Personnel Monitoring

Personnel monitoring

It refers to the monitoring of equivalent

dose to any person occupationally

exposed on a regular basis to ionizing

radiation

personnel dosimeters

Radiation exposure monitoring is

accomplished by wearing ...

Occupational radiation monitoring

... is required when there is any likelihood that an individual will receive more than one tenth of the recommended dose limit

one tenth

Occupational radiation monitoring is required when there is any likelihood that an individual will receive more than ... of the recommended dose limit

Dosimetry, dosimeters

The measure of radiation intensity is called ..., and the radiation measuring devices are called ...

T

T or F:

The occupational radiation monitoring offers no protection against radiation exposure!

Personnel dosimeters

provides an indication of the working habits

and conditions of the occupational worker

Personnel dosimeter

determines occupational exposure over a

period of time

- provides an indication of the working habits

and conditions of the occupational worker

- determines occupational exposure over a

period of time

The purpose of personnel dosimeters:

- Thyroid

- Head

- Neck

During routine radiographic procedures, the

dosimeter should be attached to the clothing on the front of the body at collar level to approximate the location of maximal radiation dose to:

outside

During fluoroscopic and special radiographic

procedures, the dosimeter should be worn ...

the apron at collar level on the anterior surface of the body

Outside, collar level ; Beneath, waist level

As a second monitor when a protective apron is used:

The primary dosimeter is worn ... the protective apparel at ... level, whereas the second dosimeter should be placed ... a wraparound-style lead apron at ... level

Second personnel monitoring device

As a monitor for the embryo-fetus:

The pregnant radiologic technologist should be provided with a ...

Philippine Nuclear Research Institute

PNRI

International Atomic Energy Agency

IAEA

Underneath, efficiency of the vest or apron

Philippine Nuclear Research Institute,

Personnel Monitoring Service:

When a lead vest/apron is used, place the dosimeter ... it in order to measure ... in protecting the personnel

- Lightweight and easy to carry

- Durable

- Detect and record both small and large exposures in a consistent and reliable manner

- Not affected by outside influences

- Cost-effective

Characteristics of Personnel monitoring devices:

1. Film badges

2. Thermoluminescence dosimeters (TLDs)

3. Optically stimulated luminescence (OSL) dosimeters

4. Pocket ionization chambers

5. Personnel digital ionization dosimeters

Types of Personnel monitoring devices currently widely used to measure occupational exposure:

Film badge

These are specially designed devices in which a

special radiation dosimetry film is sandwiched

between metal filters (usually aluminum and copper) inside a plastic holder

Aluminum and copper

Film badges are specially designed devices in which a special radiation dosimetry film is sandwiched between metal filters (usually ... and ...) inside a plastic holder

- Inexpensive

- Easy to handle and process

- Reasonably accurate

Film badge, Advantages:

- Cannot be reused and worn longer than 1 month because of possible fogging

- Exposure less than 100 µGy (10 mR) are not

measured

Film badge, Disadvantages:

Possible fogging

Film badges cannot be worn longer than 1 month because of ...

lithium fluoride (LiF), crystalline form

The sensing material of the TLD is ... in ... form (powder or small chips)

excited electrons

When exposed to x-rays, the TLD absorbs energy and stores it in form of ... in the crystalline lattice

heated

TLDs: When ... , these excited electrons fall back to their normal state with the emission of visible light

- More sensitive and more accurate than a film badge

- Can measure exposure as low as 50 µGy (5 mR)

- Does not suffer from loss of information

Thermoluminescence Dosimeters, Advantages:

- Initial cost is high

- Can be read only once

Thermoluminescence Dosimeters, Disadvantages:

1 year

TLD occupational radiation monitors can be worn for intervals up to ...

Wrist or the finger

Extremity personnel monitors are worn on the ... or the ...

Extremity dosimeters

Thermoluminescence Dosimeters (TLDs) Rings aka ...

Thermoluminescence Dosimeters (TLDs) Rings

May be used by an imaging professional as a

second monitor when performing procedures

that require hands to be near the radiation

source

Under gloves, contamination

TLDs rings are typically worn ... to avoid ...

TLD analyzer

A ... first heats the crystals to free the

trapped, highly energized electrons, and then recording the amount of light emitted by the crystals

glow curve

A ... represents a

unique signature of the

exposure received by the

TLDs

Optically Stimulated Luminescence (OSL) Dosimeter

Second most sensitive dosimeter

Optically Stimulated Luminescence (OSL) Dosimeter

It is the most common type of device used for

monitoring occupational exposure in diagnostic

imaging

Aluminum oxide detector

OSL contains ... as its sensing material

Aluminum, tin, and copper

OSL, Three different filters are incorporated into the

detector packet:

Can measure exposures as low as 10 µGy (1 mR)

Optically Stimulated Luminescence (OSL) Dosimeter, Advantages:

Control monitor

The ... measures background exposure during transportation, handling, and storage

Pocket dosimeter or pen dosimeter

Pocket ionization chamber simply called as ... or ...

Pocket Ionization Chamber

It is the most sensitive type of personnel dosimeter,

but its use in diagnostic imaging is uncommon

Pocket Ionization Chamber

It contains a slender cylindrical ionization chamber

that measures radiation exposure

- Immediate exposure readouts

- Compact, easy to carry and convenient to use

- Reasonably accurate and sensitive

- Useful for procedures of relatively short duration

Pocket Ionization Chamber, Advantages:

- Fairly expensive

- May give an inaccurate reading

- No permanent record of exposure

Pocket Ionization Chamber, Disadvantages:

Digital Ionization Dosimeter

Provides an immediate measurement of exposure while maintaining long-term

exposure tracking

1. Annual limit on intake (ALI)

2. Committed dose equivalent (CDE)

3. Committed effective dose equivalent (CEDE)

4. Deep dose equivalent (DDE)

5. Shallow dose equivalent (SDE)

6. Eye dose equivalent (EDE)

7. Total effective dose equivalent (TEDE)

Requirements for Personnel Monitoring:

Annual limit on intake

The derived limit for the amount of radioactive material taken into the body of an adult worker by inhalation or ingestion in a year.

Committed dose equivalent

The dose equivalent to organs or tissues

that will be received from an intake of

radioactive material

Committed effective does equivalent

A measure of the overall risk associated with

internal deposition of radioactive material

Deep dose equivalent, Hp(10)

- For the assessment of deep organs at a

tissue depth of 1 cm (1000 mg/cm^2)

- Provides an effective dose value sufficiently

precise for radiological protection purposes

Shallow Dose Equivalent, Hp(0.07)

- For the assessment of superficial organs at

a tissue depth of 0.007 cm (7 mg/cm^2)

- An operational quantity for individual

monitoring for the assessment of the dose

to the skin and to the hands and feet

1 cm (1000 mg/cm^2)

Deep dose equivalent:

For the assessment of deep organs at a

tissue depth of ...

0.007 cm (7 mg/cm^2)

Shallow Dose Equivalent:

For the assessment of superficial organs at

a tissue depth of ...

Eye Dose Equivalent

The dose equivalent to the lens of the eye

at a tissue depth of 0.3 cm (300 mg/cm^2)

0.3 cm (300 mg/cm^2)

Eye Dose Equivalent:

The dose equivalent to the lens of the eye

at a tissue depth of ...

Total Effective Dose Equivalent

The sum of deep dose equivalent (for

external exposures) and the committed

effective dose equivalent (for internal

exposure)

deep dose equivalent (for external exposures)

and the

committed effective dose equivalent (for internal exposure)

Total effective dose equivalent is the sum of ... and the ...

Philippine Nuclear Research Institute

Responsible for reading and monitoring our personnel monitoring devices

Minimum Detection Limit

MDL

0.10 mSv

MDL of the OSLD system is ...

Investigation limit

Radiation dose levels that are 1/3 the prescribed monthly dose limit

Action level

This has exceeded the dose limit for monthly monitoring period

Ratio error (RAT error)

Reading errors that occur when dosimeters are exposed abnormally

Exposed control

During evaluation of the dosimeter, the control badge was found to exceed the limit for the monitoring period

0.10 mSv

The MDL of the TLD system is ...