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Abstract：
Objective: This prospective study aims to evaluate acute irradiation-induced xerostomia during radiotherapy by utilizing the normalized iodine concentration (NIC) derived from energy spectrum computed tomography (CT) iodine maps. Methods: In this prospective study, we evaluated 28 patients diagnosed with nasopharyngeal carcinoma. At 4 distinct stages of radiotherapy (0, 10, 20, and 30 fractions), each patient underwent CT scans to generate iodine maps. The NIC of both the left and right parotid glands was obtained, with the NIC at the 0-fraction stage serving as the baseline measurement. After statistically comparing the NIC obtained in the arterial phase, early venous phase, late venous phase, and delayed phase, we chose the late venous iodine concentration as the NIC and proceeded to analyze the variations in NIC at each radiotherapy interval. Using the series of NIC values, we conducted hypothesis tests to evaluate the extent of change in NIC within the parotid gland across different stages. Furthermore, we identified the specific time point at which the NIC decay exhibited the most statistically significant results. In addition, we evaluated the xerostomia grades of the patients at these 4 stages, following the radiation therapy oncology group (RTOG) xerostomia evaluation standard, to draw comparisons with the changes observed in NIC. Results: The NIC in the late venous phase exhibited the highest level of statistical significance (P < .001). There was a noticeable attenuation in NIC as the RTOG dry mouth grade increased. Particularly, at the 20 fraction, the NIC experienced the most substantial attenuation (P < .001), a significant negative correlation was observed between the NIC of the left, right, and both parotid glands, and the RTOG evaluation grade of acute irradiation-induced xerostomia (P < .001, r = -0.46; P < .001, r = -0.45; P < .001, r = -0.47). The critical NIC values for the left, right, and both parotid glands when acute xerostomia occurred were 0.175, 0.185, and 0.345 mg/ml, respectively, with AUC = 0.73, AUC = 0.75, and AUC = 0.75. Conclusion: The NIC may be used to evaluate changes in parotid gland function during radiotherapy and acute irradiation-induced xerostomia.
摘要：
目的：这项前瞻性研究旨在通过利用能谱计算机断层扫描（CT）碘图得出的标准化碘浓度（NIC）来评估放射治疗期间急性辐照引起的口干症。方法：在这项前瞻性研究中，我们评估了28例诊断为鼻咽癌的患者。在放疗的4个不同阶段（0、10、20和30个部分），每位患者均接受CT扫描以生成碘图.获得左右腮腺的NIC，将0分数阶段的NIC用作基线测量。在统计比较动脉期获得的NIC后，早期静脉期，晚期静脉期,和延迟阶段，我们选择晚期静脉碘浓度作为NIC,并分析了每次放疗间隔时间NIC的变化.使用一系列NIC值，我们进行了假设检验,以评估不同阶段腮腺内NIC的变化程度.此外，我们确定了NIC衰减表现出最有统计学意义的结果的特定时间点.此外,我们评估了这四个阶段患者的口干症等级，遵循放射治疗肿瘤组（RTOG）口干症评估标准，与NIC中观察到的变化进行比较。结果：静脉晚期的NIC表现出最高的统计学意义（P<0.001）。随着RTOG口干等级的增加，NIC有明显的衰减。特别是,在20分，NIC经历了最大的衰减(P<.001)，在左侧的NIC之间观察到显着的负相关，对,和两个腮腺，和急性照射所致口干症的RTOG评估等级（P<.001，r=-0.46；P<.001，r=-0.45；P<.001，r=-0.47）。左侧的关键NIC值，对,发生急性口干症时的两个腮腺分别为0.175、0.185和0.345mg/ml，分别,AUC=0.73，AUC=0.75，AUC=0.75。结论：NIC可用于评估放疗和急性放疗引起的口干症时腮腺功能的变化。
