Abstract: The invention relates to a method for accurately positioning a patient for radiotherapy and/or radiosurgery, comprising the following steps: the patient is pre-positioned as accurately as possible with respect to a linear accelerator; at least two x-ray images of the patient and/or one of the parts of his body in the vicinity of the radiation target point are produced from different respective recording angles on a single image recorder; the x-ray image is spatially localised; at least one reconstructed image, corresponding to each x-ray image and deriving from a three-dimensional patient scan data set, is produced, the reconstructed images containing the desired image contents of the x-ray images when the patient is correctly positioned; and the real x-ray images are superimposed, and the positioning error is determined electronically and/or with computer guidance by way of particular landmarks and/or the intensity gradient or the contours in the two images; and the position of the patient is corrected by wa

Abstract: An inverse planning method and apparatus for radiotherapy treatment of a target volume in a body are characterized by using a computer to calculate the results (dose distribution) of multiple treatment solutions (proposed radiation beam arrangements); and simultaneously displaying the calculated results for at least two of the treatment solutions for comparison by a treatment planner to enable the treatment planner to select a desired one of the treatment solutions.

Abstract: The invention relates to a method for supporting the treatment of a patient, of which a patient data record was made available by an image-generating method, by means of a navigation system, the navigation system detecting and tracking the positions of the patient, of his/her parts of the body, and particularly of the target of the treatment and the treatment devices, wherein, either automatically or on demand, either one or several further current patient data records are created by means of an image-generating method, and wherein each current data record is integrated into the navigation system in a computer-aided manner.

Abstract: Process for the preparation of compounds of the formula (1) ##STR1## in which R is an alkyl (C.sub.1 -C.sub.6) group and X is a hydrogen or alkali metal atom, in which compounds of the formula (2) ##STR2## in which R and X have the abovementioned meanings, are converted into the corresponding diazonium compound with a diazotizing agent in a mineral acid at temperatures of about -5.degree. C. to about +25.degree. C., this diazonium compound is then reacted, without or after intermediate isolation, with aqueous mineral acid at temperatures of about 70.degree. C. to about 120.degree. C. and the resulting compounds of the above formula (1) are isolated.