從fMRI評估鼻咽癌病人在放射線治療前後認知功能的變化

Using fMRI to EvaluateWorking Memory Differences in Cognitive Function of NPC Patientsbefore and after Radiotherapy

楊永毅(Yung-I Yang)；呂姿瑩；(Tzu-Ying Lu)邱燕玉(Yen-Yu Chiu)；張之境(Chin-Ching Chang)；賴睿榛(Jui-Jen Lai)；黃志仁(Chih-Jen Huang)；連熙隆(Shi-Long Lian)；Tatsuhiro Hisatsune；萬羿廷(Yi-Ting Wan)；洪育菁(Yu-Jing Hong)；陳佳如(Sharon Chia-Ju Chen)

放射線治療 ； 鼻咽癌 ； 認知功能 ； 功能性磁振造影 ； Nasopharyngeal carcinoma ； functional Magnetic Resonance Imaging ； Memory function ； Radiotherapy

中華放射線技術學雜誌

39卷3期（2015 / 09 / 01）

121 - 129

繁體中文

當鼻咽癌患者在接受放射線治療時，鼻咽癌鄰近正常組織會受到輻射照射(例如，海馬迴)而產生認知能力上的改變。本研究的目的是要探討當海馬迴接收到微量劑量後，患者的認知功能在放射線治療前後是否有差異。本研究招募二十位鼻咽癌患者，接受臨床常規性的放射線治療，腫瘤劑量70Gy，而海馬迴平均接收劑量界於2~14Gy之間，為了有效探討劑量與認知能力的關係，將海馬迴平均接收劑量以7Gy為界，分為高劑量組(HD組，11人，平均海馬迴接收劑量9.23Gy)以及低劑量組(LD組，9人，平均海馬迴接收劑量4.27Gy)，所有患者在放射治療前後皆需接受0,1,2-back工作記憶測驗的fMRI掃描以及魏氏智力測驗的量表評估，用以比較功能性腦影像的評估結果與傳統量表評估是否有差異。由目前的結果，可以得到以下兩項結論：1.fMRI對於功能性活化評估較傳統量表分析靈敏；2.高低劑量組在認知測驗由易到難(從0-back,1-back到2-back)的表現，HD組在放射治療後，對於題目困難度呈負相關的表現；而LD組對於題目難易度在治療前後看不出明顯的規律性。因此，縱使海馬迴在放射線治療期間只接受微量的輻射劑量，但對於認知功能的評估仍不能忽視，以免造成永久性的認知能力缺損。

Radiotherapy has been the standard radical treatment clinically for patients with nasopharyngeal carcinoma(NPC) so far. However, brain cortex surrounding the tumor is inevitably exposed to minor dose of radiation when the tumor undergoes radiotherapy, and this might cause cognitive function change. The research focuses on whether cognitive function in hippocampus will change after it is exposed to minor dose of radiation caused by radiotherapy. Then the results can contribute to future therapy practice. Twenty NPC patients arerecruitedto go through a routine radiotherapy. The patients have to go through 35 times of therapy within 7 weeks and their target dose is set at 70Gy. All patients have to receive assessments of functional Magnetic ResonanceImaging (fMRI) scans 2 times. The first time is before the radiation treatment (bRT) andthe second time is one month after the treatment (aRT).fMRI scans include two parts: (1) high resolution anatomic T1 imaging; (2) N-back working memory task. Before receiving functional MRI assessment, all patients need to do WAIS IQ test to determine their working memory and reaction speed. Furthermore, in order to discuss whether the dose affects cognitive function, we set the average dose taken by hippocampus 7.00Gy of 20 patients as reference dose point. We categorize all 20 NPC patients who have done fMRI 2 times into 2 groups: high dose group(HD group, 11 patients, the average dose taken by hippocampus is 9.23Gy, dose range from 6.60 to 13.6Gy) and low dose group(LD group, 9 patients, the average dose taken by hippocampus is 4.27Gy, dose range from 2.00 to 5.80Gy). In the aspect of data analysis, SPM8 is used to reprocess different fMRI data, including: (1)slice timing correction, (2)realignment, (3)co-registration, (4)normalization and (5)smooth. After per-processing, two-pair t test can be used to test the differences between different groups. This research focuses on 3 memory capability-related areas, inferior parietal lobule, inferior frontal gyrus and parahippocampus. Preliminary result shows that patients in HD group suffer degradingcognitive function after the treatment in more difficult task(1-back and 2-back), but they display higher activation level after the treatment in easier task(0-back). On the other hand, in LD group, patients tend to display higher activation level after the treatment in most difficult task(2-back), and there is no obvious declination in cognitive capability in 0-back and 1-back task.