Dosimetric advantages of MRI image-guided non-coplanar intensity-modulated radiotherapy in active bone marrow sparing for patients with cervical cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第12期
- Page:
- 1390-1395
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Dosimetric advantages of MRI image-guided non-coplanar intensity-modulated radiotherapy in active bone marrow sparing for patients with cervical cancer
- Author(s):
- LI Ping1; ZHANG Shuxu2; YANG Lu2; ZENG Qingxing1; LIN Xiaohui1; ZHANG Guoqian2
- 1. Graduate School, Guangzhou Medical University, Guangzhou 510182, China; 2. Radiotherapy Center, Cancer Center of Guangzhou Medical University, Guangzhou 510095, China
- Keywords:
- Keywords: cervical cancer; radical radiotherapy; bone marrow sparing; non-coplanar intensity-modulated radiotherapy; coplanar intensity-modulated radiotherapy
- PACS:
- R811.1；R737.33
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.12.005
- Abstract:
- Abstract: Objective To investigate the dosimetric characteristics and advantages of non-coplanar intensity-modulated radiotherapy (NC-IMRT) guided by magnetic resonance imaging (MRI) in the bone marrow sparing for cervical cancer patients. Methods A total of twenty patients with cervical cancer scheduled for radiotherapy were enrolled. Two different plans, namely 9-field coplanar IMRT plan and NC-IMRT plan including 7 coplanar fields and 2 non-coplanar fields, were designed based on the active pelvic bone marrow segmented in MRI images. Both plans adopted the same target upper and lower bounds, limit doses to organs-at-risk, weighting factors and calculation grids, and the same normalization condition that 95% of planning target volume received the prescription dose was applied for evaluation. The differences in dosimetric parameters of target areas and organs-at-risk such as exposure dose, volume, conformity index and homogeneity index were compared between two groups. Results The active bone marrow volume segmented in MRI images was (219.38±9.73) cm3, 63.4% less than the volume of the pelvis segmented in positioning CT images which was (600.32±6.88) cm3, with statistical significance (P<0.05). The conformity index of planning target volume in NC-IMRT group was superior to that in IMRT group. The low-dose radiation region (V10 and V20) and high-dose radiation region (V40 and V50) of the active bone marrow of the pelvis as well as the Dmean, V10, V20, V30, V40 of the left femoral head and the Dmean, Dmax, V10, V20 of the right femoral head in NC-IMRT group were significantly reduced, with statistical differences (P<0.05). There was no significant difference in the doses to rectum and small intestine between two groups (P>0.05). Conclusion With guaranteed clinical target doses for cervical cancer patients, NC-IMRT based on active bone marrow segmentation in MRI images is advantageous over coplanar IMRT in the sparing of the active bone marrow of the pelvis.
Last Update: 2019-12-24