中国口腔颌面外科杂志

中国口腔颌面外科杂志 ›› 2021, Vol. 19 ›› Issue (3): 248-252.doi: 10.19438/j.cjoms.2021.03.013

• 论著 • 上一篇    下一篇

去伪影算法对头颈部肿瘤患者钛板植入术后放疗的剂量影响

劳峥, 毕帆, 樊文慧, 胡海生, 涂文勇, 石慧烽   

  1. 上海交通大学医学院附属第九人民医院 口腔颌面-头颈肿瘤科,上海交通大学口腔医学院, 国家口腔医学中心,国家口腔疾病临床医学研究中心,上海市口腔医学重点实验室,上海 200011
  • 收稿日期:2020-09-21 修回日期:2020-12-14 发布日期:2021-07-16
  • 通讯作者: 石慧烽, E-mail:113074222@qq.com
  • 作者简介:劳峥(1986-),女,博士,医师,E-mail: jennylao@126.com

Impact of metal artifact reduction algorithms on dosimetry of postoperative radiotherapy for head and neck cancer patients with titanium plate implantation

LAO Zheng, BI Fan, FAN Wen-hui, HU Hai-sheng, TU Wen-yong, SHI Hui-feng   

  1. Department of Oral Maxillofacial Head and Neck Oncology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology. Shanghai 200011, China
  • Received:2020-09-21 Revised:2020-12-14 Published:2021-07-16

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摘要： 目的 通过去伪影前、后CT各组织的CT值和剂量比较,探讨金属伪影消减（metal artifact reduction,MAR）算法对头颈部钛板植入术后放疗计划的剂量影响。方法 选择上海交通大学医学院附属第九人民医院2019年10月—2020年3月收治的头颈部肿瘤患者20例,均为术中植入钛板进行下颌骨重建患者。在模拟定位阶段,分别获取常规CT图像和MAR算法后的去伪影CT图像。使用自动勾画软件对基于MAR算法的CT图像进行危及器官勾画,而后将勾画复制到常规CT图像上,分别统计各危及器官的CT值。以颈2椎体前缘作为计划中心点,设置2个40 cm×40 cm的对穿照射野并计算剂量。采用SPSS 21.0软件包对结果行配对t检验。结果 在各组织的平均CT值方面,相比常规CT图像,基于MAR算法的去伪影CT图像的各组织平均CT值发生明显变化,变化范围为5.04%~127.19%,平均变化率为26.29%。除喉部、左右腮腺、咽扁桃体、垂体和甲状腺外,去伪影前、后各组织的平均CT值均存在统计学差异。剂量研究结果显示,两组CT各组织的平均剂量除口腔外均无统计学差异。结论 MAR算法可以有效降低CT图像的伪影,但也改变了无伪影区域的CT值,对剂量造成一定影响,可以将其作为靶区勾画的参照,但不可将去伪影CT图像用于剂量计算。

关键词: 去伪影算法, 头颈部肿瘤, CT值, 剂量, 钛板, 金属植入

Abstract: PURPOSE: To explore the value of metal artifact reduction(MAR) algorithms on radiotherapy dose calculation by comparing the CT values and radiation doses before and after MAR. METHODS: Twenty head and neck cancer patients admitted to Shanghai Ninth People's Hospital,Shanghai Jiao Tong University School of Medicine during Oct 2019 to March 2020 were selected. All of them underwent mandibular reconstruction with titanium plate implantation before radiotherapy. Their CT simulation scans and the images after MAR were collected. The organs at risk(OAR) were contoured by auto-segmentation software on CT images after MAR and the contouring was duplicated to original CT scan, with both the CT values of OAR recorded. Two 40 cm×40 cm opposite irradiated fields were planned with anterior margin of the second cervical vertebra set as central point, and then dose calculations were collected for paired t test with SPSS 21.0 software package. RESULTS: The average CT values of all the organs and tissue changed significantly after MAR based on MAR algorithms, compared with the original planning CT images. The average rate of change was 26.29%, with a range from 5.04%-127.19%.There was significant difference in average CT values of organs between before and after MAR except for larynx, bilateral parotid glands, pharyngeal tonsil, pituitary gland and thyroid gland. There was no significant difference in radiation dose change between the two groups, with the exception of oral cavity. CONCLUSIONS: MAR algorithms can effectively reduce metal artifacts on CT scans, but the CT values were also significantly changed, which inevitably influenced the dose calculation. It is suggested that CT images after MAR could be performed as references for target area contouring, but not suitable for dose calculation for planning of radiotherapy.

Key words: Metal artifact reduction algorithms, Head and neck cancer, CT value, Dosimetry, Titanium plate, Metal implantation

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