High precision SBRT using eXaCradle and ConeBeamCT
E. Montero Perea, Sandra Miranda, M. Órtiz Seidel · Reports of Practical Oncology & Radiotherapy · 2013
reports of practical oncology and radiotherapy 1 8 ( 2 0 1 3 ) S337-S354 Patients and methods.In ONCOSUR and CROASA between January 2010 and December 2012 we have treated 16 patients (50% female) with 45 brain metastases and mean age of 53.63 years (33-68).A total of 21 treatments have been performed.Our GTV margin was of 2-3 mm.We have evaluated clinical, therapeutic data and acute toxicity.Results.Primary tumors were 7 breasts, 3 melanomas, 5 lungs, and 1 esophagus.Only 6 patients were also treated with whole brain radiotherapy (WBRT).The radiotherapy techniques used were: 15 Volume Modulated Arc Therapy (VMAT); 1 Intense Modulated Therapy Step and Shoot (IMRT S-S); 1 Dynamic Arc Therapy (DART); and 4 3D Conformal Radiotherapy (3DCRT).The hipofractionated schemes more used were: 6 Gy × 6 fx (4 cases) and 10 Gy × 3 fx (6 cases).All patients received 2 fx per week.A variable positioning accuracy of 1-4 mm has been reported for frameless stereotactic systems.In our series, IGRT repositioning mean accuracy was: X = 0.18 mm (0.01-0.44);Y = 0.23 mm (0.06-0.66); and Z = 0.20 mm (0.01-0.40).Acute side effects were not detected.With a mean follow-up of 10.35 months (2-30), 6 patients are alive, and 10 are died.The causes of death were progression in: brain 2 patients (no WBRT); lung 3 patients; liver 1 patient; unknown 3 patients and general deterioration 1 patient.Conclusions.Frameless SRS is an effective and comfortable treatment in the management of brain metastases.Non-invasive mask fixation system plus IGRT is associated with a high repositioning accuracy with no errors up to 3 mm.