Yes, the belts are too short and everyone that flies through DTW is going to get cancer of the arms.

Seriously, x-ray emissions are line-of-sight (mostly) and the emitter likely points straight up. Other option is straight down.

The levels of energy decrease exponentially with distance from the source. They are also very easy to measure with the correct equipment and max emission levels are generally well settled, so the risk of unintentionally high exposure is so low that annual dental x-rays should concern you more.