Personnel Monitoring

217 Topic 4

Personnel Monitoring

It refers to the monitoring of equivalent dose to any person occupationally exposed on a regular basis to ionizing radiation

wearing personnel dosimeters

Radiation exposure monitoring is accomplished by

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

Measure of radiation intensity is called

Dosimeters

Radiation measuring devices

F

T/F: The occupational radiation monitor offers protection against radiation exposure

personnel dosimeter

provides an indication of the working habits and conditions of the occupational worker

personnel dosimeter

determines occupational exposure over a period of time

1. When a protective apron is not used

2. When a protective apron is used

3. As a second monitor when a protective is used

4. As a monitor for the embryo-fetus

Placement of personnel dosimeters

front of the body at collar level

During routine radiographic procedures, the dosimeter should be attached to the clothing on the ________ level to approximate the location of maximal radiation dose

Thyroid, head, neck

(when protective apron is not used) the dosimeter should be attached to approximate the location of maximal radiation dose to:

Outside apron at collar level on anterior surface of the body

When a protective apron is used, dosimeter should be worn where?

warparound-style lead apron at waist level

placement of second monitor

pregnant radiologic technologist

Who should be given with a second personnel monitoring device

under protective clothing

placement of dosimeter when dealing with penetrating radiation

outside of protective clothing to ensure proper measurement of shallow dose

placement of personnel monitor when non-penetrating radiation type (<20 keV) and the eyes or substantial areas of skin are unprotected

thin plastic bag to avoid cross contamination

placement of dosimeter for areas with potential contamination

Underneath vest

placement of dosimeter when lead vest/apron is used

1. Lightweight and easy to carry

2. Durable

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

4. Not affected by outside influences

5. Cost-effective

Personnel Monitoring Devices characteristics

Film badge

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 badge filters

related

Optical density on the exposed and processed film is ___ to the exposure received by the film badge

1. Inexpensive

2. Easy to handle and process

3. Reasonably accurate

Film badge advantages

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

2. Exposures less than 100 uGy (10 mR) are not measured

Film badge disadvantages

appropriate side to the front

Film badges must be worn with

Lithium fluoride in crystalline form (powder or small chips)

sensing material of TLD

photomultiplier tube or photodiode

How is visible light measured

1. More sensitive and more accurate than a film badge

2. Can measure exposure as low as 50 uGy (5 mR)

3. Does not suffer from loss of information

TLD advantages

1. Initial cost is high

2. Can be read only once

TLD disadvantages

1 month - 1 year

TLD occupational radiation monitors can be worn for intervals ?

wrist or finger

extremity personnel monitors are worn on the?

TLD rings

also known as extremity dosimeters

TLD rings

May be used by an imaging professional as a second monitor when performing procedures that require hands to be near the radiation source

avoid contamination

Typically worn under gloves to ___

1. heats crystals to free trapped, highly energized electrons

2. records amount of light emitted by crystals

TLD analyzer process

glow curve

represents a unique signature of the exposure received by the TLDs

Optically stimulated luminescence dosimeter

most common type of device used for monitoring occupational exposure in diagnostic imaging

aluminum oxide detector

OSL sensing material

aluminum, tin, copper

OSL filters in detector packet

proportion to the amount of radiation exposure received

When laser light is incident on the sensing material, it becomes luminescent in ____________

uGy (1 mR)

OSL can measure exposures as low as?

Control monitor

measures background exposure during transportation, handling and storage

pocket dosimeter or pen dosimeter

Pocket Ionization Chamber other name

T

T/F: the use of PIC in diagnostic imaging is uncommon

Slender cylindrical ionization chamber

PIC contains a?

1. Immediate exposure readouts

2. Compact, easy to carry and convenient to use

3. Reasonably accurate and sensitive

4. Useful for procedures of relatively short duration

Pocket Ionization Chamber Advantages

1. Fairly expensive

2. May give an inaccurate reading

3. No permanent record of exposure

Pocket Ionization Chamber Disadvantages

Digital Ionization Dosimeter

Provides an immediate measurement of exposure while maintaining long-term exposure tracking

Digital Ionization Dosimeter

contains a small ionization chamber that responds by producing small collections of electrical charge

gate ; readout

When connected to a computer, a small voltage is delivered to a transistor “__” provides a digital signal “____” that reflects the radiation exposure of the dosimeter

Lifetime

___ occupation radiation exposure must be recorded

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 Dose 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)

Shallow Dose Equivalent, Hp (0.07)

For the assessment of superficial organs at a tissue depth of 0.007 cm (7 mg/cm^2)

Eye Dose Equivalent

The dose equivalent to the lens of the eye at a tissue depth of 0.3 cm (300 mg/cm^2)

Total Effective Dose Equivalent

The sum of deep dose equivalent (for external exposures) and the committed effective dose equivalent (for internal exposure)

0.10 Sv

MDL of TLD system

0.50 mSv per month

Equivalent IL

1.67 mSv

monthly AL dose limit

partially shielding by certain artifacts, used without dosimeter holder, and/or worn without following the proper orientation, among other reasons

Ratio Error (RAT Error) Causes

normal background area, away from radiation sources

(Exposed Control) Control badge should be placed in a _