An ingestible device, adapted to travel in the gastrointestinal tract and perform a diagnostic image of tissue therein, is provided. The diagnostic image may comprise diagnostic information as a function of time, or diagnostic information as a function of distance traveled within the gastrointestinal tract. Specifically, the ingestible device may be arranged to perform a diagnostic image of nuclear radiation of a radiophamaceutical, scintillation of a scintillation liquid, responsive to nuclear radiation of a radiophamaceutical, optical fluorescence of a fluorescing-pharmaceutical or of bare gastrointestinal-tract tissue, infrared radiation of the gastrointestinal-tract tissue, temperature-differences along the gastrointestinal-tract, impedance, ultrasound reflection, magnetic resonance, and a combination thereof. The ingestible device may be adapted for general screening of a large population, on the one hand, and for specific diagnoses of suspected pathologies, on the other.
