125I放射性粒子治疗腮腺复发性腺样囊性癌的靶区设计及剂量学分析

目的 分析¹²⁵I放射性粒子单纯植入治疗腮腺区复发性腺样囊性癌的靶区设计方法及剂量学参数。方法 回顾性分析2005年1月至2019年10月北京大学口腔医院收治的行单纯¹²⁵I放射性粒子近距离植入治疗的25例复发性腮腺腺样囊性癌患者的靶区设计及剂量学参数。术前结合腺样囊性癌病理学特点对不同复发部位设计靶区范围，处方剂量为100~120 Gy，术后验证靶区范围与剂量学参数。随访统计局部控制情况及放疗相关不良反应。结果 25例患者复发部位分别为腮腺浅叶区10例，腮腺深叶区7例，颅底区及乳突颌后区复发各4例。中位植入粒子数量为59颗，粒子活度18.5~25.9 MBq，植入后验证所有患者均实现植入前靶区设计范围，D₉₀、V₁₀₀、V₁₅₀等剂量学参数与植入前相近，差异无统计学意义（P>0.05）。3年、5年局部控制率分别为81.5%和61.5%，不同部位的局部控制率差异无统计学意义（P>0.05）。结论 单纯应用¹²⁵I放射性粒子植入治疗腮腺区复发性腺样囊性癌，通过结合病理学特点及复发部位优化靶区设计，合理准确应用达到剂量学参数，可获得较好的局部控制。

Target delineation and dosimetry analysis of 125I interstitial brachytherapy for recurrent adenoid cystic carcinoma in the parotid gland

Objective To analyze the target design and dosimetric parameters of patients with recurrent adenoid cystic carcinoma (ACC) in the parotid gland who were treated with ¹²⁵I interstitial brachytherapy alone. Methods A retrospective analysis was conducted for 25 patients with recurrent adenoid cystic carcinoma in parotid gland who were histopathologically diagnosed between January 2015 and October 2019. These patients were treated with ¹²⁵I interstitial brachytherapy alone, with prescribed doses of 100-120 Gy. The target volume was designed according to the pathological characteristics of ACC and recurrence sites. The pre- and post-operation dosimetric parameters (i.e., local control rates) were calculated using the treatment planning system. Results In this study, the local recurrence sites included the superficial lobe (10/25) and deep lobe (7/25) of the parotid gland primarily and the skull base region (four patients) and mastoid posterior region (four patients) secondarily. The number of ¹²⁵I seeds ranged from 16 to 111, with a median number of 59. The activity of radioactive particles was 18.5-25.9 MBq. The 3- and 5-year local control rates were 81.5% and 61.5%, respectively. No significant differences were found between pre- and post-operative dosimetric parameters such as D₉₀, V₁₀₀, and V₁₅₀. There was no significant difference in local control rates among the four different recurrence sites. Conclusions ¹²⁵I interstitial brachytherapy is proven to be an effective approach in the treatment of recurrent adenoid cystic carcinoma in the parotid gland. Satisfying local control rates can be achieved through target delineation performed according to recurrence sites and perineural invasion characteristics of ACC.