radiation safety training - radworker-initial.pdfa wave radiation consisting of a photons travels at...

Radiation Safety Training

Radioactivity is the property of certain nuclides to spontaneously emit particles and/or waves (photons)

These nuclides are called radionuclides, radioisotopes, or just isotopes

The nucleus in the atom of a radioisotope is unstable

To become stable, it releases particles or rays

Radiation is the emission and propagation of energy in the form of particles or waves through a medium

Particulate radiation includes alpha, beta, and neutron radiation

Wave radiation include light, UV radiation, gamma radiation, and x-rays

Particulate radiation consisting of an electron

Relatively light particle moving at up to 99% the speed of light

Travels deep into matter depending upon its energy

An internal or external health hazard depending on the isotope

Plexiglas shielding

H-3: Energy max = 0.19 Mev: Internal Hazard

C-14: Energy max = 0.26 Mev: Internal Hazard

S-35: Energy max = 0.17 Mev: Internal Hazard

P-32: Energy max = 1.7 Mev: Internal and external hazard

Particulate radiation consisting of two protons and two neutrons (helium nucleus)

Emitted by heavy nuclides (uranium, thorium, radium, and radon)

Relatively heavy particle moving at 80% the speed of light

Does not travel very deep in matter Internal health hazard

A wave radiation consisting of a photons

Travels at the speed of light

Highly energetic

Deeply penetrating in matter

Lead shielding required depending on the energy of the radiation

Internal and external hazard

Cr-51 (0.32 MeV), I-125 (0.04 MeV)

A wave radiation traveling at the speed of light and similar to gamma radiation

Deeply penetrating in matter Lead shielding required depending on the

energy of the radiation Internal and external hazard Produced as an interaction with matter or by

x-ray tube emission

Literally: breaking radiation Electromagnetic radiation produced when an

electrically charged particle is slowed down by the electric field of an atomic nucleus

Example: the electron emitted by a P-32 atom will interact with lead to give off an x-ray

The Curie: abbreviated Ci

1 Ci = 37E10 disintegrations per second

1 Ci = 2.2E12 disintegrations per minute

1 Ci = 1000 milliCi – 1E6 micro Ci

The Becquerel: abbreviated Bq

International Unit

1 Bq = 1 disintegration per second

1 Bq = 2.7E-11 Ci

Also megaBq and gigaBq

A disintegration is the same as a transformation.

For example when P-32 disintegrates it is actually transforming to S-32, which is a stable isotope.

Some radioisotopes transform to another radioisotope, which is also radioactive.

Example: Radium transforms to Radon

The half life of a materials is the time required for half of the radioactive atoms present to decay

The half life is a distinct value for each radioisotope

Radiological or physical half life

Biological half life

Nitrogen–17: 4.14 seconds Phosphorus-32: 14.3 days Tritium: 12.3 years Carbon-14: 5,730 years Uranium: 4,500,000,000

years

You receive a shipment of 250 uCi of P-32

The half life of P-32 is 14.3 days

If you do not use the P-32 until 14.3 days after receiving the material, you will only have 125 uCi left

If you wait 28.6 days, you will only have 62.5 uCi left

After 10 half lives, there will only be 0.24 uCi left

The Roetgen: named after discoverer of the x-ray

Ability of photons to ionize air

Applies only to photons in air

Equal to 2.58E-4 Coulombs/Kg

Absorbed Dose (D)

D in Units of Rads

Energy actually depositied in matter

1 Rad – 100 ergs of deposited energy per gram of absorber

International Unit: 1 Gray – 100 Rads

Dose Equivalent (H)

H in units of REM

H = quality factor (Q) times the absorbed dose (D)

• Q equals 1 for beta, gamma and x-rays

• 5-20 for neutrons

• 20 for alpha

International Unit 1 Sievert = 100 REM

Anticipate only beta, gamma and x-ray emitters

Quality factor equals 1

Therefore a Roetgen equals a Rad equals a Rem

Exposure reports in REM

Natural and man-made sources of radiation everybody is exposed to in their daily lives.

*Can show up as exposure on an individuals film badge if not corrected with a control badge

Typically 40 to 50 mrem per month

620 mrem/yr according to NCRP Report 160 published in 2009

Terrestrial: rocks, soil, and radon

Cosmic: the sun and outside the solar system

Man-made: medical, consumer goods and nuclear power

Uranium and daughter products in rocks and soil (U238 Ra226 Rn222 Po218)

Radon in houses

Pb-210 and P0-210 in tobacco

Tritium in the atmosphere

Radon in domestic water

Potassium-40 in foods

Smoke detectors

Coleman lantern mantles

Airport luggage scanners

Fiesta ware

Static eliminators

Building material

Luminous watches

Terrestrial

(Cosmic) Radon Medical Consumer

products

Total

81 mRem

229 mRem 298 mRem 12 mrem

620 mRem

Data based on large exposures to individuals in the first half of the century

Exposure to radiation in excess of 50 rads (R) over a short period of time

Exposure to individuals at nuclear power plants, hospitals, and research orders of magnitudes smaller

All occupational exposure limited by city, state, or federal regulations

Researchers first working with radioactive material and radiation producing devices

Early use of radiation in the medical profession

Radium dial painters

Exposure to atomic bomb detonation

Radioactive material in medical research

Damages cells by breaking the DNA bonds Chemical or mechanical reaction Chemical: Generates peroxides which can

attack the DNA Mechanical: Direct hit to the DNA by the

radiation Damage can be repaired for small amounts of

exposure

Muscle Radioresistant

Stomach Radiosensitive

Bone Marrow Radiosensistive

Human Gonads Very Radiosensitive

Acute exposure: large dose in short period Acute Effects: symptoms arise soon after

exposure (nausea, vomiting, loss of hair, blood changes, etc.)

Chronic exposure: small doses over long period

Latent Effects: symptoms appears some time, perhaps years, after an exposure (cataracts, cancer, genetic effects)

If an individual receives a dose in excess of 100 Rem in a short period of time,

he/she will experience acute effects (changes in blood composition

observable).

Skin: early researchers using x-rays

Leukemia: Early radiologists and bomb survivors

Bone Cancer: Radium dial painters

Lung Cancer: Miners in radium mines

The amount of time over which the dose was received

The type of radiation

The general health of the individual

The age of the individual

The area of the body exposed

• The level of exposure is related to the risk of illness

• While the risk for high levels of exposure is apparent, the risk for low levels is unclear

• Estimated that 1 rem of exposure increase likelihood of cancer by 1 in 10,000

• Though the likelihood of cancer in ones life time is 1 in 3 from all other factors

State of Maine required dose limit: 5 rem whole body (WB)

USM policy requires that action be taken at: 0.5 rem

Anticipated exposure at USM is far below the 0.5 rem amount

Exposure limit to pregnant women: 0.5 rem for the term of pregnancy

Should be kept less than 0.1 mRem/hour

Use principle of ALARA

Decontaminate area as needed

Shield sources as needed

Request a waste pickup to remove “Hot” waste

Ingested radioisotopes may accumulate in certain organs

Radium and Stroncium in the bones and Iodine in the thyroid

However, is useful in diagnostic procedure

Technetium-99m

Follow the correct experimental protocol

Wear personal protective equipment

If required, use a fume hood

No eating, drinking or applying cosmetics

Clean up spills promptly

Routinely monitor work area

Secure radioactive material

Declared Pregnancy

Ordering Radioactive Material

Receipt of Radioactive Material ◦ With warning labels

◦ Without warning labels

Tracking Material

Radioactive Waste

Transfer of Material to another institution

No direct evidence of increased birth defects or childhood leukemia or other cancers from exposure at universities

May extrapolate from high-dose data, but may subject to uncertainty

The incident from radiation exposure would be masked by the natural incidence due to all other factors.

In embryo stage, cells are dividing very rapidly and undifferentiated in their structure

More sensitive to radiation exposure

Especially sensitive during the first 2 to 3 months after conception

Risk of cancer and retardation increases with exposure

Contact the RSO if you know or suspect your pregnant

Issued a special dosimeter during the term of the pregnancy

Limit total dose to 0.5 rem with a monthly dose of 0.05 during the term of the pregnancy

Follow all mandatory procedures and use protective devices

Must continue to perform duties unless alternative arrangements are made with PI

If concerned may resign or request a leave of absence

Remains in effect until the declared pregnant woman withdraws the declaration in writing.

Patient exposure for treatment and therapy

Patient exposure in diagnostic procedures

Radiation exposure to nuclear power plant workers

Radiation exposure to radiologist, radiological technicians, and nurses

Radiation exposure to medical research staff

Time: minimize the time you are exposed to radiation

Distance: Maintain the maximum distance possible between yourself and the source of the ionizing radiation.

Shielding: Protect yourself with shielding when you are working with ionizing radiation.

At one (1) foot the dose rate from a I-125 source is 10 mRem/hour.

If you stand back to two (2) feet from the source, the dose rate will decrease to 2.5 mRem/hour.

If you stand back three (3) feet from the source, the dose rate will be 1.1 mRem/hour.

Lead for gamma and x-ray emitters such as I-125, Cr-51, Na-22, Co-60, etc.

Plexiglass for high energy beta emitters such as P-32 and Sr-90

Low-level survey meter

High-level survey meter

Wipe test counting instrument

Shielded storage

Shielded waste container

Shielded L-block

Fume hood

Caution signs

Personal monitoring

Type A Laboratory: Specially designed for handling large activities of highly radioactive materials.

Type B Laboratory: Specially designed as radioisotope laboratory.

Type C Laboratory: Good quality chemical laboratory

RADIOTOXICITY

OF

RADIONUCLIDES

TYPE OF LABORATORY REQUIRED

TYPE A TYPE B TYPE C

VERY HIGH ≥ 10 mCi 10 uCi - 10 mCi < 10 uCi

HIGH ≥100 mCi 100 uCi - 100 mCi < 100 uCi

MODERATE ≥1 Ci 1 mCi - 1 Ci < 1 mCi

LOW ≥10 Ci 10 mCi - 10 Ci < 10 mCi

FACILITIES AND

EQUIPMENT

REQUIRED

TYPE OF LABORATORY

TYPE A TYPE B TYPE C

Low-level survey

meter

YES YES YES

High level survey

meter

YES YES NO

Wipe test counting

instrument

YES YES YES

Shielded isotope

storage areas or

containers

YES YES YES

Shielded waste areas YES YES NO

Shielded L-blocks YES YES NO

Fume Hood YES YES NO

Caution signs YES YES YES

Personnel monitoring YES* YES* YES*

* Depending on isotopes being handled and current approved policies.

RELATIVE RADIOTOXICITY OF RADIONUCLIDES

VERY HIGH HIGH MODERATE LOW

Am-243 Ac-228 Au-198 Co-58m

Cf-249 Bi-207 Be-7 Cs-125

Cm-244 Ce-144 C-14 Ge-71

Pa-231 Cl-36 Cr-51 H-3

Pb-210 Co-56 Gd-153 Kr-85

Po-210 Co-60 La-140 Nb-97

Pu-238 Hf-181 Na-24 O-15

Ra-226 I-125 P-32 Os-191m

Ra-228 I-131 Ru-103 Rb-87

Th-227 Ir-192 S-35 Rh-103m

Th-232 Na-22 Sc-48 Tc-99m

U-238 Sb-125 Sr-91 Xe-131m

Zr-95 Te-125m

Cs - 137 V-48

W-187

Y-90

Zn-65

Zn-69m

250 microcuries(uCi)

0.000250 Curies

9.25 megabecquerels

9,250.00 dps

Uranyl Acetate is composed of 99% U238 and <1% U235

Is radioactive and highly toxic

Emits Alpha, Beta, and minute Gamma energies

Used primarily for staining of cells to be viewed using Electron Microscopy

Uranium (VI) Oxide Depleted uranium - U238 Used for staining of cell

structures Is radioactive and highly toxic Emits Alpha, Beta, and minute

Gamma energies

Faxitron X-RAY system

Uses X-ray tube to generate x-ray

Door is double interlocked to prevent x-ray activation when open

Radiation exposure levels depend on distance from tube and energy setting.

Niton XRF Analyzer Hand held x-ray emitting device. Mounts to shielded fixture for

stand alone x-ray examination of samples

Can be “trigger” or button activated menu operated.

Geiger Mueller (G-M)

Gamma and x-ray

High energy beta particles

Sodium Iodide Detector

Gamma and x-ray

Not currently in use

Used for beta, gamma, and x-ray emitting isotopes

Best for P-32, S-35 and C-14

Good for I-125, Cr-51, & U-238

Not good for H-3

Check calibration date

Calibrated annually Check batteries Replace batteries if

necessary Confirm operational

using radioactive source on side of device.

Definition: Radioactive material in an undesired location

Undesired locations: surfaces, skin, internal, airborne

Types: removable and fixed

A survey meter may be used to detect large quantities of high energy beta and gamma emitters on a surface

For smaller quantities of contamination on surfaces and low energy beta emitters, use the wipe test method

Choose equipment and surfaces to wipe

Use a filter paper or Q-tip

Moisten the paper or Q-tip

Wipe approximately 100 cm2

Place filter paper or Q-tip in scintillation vial

Add scintillation fluid – 3mg

Place in scintillation counter

Set scintillation counter to detect radioisotopes used in laboratory

Add 3ml scintillation fluid to vials

Place Q-tip end in scintillation vial

Place in scintillation counter

Set scintillation counter to detect radioisotopes used in laboratory

Routinely, weekly for all radioisotopes Biweekly for P-32, S-35 and C-14 in amounts

greater than 10 mCi and less than 100 mCi

Weekly for P-32, S-35 and C-14 greater than 100 mCi

Biweekly for H-3 greater than 100 mCi For U-238 (Uranyl Acetate & Uranium Oxide),

conduct wipe test after each weighing or handling of substance.

RSO conducts monthly wipes of Core Lab

<200 dpm/100cm2 in unrestricted areas (hallways, offices, and labs not licensed for radioactive material)

<1,000 dpm/100cm2 in restricted areas (radioisotope laboratories)

<1,000 dpm/100cm2 immediately clean up to below 1,000 dpm/100cm2

It is strongly recommended that you always decontaminate to as low as practicable

Radioactive containers (stock, flasks, beakers)

Laboratory benches Laboratory apparatus and equipment Radioactive waste containers Refrigerator door handles Laboratory door handles Gloves and laboratory coats

Work in areas designated for radioactive material

Use absorbent pads Wear appropriate protective clothing Do not spread contamination on gloves to

other items or areas in lab Remove gloves prior to leaving laboratory Avoid spilling or spreading of material

Laboratory coat

Gloves

Safety Glasses

Ensure that there is nothing obstructing air flow

Confirm that the flow rate for the fume hood has been checked

Check that it is operational

Set the sash at the appropriate level

Required when possibility of receiving greater than 10% of exposure limit. Not required for all individuals working with radioactive materials at USM currently. Issued to employees to record exposure. Never brought home. Return promptly upon receiving new dosimeter.

Records occupational exposure.

Records exposure from gamma, x-ray and high energy beta

Not to be loaned out.

Should never be worn outside of work.