Extended Data Fig. 9: In vitro experimental setup, as well as dose and pH calibration and resolution testing.

a, Capsule operation in distilled water. The water tank was placed on a stirring hot plate to keep the solution temperature between 32 °C and 46 °C. The pH was measured with a commercial pH meter and varied by controlling the ratio of HCl and NaOH supplied to the tank via a microsyringe pump. b, Photograph of the experimental setup used for in vitro demonstration of the capsule. c, Photograph of the capsule operating wirelessly under a fresh ex vivo porcine bone sample. d, Calibration of the relationship between the dose delivered to the capsule and radioluminescence. The data show excellent linearity, with an average accuracy error of less than 0.5%. e, Radioluminescence intensity at different dose rates. The minimum detectable dose rate difference was 1.8 μGy/min. f, Calibration of the relationship between pH and the G/B colour ratio. The average accuracy error is approximately 0.13. g, G/B colour ratio at different pH values. The minimum detectable pH difference was 0.02, corresponding to a difference of 0.009 in sensor output colour ratio. h, Temperature change measured by the capsule from 36 °C to 38.5 °C in 0.5 °C intervals. It should be noted that the sensor needs to be calibrated before it can be used to measure absolute temperature. i, Response measurements of the capsule under different thicknesses of fresh ex vivo porcine samples at different dose rates.