A novel method for real-time magnetic marker monitoring in the gastrointestinal tract

Abstract

In internal medicine, a simple method for the functional examination of the gastrointestinal tract without the risk of radiation exposure is required. We describe a novel principle based on the monitoring of magnetic markers which meets these demands. Our method employs a special permanent magnet which is repeatedly aligned by a vertically oriented pulsed magnetic field. Due to this alignment, the marker position can be derived from the stray field components measured by commercial field sensors. Our method was evaluated by means of a 3D intestinal phantom. The monitoring procedure yielded the time course of the marker position as a 3D plot either in real-time or as a time-lapse movie. The spatial resolution, expressed by the mean square deviation, was better than 10 mm and is thus sufficiently high to distinguish between adjacent loops of the gut. The temporal resolution, i.e. the minimum time between two successive measurements, was about 1 s. The presented method has very moderate technical demands and allows us to monitor magnetic markers in real-time. The technique may be useful with respect to functional examination of the gastrointestinal tract. In pharmaceutical research, our method offers the opportunity for remote drug release at any position of the gut.

Biomagnetic Methods: Technologies Applied to Pharmaceutical Research

“…The permanent magnet consists of magnetic labelled dosage form which is magnetized in order to create a magnetic dipole moment. After ingestion, the magnetized dosage form can be localized at multiple positions in GI tract; then, the dipole is reconstructed from the magnetic field components (10,12).…”

“…Like SQUID systems, AMR sensors have the same principle for localization of solid dosage forms and are also based on the detection of magnetic dipole (10,91). As these sensors are less sensitive, they can be operated in unshielded rooms; however, a higher amount of magnetic material for labelling the dosage forms is needed.…”

“…In order to overcome such technical limitations, alternative methods based on biomagnetic field detection have been developed (8)(9)(10). The measurement of magnetic field produced within the human body is referred as biomagnetism.…”

Fast numerical algorithm for a high-precision 6D electromagnetic positioning navigation system

“…The tools can be operated by a robot during surgery guided by medical images. This work has attracted increasing attention from experts and various scientific research institutions in China and worldwide [1][2][3].…”

Understanding gastric forces calculated from high-resolution pill tracking

“…A superconducting quantum interference device (SQUID), radiotelemetry, ultrasound, fluoroscopy, and gamma scintigraphy are all capable of providing high-resolution pill location as a function of time data (8,(11)(12)(13)(14)(15). All of the methods are high cost and all except SQUID require image analysis to extract position data (15,16). Additionally, pill-tracking methods have primarily been used to determine gastrointestinal tract residence time.…”