Dosimetric evaluation of simplified intensity-modulated radiation therapy for thoracic tumors

To evaluate the feasibility of multi-parameters combined simplified intensity-modulated radiation therapy (sIMRT) planning in thoracic tumors and provide guidance for clinical practice. A total of 34 patients with thoracic tumors who underwent radiotherapy during 2019 to 2020 in our hospital were retrospectively analyzed. The same experienced medical physicist designed the sIMRT planning. The sIMRT planning limited the maximum number of segments per beam-field, the minimum segment area, and the minimum number of segment monitor units (MU), remaining consistent with the conventional intensity-modulated radiation therapy (IMRT). Comparative analysis of the difference in the irradiation dose to the tumor target area, and organs at risk, and delivery validate between 2 groups. The sIMRT slightly increased the tumor target area irradiation dose, but the homogeneity index was similar when compared with IMRT (P > .05). The sIMRT planning significantly reduced the low dose-volume area of the lungs (left lung, V5: 2.5%; right lung, V5: 3.1%; V10: 1.8%; lungs, V5: 3.2%; V10: 1.5%, P < .05) and significantly increased the high dose-volume area of the lungs, heart, and esophagus, while meeting the clinical dose-restriction requirements. Moreover, the planning delivery validation showed that significantly reduced the treatment time (6.5 ± 1.9 minutes vs 8.8 ± 2.0 minutes, P < .0001) and total MU (386.3 ± 109.4 MU vs 406.3 ± 107.9 MU, P < .05). This simplified sIMRT method can meet the requirements of thoracic tumors radiotherapy planning, and has higher time effectiveness. In the future, it needs to be further explored in clinical practice.