see also:

• radiation injury
• Ionising radiation
• bio-weapons / biological weapons

• polonium-210 was used in the assassination of Alexandre Litvinenko in London in 2006

• decays by alpha particle emission to lead-206 and thus is NOT detected by usual ionising radiation detectors and whilst outside the body, it does not pose harm as alpha particles can only travel a few centimetres in air
• ingested polonium-210 is likely to be fatal at oral doses above 10-30 microgram due to:
  • physical half-life of 138 days (radiation decay rate)
  • biological half-life 30-50 days (elimination from the body after oral ingestion)
  • very high specific activity of 166TBq/g
  • large amount of energy released from its decay of 140W/g
  • it was estimated in the case of Alexandre Litvinenko, that he ingested 1.5GBq which gave an estimated dose rate to the bone marrow of 5-7 Gy per day which is a fatal dose causing the usual dose-related deterministic effects of radiation injury

• this can be based upon:
  • time to onset of vomiting
  • pattern of early lymphocyte count:
    • a 50% reduction by day 2 to a count of 1,500 (may still be within normal range) suggests a whole body dose of 3 Gray
    • a drop to a count of 1,000 by day 2 suggests a whole body dose of around 4.5 Gray (moderate injury)
    • a drop to a count of 500 by day 2 suggests a whole body dose of around 5.5 Gray (severe injury)
    • a drop to a count of 100 by day 2 suggests a whole body dose of around 7 Gray (very severe injury)
  • dicentric chromosomes

• on Nov 1st, 2006, Mr Litvinenko felt ill in the evening after attending meetings earlier in the day in London and that evening his wife had prepared a special dinner to celebrate their one year anniversary in London.
• on the 3rd Nov, after 2 days of a gastro-like illness, he was taken to hospital where he was managed as a gastroenteritis patient with dehydration as blood tests showed raised urea, creatinine and Hb and WCC but platelets were normal.
• the diagnosis was not recognized as being due to polonium despite his gastro-like illness with hair loss and bone marrow failure until the last day before he died when a scientist checked his urine for alpha particles