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Radiation emergency

  1. 1. EMERGENCY RESPONSE & PREPAREDNESS in a Radiation Department 13/21/2015 LIBIN SCARIA Resident Medical Physicist Dept. of Radiation Oncology
  2. 2. Outline  Radiation Emergency  Classification of Emergency  Consequences  Source of errors leading to emergency  Regulations regarding emergency  Handling of emergency  Practise of safety  Conclusion 23/21/2015
  3. 3. “Any unintended event including operating errors, equipment failures or other mishaps, the consequences or potential consequences of which are not negligible from the radiological protection or safety point of view” 33/21/2015
  4. 4. Nature of effect:  Deterministic effect  Stochastic effect The affected ones:  Public and Staff  Patient Effect appears:  Immediate  Delayed 43/21/2015
  5. 5. Consequences of Radiological Emergencies  Individuals may expose to radiation and different radiation effect  Radiation hazards – external & internal  New threat - possibility of radiological terrorism  Environmental effects  Psychological effects  Social problems  Economical 53/21/2015
  6. 6. Sites of accidents Reactor Radiotherapy (Tele / Brachy) Industrial radiography Irradiation facilities Radio pharmaceuticals Transportation Nuclear medicine Radioactive waste Orphan sources X-ray Scrap / Melting of metals Acts of Terrorists / War63/21/2015
  7. 7. 7 Radiation in medicine Diagnostic Radiography Nuclear medicine Therapy Radiotherapy Tele-therapy Brachytherapy Nuclear medicine 3/21/2015
  8. 8. Potential for an accident in RT  RT - Prescription to delivery - very complex process which involves - a number of steps - a number of professionals - several treatment sessions with many variable parameters  Technologists treat a number patients (50 - 80) per day with patient specific parameters and personalized axillary devices  Due to complexity of equipment, techniques and procedures, there is considerable scope for errors & mistakes 83/21/2015
  9. 9. Radiation Accidents in RT : Classification Radiation accidents in Radiotherapy Events relating to Equipment Events relating to Individual patient Affects many patients Affects only that patient 93/21/2015
  10. 10. Potential accidents in EXBT Potential accidents due to machine malfunction Improper accessory mounting Use of Linear accelerator in Physical mode Mishandling of the machine malfunction Source struck & hang up Failure of interlocks Inadequate training for serving personnel Improper documentation of polices and procedures for use & servicing of the machine Inadequate routine QA procedures Improper commissioning or acceptance testing 103/21/2015
  11. 11. Potential accidents in EXBT Possible errors in Treatment Planning – Incorrect input data of Depth dose or Tissue maximum ratio – Multiple correction for use of wedge filter or compensators – Wrong application of correction factors – Misunderstanding of the algorithm – Incorrect hand calculation and inadequate training 113/21/2015
  12. 12. Possible errors in Calibration Incorrect calibration of the Teletherapy unit Using of wrong data Use of wrong decay chart for output of cobalt unit Not updating the output chart after source change Lack of communication regarding units and depth of calibration (e.g. dmax or 5 cm) 12 Potential accidents in EXBT 3/21/2015
  13. 13. Incident: Error in calculation  A 31 month old patient, being treated for a brain tumor, was to receive two field treatment of 150 cGy each, for a total dose of 300 cGy to reduce swelling behind the eye  Mistakenly treatment time was calculated for 300 cGy dose per field. The patient was treated two days, with 300 cGy per field for a total dose of 600 cGy. 133/21/2015
  14. 14. Incorrect Dose calibration  Incident: • Wrong value for pressure was used during output calibration of a cobalt unit in a hill station (1000m above sea level)  Consequence: Patients were overdosed up to 21%  Cause: No barometer was available to measure pressure Value of pressure was obtained form airport which was corrected for sea level 143/21/2015
  15. 15. Nuclear Medicine  Wrong patient/quantity/route of administration/radio-pharmaceutical/activity  Communication problems between various staff of Nuclear Medicine department  No proper labelling of radiopharmaceuticals  Lack of planning and identification of patients  No efficient quality assurance of dose calibrator  Administration to unsuspecting female pregnant patient 153/21/2015
  16. 16. • Spillage • Unfamiliar with written procedures • Busy environment, distraction • Loss of sources • Death of patient, with sources in situ • Incidents in transport of sources • Improper management of radio active waste 163/21/2015
  17. 17. 17 A technologist scanned the nuclear medicine request form for a patient & noted that it involved Tc99m- DTPA. He/She draw a standard activity of the radiopharmaceutical and injected it before noting that the requested study required inhalation of the radiopharmaceutical in aerosol form. 3/21/2015
  18. 18. Accidents in Brachy Therapy  Improper calibration of the source activity  Source struck in patient/machine  Improper identification of source  Inadequate routine QA for source integrity check  Inadequate routine QA procedure for Remote after loading unit  Incorrect use of treatment planning system  Insufficient understanding of TPS Algorithm 183/21/2015
  19. 19. Potential accidents in BT  Inadequate source movement documentation  Improper and inadequate training of personal on radiation protection aspects  Insufficient documentation of policies and procedures for handling emergencies  Use of faulty zone monitors and survey meters  Loss of source  Manuel handling of source 193/21/2015
  20. 20. Error in activity reporting • Incident: Error in units of reporting the activity for brachytherapy ribbons • Sequence: – the licensee ordered brachytherapy ribbons containing 0.79 mCi per ribbon – however, the vendor delivered ribbons containing 0.79 mg radium equivalent (1.36 mCi) per ribbon – the received shipment was checked against the order and noted that the quantities (0.79) matched – but failed to note that the amount received was measured in mg radium equivalent rather than mCi 203/21/2015
  21. 21. Diagnostic Radiology • Fluoroscopy in interventional procedures • Applications in Cardiology, General Radiology & Neuro- Radiology • More extended periods of time • Multiple use of Radiography • High exposure for both patients and personnel  No proper regulations in diagnostic radiology 213/21/2015
  22. 22. 22 Cataract in the eye of interventionalist after repeated use of old x ray systems and improper working conditions related to high levels of scattered radiation. Examples of injury when female breast is exposed to direct beam 3/21/2015
  23. 23. 3/21/2015 23
  24. 24. 24 One should never attempt to tackle the problem hurry without analysing the situation, because such an attempt will not only complicate the situation but also will result in unnecessary radiation exposures 3/21/2015
  25. 25. 3/21/2015 25 Rule – 33 of Atomic Energy (Radiation Protection) Rules, 2004  The licensee shall prepare emergency response plans and submit the plan to the Competent Authority for review  Any modification to the emergency response plan shall require prior approval of the Competent Authority  Special directives in case of accidents are issued by the Competent Authority
  26. 26. Responsibilities of Licensees  In consultation with Radiological Safety Officer, prepare emergency plans  Take protective actions required for the protection of workers & the public, if an emergency occurs  Inform the employer, the competent authority , law enforcement agency of any loss of source  In consultation with the RSO, investigate any case of over exposure & maintain records of such investigations  Inform competent authority promptly of the occurrence, investigation and follow-up actions in cases of exposure  Carry out physical verification of radioactive material periodically and maintain inventory 263/21/2015
  27. 27. Responsibilities of RSO  Developing suitable emergency response plans to deal with accidents and maintaining emergency preparedness  Investigate any situation that could lead to potential exposures  Carry out routine measurements and analysis on radiation and radioactivity maintain records  Initiation of suitable remedial measures in respect of any situation that could lead to potential exposures  Safe storage and movement of radioactive material within the radiation installation  Reports on all hazardous situations along with remedial actions taken are made available to the employer & licensee 273/21/2015
  28. 28. 3/21/2015 28 Elements of Emergency Preparedness  Emergency management within the Institution (Emergency Response Committee)  Emergency Response Manual - Action plans for each type of Emergency - Emergency contact details  Communication System  Training  Emergency drills & exercise
  29. 29. Steps to follow  Evacuate the immediate area & regulate entry  Identify, segregate and treat all exposed individuals  Assess the extent of exposure  Carry out decontamination in case of decontamination  Samples from contaminated area should be analysed urgently to take further action  Use of periodically calibrated radiation measuring devices  Instruments to collect & handles samples in case of contamination 293/21/2015
  30. 30. Management of Emergency  Emergency reporting: RSO, licensee ,AERB & law enforcement agency  Priority should be given to human safety & personnel dose should be restricted within limits  Arrange for immediate availability of experts who are trained to deal with emergency  Maintain complete records of accident and follow up procedures  If accident is in public area it should be cordoned off and appropriate authorities will be contacted for further action 303/21/2015
  31. 31. 31 T-Rod 3/21/2015
  32. 32. Source struck in TeleCobalt  Try to stop the irradiation using emergency key/button  Close collimators to a minimal field  Rotate gantry/table so patient is removed from the primary beam  Remove patient safely and quickly from the room  Route to enter the room should be chosen logically  Audio instructions can be utilized effectively  One person may remain outside & make a note of the time taken for the sequence of steps  Division of labour  Persons entering room should carry personnel dosimeter  If the source does not return it might be necessary to push it back to a safe position using an emergency rod  The RSO should be contacted, the room door closed and a warning sign hung on the door323/21/2015
  33. 33. Accident spills 33 • RSO & individuals in immediate work inform • Prevent further contamination contain • Decontaminate: personnel & work area Decontaminate 3/21/2015
  34. 34. Steps in Decontamination • Individuals nearby, RSO should be informed & entry should be banned • Prevent further contamination with out risking ourselves • Absorbent pads should be thrown over a liquid spill • Doors should be closed to prevent the escape of airborne radioactivity • Personnel monitoring should be started as soon as possible • Separate contaminated and uncontaminated • Use sensitive radiation monitoring instrument • Contaminated protective dressing must be removed & kept in plastic bag • Skin can be flushed with water • Open wounds, eyes , nose and mouth requires special care • Floor should be decontaminated • Clean ‘from outside in‘ to reduce spread • If complete decontamination is not possible better is to shield & cover the affected areas 343/21/2015
  35. 35. Source stuck in Brachytherapy • Press the button on control console or door display panel • If it is not possible, enter treatment room with a portable survey meter & personal dosimeter press stop button on after loader unit • If source still remain outside, use hand crank • If there is no indication that source is still in patient remove him/her from the treatment room • if it shows presence of radiation remove the applicator and keep in lead container • Check the radiation levels • If it shows no radiation, remove the patient from treatment room • Use forceps in removing the applicators 3/21/2015 35
  36. 36. 3/21/2015 36 Medical management of Emergency Clinical care Biological evaluation Identification of emergencies
  37. 37. Samut Prakan radiation accident Gammatron -3 Teletherapy unit Date : 24 Jan 2000 to 21 Feb 2000 Location : Bangkok, Thailand 10 people affected, 3 died Office of Atomic Energy for Peace (OAEP) solved the problem 373/21/2015
  38. 38. Mayapuri radiological accident AECL Gammacell 220 researchirradiator owned by Delhi University Date : April 2010 Location : Mayapuri, Delhi, India 8 people affected. One died DAE solved the issue. 383/21/2015
  39. 39. 393/21/2015
  40. 40. System of Radiological Protection • Justification of Practice: No practice involving exposures to radiation should be adopted unless it gives benefit to the exposed individuals • Optimization of Protection (ALARA) : In any practice, the magnitude of individual doses, no. of people exposed, and likelihood of incurring exposures, should all kept as low as reasonably achievable Time - - Distance - - Shielding • Individual Dose & Risk limits : Exposure of individuals should be subject to dose limits or to some control of risk in the case of potential exposures. These are aimed at ensuring that no individual is exposed to radiation risks that are judged to be unacceptable 403/21/2015
  41. 41. References • Chapter 11,Textbook of Radiological Safety, K Thayalan, Jaypee publishers • Presentation on Radiation Emergency, Dr. Hemant Haldavnekar, Scientific Officer ‘G’,BARC, Mumbai • Presentation on Radiation Hazard Evaluation, Naushad N, Scientific officer, AERB • www.iaea.org • www.aerb.gov.in • www.google.co.in/images 3/21/2015 41
  42. 42. Conclusion • Rethinking regarding safe practise of radiation • Chances for multiple number of errors to occur • Handling of emergencies • Responsibilities of different radiation professionals • Examples of errors happened  Learning from past 3/21/2015 42
  43. 43. 3/21/2015 43 The safety and happiness of society are the objects at which all institutions aim, and to which all such institutions must be sacrificed James Madison Fourth President of United States
  44. 44. thank you.. 3/21/2015 44

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