Application of minimum variance beamformer for estimation of tip position of a nasogastric tube

When a patient is not capable of eating a meal due to difficulty in swallowing, a nasogastric tube can be inserted through the nose to the stomach to provide nourishment in liquid form. However, it is possible to insert the tube into the lungs by mistake. In this paper, we apply a minimum variance beamformer that is commonly used in brain signal source detection to estimate the position of the magnet attached to the tip of a nasogastric tube. To reduce the computational cost, the signal source power is calculated with two different resolutions. Furthermore, the signal source power calculations are performed in parallel. The position may be estimated in less than 1.0 s, making this method suitable for detecting the tip position of a nasogastric tube in real time.