So sánh các thông số liều lượng của kỹ thuật vmat và 3d-crt trong xạ trị ung thư vú trái và hạch vùng

COMPARISON OF DOSIMETRIC PARAMETERS OF VOLUMETRIC MODULATED ARC THERAPY AND THREE-DIMENSIONAL CONFORMAL RADIOTHERAPY FOR LEFT SIDE BREAST AND REGIONAL NODESObjective: Comparative study of dose parameters of Volumetric modulated arc therapy (VMAT) and three-dimension radiotherapy (3D-CRT) in patients after left breast surgery with radiation therapy with regional lymph nodes. Materials and Methods: Twenty-four plans of 12 left-breast cancer patients were treated with VMAT with 4 partial arc and 3D-CRT plans were added to compare each other, from 1/2018 to 3/2019 at the Vinmec TimesCity International Hospital. Results: The average coverage dose to the treatment volume (PTV) of VMAT plans is better than the 3D-CRT plan (99.10 ± 0.17 % compared to 98.7 ± 0.34 %; p = 0.01). Conformity index (CI), homogeneity index (HI) for VMAT plans also better results CI: 0.99 vs. 0.98; p = 0.26 and HI: 0.096 compared to 0.119; p = 0.02). Organs at risk, at low doses V5Gy, V10Gy VMAT plans do not avoid good doses by 3D-CRT plans: V5Gy for left lung (78.8 ± 4.6 % compared to 55.37 ± 4.38 %) and heart (77.15 ± 9.52 % compared to 19.15 ± 7.93 %) (p 0.05), V30Gy (9.25 ± 5.56 % compared to 2.13 ± 1.89 %) and V40 Gy (7.54 ± 5.03 % compared with 0.2 ± 0.25 %). Dose to coronary arteries also decreased significantly for VMAT plans compared to 3D-CRT: V20Gy (0.8 ± 1.01 % compared to 27.29 ± 15.19 %) V30Gy (0.00 % compared to 23.09 ± 10.73 %). Conclusion: VMAT is dosimetrically superior to the 3D-CRT for left‑sided breast cancer patients with regional nodes by dose coverage to PTV and good ability to avoid heart and lung and coronary arteries than.Key words: Breast cancer, Postmastectomy radiotherapy, Three-dimension conformal radiotherapy, Volumetric modulated arc therapy.