General Radiation Safety

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Do not adjust your set
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Radiation Safety in Medical Practice

• John Saunderson
• Radiation Protection Adviser
• (TPRH ext. 6690, john.saunderson_at_hey.nhs.uk)

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Programme

• Introduction
• Radiation basics and hazards
• Organising radiation safety
• Radioactive patients
• Any questions?

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• Ionising radiations
• x-rays
• gamma rays (?-rays)
• beta particles (?)
• electron beams

• Not ionising radiations
• lasers
• ultraviolet (UV)
• infrared (IR)
• ultrasound
• MRI

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Radiation basics and hazards

• Why is it dangerous?
• Radiation in hospitals

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Ionising radiation can cause chemical reactions
in the bodys cells which may

• do no harm
• kill the cell
• cause the cell to multiply out of control
  (cancer)
• cause the cell to misfunction in some other way.

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Where very large doses kill many cells

• radiation burns
• cateract
• radiation sickness.

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Threshold risksVery large doses onlyThe bigger
the dose, the more severe the effect
Staff doses never this big
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Cancer risksIt is assummed that any dose of
radiation could potentially cause cancer.The
bigger the dose, the more likely the effect will
occur, (but it will probably never occur).
i.e. a bit like crossing the road - the more
times you cross the more likely you are to be run
over, but probably never will.
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Radiation in hospitals

• Radioactive substances
• nuclear medicine
• pathology
• radiotherapy
• X-ray sources
• Radiology
• Radiotherapy
• Pathology .

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Leakage
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All doses should be kept

• As
• Low
• As
• Reasonably
• Achievable
• The ALARA Principle .

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Basic Principles

• Time
• Distance
• Shielding

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Distance

• Double distance 1/4 dose
• Triple distance 1/9th dose.

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Shielding
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Shielding
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Typical Transmission through Shielding (90 kV)

• 0.25 mm lead rubber apron ? 8.5
• 0.35 mm lead rubber apron ? 5
• 2 x 0.25 mm apron ? 2.5
• 2 x 0.35 mm apron ? 1.0
• Double brick wall ? 0.003
• Plasterboard stud wall ? 32
• Solid wooden 1 door ? 81
• Code 3 lead (1.3 mm) ? 0.1.

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Lead Apron Storage

• Always return to hanger
• Do not
• fold
• dump on floor and run trolleys over the top of
  them!!!
• X-ray will check annually
• But if visibly damaged, ask X-ray to check them.

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Organising radiation safety

• Controlled Areas
• Local Rules
• Radiation Protection Supervisor
• Radiation Protection Adviser
• Radiographer .

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www.hullrad.org.uk
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Radioactive Patients

• Patients may be radioactive if
• theyve been injected with or swallowed
  radioactive pharmaceuticals
• they have solid radioactive sources surgically
  implanted
• they have been involved in an accident with
  radioactive materials .

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Radioactive Decay - half life
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Nuclear Medicine Scan

• Patient injected with or swallows a radioactive
  pharmaceutical
• Gamma camera traces where that radiopharmaceutical
  is concentrated .

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Thyroid treatments with radio-iodine

• Hyperthyroidism / thyrotoxicosis
• overactive thyroid - 400 MBq
• Thyroid cancer
• must destroy all tumour - 3000 MBq
• c.f. thyroid scan - 0.2 MBq.

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Other unsealed source therapies

• Phosphorus-32 for polycythemia (too many red
  blood cells)
• Yttrium-90 colloid for arthritic conditions
• Strontium-90 for bone metastases.

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Brachytherapy (radioactive implants)

• Intracavity afterloading
• Iridium wire afterloading
• Iridium pins
• Iodine-125 seeds .

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LDR-Selectron
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HDR-microSelectron
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Iridium Implant
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Casualties Contaminated by Low Level Radioactive
Substances

• Life saving treatment will override all other
  action
• Seek expert advice from radiation physicist
  a.s.a.p.
• Avoid spread of contamination
• Collect everything that comes into contact with
  radioactive substances (e.g. clothes, swabs,
  fluids, etc.).

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