The Muto Vim guidelines have this interesting bit...
How does relate to Perdo Vim and dispelling? Is it possible to cast a PeVi spell with Personal range to dispel effects affecting you? Or does it have to be Touch or even Voice?
Personal range affects "the casting magus or things that he is wearing or carrying." Given the the second part, I'd be inclined to include spells currently affecting him (although not area of effect spells he happens to be caught in). I agree with Telus that this would only affect spells that are already in effect: if you want to dispel a spell before it affects you, range Voice (and fast casting) is necessary.