Radiation Safety Training - University of Southern …...Patient exposure in diagnostic procedures...

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: alpha, beta and neutron

Wave: gamma and x-ray (photons)

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: Internet Hazard

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

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

P-32: Energy max = 1.7 Mev: Internet 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 photon

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

Also produced by x-ray machine

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

250 microcuries

0.000250 Curies

9.25 megabecquerels

9,250.00 dps

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 in REM

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

Q equals 1 for beta, gamma and x-rays, 5-20 for neutrons, and 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 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

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

State of Maine required dose limit: 5 rem 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 the embryo/fetus: 0.5 rem to a women who has declared she is pregnant and avoid month-to-month variation in the dose.

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

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.

Reduce time

Increase distance

- inverse square law

- dosea = dosebx(r b/ra)2

Use appropriate shielding

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 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

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

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

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

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

•<1,000 dpm/100cm2 in unrestricted 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 aerosols

Laboratory coat

Gloves

Safety Glass

Dosimetry (P-32 or gamma and x-ray emitters)

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

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

Ingested radioisotopes may accumulate in certain organs

Radium on the bones and Iodine in the thyroid

However, is useful in diagnostic procedure

Technetium-99m

Geiger Mueller (G-M)

- Gamma and x-ray

- High energy beta particles

Sodium Iodide Detector

- Gamma and x-ray

Used for beta, gamma and x-ray emitters

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

Good for I=125 and Cr-51

Not good for H-3

Check calibration date

Calibrated annually

Check batteries

Replace batteries if necessary

Confirm operational using radioactive material

Used for gamma and x-ray emitters

I-125 and Cr-51

Also x-ray units

Not used for beta emitters such as P-32

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

Required when possibility of receiving greater than 10% of exposure limit.

Required for all individuals working with radioactive materials at USM.

Worn by individual to who it is issued.

Never bring home.

Return promptly upon receiving new dosimeter

Monitors occupational exposure.

Worn for 3 months.

Typically, monitors for gamma, x-ray and high energy beta

Do not loan out.

Promptly return after receiving new one.

Monitors exposure to the hands.

Used for high energy beta and x-ray radiation.

Worn when handling > 500 mCi of P-32 or x-ray machines