The present application is directed to a medical system comprising one or more optical sensors configured to be coupled to a patient's chest, and a controller configured to determine patient's respiration based on signals received from the one or more optical sensors. Further, the present application is directed to a medical system comprising one or more optical sensors configured to be coupled to a patient's body and/or a structure used to stabilize the patient's body, and a controller configured to determine one or more position and/or orientation variables of the patient's body based on signals received from the one or more optical sensors. Finally, the present application is also directed to methods corresponding to the features of the above mentioned medical systems.
