Health authorities do not currently recommend early detection techniques, which include expensive imaging and invasive procedures.

A handful of officers, specially trained in behavioural detection techniques, were evaluating the crowd.

All types of detection techniques were discussed, but radio-location received the greatest attention.

Further pursuit of active detection techniques was then abandoned because of the limit of infrared energy available from searchlight sources.

It has taken almost twenty years to overcome the consequent problems, using multiple cores and new detection techniques to complete the sequence.