Object tracking in the GI tract: a novel microcontroller approach

In addition to drug delivery, telemetry capsules with tissue/fluid sampling capability are extremely useful for GI related diseases where diagnosis can only be made by taking a biopsy from the intestinal walls. Such biopsies have traditionally been preformed using an endoscope, which has been customized so that it is capable to taking tissue or fluid samples. In order to be effective in the tasks mentioned above, accurate knowledge of the location of telemetry capsules is necessary. This paper presents a method of tracking an object, i.e. a capsule inside the human gastro-intestinal (GI) tract based on the application of a microcontroller to control the generation and transmission of ultrasonic pulses. In this method, more than one receiver is used to communicate with the object, which is able to transmit and receive a pulse signal. Only one of the receiver stations is able to transmit and receive, others are receive-only stations. This guarantees the collection of a reliable round-trip time of flight (TOF) data. Application of triangulation to the TOF data facilitates the determination of the real-time positions of the object. Consequently, the distance traveled can be computed with a small degree of error