鼻咽癌患者放疗前后腮腺功能的变化

Scintigraphic assessment of parotid function prior to and after radiotherapy for patients with nasopharyngeal carcinoma

目的 :研究鼻咽癌患者放射治疗前后腮腺功能的变化及其与照射剂量、照射野范围之间的关系 ,以及随访中腮腺功能恢复程度。方法 :1995年 8月— 1997年 8月 ,82例鼻咽癌患者接受根治性放疗。分别在放疗前、放疗第 5次 (鼻咽肿瘤剂量约 9.5Gy)或第 10次 (鼻咽肿瘤剂量约 19Gy)、疗程结束时以及放疗后 2年内每半年进行一次定量的腮腺99mTc清除率测定。面颈联合野照射 44例 ,鼻咽中位肿瘤剂量 7393cGy,5 3天 ;耳前野照射 38例 ,鼻咽中位肿瘤剂量 7138cGy ,5 1天。静脉注射 185MBq(5mCi)的过锝酸盐 ,探头连续记录 30分钟双侧腮腺及头颅正位放射性计数 ,15分钟时给予酸刺激涎液排泄。资料经计算机处理 ,得出腮腺功能评价参数摄取率 (UR)、酸反应排泄率 (ER)及酸反应排泄指数 (EI)。结果 :酸反应排泄率及酸反应排泄指数在鼻咽放疗肿瘤剂量 9.5Gy ,5次和19Gy ,10次后就明显低于放疗前 ,在放疗结束时降低到最低点 ,且在随访 2年时间内未见明显升高。摄取率放疗前和放疗后 1年内无差异 ,但在 1年后进行性下降。面颈联合野和耳前野相比较 ,放疗前和放疗后 6月内酸反应排泄率和排泄指数两者无差异 ;但在放疗后 1— 1.5年 ,耳前野照射病例的酸反应排泄率和排泄指数较面颈联合野照射者高 (P <0 .0 5 )。结论 :腮腺功能?

Purpose:To study the parotid function with quantitative 99m Tc pertechnetate salivary scintigraphy prior to and after radiotherapy for patients with nasopharygeal carcinoma (NPC) and to analyze irradiation induced changes in relation to radiation dose, fields size and time interval after radiotherapy. Methods:From August 1995 to August 1997, 82 histologically proven NPC patients were referred to receive radical radiotherapy. 44 patients were treated with faciocervical fields (median doses: 7393 cGy/53days) and 38 patients with pre auricular fields (median doses: 7138 cGy/51days) to the primary regions. The parotid scintigraphy was performed prior to radiotherapy and at doses of 9.5Gy/5Fx or 19Gy/10Fx, at the end of radiotherapy, and every 6 months for 2 years 9.5Gy/5Fx and 19Gy/10Fx as compared to that of pretherapy, and to the lowest level at the end of radiotherapy. During the 2 years follow up period, no increase of ER and EI was observed. UR did not decrease significantly until 1 year after radiotherapy. The ER and EI of after radiotherapy. After intravenous administration of 185 MBq (5 mCi) 99m TcO - 4, sequential minute frames were acquired simutaneously. After 15 minutes, 200 mg of vitamin C were placed on the tongue to stimulate salivary excretion. Data were analyzed by computer and parameters including uptake rate (UR), excretion rate (ER) and excretion index (EI) were acquired. Results:ER and EI decreased significantly after doses of pre auricular fields were higher than those of faciocervical fields more than 1 year after radiotherapy. Conclusions:Parotid function decreased significantly after small doses of 9.5 Gy to the nasopharynx, and no increase was observed during the 2 years follow up time. It would contribute to improvement of the quality of life of the patients if the volume and dose of irradiation to the parotid were reduced.