Even single type of home is susceptible to radon gas regardless if there is a basement or not.
If you live in a split level, ranch, 2nd floor apartment, or a 2-story home with a basement, radon is a potential threat to you.
Why? Because radon comes up out of the ground and enters the home through its foundation, which every home has, each house is susceptible to radon gas.
It makes no difference if the building is old, new, insulated, or drafty. All types of homes are at risk of radon whether or not they have a basement.