DOSE LIMITS FOR EPOSURE TO IONIZING RADIATION

Effective dose (EfD)

A dose calculated using the formula EfD = D x WR x WT, which factors in the type of radiation and the sensitivity of the tissue.

Equivalent dose (EqD)

A dose calculated using the formula EqD = D x WR, which accounts for the biological effect of different types of radiation.

ICRP

International Commission on Radiological Protection, an organization that provides radiation protection guidance and recommendations for dose limits.

NCRP

National Council on Radiation Protection and Measurements, reviews ICRP recommendations and formulates guidelines for US radiation protection.

UNSCEAR

United Nations Scientific Committee on the Effects of Atomic Radiation, evaluates ionizing radiation exposure and derives risk assessments.

Stochastic effects

Effects that occur by chance and whose probability increases with each radiation exposure, including cancer and genetic alterations.

Tissue reactions

Biologic somatic effects of radiation that are directly related to the dose received, can exhibit a threshold dose.

ALARA principle

A radiation safety principle ensuring exposure is kept 'As Low As Reasonably Achievable'.

NCRP report No. 116

Outlines Cumulative Effective Dose limits for radiation workers, recommending limits based on age.

Radiation Hormesis

The theory that low doses of radiation may have beneficial effects on health, though not yet proven.

NRC

The agency responsible for enforcing radiation safety standards.

Cumulative Effective Dose (CumEfD)

The total effective dose of ionizing radiation that a person has received over time.

Dose-Response Relationship

The correlation between the dose of radiation received and the biological effect observed.

Occupational Risk

The likelihood of exposure to hazardous conditions in the workplace.

Stochastic Effects

The probability of effects occurring increases with dose, without a threshold.

Radiation Safety Officer (RSO)

A professional responsible for developing and implementing radiation safety programs.

Monthly Equivalent Dose Limit

The maximum allowable radiation dose to be received by an individual in a month.

Embryo-Fetus Limit

The recommended dose limit for radiation exposure to a developing fetus during pregnancy.

Annual Occupational Effective Dose

The maximum amount of radiation exposure allowed for radiation workers in a year.

NCRP

National Council on Radiation Protection and Measurements; sets recommendations for radiation exposure limits.

What agency is responsible for enforcing radiation safety standards?

NRC

Determine the cumulative effective dose (CumEfd) to the whole body of an occupationally exposed person who is 27 years old.

270 mSv

Biologic effects such as cataracts that result from exposure to ionizing radiation appear to have what?

a sigmoid threshold dose - response curve

For radiation workers, such as a medical imaging personnel, occupational risk may be equated with occupational risk in…?

other industries that are generally considered reasonably safe

Revised estimates derived from more recent reevaluations of dosimetric studies on the atomic bomb survivors of Hiroshima and Nagasaki indicate what?

An increase in the number of solid tumors in the survivor population

when exposed to radiation as part of their educational experience, 18 year old students should NOT exceed an effective dose limit of _____ annually.

50 mSv

What group was provided sufficient evidence of the induction of stochastic effects in humans resulting from high radiation absorbed doses?

Japanese atomic bomb survivors

Responsibilities of a medical facility’s radiation safety officer (RSO) include what?

Developing an appropriate radiation safety program

Maintaining radiation monitoring records for all personnel

To reduce exposure for pregnant imaging professionals and to control the exposure of the unborn during potentially sensitive periods of gestation, the NCRP now recommends a monthly equivalent dose limit not exceeding ______ per month to the embryo-fetus and a limit during the entire pregnancy no to exceed ______ after declaration of a pregnancy.

0.5 mSv, 5.0 mSv

What is the annual occupational effective dose that applies to radiographers during routine operations?

50 mSv

Name all the Radiation protection standards organizations?

National Council on Radiation Protection and Measurements (NCRP),

International Commission on Radiological Protection (ICRP),

United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR),

American National Standards Institute (ANSI).

name all the US regulatory agencies?

Nuclear Regulatory Commission (NRC), Environmental Protection Agency (EPA), Occupational Safety and Health Administration (OSHA),

Food and Drug Administration (FDA).

Which US regulatory angency has a primary function to oversee the nuclear energy industry?

NRC

Most states in the US are known as _________ with the NRC, assuming the responsibility for enforcing radiation protection regulations through their respective health departments.

agreement States

_______ conducts product radiation control program, regulating the design and manufacturing of electronic products, including x-ray equipment.

Food and Drug Administration (FDA)

The _____ directs the federal agencies and has authority for specific areas such as determining the action level of radon. All of which to protect the health of humans and for safeguarding the natural environment.

Environmental Protection Agency (EPA)

_____ functions as a monitory agency in places of employment, regulates occupational exposure to radiation, and makes employees aware of hazards in the work place.

Occupational Safety and Health Administration (OSHA)

RSO duties

identify radiation safety problems
initiate, recommend, or provide corrective action

stop unsafe operations involving by-product material

Verify implementation of corrective actions

define the term ALARA and its purpose

ALARA stands for "As Low As Reasonably Achievable" and emphasizes minimizing radiation exposure to workers and the public by using all reasonable methods to reduce doses.

What are considered EARLY tissue reactions?

erythema

acute radiation syndrome

epilation

What are considered LATE tissue reactions?

cataracts

sterility

What are considered STOCASTIC EFFECTS?

cancer

What are considered GENETIC EFFECTS?

mutagenesis

What is the annual EfD limit?

50 mSv

What is the Cumulative EfD limit?

10 mSv x age

What is the Lens of eye for EqD annual limits for tissues and organs?

150 mSv

What is the Localized skin, hands, feet for EqD annual limits for tissues and organs?

500 mSv

For public exposures; What is the EfD, frequent exposure

1 mSv

For public exposures; What is the EfD, infrequent exposure

5 mSv

For public exposures; What is the EqD for tissue and organs, Lens of eye

15 mSv

For public exposures; What is the EqD for tissue and organs, Skin, hand, feet

50 mSv

For education and training exposures; EfD limit > 18 yrs

5 mSv

For education and training exposures; EfD limit < 18 yrs

1 mSv

For education and training exposures; EqD for tissues and organs, Lens of eye

15 mSv

For education and training exposures; EqD for tissues and organs, skin, hands, feet

50 mSv

For Embryo and fetus exposures; EqD for monthly

0.5 mSv

For Embryo and fetus exposures; EqD for Entire gestation

5.0 mSv