OzEMedicine - Wiki for Australian Emergency Medicine Doctors

see also radiation injury, ionising radiation, management summary, disaster medicine

• a person or object exposed to radiation does not make them radioactive
• a person or object contaminated by radioactive material whether on the skin or ingested, does become radioactive, although the risk to others is very small if adequate precautions are taken
• minimise radiation dose by:
  • minimise duration of exposure
  • keep your distance
  • avoid getting contaminated by wearing protective clothing - lead aprons are NOT helpful for gamma rays
• 3 types of radiation detectors in hospitals:
  • area radiation monitor at entrances - only for significant gamma ray sources
  • RADOS personal monitors - keeps track of accumulated dosage & dose rates
    • if alarms, then dose rate too high, rotate staff to minimise exposure
  • Cypher contamination monitor - used to measure contamination levels on parts of a person
    • ensure it does not get contaminated itself by using a glove over it & holding it 2cm from skin and above it so that dust will not drop onto the probe.
    • initially this will be used in the external control area to triage & assess decontamination measures
    • later this will be used in ED treatment area to survey patients who have bypassed decontamination due to medical condition and also to assess staff
    • finally this will be used in the survey of cleaning process & waste management in any potentially contaminated areas within hospital such as ED and theatre
• medical emergency stabilisation has higher priority than radioactive decontamination.
• try to minimise clean up operations by protecting the room and keeping contaminants contained in waterproof plastic bags.

• terrorism:
  • intentional dispersion of radioactive materials using conventional explosives creating a contamination “nuisance”
  • deliberate introduction of radioactive substances into essential services such as major water supplies or food chains creating a scare but radiation doses would be negligible
  • exposure of small numbers of people to a highly radioactive source resulting in clinical effects after a few hours to a few days

• dose is proportion to time exposed
• do not spend unnecessary time in an area of elevated radiation levels

• dose is inversely proportion to the square of the distance thus dose rate at 3m is 1/9th that at 1m from source

• type of shielding needed depends on radiation type
• should not interfere with provision of medical aid to casualties

• involves all agencies
• Vic. Govt Dept. Human Services (DHS):
  • regulates the use of radioactive sources & radiation equipment through Part 5 of the Health Act & the Health (Radiation Safety) Regulations
  • under the Emergency Management Act 1986, DHS is the control agency for incidents involving radioactive material
• Radiation Safety Program (RSP):
  • radiological response role:
    • contact & response:
      • contact DHS EHU on ph: 13 2222, #87457 to contact RSP officers
      • RSP officers are on 24hr call & have a fully equipped vehicle
      • RSP is able to provide initial advice over the phone prior to attending at a radiation emergency & will be able to attend in about 30min in the case of most metropolitan areas
  • restoration of radiological safety:
    • measurement of radiation levels
    • localisation of distinct radioactive sources (pre-explosion) and areas of contamination (post-explosion)
    • retrieval of distinct sources & supervise clean up of contaminated areas
    • establishment of hot, warm & cold zones with police assistance
    • safety perimeter set where level is < 0.1mSv/hr
    • control points to be up-wind of the source
    • control point at the safety perimeter to ensure access to & from zone is limited and decontamination is controlled
    • a more distant access control point to act as a staging area & command post
    • advice on decontamination - personal (may be via MFB/CFA), onsite & off-site
    • assistance with counselling of exposed or contaminated persons
• MFB / CFA
• police
• ambulance
• medical DISPLAN
• hospitals:
  • critically ill are managed in ED resus without need for prior decontamination procedures
  • medically stable patients are checked for radiological contamination & if contaminated are decontaminated prior to entering “Clean” area in hospital

• selected hospitals will have 2 of these monitors, one for ambulatory entrance and one for ambulance entrance to the ED
• designed to alarm upon the entry of a hazardous radioactive source into the ED, eg. as shrapnel embedded in a patient
• will not usually detect radioactive contamination on pts entering ED unless they stand for more than 2 secs near the probe.
• only detects gamma radiation with measurement range of 1microSv/hr to 5mSv/hr
• wall mountable with separate detector probe with cable >3m that can also be used to scan patients
• AC powered with rechargeable battery backup
• audible alarm 90dba at 30cm (can turn volume down by rotating plastic wheel over the speaker to muffle it)
• visible red flashing light alarm
• alarm able to be set to any point on measurement scale
• what do do if alarm goes off:
  • ask patient who set alarm off if have been to nuclear med (eg. for bone scan, V/Q scan) recently, if so, just turn alarm off and ignore
  • if unable to determine who set alarm off, can use the probe to scan each person - ensure probe does not touch anything to avoid it being contaminated (can use a glove over it if contamination is a possibility)
  • if person sets alarm off and has not had a nuclear med exam recently or reasonable explanation for the radiation, then contact senior staff to consider activating the radiation emergency response as above.
  • NB. the NUM has an operation manual for this device.

• DHS supplies 2 per hospital to be worn by key hospital personnel treating contaminated pts
• detects gamma radiation
• measures both dose rate & accumulated dose
• normal background level is 0 microSv/hr, set to alarm at 100 microSv/hr
• slow response time - up to 20secs 
• time to receive dose of 20mSv (ie. 1000 CXR's) = 200hrs if 100 microSv/hr ie. 8days 8hrs
• usage:
  • long press to turn monitor on
  • 4 short presses to get to CLR
  • long press displays accumulated dose (flashing)
  • long press zeroes accumulated dose, monitor then reverts to dose rate mode after ~8secs
  • in dose rate mode:
    • long press displays accumulated dose (flashing)
    • 2 short presses to get to OFF, then one long press turns monitor off

• DHS supplies 1 monitor per hospital to be used by hospital health physicist or RSO to detect radiological contamination on patients
• detects alpha, beta & gamma radiation
• typical background reading is 0-2 counts per second (cps) in which case a reading > 6 cps indicates contamination
• cut-off level for contamination is different if background reading is higher than 2cps - ask RSP
• usage:
  • connect probe to monitor
  • press power button on, monitor goes to cps mode after a couple of “test displays”
  • the up-arrow button toggles audio on & off
  • remove plastic cover on probe
  • place probe in surgical glove to avoid contamination of probe (will not detect alpha rays when glove on)
  • holding probe ~2cm from pt skin, systematically survey the entire body from head to toe on all sides, moving the probe slowly at a few cm per second
  • do not let the probe touch anything - if it gets contaminated you will get false readings!
  • try to maintain a constant distance & pay particular attention to hands, face & feet

• warning signs
• barricade tape

• medical problems take priority over radiological concerns
• medical triage principles are the same regardless of contamination
• do not delay rescue or transport of a seriously injured, contaminated patient
• remove victims from the exposure area once stabilised
• radiological triage to determine contamination status

• remove contaminated outer clothing
• place casualty on a clean sheet on the stretcher
• fold the sheet over the casualty to form a “package” to contain any remaining contamination
• advise hospital of presence of contamination
• transport
• ambulance personnel & vehicle must be “cleared” before departing hospital

• establish controlled area with temporary barriers, signs & security staff
• cover floor of controlled area and tape in place to enable cleaning afterwards to be easier - don't delay medical Rx if not done.
• large bins with plastic liners for waste
• sufficient plastic bags for samples
• remove or cover non-essential equipment from controlled area
• establish control lines & monitor anyone or anything leaving the controlled area

• gown & waterproof apron
• cap
• waterproof shoe covers
• double glove - the inner pair taped to the gown, the outer to remove & replace as indicated
• surgical mask
• eye protection
• personal radiation dosimeters
• NB. lead aprons do not provide sufficient shielding from gamma radiation and are unnecessary

• triage casualties with life threatening conditions to treatment area & stabilise, PRIOR to decontamination
• casualties with less serious injuries should be directed to a controlled area for radiation monitoring by the hospital RSO & decontamination

• have the person stand on a clean pad
• instruct person to stand straight, feet spread slightly, arms extended with palms up & fingers straight out
• monitor both hands & arms, then repeat with hands & arms turned over
• starting at top of head, cover the entire body, monitoring carefully the forehead, nose, mouth, neckline, torso, knees & ankles
• have the subject turn around, and repeat survey on the back of the body
• monitor soles of feet

• establish incident site decontamination facilities upwind
• commence decontamination as soon as feasible - this may be at hospital following stabilisation of life-threatening injuries
• preferably decontaminate walking wounded at the incident site to avoid transfer of contamination to hospitals
• remove clothing, double bag & set aside for monitoring
• decontamination priorities:
  • wounds
  • orifices
  • intact skin
• local:
  • for localised contamination, may be able to wash under a tap rather than have a shower
• whole body:
  • wash under running tepid water for at least 5 mins with soap, soft brush or cotton wool swab
  • wounds are first draped to limit spread of radioactive material, then irrigated with saline or water
• body orifices:
  • mouth - brush teeth & rinse frequently
  • pharyngeal region - gargle with 3% hydrogen peroxide
  • swallowed radioactive material - gastric lavage
  • eyes - direct stream of water (?normal saline) from inner to outer canthus whilst avoiding contamination of the nasolacrimal duct
  • ears - external rinsing & ear syringe if tympanic membrane intact
• decontamination end point:
  • avoid harsh scrubbing resulting in erythema or abrasion, as this will result in increased absorption of contaminant
  • repeat radiation survey at end of decontamination, paying special attention to areas of greatest contamination
  • it is unlikely all contamination will be removed
  • a satisfactory end point is a reading which is twice that of background radiation.

• radioactive iodine:
  • 130mg KI tablet
  • blocks thyroid deposition
• rare earths, plutonium, transplutonics, yttrium:
  • chelation Rx with zinc-DTPA or calcium-DTPA iv
• uranium:
  • urinary alkalinisation, reduces chance of renal tubular necrosis
    • ⇒sodium bicarbonate via saline or tablets
• caesium, rubidium, thallium:
  • Prussian blue in aqueous solution blocks absorption from GIT & prevents recycling
• tritium:
  • Rx with water which results in isotopic dilution