• Occupational ExposureOccupational ExposureProtection of the WorkerProtection of the Worker

Lab # 6

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Protection of Protection of the workerthe worker

• The use of radiations and radiolabeled products for any purpose is governed by regulatory agencies in different countries all over the world.

• The use of radiopharmaceuticals in humans was almost unregulated until the late 1950s.

• Until 1963, all reactor-derived radiopharmaceuticals were under the control of the Atomic Energy Commission– (AEC, now the Nuclear Regulatory Commission, (NRC))

only for their radiation hazards.• The therapeutic or diagnostic efficacy and the pharmaceutical

quality of radiopharmaceuticals were not regulated by the AEC or by the U.S. Food and Drug Administration (FDA) until the early 1960s.

• In 1963 the FDA introduced rules stating that the clinical efficacy of all radiopharmaceuticals.

Radiation Protection

•Because radiation can cause damage in living systems, international and national organizations have been established to set guidelines for the safe handling of radioactive materials.

•The International Committee on Radio logical Protection (ICRP) •The National Council on Radiation Protection and Measurement (NCRP)

•They set guidelines for all radiation workers to follow in handling radiations

Occupational Exposure Protection of Occupational Exposure Protection of the Workerthe Worker

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Licensees shall ensure for all workers that:

•Occupational exposure be limited and optimized•Suitable and adequate facilities, equipment and services for protection be provided•Appropriate protective devices and monitoring equipment be provided and properly used•Appropriate training be provided as well as periodic retraining and updating

RESPONSIBILITIESRESPONSIBILITIES

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“Workers shall:

•Follow any applicable rules for protection•Use properly the monitoring devices and the protective equipment and clothing provided

RESPONSIBILITIESRESPONSIBILITIES

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Caution Signs and Labels Caution Signs and Labels •The NRC requires that specific signs, symbols, and labels be used to warn people of possible danger from the presence of radiations•These signs use purple, and black colors on a yellow background•Some typical signs are shown in the figures

• Caution: Radiation Area: This sign must be posted in radiation areas.

• Caution: High Radiation Area or Danger: High Radiation Area: This sign must be posted in high radiation areas.

• Caution: Radioactive Material or Danger: Radioactive Material: This sign is posted in areas or rooms in which 10 times the quantity or more of any licensed material specified in Appendix C of 10CFR20 are used or stored.

• All containers with quantities of licensed materials exceeding those specified in Appendix C of 10CFR20 should be labeled with this sign.

• Sources of exposureSources of exposure

Occupational Exposure Protection of Occupational Exposure Protection of the Workerthe Worker

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EXPOSURES IN NUCLEAR MEDICINEEXPOSURES IN NUCLEAR MEDICINE

InternalIngested and/or inhaledradionuclides

ExternalVials, syringes, patients.

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•Unpacking radioactive material•Activity measurements•Storage of sources•Internal transports of sources•Preparation of radiopharmaceuticals•Administration•Examination of the patient•Care of the radioactive patient•Handling of radioactive waste•Accidents

Exposure of the workerExternal Exposure

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•spills•improper administration•experimental work with animals•emergency surgery of a therapy patient

Contamination of the worker

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0

0,5

1

1,5

2

2,5

Dispensing Injection Examination

Do

se (

uS

v)

Dose to worker

Measurements of this kind can show different results in different hospitals

• Personal protective equipment. Safe Personal protective equipment. Safe handling of sources.handling of sources.

Occupational Exposure Protection of Occupational Exposure Protection of the Workerthe Worker

Principles of Radiation Protection

• Of the various types of radiation the alpha particle is most damaging due to its great charge and mass followed by the b particle and the g rays

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Radiation Protection Measures

Depend on:•Time•Distance•Shielding

•Type of radionuclide and its chemical properties

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TimeTimeDose is proportional to

the time exposed

it is wise to spend no more timethan necessary near radiation sources

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ConsequenceConsequence

• Reduce time in contact with radiation Reduce time in contact with radiation sources as much as compatible with the sources as much as compatible with the tasktask

• Training of a particular task using non-Training of a particular task using non-radioactive dummy sources helpsradioactive dummy sources helps

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DistanceDistance

•It is recommended that an individual remains as far away as possible from the radiation source. •Procedures and radiation areas should be designed such that only minimum exposure takes place to individuals doing the procedures or staying in or near the radiation areas.

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Patient with iodine-131Patient with iodine-131

1000 MBqI-131

0 0.5 1 2 m

0.5 0.1 0.06 0.03

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ConsequenceConsequence

• Distance is very efficient for radiation Distance is very efficient for radiation protection as the dose falls off in square protection as the dose falls off in square

• Examples:Examples:– long tweezers for handling of sourceslong tweezers for handling of sources– big rooms for imaging equipmentbig rooms for imaging equipment

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ShieldingShielding•Various high atomic number (Z) materials that absorb radiations can be used to provide radiation protection

•The ranges of alpha and b particles are short in matter the containers themselves act as shields for these radiations

– Alpha can be stopped by a piece of paper– Beta low molecular weight element Al or glass can stop its effect.

(Whay don’t we use lead for shielding of beta radiation?)

•Gama radiations are highly penetrating absorbing material must be used for shielding of g-emitting sources

– Lead is most commonly used for this purpose.

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ShieldingShielding

incident radiation transmitted

radiation

Barrier thickness

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ShieldingShielding

Bench top shieldVial shieldsSyringe shields

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SHIELDING OF SOURCESSHIELDING OF SOURCES

Factors affecting the design:

•radionuclide•activity•shielding material

• Devices to measure personnel radiation exposure. • The film badge is most popular and cost-effective for

personnel monitoring and gives reasonably accurate readings of exposures from b, g, and x radiations.

• A: Pocket dosimeter. B: Film badge holder. • C: Film badge. D: Thermoluminescent chip in finger

badge

Dos and Don’ts in Radiation Protection Practice

• Do post radiation signs in radiation areas.• Do wear laboratory coats and gloves when working with

radioactive• materials.• Do work in a ventilated fumehood when working with

radioactive gases.• Do cover the trays and workbench with absorbent paper.• Do store and transport radioactive material in lead containers.• Do wear a film badge while working in the radiation laboratory.• Do identify all radionuclides and dates of assay on the

containers.

• Do survey work areas for any contamination as frequently as possible.

• Do clean up spills promptly, and survey the area after cleaning.

• Do not eat, drink, or smoke in the radiation laboratory.• Do not pipette any radioactive material by mouth.• Do monitor hands and feet after the day’s work.• Do notify the RSO in case of any major spill or other

emergencies related to radiation.

Dos and Don’ts in Radiation Protection Practice

Well, ask a question and feel stupid for 5 minutes or don't ask and be stupid forever.