Fig. 1

An overview of target volumes for postoperative resection cavity is presented on post-contrast T1-weighted MRI sequences and CT scans. The gross tumor volume (GTV) is presented in red, the clinical target volume (CTV) in blue and the planning tumor volume (PTV) in pink. For this case, CTV was created by 1-mm expansion of the GTV, extended by 5 mm along the bone flap beyond the initial region of preoperative tumor contact. Note that an extension by 10 mm along the meningeal margin for brain metastases with preoperative dural contact [59] or the inclusion of the entirety of the craniotomy site [71] has been suggested by some authors