To be blunt, this is an issue that you need to deal with, not the women you are interacting with. First and foremost, color me highly skeptical to say the least that women at an "academic conference" are "scantily clad". That does not jibe with any academic conference I have ever heard of, like, anywhere. But regardless, even if all the women at said conference are wearing string bikinis, the fact that you can't concentrate around them is your problem, not theirs. Millions of men around the world are able to concentrate just fine when surrounded by women dressed in all manner of clothing.
My first recommendation would be to talk to a therapist. You may not want to do this; well, what would you like to do less: speak to a therapist and get over what sounds like deep seated gender-oriented anxiety issues, or do poorly at your conference because you never addressed them? It will necessarily be hard and I predict there are a great many things you will hear in those talks that you will not like, but
If you are in the United States you might get away with asking for some kind of religious accommodation but I think that's unlikely. I do not know if you are religious and am only guessing because I honestly have not met very many non-religious people with your particular hang-ups with the opposite sex. However, I don't believe that you can expect other people to cover up to a level you deem appropriate. That is not accommodating your religious beliefs so much as it is forcing everyone else at the conference to be subservient to yours.
At the end of the day - and this may well be one of the tough things that your therapist tells you, but it doesn't make it any less true - I think you're best off considering that each and every single woman you are losing concentration over due to "scanty clothing" is a human being in their own right with their own thoughts, feelings, desires, and expectations. In fact, given that this is an academic conference I would go so far as to say that many of these women may know as much or more about your field than you do and you may well find yourself in a situation where you can learn things from them. I suspect that thinking of women as primarily sexual objects is something that has been ingrained in you from a young age; considering why each woman you meet, individually, is there might help you begin to overcome this.