A method of deriving one or more individual thoracic parameters of a subject. The method comprises instructing a subject to perform a thoracic volume manipulation, receiving a plurality of measurements of a plurality of EM signals from a thoracic intrabody area of lungs of the subject during the thoracic volume manipulation, deriving a plurality of thoracic volume values at a plurality of different intervals during the thoracic volume manipulation so that each the thoracic volume value correspond with another of a plurality of estimated thoracic volumes achieved during the thoracic volume manipulation, and calculating at least one individual thoracic parameter of the subject by combining between the plurality of measurements and the plurality of thoracic volume values.