Dosimetric comparison of intensity-modulated photon radiotherapy planning and intensity-modulated proton radiotherapy planning for glioma / 肿瘤研究与临床

ABSTRACT

Objective:To compare the dosimetric difference between intensity-modulated photon radiaotherapy (IMRT) planning and intensity-modulated proton radiotherapy (IMPT) planning for glioma.Methods:The clinical data of 15 glioma patients who underwent IMRT in ion medical center of the First Affiliated Hospital of USTC from November 2020 to April 2022 were retrospectively analyzed. IMRT planning and IMPT planning were designed for the image of each patient in the therapy planning system. Main dosimetric parameters were compared including plan target volume (PTV), coverage index (CI), dose homogeneity index (HI), and maximal dose (D max) and mean dose (D mean) of organs at risk between both plans. Results:There were no significant differences between IMRT planning and IMPT planning in terms of D max and D mean of PTV1 and PTV2, CI and HI (all P > 0.05). Compared with IMRT planning, brainstem D mean [6.92 GyE (0.09 GyE, 12.58 GyE) vs. 24.41 GyE (2.59 GyE, 34.18 GyE)], left optic nerve D max [0.78 GyE (0.04 GyE, 25.18 GyE) vs. 20.42 GyE (6.38 GyE, 37.17 GyE)], left optic nerve D mean [0.10 GyE (0.01 GyE, 11.63 GyE) vs. 9.74 GyE (2.99 GyE, 20.87 GyE)], right optic nerve D mean [1.57 GyE (0.13 GyE, 14.90 GyE) vs. 14.08 GyE (2.66 GyE, 23.67 GyE)], left len D max [0 GyE (0 GyE, 2.91 GyE) vs. 4.84 GyE (1.42 GyE, 5.48 GyE)], left len D mean [0 GyE (0 GyE, 1.73 GyE) vs. 3.84 GyE (1.25 GyE, 4.30 GyE)], right len D max [0.25 GyE (0.04 GyE, 4.55 GyE) vs. 4.28 GyE (1.58 GyE, 5.84 GyE)], right len D mean [0.16 GyE (0.01 GyE, 1.95 GyE) vs. 3.73 GyE (1.04 GyE, 4.86 GyE)], pituitary D max [6.97 GyE (0.18 GyE, 39.70 GyE) vs. 36.60 GyE (2.74 GyE, 45.19 GyE)], pituitary D mean [1.36 GyE (0.06 GyE, 13.85 GyE) vs. 24.74 GyE (2.42 GyE, 32.80 GyE)], hippocampus D max [5.10 GyE (0.24 GyE, 26.52 GyE) vs. 35.83 GyE (5.03 GyE, 46.11 GyE)], hippocampus D mean [0.36 GyE (0.04 GyE, 25.65 GyE) vs. 18.79 GyE (2.37 GyE, 28.10 GyE)] in IMPT planning were lower, and the differences were statistically significant (all P < 0.05). There were no statistical differences in brainstem D max [51.98 GyE (0.66 GyE, 53.43 GyE) vs. 53.29 GyE (3.87 GyE, 53.48 GyE)], right optic nerve D max [9.60 GyE (0.01 GyE, 43.32 GyE) vs. 25.37 GyE (3.45 GyE, 41.25 GyE)] of both plans (all P > 0.05). Conclusion:In the radiotherapy for glioma, IMRT and IMPT can meet the dose demand in clinic. Furthermore, IMPT planning can protect organs at risk and reduce radiation dose in hippocampus, brainstem, optic nerve, lens and pituitary.