5. Personnel Monitoring 👨‍⚕️ - Film Badges

What are the 4 types of Personnel monitoring devices?

Film Badge

Pocket Dosimeter

TLDs

OSL

What is the most commonly used personnel monitoring device?

Film Badge

Materials used in film badge

1. dental film with lead foil (to absorb backscatter)

2. varying thicknesses (and materials) used to measure the Energy of the radiation that the worker was exposed to

Film Badge (or any personnel monitoring badge) will have ___ doses and ___ doses.

shallow (low dose)

deep (high dose)

Deep doses + shallow doses

Total Effective Dose Equivalent (TEDE)

another def for shallow dose

any internal dose

received by ingestion or inhalation

during the handling of radioactive materials

What types of radiation do Film Badges measure?

1. x-rays

2. gamma

3. beta

4. electrons

5. neutrons

Dose Range for film badge readings:

• 10mR-2000 REM

• doses ↓ 10mR = M (as in minimal)

mR (miliREM)

T/F: Film Badges protect you from exposure

False

1. Accuracy of Film Badges

2. Accuracy can be affected by

± 20%

1. anything that affects film

   1. heat

   2. mechanical pressure

   3. humidity

   4. etc

Duration for wearing film badges:

4 weeks

Where do you wear film badges?

1. on the Ant surface of the body. Between the neck and waist

2. At the collar if there is potential for significant exposure to eyes/thyroid-best answer

When wearing a lead apron, where should you wear your film badge? Over or under the apron?

over

Where should you store a film badge?

an area unexposed to light at the facility

Film badge disadvantage

length of time between readings

ring badge

1. what is it made of

2. where do you wear it

3. What is it used for

1. radiographic film

2. around your finger

3. for brachytherapy and nuclear medicine workers

Neutron badge: who wears these?

nuclear reactor and cyclotron workers

Pocket Dosimeter

1. Appearance

2. Principle of operation

fits in your shirt pocket

It is a condenser chamber (ion)

Pocket Dosimeter

1. Advantages

2. Disadvantages

1. immediate readings

2. A. Accuracy depends on avoiding:

   1. high humidity

   2. mechanical shock

   B. Calibration problems (FYI: has to constantly be recalibrated)

Pocket Dosimeter

Uses

Due to high upfront and calibration costs, and them being high maintenance, they are most useful for:

Personnel monitor in area of HIGH radiation concerns:

1. Nuclear power plants

2. Pantex

TLD stand for

Thermoluminescent Dosimeter

Thermoluminescent Dosimeter

Principle of Operation

TLDR: Thermoluminescent Dosimetry is based on imperfections in the crystal lattice and their ability to capture electrons released by ionizing radiation.

1. Crystal lattice is exposed to ionizing radiation which releases electrons

2. Electrons are trapped in imperfections (Mg) in the crystal lattice

3. TLD is sent off to be read

4. Crystal is heated up which releases Energy trapped in the lattice

5. Energy released comes out in the form of light

6. TLD reader reads the amount of light released

   The amount of light released is proportional to the dose

Crystals used for TLDs

1. Lithium Fluoride- most common

2. Lithium Borate

3. Calcium Fluoride

TLD:

1. advantages

2. disadvantages

1. Advantages

   1. Reusable

   2. Economical

   3. Small

   4. Accurate: ± 5%

2. Disadvantages:

   1. Storage instability

   2. Fading (less accurate after every use)

   3. TLD readers can be unstable

TLD uses

1. Personnel monitoring

2. Machine Dosimetry (calibration of machine)- tho not as useful for this

3. TSI: total skin irradiation

4. TBI: total body irradiation

5. Long term area surveys (e.g. brachytherapy room)

Define

1. TSI

2. TBI

1. TSI: irradiate the whole skin with electron tx

2. TBI: irradiate the whole body with MV x-rays

OSL stand for

Optically Stimulated Luminescence

OSL

Principle of Operation

1. Aluminum Oxide (Al2O3) is irradiated

2. Electrons are trapped in Aluminum Oxide

3. A laser light “reader” stimulates the electrons

4. The electrons recombine and give off light which is proportionate to the dose

5. Additionally, they use filters like film badges to determine radiation Energy

OSL:

1. Advantages

2. Disadvantages

1. Advantages

   1. Can read doses as low as 1mR (compared to 10mR for film badges)

   2. Accurate: ± 1mR

2. Disadvantages

   1. NA

Which company produces and reads most film badges and OSLs?

The Landauer Company