Health and Safety

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Health and Safety
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• Explain how X- and ?-radiations damage cells
  through ionisation.
• Evaluate the consequent health hazards and
  identify the radiological protection measures
  taken in an X- and ?-ray imaging and radiotherapy
  treatment areas, to monitor and minimise the dose
  received by staff and the damage done to healthy
  tissue of patients half-thickness value of lead
  screening used.

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How are cells damaged?
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Effects of irradiationshort term

• Radiation sickness
• Blood changes
• Vomiting, fatigue
• Hair loss
• Damage to gastro-intestinal tract
• Damage to CNS- death in hours
• Spasmodic seizures
• Radiation burns
• Birth defects of unborn children

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Effects of irradiation long term

• Leukaemia
• Cancer
• Cataract formation
• Life shortening

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Radiological protection

• Principle of justificationsThe benefits of using
  radiation must outweigh the drawbacks.
• Principle of optimisation (ALARA principle, As
  Low As Reasonably Achievable)Radiation exposure
  caused by the use of radiation must be kept as
  low as reasonably achievable.
• Principle of limitationExposure of  radiation
  workers and individuals of public must not exceed
  dose limits.

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Film badge
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• 1.) An open window which allows all incident
  radiation that can penetrate the film
• wrapping to interact with the film. This allows
  for the film serial number to be
• displayed.
• 2.) A thin plastic filter which attenuates beta
  radiation but passes all other
• radiations.
• 3.) A thick plastic filter which passes all but
  the lowest energy photon radiation and
• absorbs all but the highest energy beta
  radiation.
• 4.) A dural filter which progressively absorbs
  photon radiation at energies below 65
• KeV as well as beta radiation.
• 5.) A tin/lead filter of a thickness which allows
  energy independent dose response of the film over
  the photon energy range 75 KeV to 2MeV.
• 6.) A cadmium/lead filter where the capture of
  neutrons by cadmium produces
• gamma rays which blacken the film thus enabling
  assessment of exposure to
• neutrons. In addition a strip of indium foil may
  be housed in a recess in the
• badge. This foil becomes radioactive after
  exposure to neutrons and can be
• used to identify exposed personnel in the event
  of a criticality accident.

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Radiography Department

• Walls
• Primary beam
• Lead glass screens
• Lead gloves, aprons or sheets
• Beam filtration
• Exposure times
• Beam definers and collimators
• Intensifying screens

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Nuclear medicine department

• Lab design
• Negative pressure
• Fume cupboards
• Waste
• Protective clothing
• Long handled tongs
• Finger radiation monitors
• Wall mounted monitors

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Radiotherapy department

• Medical personal leave the room
• Safety locks
• Lead shielding
• Treatment plan
• X ray beams collimated
• Exposure
• Dose monitors

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Radioisotopes

• Destruction of cancer
• Powering pacemakers
• Looking inside the body

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Radioactive tracers

• Radionuclide- unstable nuclide that spontaneously
  decays by emitting radiation, preferably
  ?-radiation
• Becquerel (Bq)- is an activity of 1
  disintegration per second.
• Half-life (T1/2) average time taken for half the
  radioactive atoms in the sample to decay

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Effective half life

• 1/TE 1/TB 1/TP
• TE effective half life
• TB biological half life
• TP physical half life

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Example

• The human serum albumin labelled with 125I is
  sometimes administered during radioactive tracer
  investigations. 125I has a physical half life of
  60 days, but itas biological cleared from the
  body with a half life of 21 days. Estimate the
  effective half life

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Example cont

• 1/TE 1/TB 1/TP
• 1/TE 1/60 1/21
• 1/TE 9/140
• TE 140/9
• TE 15.5555
• TE 16 days (2sf)

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• Do question 23.3 on pg 54 of your revision guide