You sure can. If you call Koodo you can put your phone on what's called a "Seasonal Hold" for a maximum of six months. That way you can keep your account active at only $15 a month so when you get back to Canada you can reactivate your line with the same number.
However, the Seasonal Hold is a plan in and of itself. So applying this hold results in a plan change and if you're on a grandfathered plan (an expired plan that you got while it was in-market) you can't get it back.