[Image-guided radiation therapy. Paradigm change in radiation therapy].

CLINICAL ISSUE: The introduction of image-guided radiotherapy (IGRT) has changed the workflow in radiation oncology more dramatically than any other innovation in the last decades. STANDARD TREATMENT: Imaging for treatment planning before the initiation of the radiotherapy series does not take alterations in patient anatomy and organ movement into account. TREATMENT INNOVATIONS: The principle of IGRT is the temporal and spatial connection of imaging in the treatment position immediately before radiation treatment. DIAGNOSTIC ASSESSMENT: The actual position and the target position are compared using cone-beam computed tomography (CT) or stereotactic ultrasound. PERFORMANCE: The IGRT procedure allows a reduction of the safety margins and dose to normal tissue without an increase in risk of local recurrence. ACHIEVEMENTS: In the future the linear treatment chain in radiation oncology will be developed based on the closed-loop feedback principle. PRACTICAL RECOMMENDATIONS: The IGRT procedure is increasingly being used especially for high precision radiotherapy, e.g. for prostate or brain tumors.