SU-E-T-810: Simultaneous Integrated Boost with Forward IMRT for Multiple Brain Metastases: A Planning Study

Abstract

Purpose: To evaluate the dose conformity and feasibility of whole brainradiotherapy with a simultaneous integrated boost by forward intensity‐modulated radiation therapy in patients with 1–3 brain metastases. Methods: Forward intensity‐modulated radiation therapy plans were generated for 10 patients with 1–3 brain metastases on Pinnacle 6.2 Treatment Planning System. The prescribed dose was 30Gy to the whole brain (PTVwbrt), 40Gy to individual brain metastases (PTVboost) simultaneously, both doses were given in 10 fractions. The maximum diameters of individual brain metastases ranged from 1.6 to 6 cm, and the summated PTVboost per patient ranged from 1.62 to 69.81 cc . Conformity and feasibility were evaluated and compared with those reported in the literature which had been planned by helical tomotherapy, regarding conformation number (CN) and treatment delivery time. Results: One hundred percent volume of PTVboost received at least 95% of the prescribed dose in all cases. The maximum dose was less than 110% of the prescribed dose to PTVboost . And all of the hot spots were within PTVboost . The volume of PTVwbrt received at least 95% of the prescribed dose ranged from 99.2% to 100%. The mean values of CN were 0.682. The mean treatment delivery time was 2.79 minutes. Ten beams were used on average in these plans. Conclusions: Whole brainradiotherapy with a simultaneous integrated boost by forward IMRT for patients with 1–3 brain metastases is feasible. Dose conformity was comparable to those planned by helical tomotherapy in the literature and treatment delivery time was shorter.