A computer-implemented method (400, 700, 900) for determining a need for a re-registration of a first tracker attached to a patient with medical image data of the patient, wherein the first tracker comprises a first acceleration sensor configured to generate inertial data indicative of an acceleration of the first tracker and wherein a first tracker coordinate system associated with the first tracker or image data thereof has been registered with a medical image coordinate system associated with the medical image data of the patient, wherein a second tracker comprising a second acceleration sensor is attached to the patient, and a second tracker coordinate system associated with the second tracker has been registered with the medical image coordinate system, the method (400, 700, 900) comprising the following steps performed by a processor: receiving (410, 710, 910) inertial data acquired by the first acceleration sensor of the first tracker; analyzing (420, 720, 920) the received inertial data, or data derived therefrom, with respect to at least one first predetermined condition indicative of at least one of i) a drift of the first tracker; and ii) an impact on the first tracker; and generating (430, 730, 930), when the at least one first predetermined condition is fulfilled, at least a first re-registration signal, wherein at least the first re-registration signal triggers one of i) re-registering the first coordinate system with the medical image coordinate system; and ii) suggesting the re-registration; receiving inertial data acquired by the second acceleration sensor of the second tracker; analyzing the received inertial data, or data derived therefrom, with respect to at least one second predetermined condition indicative of at least one of i) a drift of the second tracker; and ii) an impact on the second tracker; and wherein, in case of the first predetermined condition being fulfilled and the second predetermined condition not being fulfilled, the re-registration is executed or suggested based on the registration of the second tracker coordinate system with the medical image coordinate system. the first tracker comprises a first acceleration sensor configured to generate inertial data indicative of an acceleration of the first tracker and wherein a first tracker coordinate system associated with the first tracker or image data thereof has been registered with a medical image coordinate system associated with the medical image data of the patient, wherein a second tracker comprising a second acceleration sensor is attached to the patient, and a second tracker coordinate system associated with the second tracker has been registered with the medical image coordinate system, the method (400, 700, 900) comprising the following steps performed by a processor: receiving (410, 710, 910) inertial data acquired by the first acceleration sensor of the first tracker; analyzing (420, 720, 920) the received inertial data, or data derived therefrom, with respect to at least one first predetermined condition indicative of at least one of i) a drift of the first tracker; and ii) an impact on the first tracker; and generating (430, 730, 930), when the at least one first predetermined condition is fulfilled, at least a first re-registration signal, wherein at least the first re-registration signal triggers one of i) re-registering the first coordinate system with the medical image coordinate system; and ii) suggesting the re-registration; receiving inertial data acquired by the second acceleration sensor of the second tracker; analyzing the received inertial data, or data derived therefrom, with respect to at least one second predetermined condition indicative of at least one of i) a drift of the second tracker; and ii) an impact on the second tracker; and wherein, in case of the first predetermined condition being fulfilled and the second predetermined condition not being fulfilled, the re-registration is executed or suggested based on the registration of the second tracker coordinate system with the medical image coordinate system. receiving (410, 710, 910) inertial data acquired by the first acceleration sensor of the first tracker; analyzing (420, 720, 920) the received inertial data, or data derived therefrom, with respect to at least one first predetermined condition indicative of at least one of i) a drift of the first tracker; and ii) an impact on the first tracker; and i) a drift of the first tracker; and ii) an impact on the first tracker; and generating (430, 730, 930), when the at least one first predetermined condition is fulfilled, at least a first re-registration signal, wherein at least the first re-registration signal triggers one of i) re-registering the first coordinate system with the medical image coordinate system; and ii) suggesting the re-registration; i) re-registering the first coordinate system with the medical image coordinate system; and ii) suggesting the re-registration; receiving inertial data acquired by the second acceleration sensor of the second tracker; analyzing the received inertial data, or data derived therefrom, with respect to at least one second predetermined condition indicative of at least one of i) a drift of the second tracker; and ii) an impact on the second tracker; and wherein, i) a drift of the second tracker; and ii) an impact on the second tracker; and wherein, in case of the first predetermined condition being fulfilled and the second predetermined condition not being fulfilled, the re-registration is executed or suggested based on the registration of the second tracker coordinate system with the medical image coordinate system.