Digital tumor fluoroscopy -DTF- - a new direct imaging system in the therapy planning for brain tumors

Digital Tumor Fluoroscopy is an expanded x-ray video chain optimized to iodine contrast with an extended Gy scale up to 64000 Gy values. Series of pictures are taken before and after injection of contrast medium. With the most recent unit, up to ten images can be taken and stored. The microprogrammable processor allows the subtraction of images recorded at any moment of the examination. Dynamic views of the distribution of contrast medium in the intravasal and extravasal spaces of brain and tumor tissue are gained by the subtraction of stored images. Tumors can be differentiated by studying the storage and drainage behavior of the constrast medium during the period of examination. Meningiomas store contrast medium very intensively during the whole time of investigation, whereas astrocytomas grade 2-3 pick it up less strongly at the beginning and release it within 2 min. Glioblastomas radiography and MR-imaging the most important advantage of Digital Tumor Fluoroscopy is that direct inf ormation on tumor localization is gained in relation to the skull-cap. This enables the radiotherapist to mark the treatment field directly on the skull. Therefore, it is no longer necessary to calculate the tumor volume from several CT scans for localization. In Radiotherapy Digital Tumor Fluoroscopy a unit combined with a simulator can replace CT planning. This would help overcome the disadvanteages arising from the lack of a collimating system, and the in accuracies which result from completely different geometric relationship between a CT unit and a therapy machine.