[Reproducibility of x-rays of the spinal column while standing].

Standing x-rays, especially of children, are often used for therapeutic decisions. As it is known, wrong decisions happen because of temporary one--sided bearing when different weight is put on the feet. This can be avoided by using a new pair of scales which compares the weight of both feet. The patient and the technologist are given optical and acoustic signals when the weight of both feet is the same. Using this pair of scales means that correctly reproducible x-rays can be taken, provided that the patient's knees are extended.