Short induction

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Short induction

  1. 1. Do not adjust your set
  2. 2. Radiation Safety Induction for Radiology Registrars John Saunderson Radiation Protection Adviser TPRH ext 6690
  3. 3. Ionising radiations • x-rays • gamma rays (γ-rays) • beta particles (β) • electron beams Not ionising radiations • lasers • ultraviolet (UV) • infrared (IR) • ultrasound • MRI Ionising / Non-ionising
  4. 4. Part 1 Physics Lectures • Basic Physics (4h) – Trevor Davies (Nuclear Medicine Physicist) – CHH ext 2119 / 2125 trevor.davies@hey.nhs.uk • Radiation hazards and dosimetry (10h) – John Saunderson (Consultant Physicist/Radiation Protection Adviser) – PRH ext 6690 john.saunderson@hey.nhs.uk • Diagnostic radiology (10h) – Jenny Wilson (Radiation Physicist) – PRH ext 6693 jenny.wilson@hey.nhs.uk • CT (2h) – Craig Moore (Radiation Physicist) – PRH ext 6808 craig.moore@hey.nhs.uk • Radionuclide Imaging (2h) – Graham Wright (Nuclear Medicine Physicist) – CHH 2125 / 2115 graham.wright@hey.nhs.uk • + 9h radiographer sessions Exam 11 Dec 2006
  5. 5. Wilhelm Roentgen • Discovered X-rays on 8th November 1895 .
  6. 6. Frau Roentgen’s hand, 1895 Colles’ fracture 1896 .
  7. 7. Mihran Kassabian (1870-1910)
  8. 8. Dose Reduction Precautions • X-ray tubes shielded • Collimation • Aluminium filters • Weekly exposure limits introduced
  9. 9. Radiation Effects • Acute radiation syndrome • Including vomiting, diarrhea, reduction in the number of blood cells, bleeding, epilation (hair loss), temporary sterility in males, and lens opacity (clouding ) • Late 1940’s Dr Takuso Yamawaki noted an increase in leukaemia • 20% of radiation cancers were leukaemia (normal incidence 4%) • Incidence peaked at 6-8 years • Solid cancers – excess seen from 10 years onwards.
  10. 10. • Early X-ray pioneers – Acute effects – Precautions introduced • Atomic bomb survivors – Acute effects similar in nature to pioneers – Some increased cancer risk • But what about radiology today?
  11. 11. Cancer Risk • 1 in 20,000 risk of fatal cancer per millisievert – Chest x-ray: 0.02mSv ► 1 in a million risk – Abdomen x-ray: 1mSv ► 1 in 20,000 – Barium meal: 3mSv ► 1 in 7,000 – CT abdomen: 10mSv ► 1 in 2,000 – (Typical interventional radiologist dose < 3 mSv/y) • Small risk compared to natural cancer risk • Why worry?
  12. 12. 700 CANCER CASES CAUSED BY X-RAYS X-RAYS used in everyday detection of diseases and broken bones are responsible for about 700 cases of cancer a year, according to the most detailed study to date. The research showed that 0.6 per cent of the 124,000 patients found to have cancer each year can attribute the disease to X-ray exposure. Diagnostic X- rays, which are used in conventional radiography and imaging techniques such as CT scans, are the largest man-made source of radiation exposure to the general population. Although such X-rays provide great benefits, it is generally accepted that their 30 January 2004 Average X-ray examination dose = 0.5mSv ► 1 in 40,000 risk UK Radiology = 41.5 million X-rays per year
  13. 13. Basic Principals of Radiation Protection • Justification – Benefit > risk • Optimisation – Doses as low as reasonably achievable • Limitation – Absolute legal limits for staff and public – Reference levels as guidance for patients.
  14. 14. Regulations • Ionising Radiations Regulations 1999 (IRR99) – Local rules, radiation protection supervisors • Ionising Radiation (Medical Exposures) Regulations 2000 (IRMER2000) – Referrers, practitioners, operators – Justification & optimisation • Medicines (Administration of Radioactive Substances) Regs 1978 (ARSAC) – Nuclear medicine
  15. 15. Organising radiation safety • Controlled Areas • Local Rules • Radiation Protection Supervisor • Radiation Protection Adviser • Radiographer.
  16. 16. IRMER Ionising Radiation (Medical Exposures) Regulations 2000 • Referrers – allowed to request medical exposure – Trust decides who can e.g. GP, consultant, etc. • Practitioners – Justifies X-ray - decides there is net benefit – Trust decides who can e.g. radiologist • Operator – Performs “practical aspects” – Trust decides who can e.g. radiographer, technician .
  17. 17. 19 Medicines (Administration of Radioactive Substances) Regs 1978 (“MARS” / “ARSAC”) • “No person shall administer to a human being (otherwise than to himself) any radioactive medicinal product unless he is doctor or dentist holding a certificate issued by the Health Minister for the purposes of section 60 of the Act in respect of radioactive medicinal products (hereinafter referred to as a “certificate”) or a person acting in accordance with the directions of such a doctor or dentist.” .
  18. 18. Radiation in hospitals • Radioactive substances – nuclear medicine – pathology – radiotherapy • X-ray sources – Radiology – Radiotherapy – Pathology .
  19. 19. X-ray tube Primary beam Scattered radiation Patient Leakage
  20. 20. Basic Principles • Time • Distance • Shielding
  21. 21. Distance •Double distance = 1 /4 dose •Triple distance = 1 /9 th dose.
  22. 22. Shielding
  23. 23. Shielding
  24. 24. 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%.
  25. 25. 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.
  26. 26. First Physics lectures • Tuesday 12 September • 2pm start (please be prompt) • The Princess Royal Hospital, Saltshouse Road
  27. 27. The End

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