A data processing method for calculating the contact position of a medical ultrasound transceiver on the head of a patient, comprising the steps of: a) acquiring ROI data which represent a region of interest (ROI) corresponding to at least a part of a vessel in a vascular structure； b) acquiring contact region data which represent a contact region for the ultrasound transceiver on the head, wherein the contact region corresponds to one or more acoustic windows； c) determining at least one target point in the region of interest； d) determining at least two entry points on the contact region； e) calculating a set of lines which comprises the lines between the two points of each respective possible pair consisting of one entry point and one target point； f) eliminating lines which pass through a bony structure other than the bone immediately beneath the contact region； g) calculating a score for each of the remaining lines； and h) selecting the entry point of the line with the highest score as the contact position of the ultrasound transceiver.
