Effect of different incidence angles on dosimetric parameters of radiotherapy for esophageal cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第8期
- Page:
- 908-913
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Effect of different incidence angles on dosimetric parameters of radiotherapy for esophageal cancer
- Author(s):
- LÜ Mingyue; LI Ping; CHEN Weixiang; WANG Yiming
- Department of Oncology, the First Affiliated Hospital of Ji’nan University, Guangzhou 510630, China
- Keywords:
- ; Keywords: esophageal cancer; three-dimensional conformal radiotherapy; intensity-modulated radiotherapy; dosimetric comparison
- PACS:
- R812；R735.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.08.009
- Abstract:
- Abstract: Objective To compare the dosimetric differences among esophageal cancer plans with different incidence angles for determining an optimal plan which can optimize target doses and minimize the damages to organs-at-risk. Methods Eleven patients with esophageal cancer were enrolled in this study. Four radiotherapy plans, namely three-dimensional conformal radiotherapy (3D-CRT), 4-field intensity-modulated radiotherapy (4F-IMRT), 7-field intensity-modulated radiotherapy (7F-IMRT) and 9-field intensity-modulated radiotherapy (9F-IMRT), were designed for each patient. The prescription dose of PTVg and planning target volume (PTV) was 60 Gy/27 F and 50 Gy/27 F, respectively. The dosimetric parameters of target areas and organs-at-risk in different plans were compared. Results 4F-IMRT plan was superior to 3D-CRT plan in the conformity index (CI) of PTVg and the CI and homogeneity index (HI) of PTV, and was superior to 7F-IMRT plan in the CI of PTV, with statistical differences (P<0.05). The V20 of lung in 4F-IMRT plan was lower than that in 3D-CRT plan; the V20 and V30 of lung in 4F-IMRT plan were lower than those in 7F-IMRT plan; and the V5 of lung in 4F-IMRT plan was lower than that in 9F-IMRT plan, with significant differences (P<0.05). In the 4 kinds of plans, the maximum dose of spinal cord was less than 45 Gy and the V33 of the heart was less than 46%, which met the clinical requirements (P>0.05). Conclusion The doses of the heart and spinal cord in 4F-IMRT plan are similar to those in 7F-IMRT and 9F-IMRT plans, but the lung dose of 4F-IMRT plan is significantly reduced and the radiation time was 2-3 times less than that of 7F-IMRT and 9F-IMRT plans. 4F-IMRT plan can not only improve target conformity, but also better protect organs-at-risk and significantly reduce the low-dose volume of lung.
Last Update: 2019-08-26