Lord Sebastian Coe has admitted that it is impossible to guarantee that next month's World Athletics Championships will be completely clean of drug use.
Athletics has been rocked by a number of high-profile doping cases in recent years, arguably the biggest of which has led to Russian Federation athletes being banned from competing in London.
Lord Coe is hopeful of seeing the Championships pass by without incident, however, claiming that it is now a lot easier to spot drug cheats.
"It's a very utopian view, people will always seek to cheat," he told BBC Sport. "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."
Russia have been barred from competing in international athletics events following the release of the McLaren report last year, which revealed the use of a state-sponsored doping programme between 2011 and 2015.
Germany
Hungary
Scotland
Switzerland
