14. Cardinal Rules of Radiation Protection & Film Badges

The 3 cardinal rules of rad protection

STD:

1. shielding

2. time

3. distance

Which of the 3 cardinal rules is most important for teletherapy

shielding

Which of the 3 cardinal rules is most important brachytherapy

distance

Which of the 3 cardinal rules is least important for loading and unloading sources?

Shielding (cuz it’s usually  not available)

What is the most common type of personnel monitoring device?

Film badge

Recommended length of time to wear film badge

4 weeks

Film badges consist of

dental x-ray film with a lead foil to absorb backscatter

Types of radiation film badges can record?

• x-rays

• gamma

• beta (electrons)

• fast neutrons

Film badges will typically specify doses as either ___or___

deep or shallow

What is the sum of the deep + shallow doses measured in a film badge?

TEDE: Total Effective Dose Equivalent

What does TEDE stand for?

Total Effective Dose Equivalent

“Shallow dose” is also assigned to any internal dose received by

ingestion or inhalation during the handling of radioactive materials

Accuracy of film badges

± 20 %

Dose range for film badges

10mR -2000 REM (.1mSv - 20 Sv)

Readings less than 10 mR are reported as

“M” for minimal/minimum

Where do you wear film badges?

anterior surface of the body 

between the chest & waist 

What is the best single place to wear a badage?

Around the collar on the anterior surface of the body

The film badge should be worn (under/over) the lead apron

over

The film badge should be worn (under/over) the lead apron if you are pregnant

under

Atmospheric and adverse conditions that affect film badge readings

1. heat

2. humidity 

3. mechanical pressure 

4. exposure to light

5. prolonged delay between exposure and processing

Where should film badges be stored

unexposed area at the facility

Disadvantage of film badges

length of time between readings

Film badges (should/ should not) be worn during medical or dental exams

should not

Besides film badges name 3 other personnel monitoring devices

TLD

OSL

Pocket dosimeter

TLD stand for

Thermoluminescent dosimeter

OSL stand for

Optically stimulated luminescence

Active crystal in TLDs

Lithium Fluoride

What is more sensitive? OSLs or Film badges

OSL

Which is better at deliniating beam energy? film badges or OSL

OSL

OSLs can read doses starting from:

1mR (vs10 mR film badges)

Personnel monitoring device company

Landauer company