Dosimetric comparison of fixed jaw and jaw tracking applied in intensity-modulated 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3期
- Page:
- 249-253
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Dosimetric comparison of fixed jaw and jaw tracking applied in intensity-modulated radiotherapy for esophageal cancer
- Author(s):
- CHEN Yan1; HUANG Yuliang2; WU Hao2; JIA Dong1; JIA Lin1; HAN Jianjun1; LI Chenguang2; ZHANG Yibao2
- 1. Sichuan Mental Health Center, the Third Hospital of Mianyang, Mianyang 621000, China; 2. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing 100142, China
- Keywords:
- ; Keywords: esophageal cancer; fixed jaw; jaw tracking; intensity-modulated radiotherapy
- PACS:
- R730.55；R811.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.03.001
- Abstract:
- Abstract: Objective To compare the dosimetric effects of jaw tracking and fixed jaw techniques on intensity-modulated radiotherapy (IMRT) for esophageal cancer, especially on the lung dose. Methods The clinical data of 48 patients with stage IV esophageal cancers were analyzed retrospectively. The mean planning target volume of all 48 patients was (542±192) cm3. Based on Eclipse 10.0 treatment planning system, 7-field IMRT plan was designed for each patient. Moreover, 95% of planning target volume was irradiated by at least 50.4 Gy. Keeping beam geometry and optimization conditions unchanged, the plans were optimized using jaw tracking (Tracking group) or fixed jaw techniques (Fixed group). Subsequently, the hotspots of Fixed group were post-processed to ensure that the plans meet clinical requirements (Modified group). Finally, the dose-volume histogram was used to compare the dosimetric effects of jaw tracking and fixed jaw techniques on IMRT for esophageal esophageal cancer in 48 patients. Results Compared with those in Tracking group, the V30 Gy, V40 Gy, Dmean of heart and the V5 Gy, V20 Gy, Dmean of lungs in Fixed group were reduced by an average of 0.68%, 1.89%, 1.77%, and 6.84%, 1.50%, 4.06%, respectively. However, the Dmax of spinal cord and global Dmax in Fixed group were increased by 0.58% and 2.14%, respectively. After hotspot post-processing, the issues were well resolved. The Dmax of spinal cord and global Dmax in Modified group were 1.92% and 2.38% lower than those in Tracking group (P<0.001). Moreover , the V30 Gy, V40 Gy, Dmean of heart and the V5 Gy, V20 Gy, Dmean of lungs in Modified group were reduced by 7.69%, 2.00%, 2.42%, and 6.56%, 1.33%, 3.73%, respectively, with statistical differences (all P<0.05). Conclusion For special cases, the fixed jaw technique is superior to jaw tracking technique in protecting organs-at-risk, such as heart and lungs, which should be taken into full consideration during the IMRT for esophageal cancers.
Last Update: 2019-03-25