Dosimetric Comparison of Stereotactic Body Radiotherapy in Lung Cancers: CyberKnife Versus Helical Tomotherapy Versus Volumetric Modulated Arc Therapy

Aim: Stereotactic body radiotherapy (SBRT) is widely used in the treatment of early- stage lung cancer. There are several SBRT techniques. We aimed to compare three planning techniques: CyberKnife (CK), Helical Tomotherapy (HT), and Volumetric Modulated Arc Therapy (VMAT).

Materials and Methods: This study included 15 patients with early-stagelung cancer who were treated in our clinic. For this study, the images obtained were recontoured and replanned in CK, HT, and VMAT. Treatment plans were compared in terms of target volume and organ-at-risk doses.

Results: The HT plan differed significantly from the other plans in terms of conformity (CI), and gradient indexes (GI) (p<0.001). There was a significant difference between the plans in terms of homogeneity indexes (HI) favoring HT (p<0.001). VMAT plan reduced the monitor unit per fraction and beam on time per fraction values (p < 0.001). The lowest lung V5 (22.7%, p = 0.046), Dmax, and the dose of 5 cc of trachea (499.4 cGy vs 252.4 cGy; p=0.017, p=0.034) and esophagus (673.9 cGyvs237.3 cGy; p=0.014 and p=0.08) were observed with the VMAT plan.

Conclusions: All plans met the organ-at-risk dose constraints and target volume doseswith acceptable limits. Each clinic should select an appropriate technique based on the available resources and experience.