The present invention relates to a method for acquiring the body temperature of a patient, wherein the patient has a fistula for removing blood into an extracorporeal circuit and/or for supplying blood from an extracorporeal circuit, wherein a thermal image recording of the fistula or a part of the fistula is made by means of an infrared camera for the purposes of acquiring the body temperature of the patient. Furthermore, the present invention relates to a dialysis device.
