Analysis on the dose characteristics of Body γ Knife and Tomotherapy treatment for hepatocellular carcinoma

Abstract

Objective To study the dose characteristics of Body y Knife and Tomotherapy treatment plans for hepatocellular carcinoma, and compare their differences between organs at risk (OAR) dose and the range of low dose. Methods CT simulation images of twelve patients with hepatocellular carcinoma were selected, the target volume and OAR were drew by doctor. Body γ Knife and Tomotherapy treatment plans were optimized with their own planning station. The dosimetric characteristics were evaluated by dose volume histograms and were compared. To analyze the difference between the two techniques, the paired t-test was applied. Results The Dmax and Dmean of target with Body γ Knife were higher than Tomotherapy (P=0.002,0.000) , but the conformal index of PTV of Tomotherapy was superior to the Body γ Knife (P=0.001). The Dmax of spinal cord and left kidney with Body γ Knife was lower than Tomotherapy (P=0.013, 0.012) , and it was also in the Dmean of stomach and left kidney (P=0.010,0.023). In the volume dose comparison, the V40, V35, V30, V25 and V20 of normal tissue (all Body - PTV) and liver (all liver-GTV) with Body γ Knife were higher than Tomotherapy (P=0.001, 0.001, 0.001,0.007, 0.029) , but the V10 and V5 were lower (P=0.019,0.031) , the Dmax of stomach, Dmean of right kidney and liver were no statistical difference (P=0.247, 0.308, 0.401) . Conclusions Both treatment plans could meet the clinical dosimetric need, by the same prescription dose, Dmax and Dmean of target of Body y Knife were higher than Tomotherapy. Tomotherapy had excellent dose-target conformal and could reduce the range of V25-V40 of OAR and normal tissue, but the range of V5-V10 was increased obviously. Key words: Dosimetry; Body γ Knife; Tomotherapy; Hepatocellular neoplasms