radiation protection. internal/external hazard internal hazardinternal hazard arises through...
Post on 28-Mar-2015
Embed Size (px)
- Slide 1
Radiation Protection Slide 2 Internal/External Hazard Internal hazardInternal hazard arises through ingestion or inhalation of a radiation material not a problem in radiology. Slide 3 Internal/External Hazard External hazardsExternal hazards Arise from exposure to external sources. X-ray sets, emissions from sources etc Slide 4 Reducing Radiation Dose from external hazard TIMEDISTANCESHIELDING PERSONNAL PROTECTION CLOTHING Slide 5 Reducing Radiation Dose from external hazard - TIME The longer you are exposed to a field of ionising radiation the higher the dose you will receive. Double to time double the dose Slide 6 Reducing Radiation Dose from external hazard - DISTANCE The nearer you stand to an source of radiation the higher the dose so stand away! Double the distance quarter the dose Slide 7 Reducing Radiation Dose from external hazard - Shielding Lead shielding can be used to attenuate X-rays Room shielding Screens Protective clothing Slide 8 Shielding Need to know type of radiation Nuclear Imaging uses radiation Radiochemical Labs use radiation Plan to use Local Shielding May also need Wall Shielding Slide 9 Local Shielding1 Vial Shielding emitters -Perspex Vial shields & Storage emitters - Tungsten Vial shields & lead-lined box for Storage Slide 10 Vial Shielding emitters Slide 11 Slide 12 Local Shielding2 Nuclear Medicine Syringes emitters - Tungsten syringe shields lead-lined box for Storage Slide 13 Syringe Shields emitters Slide 14 Local Shielding3 L- Bench Shielding emitters - Lead-lined shields & Lead-glass emitters -Perspex L shields Slide 15 Lead L- Bench emitters Slide 16 PET Dispensing Station Slide 17 Perspex L Bench emitters Slide 18 Local Shielding4 Radioactive Waste Shielding emitters - Sharps bins & Lead-lined containers emitters -Perspex waste containers, often lined with polythene bags Slide 19 Sharps bins & Lead-lined containers emitters Slide 20 Perspex waste containers emitters Slide 21 Wall Shielding Often unnecessary for labs However, same principles employed for X-ray rooms should be applied to assess requirements for Radiochemical Laboratories Slide 22 Room shielding Lead lined plaster board Lead glass viewing window Slide 23 Reducing Radiation Dose from Internal hazard PERSONNAL PROTECTION CLOTHING (Training, technique, experience) Slide 24 Personal Protective Equipment Slide 25 Radiation protection in X-ray Slide 26 Personal Monitoring Why monitor non-classified workers? Not likely to receive > 3/10 relevant dose limit (e.g. effective dose > 6 mSv / yr) How do you prove this? Easiest way is to provide ongoing monitoring Slide 27 Thermoluminescent dosemeters Measurement range 0. 1 mSv to 5 Sv Only issued if risk assessment concludes they are required Slide 28 Electronic Dosimeters Give an instant reading of dose. Measurement range 0.001 mSv to 1 Sv Slide 29 Other Monitoring Extremity rings - tlds or electronic Eye - tlds Internal e.g Iodine uptake doserate measurements swabs samples Slide 30 Contamination Spilt or misapplied radionuclides adheres to or lies on surface of skin, clothing, equipment or furniture. Spills give rise to: external radiation activity entering body via ingestion inhalation absorption leading to internal radiation Slide 31 Instrumentation for detecting ionising radiation Slide 32 Gas based detectors Geiger- Muller counter, GM tube, or Geiger counter Scintillation detectors - Solid state Liquid Slide 33 Gas filled detectors Slide 34 Scintillation detectors Slide 35 Scintillation detector Slide 36 Liquid scintillation - coincidence detection Slide 37 Liquid scintillation vial Contaminant in intimate contact with scintillation medium Pulse of light produced with radiation absorbed Swab Liquid scintillant Slide 38 Slide 39 Mini 900 series EP15 probe GM gas counter Slide 40 Mini 900 series E type probe GM gas counter Slide 41 Mini 900 series 44A probe Solid state scintillation counter Slide 42 Using the right detector Beta Tritium (Hydrogen-3) Carbon-14 Sulphur-35 Phosphorus-32 Phosphorus-33 18.6 keV 157 keV 167 keV 1.7 MeV 2.5 keV Liquid scint GM tube EP15 GM tube EP15 / Scint 44A GM tube EP15 Gamma Iodine-125 Cobalt-60 Caesium-137 36 keV 1.17 MeV & 1.33 MeV 662 Scint 44A / GM tube EP15 Scint 44A Slide 43 Identifying the detector type Look at the label on probe Scintillation probe heavier Scintillation detector higher background rate, switch it on. When in doubt ASK YOUR RPS Slide 44 Wipe testing Use a swab and wipe surface using tweezers Present to appropriate contamination monitor in low background area For low energy Beta use liquid scintillation counting Slide 45 Wipe testing low level contamination and low energy Beta. Contamination lifted using absorbent material and counted in a gamma counter or liquid scintillation counter Slide 46 Radiation spill /incident Dont Panic !!! Slide 47 When dealing with spillage of radioactive material Do not to delay medical care unnecessarily Protect yourselves Attend to contaminated persons first Prevent the spillage becoming worse Prevent additional people from becoming contaminated Clear up and decontaminate the area so it can be put into use Slide 48 Urgent medical care 1.If anyone requires urgent medical care, either by immediate first aid or transfer to A&E DO THIS FIRST. Inform A&E that the casualty is contaminated. Take any obvious steps to reduce or eliminate the hazard to the casualty, to yourselves or anyone attending the casualty. Contact Radiation Protection Service Slide 49 Protect yourselves Pause, take stock and gather information Don protective clothing If in doubt and there are no casualties involved, GET HELP but bear in mind that you should always try and ensure the incident is not made worse by your actions Slide 50 Contaminated persons Washing with soap and water. Always try to localise the contaminated area and just wash that bit. A whole body shower is seldom the best approach. Remove contaminated clothing Washing out any open wound, eyes, mouth, nose etc. If contamination persists contact radiation protection. Slide 51 Prevent spillage becoming worse Use temporary barriers or close the door. Prevent people walking through the contaminated or potentially contaminated. Use an appropriate contamination monitor to assess the extend of the spill. Check personnel for contamination before they leave the vicinity. Slide 52 Clear up and decontaminate Purpose is to transfer the radioactive material from the floor or person to the waste store. Use absorbent material i.e. paper towels to soak up the material. Dispose in appropriate bin. Estimate activity. For stubborn areas of contamination use a normal detergent or decon. When clearing up a spill always work from the outside in. Use your contamination monitor!!! Slide 53 Contamination monitoring Know which is the correct monitor to use. Take care not to contaminate the monitor. Get down close to the contamination. Monitor area systematically. Be thorough. Slide 54 Other points to note Some one should take charge of the situation. Work as a team not as teams of individuals. Have a plan