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Radiation Protection. Internal/External Hazard. Internal hazard arises through ingestion or inhalation of a radiation material – not a problem in radiology. Internal/External Hazard. External hazards Arise from exposure to external sources. X-ray sets, emissions from sources etc.
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Internal/External Hazard • Internal hazard arises through ingestion or inhalation of a radiation material – not a problem in radiology.
Internal/External Hazard • External hazards Arise from exposure to external sources. X-ray sets, emissions from sources etc
Reducing Radiation Dose from external hazard TIME DISTANCE SHIELDING PERSONNAL PROTECTION CLOTHING
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
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
Reducing Radiation Dose from external hazard - Shielding Lead shielding can be used to attenuate X-rays Room shielding Screens Protective clothing
Shielding • Need to know type of radiation • Nuclear Imaging uses g radiation • Radiochemical Labs use b radiation • Plan to use Local Shielding • May also need Wall Shielding
Local Shielding 1 • Vial Shielding • b emitters - Perspex Vial shields & Storage • g emitters - Tungsten Vial shields & lead-lined box for Storage
Local Shielding 2 • Nuclear Medicine Syringes • g emitters - Tungsten syringe shields lead-lined box for Storage
Local Shielding 3 • L- Bench Shielding • g emitters - Lead- lined shields & Lead-glass • b emitters - Perspex L shields
Local Shielding 4 • Radioactive Waste Shielding • g emitters - Sharps bins & Lead-lined containers • b emitters - Perspex waste containers, often lined with polythene bags
Wall Shielding • Often unnecessary for labs • However, same principles employed for X-ray rooms should be applied to assess requirements for Radiochemical Laboratories
Room shielding Lead glass viewing window Lead lined plaster board
Reducing Radiation Dose from Internal hazard PERSONNAL PROTECTION CLOTHING (Training, technique, experience)
Personal MonitoringWhy 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
Thermoluminescent dosemeters • Measurement range 0. 1 mSv to 5 Sv • Only issued if risk assessment concludes they are required
Electronic Dosimeters • Give an instant reading of dose. • Measurement range 0.001 mSv to 1 Sv
Other Monitoring • Extremity • rings - tlds or electronic • Eye - tlds • Internal • e.g Iodine uptake • doserate measurements • swabs • samples
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
Gas based detectors – • Geiger- Muller counter, • GM tube, or • Geiger counter • Scintillation detectors - • Solid state • Liquid
Liquid scintillation vial Contaminant in intimate contact with scintillation medium Swab Pulse of light produced with radiation absorbed Liquid scintillant
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
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
Wipe testing • low level contamination and low energy Beta. Contamination lifted using absorbent material and counted in a gamma counter or liquid scintillation counter
Radiation spill /incident Don’t Panic !!!
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
Urgent medical care • 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
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
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.