Due to my health reasons, I want to put in carpeting.
I have a dog - he hardly ever has an accident, but he is getting older and over the next year or two, that may happen more often.
Is there a specific type or brand of carpeting you could suggest? Would it be better to put in "commercial" carpet?

Many carpet companies have advertised their own versions of Stainmaster or ScotchgardTM Fabric Protector. I would try to stick with them and keep to the tightest weave, not shags. If you get commercial carpet you'll pay a lot and end up having it for decades. Maybe buy the cheapest stuff around with throwing it out in 5 years after Rover is not in the picture. Its your call and good luck.

Id agree with ballengerb1, stick with a stainmaster or scotchgard, it has worked for me, and my dog tested it often till I moved him outside.

I guess I have to ask, what health issues makes you need carpeting, most cases you have to get rid of it. i.e. trip, breathing and so on