polonium-210 was used in the assassination of Alexandre Litvinenko in London in 2006
polonium-210
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
estimation of ingested dose
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
the assassination of Alexandre Litvinenko
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