Dosimetric comparison between jaw tracking technique and static jaw technique in intensity-modulated radiotherapy for non-small cell lung cancer

Abstract

Objective To study the dosimetric difference between jaw tracking technique (JTT) and static jaw technique (SJT) in intensity-modulated radiotherapy (IMRT) for local advanced non-small cell lung cancer (NSCLC). Methods SJT and JTT were used to design the intensity-modulated plans for 30 patients with local advanced NSCLC, respectively. For both SJT and JTT plans, 95% volume of the planning target volume (PTV) satisfied the prescribed dose, then we compared the conformity index (CI) and homogeneity index (HI) of PTV, dose distributions of organs-at-risk, and the total machine unit. The dose of two treatment plans were verified by Mapcheck2. Results For both JTT and SJT plans, the dose distribution of the target areas satisfied the clinical requirement. There were no statistically significant differences in the HI and CI of PTV between JTT plan and SJT plan. Compared with SJT plan, JTT plan significantly decreased the V5, V10, V20, Dmean of the lung, V5, V10, Dmean of the heart, Dmax, Dmean of the PRV spinal cord, and increased the total machine unit (P<0.05). There were no statistically significant differences in the V30, V40 of the lung and the V20, V30, V40 of the heart between JTT plan and SJT plan. Conclusions Based on the JTT and SJT techniques, the dose distributions of target areas and organs-at-risk in the intensity-modulated radiotherapy (IMRT) for local advanced NSCLC can meet the clinical requirement, but JTT technique can better decrease organs-at-risk dose. Key words: Non-small cell lung cancer; Jaw tracking technique (JTT); Static jaw technique (SJT); Intensity-modulated radiotherapy; Dosimetry