PMC7154243_01
Magnetic resonance images of the patient's brain in the course of the disease, with brain metastasis in the right temporal lobe (blue arrow). Dates are given in the format DMY. 1.OP, first operation; 2.OP, second operation; RT, radiotherapy.
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F1
Brain MRI showed a solitary lesion in the right temporal lobe (Fig. 1). This MRI, performed 2.5 months after the surgery, unfortunately showed early local recurrence with an enhancing lesion localized ventral from the resection cavity and widely touching the dura with perifocal edema (Fig. 1).
Illustration of the radiotherapy planning process. A Contouring of the target volumes. The red curve represents the clinical target volume, and the blue curve the planning target volume. B Isodoses of the final irradiation plan. C Layout of the irradiation fields (volumetric modulated arc technique).
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F2
An isocentric margin of 3 mm was added to the CTV, leading to the planning target volume (PTV; generally speaking, it is an additional margin to accommodate for all potential causes of uncertainty, such as interindividual variability in target volume definition, inaccuracies in image coregistration, movements of patients during RT, etc.) (Fig. 2). The patient was irradiated on a Varian TrueBeam STx linear accelerator (Varian Medical Systems) utilizing the volume-modulated RT technique delivered by 2 coplanar (209 ) 6-MV arcs (Fig. 2).