division of medical physics and radiation safety basic radiation safety training for boston...

Division of Medical Physics and Radiation Safety

Basic Radiation Safety Training for

Boston University and Boston Medical Center

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Boston University and Boston Medical Center

Basic Radiation Safety TrainingRequired for all users of radioactive material at BU/BMCCovers material license conditions, regulations and all safety practices associated with use of radioactive materials.

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Course Outline• Organizational Structure of the Program• Radiation Safety Principles• Biological Effects and Risk• Postings and Labels• Contamination Control and Spills• Proper Survey Techniques• Survey meter and wipe test• Radiation Safety Checklist• Security of stock vials• Radioactive Waste Disposal• Contact Information

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BOSTON UNIVERSITY

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Radiation Safety Committee (RSC)Radiation Safety Officer

Division of Medical Physics and Radiation Safety (DMPRS)

• The (RSC) oversees all uses of radioactive material permitted by the materials license and has overall responsibility for development and recommendation of comprehensive polices and guidelines for the safe use of all sources of radiation

• The RSO ensures that radiation safety activities are being performed in accordance with approved procedures and regulatory requirements

• Medical Physics and Radiation Safety is responsible for ensuring that all clinical and research uses of radioactive materials is safe for workers, patients and the general public

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Basic Terms

Radiation: energy in transit in the form of high speed particles or electromagnetic waves.

Radioactivity: Characteristic of an unstable atom that releases energy in the form of a particle or electromagnetic wave.

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Types of Ionizing Radiation

Alpha particles: contains 2 neutrons and 2 protons, which is ejected from the nucleus of a radioactive atom.

Beta particles: A high-speed electron or positron, usually emitted by an atomic nucleus undergoing radioactive decay. Electrons carry a negative charge.

X-rays: Electromagnetic radiation originating in the electron field of an atom.

Gamma rays: A gamma ray is an electromagnetic radiation originating in the nucleus of an atom.

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Radiation is Energy

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Types of Radiation

Ionizing Radiation: Radiation capable of liberating electrons from an atom. ex. beta particles, x-rays

Non-ionizing radiation: Radiation not capable of liberating electrons, but can excite the atom.

ex. microwaves, radio waves, lasers

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Radiation Units

There are two systems of units used in the measurement of radioactivity and radiation dose.

The older units (Curie, rad and rem) are commonly used in U.S. regulatory language.

The SI units (Becquerel, Gray and Sievert) are commonly used internationally.

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Radiation Unit

Roentgen: unit for measuring the amount of ionization in air (exposure) due to gamma or x-rays. (SI unit is Coulomb per kilogram)

RAD : Radiation Absorbed Dosea unit used to describe the amount of energy deposited per

unit mass from radiation in any type of medium.SI Unit: 100 rads = 1 Gray

REM: Roentgen Equivalent Man a unit used for measuring human dose equivalent.

SI Unit: 100 rem = 1 Sievert

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Radiation Quantities

Curie: 3.7x1010 disintegrations per second or 2.2x1012 disintegrations per minute.

1 milliCurie (mCi) = 2.2 x 109 dpm1 microCurie (Ci ) = 2.2 x 106 dpm100 Ci = 0.1 mCi

Becquerel: one disintegration per second. (SI system)

1 mCi = 3.7x107 dps = 37 MegaBecquerel (MBq) 1 Ci = 3.7x104 dps = 37 kiloBecquerel (kBq)

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Radiation Quality Factors

Two different types of radiation may deliver the same absorbed dose, but produce a different biological effect, and hence, dose equivalent.

1 rad of alpha = 20 rem1 rad of beta = 1 rem

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Half-Life

The time required for any given radioisotope to decrease to one-half of its original activity by radioactive decay.

This period of time is called the half-life 32P - 14.3 days 14C - 5730 years3H - 12.3 years 35S - 89.7 days125I - 60 days

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External Exposure

Common isotopes with external exposure potential

P-32, I-125, Cr-51

Not all radioisotopes are external exposure hazardsH-3, C-14, S-35

External exposure occurs when all or part of the body is exposed to penetrating radiation from an external source.

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Pathways of Internal Exposure

Ingestion Absorption Inhalation Puncture

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Contamination and Exposure

Radioactive Contamination is

Radioactive material where it shouldn’t be. e.g. floors, bench tops, handsFixed vs. Removable Contamination

All radioisotopes have contamination potential even if they do not have external exposure potential. The goal is to prevent contamination from getting on to your skin and/or inside your body.

How Contamination Differs From Exposure:A person exposed to radiation is not necessarily contaminated with radioactive material.

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You are NOT radioactive if you receive an external exposure from radioactive

material.

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ALARA

The goal of radiation protection is to keep radiation doses As Low As Reasonably Achievable

BUMC is committed to keeping radiation exposures to all personnel ALARA

NCRP Definition of ALARA

As Low As Reasonably Achievable (ALARA): A principle of radiation protection philosophy that requires that exposures to ionizing radiation be kept as low as reasonably achievable, economic and social factors being taken into account. The protection from radiation exposure is ALARA when the expenditure of further resources would be unwarranted by the reduction in exposure that would be achieved.

Contributions from Man Made and Natural Background Source of Radiation

20From NCRP Report No. 160, “Ionizing Radiation Exposure of the Population of the United States” (2009)

Annual Exposure 620 millrem/yr.

NCRP SUMMARY

• Average dose to individual is 620 mrem/yr– Approximately 37% of dose was attributed to

radon– An additional 13% attributed to other natural

sources (cosmic, terrestrial, internal)– Total ~50% attributed to natural sources– Medical comprised ~48%– Dose from nuclear power was grouped into a

category comprising <0.1%

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0

50

100

150

200

250

300

350

400

450

500

Research 30

Nursing 100

Rad. Med. 200

Nuc. Med. 350

mR/yr.

mrem/yr

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Annual Occupational Exposures at BU/BMCAverage dose/year

*Annual Allowable Exposure limit for Radiation Worker = 5000 mR/yr

Latest Biological Effects Studies

If 100,000 persons were exposed to 10 Rem of radiation each, 800 excess cancer deaths would be expected during their remaining lifetimes in addition to the nearly 20,000 cancer deaths that would occur in the absence of radiation.

- BEIR V Report, page 162 - 1989

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Genetic Effects

Damage to cells DNA Effects have not been observed in human

populations Extrapolated from larger doses and animal

studies

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Declared Pregnant Worker

Any radiation worker who is pregnant may voluntarily declare her pregnancy and the estimated date of conception in writing to the DMPRS and thereafter her occupational radiation exposure shall be limited to 500 millirem (50 millirem/month) for the entire period of gestation.

If you are pregnant and want to declare pregnancy, please contact the DMPRS for consultation.

Ref: US NRC Regulatory Guide 8.13 rev. 3 1999

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MINIMIZE EXTERNAL EXPOSURE

Time(Reduce exposure time)

Distance(Increase Distance)

Shielding(Place dense object between you

and source of radiation)26

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How To Minimize External Exposure

TIME : 60 mR/hr = 6 mR in 6 minutes

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How To Minimize External Exposure

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Shielding• Alpha particles can be

stopped by a sheet of paper.

• Most Beta particles can be stopped by 1-2 cm of plexiglass.

• Most gamma and x-ray photons can be absorbed by several cm of lead.

• Neutrons may require several feet of concrete.

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Do you workdirectly with a

source of radiation?

NoBadge

Required

Is the radiationsource an

isotope or a machine?

No

Yes

Do you work with one of the followingisotopes? * badge type in ( )

Brachytherapy Sources (1 and 4) >1 mCi. of gamma or positron emitter (1 and 4) >1 mCi. high (>500 keV) max energy Beta emitter (1 and 4)Nuclear Medicine (1 and 4)

Do you work with any one of the following machines? * badge type in ( )

Fluoroscope (2 and 3)LINAC (1)Diagnostic x-ray (1)CT (1)

Isotope Machine

A badge is mandatory

A badge is voluntary

Yes

NoNo

Badge Type(1) – Whole body(2) – Collar(3) – Waist(4) – Ring

Dosimetry Requirement Decision Tree

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Labeling

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Refers to quantities of radioactive material used or stored.

Refers to areas accessible to personnel, in which a major portion of the body could receive a dose of 5 mrem in any one hour at 30 centimeters from the radiation source or from any surface that the radiation penetrates

Postings

2 Postings:•Massachusetts Department of Public Health “Notice to Employee”•Boston University Medical Center “Rules Governing the Use of Radioactive Materials”.

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Contamination Definition: Radioactive material where it shouldn’t be. e.g. floors, bench tops, hands

All radioisotopes have contamination potential even if they do not have external exposure potential.

The goal is to prevent contamination from getting on to your skin and/or inside your body.

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Skin Contamination Cool water, mild soap

2-3 minutes working up a good lather, dry

No harsh chemicals or detergents

Survey for contamination

Notify the RPO 617-638-7052 BUMC -Control Center 617-638-4144

off hours (8-6666) CRC-617-353-SAFE

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• Notify the people in area that a spill has occurred• Report incident to the DMPRS• Prevent the spread of contamination. Cover the spill with

absorbent material and prevent access to the area by unauthorized personnel

• Clean Up using disposable gloves• Survey area with a low range thin window GM survey

instrument

Emergency Office PhoneMedical Campus - RPO 617-638-5795

- Control X 8-4144 (off-hours)Charles River Campus - 3 -SAFE (24 hours)

Spill Response

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Direct SurveySurvey Meters

• “Pancake probe” Model 44-9• Used to monitor: 14 C, 35S, 32P, 33P • Move slowly at 2 inches/second from a distance no

greater than 1 cm above the surface

* Annual Survey Meter calibration is required

• Model 44-3 known as a “Scintillation” or “NaI” Probe

• Used to monitor low energy gammas such as I-125

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Radiation Detection Instruments

Liquid Scintillation counter is required for Tritium Contamination surveys

End Window(S-35, P-32, P-33, C-14)

*Lower Detection Efficiency than End

Window

Pancake(S-35, P-32, P-33, C-14)

*Better Detection Efficiency than End

Window GMPortable Survey

Meter

Gamma Scintillator (NaI) probe

(I-125 and Cr-51)

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Proper Survey Technique

Use appropriate survey meter– Check Calibration Status (Sticker)– Check battery– Audible on– Check background level– Start at the lowest scale

Audio On/Off Switch

Rotary Switch Off Battery Check Scalar Multiplier

Battery Compartment

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Survey Meter Face Plate

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Scale: 0 - 5 K cpm on X 1 multiplier*Some meter faces will have the Middle and Bottom

scale (As shown on left). In research setting the CPM scale is the only scale we use

Use This Top ScaleUse This Top Scale

Direct Monitoring

• Set meter on lowest scale and observe background.• Bring probe 1/4 to 1/2 inch from surface without

touching. • Move probe slowly. (2 inches/sec)• Listen for audible chirp and observe count rate.• Results expressed in units of counts per minute (CPM).

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Wipe Tests A wipe test only assesses removable contamination. Use absorbent paper to wipe an (100 cm2 )area For H-3, a wipe test is the only means to assess potential

removable contamination. For other isotopes (i.e. P-32, S-35, C-14) a Geiger

Counter may be used to assess removable contamination. (Note: efficiency is much lower than wipe test counted with LSC)

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Liquid Scintillation

Counter

Radioisotope Ordering Process1. Order placed through DMPRS via BU Works ISR2. DMPRS places order with vendor3. Package arrives at DMPRS for inspection4. DMPRS delivers package to your lab5. Lab personnel (RAM authorized user) receives and

secures package.

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Security of Radioactive Material

• You must do the following: Keep radioactive material in constant view Lock up radioactive stock solutions Lock the laboratory Always keep the access door to your floor of the

building locked. – (Use Key Card Access or the Combination Lock)

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Radioactive Material Transfer

Contact DMPRS for authorization prior to transfer of radioactive material on and off campus.

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Iodination Precautions

Verified negative pressure hood Double glove Lab coat Double bag radwaste Lead bricks in front of hood causes turbulence Use charcoal to absorb iodine vapors Air sampling and thyroid monitoring required

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Fume Hood

REQUIRES ADDITIONAL TRAINING: Iodination procedures

Sulfur 35 - Amino Acid Precautions

Because of volatility:

• Open Stock vial in hood• Place charcoal in incubators, water baths, etc.

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Phosphorous-32 Precautions

3/8 inch lucite lab coat, double gloves, safety goggles absorbent paper or trays Dosimetry (> 1 mCi)

whole body badge and ring dosimeter

Geiger counter

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Use flat top tube opener to reduce radiation levels to fingers

Use of Radioactive Materials in Animals

Radioactive material in animal use must be approved by– Radioisotope Committee– IACUC (Animal Care Committee)

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Radioactive Waste Categories

a. Solid waste b. Aqueous liquid waste c. Organic liquidd. Deregulated liquid scintillation vialse. Regulated liquid scintillation vialsf. Animal carcass/tissueg. Volatile materialh. Stock vials

All rad waste pick up requests are scheduled online at: http://www.bu.edu/orc/forms/environmental-health-safety/radioactive-waste-pickup-request/

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Radioactive Waste Guidelines

Environmental Waste Management approved containers by half-life:

< 30 DAYS, 30-90 DAYS, > 90 DAYS4 ml thick plastic bagInventory sheetNo radioactive waste is allowed in cold trash or biohazard bagsAll rad labels must be defaced before placing in waste containerswaste pickups are scheduled on-line

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Radwaste Guidelines Put radioactive needles etc., in

“radioactive” sharp container No liquids No lead pig (Deface and store lead pigs

in separate containers next to waste. Environmental management will pick up at time of waste pick up)

Assure radwaste container labeled to prevent housekeeper from emptying trash

Call Environmental Waste Management for any questions at 617-638-8832.

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Sink Disposal• You must ensure:

Liquids disposed down sinks designated for radioactive liquid disposal only.[No mixed waste].

Activity/Isotope disposed are less than the posted sink limit.

Liquid is aqueous, soluble, and dispersible.

Sink disposal log is complete

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Radiation Safety Records

Are all records filled out and up to date?

Inventory Surveys Waste logs Sink logs

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Inventory Records

You record: What material was received When it arrived (day, month and year) Activity received Chemical form When it was used, who used it Running total of activity on hand

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Telephone Numbers

BU & BMCOffice – 617-638-7052 (8am – 5pm)Fax – 617-638-7509Emergency- Control Center -617-638-4144

CRCDMPRS Office – 617-638-7052 (8am – 5pm)Emergency – 617-353-SAFE – 617-353-7233

DMPRS personnel on call 24 Hr/day

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Important Resources

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• Main DPMRS Website: http://www.bu.edu/ehs/plans/management-plans/rpo/

• DMPRS Operational Forms: http://www.bu.edu/ehs/plans/management-plans/rpo/forms/

• Environmental Waste Management: http://www.bu.edu/ehs/services/waste/radioactive-waste/