Iplan version 3

Palliative RT was applied in cases of metastatic bone lesions of spinal cord compression, pain affecting the patients’ QOL, high risk of pathologic fractures, and weight-bearing sites without symptoms.
Gross tumor volume (GTV) was contoured as the enhancing mass and osteolytic or osteoblastic changes of the bone in planning CT or diagnostic images. For hypofractionated RT, clinical target volume (CTV) included GTV plus a 2–3 cm margin longitudinally and 1 cm axially in long bones and 1–2 cm in all directions in the other bones. Planning target volume (PTV) was formed by expanding 7–10 mm from the CTV. For stereotactic body radiotherapy (SBRT), CTV included the gross tumor and the involved spine. PTV was produced by adding 0–2 mm to the CTV [22 (link),23 (link)]. SBRT was applied to the lesions limited to the vertebral bodies with oligometastases, and hypofractionated RT was conducted for all other patients.
Hypofractionated RT and SBRT were planned with Eclipse version 8.6 (Varian, Palo Alto, CA, USA) and iPlan version 3.0 (Brainlab, Feldkirchen, Germany), respectively. They were performed using Varian iX (Varian) and Novalis (Brainlab), respectively. Total irradiation dose, fraction size, and the modality of RT were determined by the sites of metastatic bone lesions and adjacent normal structures.

Planning computed tomography (CT) was taken with a slice thickness of 2 mm after immobilizing the patient’s head using an individual thermoplastic stereotactic mask (Brainlab, Feldkirchen, Germany). CT data were fused with T1-weighted axial post-contrast MRI scans on iPlan version 3.0 (Brainlab) for contouring target volumes and organs at risk (OAR) and producing stereotactic RT plans. Gross tumor volume (GTV) and OAR were outlined on the MRI scans. Planning target volume (PTV) was the same as GTV without margin. Stereotactic RT plans were mostly composed of 3–6 arc beams, except for 2 patients who received intensity-modulated RT with 7–8 beams, and aimed to deliver 90% of the prescribed dose to the PTV. Stereotactic RT was performed using Novalis linear accelerator from single to 10 fractions under image-guidance using an ExacTrac device (Brainlab).