
group that assists in the development of the radiation safety program in the health care facility provides guidance for the program and facilitates ongoing operation
Radiation safety officer (RSO)
medical physicist, health physicist, or radiologist responsible to ensure the internationally accepted guidelines for radiation protection are followed in the facility
what are the responsibilities of an RSO
implement and enforce the policies of the radiation safety program reviews and maintains radiation monitoring records for all personnel and be available to provide counseling for individuals
what is the required training and experience for and RSO
certification by a professional board approved by the NRC didactic and work experience identification as an authorized user
duties of the RSO
identify radiation safety problems initiate, recommend or provide corrective action stop unsafe operations verify implementation of corrective actions
radiation control for health and safety public law 90-602
passed by congress to protect the public from the hazards of unnecessary radiation resulting from electronic products such as microwaves and tv’s
what did the radiation control for health and safety public law 90-602 permit
it permitted the establishment of center for devices and radiological health CDRH
what are the responsibilities of the radiation control for health and safety law 90-602
assessing biologic effects of ionizing radiation evaluating radiation emissions from electronic products in general conducting research to reduce radiation expsure
what is the code of standards for diagnostic xray equipment
strictly an equipment performance standard
when did the code of standards for diagnostic xray equipment go into effect
august 1 1974
ALARA is synonymous with the term
optimization in accordance with ICRP publications
the ALARA concept presents a model in which the relationship is a
linear nonthreshold
what is stated in the FDA document known as the White Paper
each patient should get the right imaging exam at the right time with the right radiation dose
the FDA intends to take action to (3)
- promote safe use of medical imaging devices 2. support informed clinical decision 3. increase patient awareness
consumer-patient radiation health and safety act of 1981
provides federal legislation requiring the establishment of minimal standards for the accreditation of education programs for persons who perform radiologic procedures and the certification of such persons
what is the purpose of the consumer-patient radiation health and safety act of 1981
to ensure standard medical and dental radiologic procedures adhere to rigorous safety precautions and standards
NCRP reprot No. 116 limitation of exposure to ionizing radiation states the goal of radiation protection is
to prevent the occurrence of serious radiation induced cautions
what are the 2 categories for radiation induced responses
- deterministic effects 2. stochastic effects
deterministic effects
biologic somatic effects that can be directly related to the dose received occur only after high doses have a threshold dose
examples of early deterministic effects are
erythema epilation ARS
examples of late deterministic effects are
cataract formation fibrosis organ atrophy reduced fertility
stochastic effects
randomly occurring biologic somatic changes chance of occurring increase with increased radiation exposure
a stochastic event is
an all or non random effect and could result form exposure of a single cell or from damage in a sensitive structure . no safe dose exists
examples of stochastic effects
cancer genetic effects
2 objectives or radiation protection
- to prevent any clinically important radiation induced deterministic effects 2. to limit the risk of stochastic responses to a conservative level
current radiation protection philosophy is based on what?
the assumption of a linear nonthreshold relationship between dose and biologic response meaning even the smallest dose has a potential to cause harm
risk in general terms
the probability of injury ailment or death resulting from an activity
risk from medical imaging standpoint
the possibility of inducing radiogenic cancer or a genetic defect after irradiation
what is the current method for assessing radiation exposure and associated risk of biologic effects to radiation workers and the general public?
the effective dose limiting system
the effective dose limit concerns
the upper boundary dose of ionizing radiation that results in a negligible risk of bodily injury or hereditary damage
NCRp recommends radiation protection programs be designed to prevent individual workers from having
a total external plus internal cumulative EFD in excess of their age in years times 10 mSv
the greatest risk of radiation induced mental retardation occurred when the embyro fetus was exposed
8-15 weeks after conception
the concept underlying radiation protection
the essential concept is that any organ in the body is vulnerable to damage from radiation exposure
critical organs defined by the NCRP include
gonads, bone marrow, and lung tissue
tissue weighting factor indicates the
ratio of the risk of stochastic effects attributable to irradiation of a given organ or tissue to the total risk when the whole body is uniformly irradiated
what is the annual occupational effective dose limit
50 mSv (5rem)
the lifetime EfD limit should not exceed
10 times the occupationally exposed person’s age in years
cumulative Effective dose limit
radiation worker’s lifetime effective dose must be limited to his/her age in years times 10 mSv
effective dose limits do not include
radiation exposure from natural background radiation exposures from radiation worker undergoing medical imaging procedure
effective dose limits do include
internal exposure external exposure
collective effective dose
designated for use in the description of population or group exposure from low doses of different sources of ionizing radiation
collective effective dose is the product of
the average effective dose for an individual belonging to the exposed group and the number of persons exposed
what is the unit to express collective effective dose
person-sievert
ICRP recommendation for downward revision of the annual effective dose limit: in 1991 the ICRP recommended the reduction of the annual EFD limit for occupationally exposed persons from 50 mSv to what
to 20 mSc (2rem)
NCRP is still considering the possibility of reducing exposure standards because of 2 things
- revised risk estimates from a-bomb survivors 2. appearance from longer follow up time of increased numbers of solid tumors in the survivor population
the annual whole body EfD for ocupationally exposed persons in the U.S. may be limited to what per year
10-20 mSv per year
in the US lowering the current EfD limits is the responsibility of who
NRC, individual states and the FDA
Limits for non occupationally exposed individuals: EFD limit is what for continuous or frequent exposures from artificial sources other than medical irradiation and natural background radiation
1 mSv
Limits for non occupationally exposed individuals: EFD limit is what annually for infrequent exposure
5 mSv
limits for pregnant radiation workers NCRP recommends a monthly EqD limit not exceeding what to the embryo fetus
0.5 mSv per month to the embryo fetus
limits for pregnant radiation workers NCRP recommends a limit during the entire pregnancy not to exceed what
5.0 mSv after declaration of pregnancy
limits for education and training purposes: the limit for any education and training exposures of individuals under the age of 18 yrs is an EfD of
1mSv annually
limits for tissues and organs exposed selectively or together with other organs: what is the dose limit to crystalline lens of the eye
150 mSv
limits for tissues and organs exposed slectively or together with other organs: what is the dose limit for localizd areas of the skin, the hands, and feet
500 mSv
Negligible individual dose: an annual negligible individual risk of what per source of practice has been set
0.01 mSv a year
radiographers personnel dosimeter reading should be
well below a tenth of the max EfD limits
action limits
limits for occupational exposure that are set by the medical facility well below the regulatory values as they appear in state or federal regulations
what is radiation hormesis
effect that is a beneficial consequence of radiation for populations continuously exposed to moderately higher levels of radiation
radiation hormesis suggests that
risk from very small radiation exposure may be incorrect, however, until radiation hormesis theroy is proven we will always follow ALARA
effective dose limits for radiation workers and the population as a whole: as radiation workers the EfD is what for whole body occupational dose
50 mSv/year whole body occupational dose
special limits for selected areas: special limits are set for crystalline lens of eye and localized areas of the skin, hands, and feet to prevent
deterministic effects
