Radiometer according to Dr. Guido Holzknecht

Early radiometer to determine the radiation dose for radiation theapy. Test stripes are placed on the patient's body and are also radiated. The strips change colour due to radiation. The final colour is compared with the table. The unit of this radiometer is called "Holzknecht" after its developer, Dr. Guido Holzknecht (1872-1932). Holzknecht was a radiologist in Vienna, Austria. With his method the radiation damage declined significantly in his institute.