Comparison of different treatment techniques using deformed margin drawing method in stereotactic body radiotherapy treatments in lung cancer

Primary treatment for early stage lung cancer is surgery, however SBRT results similar local control and survival rates for medically inoperable patients. In this dosimetric study, early stage medically inoperabl lung cancer SBRT plans were compared in terms of 3DCA and VMAT while using RPG method for 3DCA. With 3DCA-RPG technique, a sharper dose fall off and control of the high dose region has been targeted. It was aimed to show that the technique is superior to the 3DCA plans and is at least as good as VMAT plans, based on criteria such as CI, IDSvolume, IDSlocation, lung V20Gy values controlled in SBRT plans in RTOG0915 protocol and low MU, short treatment times, control of hot dose zones. 20 patients' plans were studied. In the 3DCA-RPG plans, CI values showed a significant superiority to the VMAT technique (p <0.001), and there was also a significant difference between 3DCA and 3DCA-RPG plans (p <0.001). 3DCA RPG plans did not show significant superiority in IDSvolume value to VMAT technique (p <0,080). There was a significant difference in IDSvolume value between 3DCA and 3DCA-RPG plans (p <0,046). The IDSlocation value of the 6FFF-3DCA RPG plans showed a significant advantage over the VMAT technique (p = 0.011). The MU value in 6FFF-3DCA-RPG plans was significantly superior to the VMAT plans (p <0.001). There was a significant difference in MU between 3DCA and 3DCA-RPG plans (p = 0.015). 3DCA RPG plans were not superiority to VMAT technique in V20 values, but it was able to provide a significant advantage in terms of V2.5 and MLD values (p = 0,881, p <0,001, p = 0,002, respectively). The 3DCA-RPG method gives superior results in terms of all parameters from the conventional 3DCA method. In addition, 3DCA-RPG method has similar or superior to VMAT plans in terms of acceptance criteria of RTOG 0915. The 3DCA-RPG method is advantageous in terms of treatment time and MU and this technique can be used as an alternative to VMAT technique.