Intensity modulated radiotherapy isodose map of patient no. 2. This patient has a large meningioma with bitemporal spread surrounding the optic nerves and chiasm. Shown are transversal (upper left), sagittal (lower left) and coronal (right) views. In order to err on the side of caution due to the estimated 6.6 Gy PRRT dose, the optic tract was limited to 45 Gy (thick green line) and the PTV encompassing dose was limited to 49 Gy (thick orange line) instead of the originally planned 54 Gy.