A computer-implemented medical data processing method for navigating an anatomical body part, the method comprising the following steps: a) planning image data is acquired which depicts an anatomical body part supported by a patient support device and at least three image markers provided in or on a registration frame attached to the patient support device, wherein the planning image data describes a frame-patient-transformation (M R) defining a relative position between the at least three image markers on the one hand and the anatomical body part on the other hand, wherein the planning image data further describes a tracking-registration-transformation (M TR) defining a relative position between an image marker provided in or on a tracking frame connector connected to the registration frame on the one hand and the image markers provided in or on the registration frame on the other hand, wherein the tracking frame connector is included in a tracking frame which includes a tracking marker array including at least three optical markers, wherein the tracking frame connector is connected to both the tracking marker array and the registration frame, wherein the tracking frame is attached to the registration frame at a predetermined position on the registration frame, and wherein the location of the predetermined position at which the tracking frame is attached to the registration frame is determined based on the tracking-registration-transformation (M TR) and the relative position between the image markers provided in or on the registration frame is determined based on the location of the predetermined position and the construction data; b) construction data is acquired which describes a predetermined tracking frame-transformation (M T) defining a relative position between the at least three optical markers and the image marker provided in or on the tracking frame connector; c) a registration of the anatomical body part is determined as a relative position between the optical markers and the depiction of the anatomical body part by the planning image data, wherein the registration is determined based on the frame-patient-transformation (M R) and by determining the relative position between the image markers provided in or on the registration frame on the one hand and the optical markers on the other hand based on the tracking-registration-transformation (M TR) and the tracking frame-transformation (M T), characterized in that the tracking marker array and the tracking frame connector are provided as separate connected pieces. a) planning image data is acquired which depicts an anatomical body part supported by a patient support device and at least three image markers provided in or on a registration frame attached to the patient support device, wherein the planning image data describes a frame-patient-transformation (M R) defining a relative position between the at least three image markers on the one hand and the anatomical body part on the other hand, wherein the planning image data further describes a tracking-registration-transformation (M TR) defining a relative position between an image marker provided in or on a tracking frame connector connected to the registration frame on the one hand and the image markers provided in or on the registration frame on the other hand, wherein the tracking frame connector is included in a tracking frame which includes a tracking marker array including at least three optical markers, wherein the tracking frame connector is connected to both the tracking marker array and the registration frame, wherein the tracking frame is attached to the registration frame at a predetermined position on the registration frame, and wherein the location of the predetermined position at which the tracking frame is attached to the registration frame is determined based on the tracking-registration-transformation (M TR) and the relative position between the image markers provided in or on the registration frame is determined based on the location of the predetermined position and the construction data; b) construction data is acquired which describes a predetermined tracking frame-transformation (M T) defining a relative position between the at least three optical markers and the image marker provided in or on the tracking frame connector; c) a registration of the anatomical body part is determined as a relative position between the optical markers and the depiction of the anatomical body part by the planning image data, wherein the registration is determined based on the frame-patient-transformation (M R) and by determining the relative position between the image markers provided in or on the registration frame on the one hand and the optical markers on the other hand based on the tracking-registration-transformation (M TR) and the tracking frame-transformation (M T),