To communicate via such a device

The therapeutic use of ionizing radiation, almost exclusively used for the treatment of malignant disease.

A miniature radio carried aloft (e.g. by an uncrewed balloon, an airdrop from a crewed aircraft, or a sounding rocket) to automatically transmit measurements of the upper air such as the wind speed, pressure, temperature, and relative humidity to a receiving station on the ground.

Someone who works with radiography. This term seems to be more common in British English.

A device that measures radiant energy.

(physics, chemistry, medicine) A radioactive isotope which, when injected into a chemically similar substance, or artificially attached to a biological or physical system, can be traced by radiation detection devices.

material settling from a radioactive plume, and its subsequent surface deposition

wireless telegraphy

To communicate or transmit by wireless telegraphy.

A person who operates a radio transceiver, especially when a title or position in a crew.