A mobile electronic device for detecting nuclear radiation levels, where the device has image capturing means comprising a sensor capable of receiving nuclear radiation and converting same to a value indicative of the nuclear radiation level. The device also comprises a shutter translatable from a first orientation covering the sensor (in which radiation level monitoring is allowed) to a second orientation revealing the sensor (in which radiation level monitoring is disallowed). The device may be a modified cellular telephone, satellite telephone, personal digital assistant or tablet personal computer provided with a digital camera, such that camera functionality is maintained and permitted when the shutter is in the second orientation.