There are no guarantees next month's Athletics World Championships or the sport in general will be clean in the future, according to IAAF president Sebastian Coe.
London Stadium, the main venue for the 2012 Olympic Games and now the home of Premier League club West Ham, will revert to its former configuration as an athletics arena for the prestigious quadrennial event, which is due to be begin on August 4.
While three neutrals have been cleared to take part, nationally-affiliated Russian athletes are not permitted to attend following revelations of state-sponsored doping that saw the country's competitors banned for track and field events at the Olympic Games in Rio de Janeiro last year.
Attempting to ensure athletics is clean has become a huge priority for the IAAF and the International Olympic Committee in a bid to safeguard the integrity of the sport.
But Coe, speaking in a BBC television appearance less than two weeks before the start of the World Championships, acknowledged the scale of the task facing his organisation and the World Anti-Doping Authority.
"It's a very utopian view, people will always seek to cheat," Coe said.
"We have the technology that allows us to be very much more specific about what we are looking for.
"I would love to tell you that we will have a drug-free sport in future. Everything we are doing is engaged in trying to achieve that but we know a few people will cheat.
"What we do have in place now is an independent athlete integrity unit, we have independent sanctioning and discipline and we will be able to be a lot tougher and speed up the process."