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General Radiation Safety

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Ionising radiation can cause chemical reactions in the body's ... Brachytherapy (radioactive implants) Intracavity afterloading. Iridium wire afterloading ... – PowerPoint PPT presentation

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Title: 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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