Basic Radiation Protection & Terminology

Most effects occur with high levels of radiation are not typically seen in diagnostic imaging

True

Factors influencing the effect of exposure to ionizing radiation:

1. dose received

2. rate at which the dose was received

3. age at exposure

4. type of radiation

5. sensitivity of the irradiated cells

6. portion of the body that was irradiated

Who determines that the diagnostic benefit of a radiologic exam far outweighs the risk from diagnostic levels of x-ray exposure?

Ordering physician/radiologist

Who was the first radiation-induced fatality in the U.S?

Clarence Dally in 1904

Early radiation workers suffered injuries that are easily prevented nowadays

True

In what year did the concerns over the effects of radiation lead to investigations and radiation protective devices?

1910

During the early days, how were x-ray workers routinely observed and monitored?

Periodic blood work

What is the number one source of Natural Environmental Ionizing radiation each year in the U.S?

Radon (2.0 mSv)

What is the number one source of Man-Made Ionizing radiation each year in the U.S?

CT Scanning (1.5 mSv)

Approximately what percentage of annual public exposure, in the U.S, is from medical sources?

50%

Sources of natural background radiation contributing to whole body radiation dose include:

Terrestrial radionuclides, internal radionuclides

Which has been identified as sources of radon exposure?

Indoors (basements), smoking cigarettes

What does ALARA stand for?

As Low As Reasonably Achievable

What are the Ten Commandments of Radiation Protection?

1. Understand and apply the principals of radiation control: time, distance, shielding

2. Do not allow familiarity to result in false security

3. Never stand, or place any part of your body in the primary beam

4. Always wear protective apparel when not behind a protective barrier

5. Always wear an occupational radiation monitor and position it outside the protective apron at collar level

6. Never hold a patient during radiologic exam, have family or friends do it

7. The person who is holding the patient must always wear a protective apron, thyroid collar, and protective gloves

8. Use gonadal shielding on all people of child-bearing age when such use will not interfere with the exam

9. Examination of the pelvis and lower abdomen of a pregnant patients should be avoided whenever possible, especially during the first trimester

10. Always collimate to the smallest field size appropriate for the exam

Is the use of a grid a means utilized to reduce patient exposure?

No

What organization that developed standards and regulations for radiation protection was charted by Congress in 1964?

National Council on Radiation Protection and Measurements (NCRP)

Kerma

This unit stands for the kinetic energy release in matter

Roentgen/ Gya

This measure of tube output applies only to x-rays and gamma rays and their interactions in air

Rem/ sievert

This is the unit of measure for the dose to biologic material and is used only for radiation protective purposes

Effective dose

This is the equivalent whole body dose

Rad/ Gyt

The unit describes the quantity of any type of ionizing radiation received by the patient

____ R = _____ rad = _____ rem

1

1 gray = _____ rad

100

What are the units of absorbed energy, absorbed dose, or energy deposited in any absorbing material?

Rad or gray (Gyt)

What does the acronym REM stand for?

Radiation equivalent man

Occupational radiation monitoring devices are typically analyze in terms of

Sievert or rem (mrem)

What is another way to express the formula absorbed dose x Wr x Wt= Effective dose?

Rad x QF = rem

What are the two quality factors?

• Wt = tissue weighing factor

• Wr = Radiation weighing factor

1 R = ____ C/kg

2.58 × 10^-4

Radiation output from a diagnostic x-ray tube is measured in which of the following units of measurement?

Air kerma (Gya)

What is the SI unit for the quantity of radioactive material, not radiation emitted by that material?

Curie/ becquerel

10 rad= ____ rem

10

The SI unit for rad is

Gray

The SI unit for exposure is

C/kg

1 rem= _____ Sv

0.01

1 Ci= _____ Bq

3.7 × 10^10

What are the units for absorbed dose?

Rad or gray

Occupational radiation exposure is expressed by what units?

Rem and sievert

This is the only unit that is used for radiation protection purposes and is used to express occupational exposure

Rem (Sievert)

This organization was charted by Congress in 1964

NCRP

In the equation (rad x QF)=rem, what does the QF stand for?

Quality factors