the use of personal protective equipment in nuclear medicine...2017/09/22 · in nuclear medicine...

PPE in nuclear medicine

25-9-2017 | 1

The use of personal protective equipment in nuclear medicine

Danielle Berus Dienst fysische controle [email protected]

Which PPE to use in a nuclear medicine department?


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Different opinions, different guidelines

Occupational exposure in nuclear medicine


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Technologists in NM belong to the highest exposed workers in hospital practice 1 – 5 mSv/12 months

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Whole body dose (mSv/12 m)

Occupational exposure in nuclear medicine


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≠ Exposure situations

- Unpacking and storage

- Activity measurements

- Preparation, administration and imaging

- Care of the radioactive patient

- Handling waste

- Incidents

≠ Exposure pathways

-External exposure

-External contamination

-Internal contamination/exposure

Different types of radiation and energies


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Nuclear medicine: different types of radiation with a wide range of energies

Radiology: low energy scattered X-rays

≠ Types of radiation -> Photons, electrons, positrons ≠ Energies -> 6keV (Fe-55) -> 1116 keV (Zn-65) ≠ Radionuclides -> Tc-99m, F-18, Ge-68, I-131, .....

Keeping occupational exposure as low as reasonably achievable


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By combination of different tools

Shielding

Personal protective equipment

Exposure control procedures

Shielding: Workplace related


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In NM shielding the source is more efficient for dose reduction

What about the use of a lead apron?


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ALARA ? Reasonably? 1° The use of PPEs may not hamper the work ‒ Prolong the exposure time? ‒ Increase the risk on radioactive contamination? 2° Can cause physical stress (back, neck, knees) ‒ Balance benefit/cost (to the technologist)? 3° Gives only limited dose reduction

?

Lead apron in NM -> Limited dose reduction

70 - 120 kVp X-rays

- 99 - 88% dose reduction with 0.5mm PbEq-apron

99mTc – g 140keV

- 78% dose reduction with 0.5mm PbEq-apron

- 35- 40% attentuation for composite lead aprons

18F – b 634keV, g 511keV

- <10% dose reduction with 0.5mm PbEq-apron


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The attentuation rates of lead aprons are in general measured for X-ray

energies

Shielding the sources

Lead glass shielding used during preparation

-> >90 % dose reduction

Syringe shields used during administration

-> > 90% dose reduction

-> personal protective equipment?


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Syringe shields as PPE?

Measuring campaing on hand contamination

- 10 months survey, 560 inspections

Results

- 40 measured contaminations

- For 12 (31%) of the detected contaminations the technologist was not aware

- Cross contamination through the use of syringe shields

>> Introducing personal syringe shields


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The use of shielding in NM - summary

In nuclear medicine shielding the source is more efficient than shielding the

worker

For each manipulation the proper shielding must be present, they can be

workplace related or personal

When (lead) aprons are available in a nuclear medicine department know that:

- Lead free aprons may not be appropriate for shielding gamma emission

- 0.25 or 0.5 mm PbEq aprons provide a modest amount of radiation protection

- They create a false feeling of safety which can result in longer exposure times


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To prevent personal contamination


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Most common, the use of disposable gloves Apply rules of good practice to prevent cross contamination -> Regular change of gloves

-> with every manipulation/patient -> with every presumption of contamination -> when leaving the controlled area/room

Depending on the method of administration other disposables are necessary to prevent contamination

Ex: Lung ventilation/perfusion procedures


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Administration - Injection - Inhalation <<<

Tracers - Inert gas 133Xe, 81mKr - Aerosol 99mTc-DTPA - Technegas <<<

Technegas


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- 99mTc-labeled solid graphite particles - submicron diameter (0.005 – 0.2 µm) - argon carrier gas

Increased risk for contamination - Opening the gas preparation door - Dysfunctioning valve inside apparatus - Leakage in case of uncoöperative patient - Patient with productive cough during administration

Administration of technegas


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The use of additional disposables was introduced to prevent personal contamination - Gloves - Mouth mask - Hair cap - Disposable over-apron

Technegas administration: In 24% of cases activity was detectable on staff (hair and nose) Ref: Lloyd JJ, Nuclear Medicine Communications, June 1994

Administration of technegas - summary


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High risk on contamination when not using the proper PPE Disposable gloves, cap, mask and apron must be worn Lead apron can reduce the external exposure (99mTc) but must be covered by a disposable apron

Contamination check up must be performed after each administration


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Thank you for your attention

the use of personal protective equipment in nuclear medicine...2017/09/22 · in nuclear medicine...

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