Dose Limits for Exposure to Ionizing Radiation

What is the effective dose (EfD) equation?

D x W_R x W_T

What is the equivalent dose (EqD) equation?

D x W_R

What is the 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

The effective dose limiting system is based on the risk of ___

radiation-induced malignancies

The EfD limiting system limits are documented in the ___

code of federal regulations

What are the 4 radiation protection standards organizations?

1. ICRP

2. NCRP

3. UNSCEAR

4. NAS/NRC-BEIR

What is the major difference between the radiation protection standards organizations and the regulatory agencies?

radiation protection standards organizations do the research

regulatory agencies make the laws

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 Committee on the Biological Effects of Ionizing Radiation

The international authority on the safe use of sources of ionizing radiation is the ___

ICRP

What is the leading international organization responsible for providing clear and consistent radiation protection guidance?

the ICRP

The ICRP provides recommendations for ___ and ___

occupational dose limits and public dose limits

The NCRP reviews recommendations formulated by the ___, and determines how they are ___

ICRP; incorporated into US radiation protection criteria

The NCRP formulates general recommendations that are ___ for federal and state agencies

guidelines

UNSCEAR assists in the formulation of ___

radiation protection guidelines

UNSCEAR evaluates ___ and ___ ionizing radiation exposures from a variety of sources

human and environmental

UNSCEAR evaluates what sources for ionizing radiation?

radioactive materials, radiation-producing machines, radiation accidents

UNSCEAR derives radiation risk assessments for ___ and ___

radiation-induced cancer and genetic (hereditary) effects

NAS/NRC-BEIR is an advisory group that reviews studies of biologic effects of ___ and ___

ionizing radiation and risk assessment

NAS/NRC-BEIR recommends for ___ limits and ___ limits

EfD and EqD

NAS/NRC-BEIR studies groups of people who were ___

routinely or accidentally exposed to ionizing radiation (such as early radiation workers, atomic bomb victims of Hiroshima and Nagasaki, evacuees from Chernobyl)

What are the 5 U.S. regulatory agencies?

1. NRC

2. agreement states

3. EPA

4. FDA

5. OSHA

What does NRC stand for?

Nuclear Regulatory Commission

What does EPA stand for?

Environmental Protection Agency

What does FDA stand for?

(U.S.) Food and Drug Administration

What does OSHA stand for?

Occupational Safety and Health Administration

What organization was formerly known as the Atomic Energy Commission?

the NRC

The NRC is a federal agency that has the authority to control ___

the possession, use, and production of atomic energy in the interest of national security

Does the NRC enforce radiation protection standards or regulate x-ray imaging facilities?

enforce radiation protection standards

The NRC supervises what 4 things?

1. design and working mechanics of nuclear power stations

2. production of nuclear fuel

3. handling of expended fuel

4. hazardous radioactive waste material

Explain agreement states

agreements permit the contracting state to undertake the responsibility of licensing and regulating the use of radioisotopes and certain other radioactive materials within that state

Agreement states assume the responsibility for enforcing ___

radiation protection regulations through respective health departments

The EPA is an agency responsible for protecting ___ and safeguarding ___

protecting the health of humans

safeguarding the natural environment

The EPA facilitates the development and enforcement of regulations pertaining to ___

the control of radiation in the environment

The FDA conducts ___ and ___

product radiation control programs

regulating design and manufacturing of electronic products (including Dx x-ray equipment)

Which organization conducts onsite inspections of x-ray equipment?

FDA

Which organization makes sure employees’ “right to know” with regard to hazard material is present in the workplace?

OSHA

OSHA regulates occupational exposure through ___

the US Code of Federal Regulations

The ___ ensures adequate safety of patients and radiation workers

radiation safety program

The NRC mandates that a radiation safety committee be established for a facility for ___

guidance of the safety program and facilitating ongoing operation

What 2 things is the radiation safety officer selected to do?

1. oversee the program’s daily operation

2. provide for formal review of program each year

According to federal regulations, a radiation safety program must have detailed procedures for handling and disposal of ___

radioactive materials

Containers are kept for a period of ___ half lives

10

Explain the Radiation Control for Health & Safety Act of 1968

• protect the public for hazards of unnecessary radiation exposure from electronic products

• assess biologic effects of ionizing radiation

• evaluate radiation emissions from electronic products

• conduct research to reduce radiation exposure

Another term for ALARA is ___

ORP (optimization for radiation protection)

The relationship between ionizing radiation and potential risk follows a ___ model

linear non-threshold

Explain the FDA “white paper” (2010)

• follows the premise that each patient should get the right imaging exam at the right time with the right dose

• promotes safe use of medical imaging devices

• supports informed clinical decisions

• increases patient awareness

Explain the Consumer-Patient Radiation Health and Safety Act of 1981

• provides federal legislation requiring minimal standards for the accreditations of education programs for persons who perform radiologic procedures and the certification of such persons

  • Requires federal laws that set basic standards for accrediting education programs for people who perform radiologic procedures and certifying those individuals.

• ensures that medical and dental radiologic practices adhere to safety standards

Tissue reactions are ___ that can be directly related to the dose received

biologic somatic effects of ionizing radiation

Tissue reactions exhibit a ___ dose

threshold

Erythema, decreased WBCs, epilation/alopecia, and acute radiation syndrome are examples of ___

early tissue reactions

Cataracts, fibrosis, atrophy, cell loss, reduced fertility, and sterility are examples of ___

late tissue reactions

Stochastic effects follow the assumption that ___

no minimal safe dose exists (any dose, no matter how small, can not be considered safe)

randomly occuring

___ effects are non-threshold

stochastic

Cancer and genetic alterations are examples of ___

stochastic effects

Define deterministic (tissue) effects

effects that occur in all individuals who receive greater than the threshold dose and for which the severity of the effect varies with the dose

What is the current method for controlling risk of biologic damage to radiation workers and the general public from radiation exposure?

effective dose (EfD) limiting system

What does EDL stand for?

effective dose limit

What is the EDL?

upper boundary dose of ionizing radiation that results in negligible risk of bodily injury or hereditary damage

Evidence of dose-dependent increase in the incidence of severe intellectual disability for fetal doses greater than ___

0.4 Sv

Greatest risk for intellectual disability occurred when embryo-fetus was exposed ___ weeks after conception

8-15

What is the Cumulative Effective Dose (CumEfD) limit?

lifetime EfD must be limited to age in years times 10 mSv

The ICRP wants to decrease EfD limit from 50 mSv annually to ___ mSv annually

20

What are action limits?

limits for occupational exposure that are set by the medical facility well below the regulatory values (purpose is to trigger an investigation when they are exceeded)

What is radiation hormesis?

concept that there is a beneficial result from continuing exposure to small amounts of radiation (IS NOT PROVEN)