MRI scans emit at a frequency of 1MHz-300MHz, which is below the frequency of Wi-Fi (2.4GHz and 5GHz). Gamma rays (Exahertz) and X-rays (Petahertz) are happening at frequencies much higher than RF as well. Kitchens can be source of 2.4GHz interference with microwave ovens.
People have mobile devices in patient rooms such as tablets and cellphones which adds to the rf noise on 2.4Ghz and 5Ghz.

Explanation
https://www.metageek.com/training/resources/wifi-and-non-wifi-interference

To support VoWLAN services and provide roaming recommendations to supported voice clients without impacting non-VoWLAN clients, the feature that should be enabled on the VoWLAN SSID is 802.11k neighbor lists. This feature allows APs to provide information about neighboring APs that are candidates for roaming, which helps clients make better decisions about when and where to roam.