Clinical implementation of total body irradiation with multi isocentric volumetric modulated arc

Total Body irradiation (TBI) is conditioning regimen in conjunction with chemotherapy before Bone Marrow Transplant (BMT) for a patient with hematological malignancies. TBI kills malignant cells and suppresses the immune system which helps to prevent transplant rejection. Various dose and fractionation schemes were used in the past treatments but in general dose fractionation schemes for TBI is 12-15 Gy given in 6-12 fractions over 3-6 days. Several publications reported various treatment techniques such as left and right side treatment with sitting patient on chair, AP-PA technique with extended SSD, Translational technique and sweeping beam technique with column mounted Linac. All these techniques required dedicated equipment and accessories for treatment, shielding materials for critical OARS and larger size room which is not feasible in regular linear accelerator. In recent years publications reported that Helical Tomotherapy was implemented the TBI treatment as an approach of reducing dose to critical organs especially lungs