Obsevations on the Clinical Use of Radio Pills

The invention of the transistor made it possible to design a self-contained radio-transmitter with a transducing system for modulating it which is small enough to be swallowed as easily as a pill.The radio signal is picked up by an aerial, and the output of the receiver is fed into a loudspeaker and a pen recorder (Fig. 1).Radio pills containing transducers sensitive to pH, temperature, and pressure have already been used for telemetering continuous information about one or other of these variables from the lumen of the gut (Fig. 2). Advantages and Limitations of TelemeteringThis development seemed to herald a tubeless era for gastro-intestinal investigations.The news was welcomed by patients and doctors alike because the nausea and emo-