A device for positioning a patient in a fixed location comprising: a) a locator attachable to a patient and having a registration portion for registration with a portion of a patient's body, and b) means for transmitting information concerning the position of the portion of the patient to an information receiving means, the means being rigidly connected with the locator; a system for positioning a patient in a fixed location comprising the above device in combination with means for receiving said information concerning the position of said portion of said patient; and a method for locating a portion of a patient in a predetermined fixed position comprising: a) affixing to a patient the above device by registering the registration portion of the device with the portion of the patient, b) transmitting information concerning the position of the portion of the patient from the device to an information receiving means, and c) locating the portion of the patient in the predetermined fixed position based on the transmitted information.