A pH-measuring radio capsule for the alimentary canal

Merits of a new telemetering system designed to measure pH in the gastrointestinal tract are briefly discussed in conjunction with present technics. In vitro evaluation of the Corning Acido Capsule system includes (a) temperature stability measurements, (b) speed of response to abrupt changes in pH, (c) accuracy of pH indication in the range of pH 1 to pH 8, and (d) long-term stability of the system. The data show that the pH determination is accurate to ± 0.2 pH units for tests lasting up to 18 hours. Preliminary in vivo evaluations indicate that the capsule system provides a convenient and accurate method of measuring hydrogen-ion activity in the alimentary canal, and suggest further in vivo evaluation of the system.The authors would like to acknowledge the help of the departments of the Electronic Research Laboratory that were involved in the research and development work of this system.