Devices, methods and systems for frameless guidance of image-based medical procedures such as stereotactic radiotherapy and surgery. Devices including custom fitting subject-specific articles include contoured surfaces that provide spatial reference to the location of target regions within the subject. The devices are attached exclusive of fasteners anchored to the tissue of the subject and reside on the front of a head of the subject when attached. The devices and articles can be fabricated using computer-directed fabrication technology.