Figure 6
Location of the nasogastric tube determined by magnet tracking versus chest X-ray (CXR) for (a) tracking device was placed on the sternal angle, and (b) tracking device was placed on the xiphisternum. Each sub-graph shows the data from an individual labelled by the subject (S) number. The processed tracking data for insertion are indicated by blue dash line with circle marker. The processed tracking data for withdrawal are indicated by red line with cross marker. The black dot line with dot markers are the measurements from CXR. The dot-dash horizontal purple line indicates the level of the xiphisternum in each patient. The data points with markers are spaced 2 cm apart in Z axis to match with the CXR measurements. The coordinate system has been introduced in Fig. 3.
