I need help with installing windows 7 on my iMac

Hi guys
I've got a copy of windows 7 & I want to install it on my iMac,
The superdrive on my iMac is busted
I have a Sandisk 16GB Flash drive & I was wondering if its possible to install windows 7 from USB

 

Yeah i've tried to do the whole bootcamp install from USB option and when i boot up its not showing me the option of choosing the USB to boot from, ive tried removing the USB and putting it into a different port but still no luck! I've hit the option key whilst booting too.. still nothing! stuck here