An apparatus for treating a body part of a patient, comprising: a support for at least partially supporting and holding the body part of the patient, and a manipulator connected to the support for supporting and manoeuvring the support; wherein the manipulator comprises a parallel linkage device; the apparatus comprising a first portion and a second portion, wherein the first or the second portion comprises an object which is wearable on the body part, such as a helmet, a spectacles-frame, a head band, a wrist strap, etc.; wherein one of the first and second portions comprises a plurality of sources (31A, 31B, 31C) for emitting a signal and the other one of the first and second portions comprises a plurality of detectors (33A, 33B, 33C) for detecting at least a portion of the signal, and/or one of the first and second portions comprises at least one inclinometer and/or gyroscope and at least one signal source or, respectively, detector and the other one of the first and second portions comprises a plurality of detectors or, respectively, signal sources, wherein each signal emitted from a source and detected by a detector has a signal travelling time between the respective source and detector; characterized in that the apparatus comprises a controller configured to determine a plurality of signal travelling times between at least some of the sources and at least some of the detectors, and/or, respectively, a plurality of signal travelling times between the at least one signal source or detector and the plurality of detectors or signal sources, and to determine, on the basis of the determined plurality of signal travelling times and measurement data of the inclinometer and/or gyroscope, where applicable, the spatial position and orientation of the first and second portions relative to each other, wherein the apparatus further is configured to store information comprising a plurality of the determined spatial positions and orientations of the first portion and the second portion relative to each other in a memory, and wherein the apparatus comprises a controller configured to read at least part of the information stored in the memory, to define at least a first manoeuvring sequence of the body part as a function of the information stored in the memory, and to control the apparatus to operate the manipulator to manoeuvre the support in such a way that the body part, when appropriately positioned on, and possibly held by, the support, is manoeuvred according to at least the first manoeuvring sequence. a support for at least partially supporting and holding the body part of the patient, and a manipulator connected to the support for supporting and manoeuvring the support; wherein the manipulator comprises a parallel linkage device; the apparatus comprising a first portion and a second portion, wherein the first or the second portion comprises an object which is wearable on the body part, such as a helmet, a spectacles-frame, a head band, a wrist strap, etc.; wherein one of the first and second portions comprises a plurality of sources (31A, 31B, 31C) for emitting a signal and the other one of the first and second portions comprises a plurality of detectors (33A, 33B, 33C) for detecting at least a portion of the signal, and/or one of the first and second portions comprises at least one inclinometer and/or gyroscope and at least one signal source or, respectively, detector and the other one of the first and second portions comprises a plurality of detectors or, respectively, signal sources, wherein each signal emitted from a source and detected by a detector has a signal travelling time between the respective source and detector; wherein one of the first and second portions comprises a plurality of sources (31A, 31B, 31C) for emitting a signal and the other one of the first and second portions comprises a plurality of detectors (33A, 33B, 33C) for detecting at least a portion of the signal, and/or one of the first and second portions comprises at least one inclinometer and/or gyroscope and at least one signal source or, respectively, detector and the other one of the first and second portions comprises a plurality of detectors or, respectively, signal sources, wherein each signal emitted from a source and detected by a detector has a signal travelling time between the respective source and detector; characterized in that the apparatus comprises a controller configured to determine a plurality of signal travelling times between at least some of the sources and at least some of the detectors, and/or, respectively, a plurality of signal travelling times between the at least one signal source or detector and the plurality of detectors or signal sources, and to determine, on the basis of the determined plurality of signal travelling times and measurement data of the inclinometer and/or gyroscope, where applicable, the spatial position and orientation of the first and second portions relative to each other, wherein the apparatus further is configured to store information comprising a plurality of the determined spatial positions and orientations of the first portion and the second portion relative to each other in a memory, and wherein the apparatus comprises a controller configured to read at least part of the information stored in the memory, to define at least a first manoeuvring sequence of the body part as a function of the information stored in the memory, and to control the apparatus to operate the manipulator to manoeuvre the support in such a way that the body part, when appropriately positioned on, and possibly held by, the support, is manoeuvred according to at least the first manoeuvring sequence.