Abstract: There is provided an apparatus for positioning a front sensor and/or a back sensor across a thorax of a target individual, the apparatus comprising: a back positioning element comprising: a collar sized and shaped for fitting to a shoulder line and base of a back of a neck of the target individual, and an elongated element having a first end region connected to the collar, and a second end region with a location marker set to correspond to a target anatomical feature of the spine of the target individual, wherein when in use, the elongated element is positioned parallel to and over a long axis of a spine on the back of the target individual, and at least one front sensor and at least one back sensor are positioned on the thorax of the patient relative to the back positioning element for transmitting to and/or sensing from the target region.