Each little pixel on your screen is able to detect cosmic background radiation. Because of the touchscreen, this app is only able to detect roentgen radiation up to 14 millimeters behind the screen. We're working on it, we may be able to extend that to about 35 millimeters.
Please note, this app is purely for fun, no android phone is able to perform x-ray scans nor detect roentgen radiation.
This app has been tested and works correctly on:
Go Launcher EX