Volumetric modulated arc therapy for spine SBRT patients to reduce treatment time and intrafractional motion

Abstract

Volumetric modulated arc therapy (VMAT) is an efficient technique to reduce the treatment time and intrafractional motion to treat spine patients presented with severe back pain. Five patients treated with spine stereotactic body radiation therapy (SBRT) using 9 beams intensity modulated radiation therapy (IMRT) were retrospectively selected for this study. The patients were replanned using two arcs VMAT technique. The average mean dose was 104% ± 1.2% and 104.1% ± 1.0% in IMRT and VMAT, respectively (p = 0.9). Accordingly, the average conformal index (CI) was 1.3 ± 0.1 and 1.5 ± 0.3, respectively (p = 0.5). The average dose gradient (DG) distance was 1.5 ± 0.1 cm and 1.4 ± 0.1 cm, respectively (p = 0.3). The average spinal cord maximum dose was 11.6 ± 1.0 Gy and 11.8 ± 1.1 Gy (p = 0.8) and V_10Gy was 7.4 ± 1.4 cc and 8.6 ± 1.7 cc (p = 0.4) for IMRT and VMAT, respectively. Accordingly, the average number of monitor units (MUs) was 6771.7 ± 1323.3 MU and 3978 ± 576.7 MU respectively (p = 0.02). The use of VMAT for spine SBRT patients with severe back pain can reduce the treatment time and intrafractional motion.