建立PET/CT使用飛行時間與點擴散函數技術之18F-FDG標準攝取值生理分布並比較使用前後對標準攝取值的影響

Study of point-spread function and time-of-flight: To characterize the standardized uptake values of 18F-FDG PET/CT in normal organs using the techniques and to compare the standardized uptake values determined with and without use of the techniques

李佩璇(Pei-Hsuan Li)

指導教授 ： 鍾相彬

高雄醫學大學/健康科學院/醫學影像暨放射科學系碩士在職專班/碩士(2017年)

摘要

目的：本研究的目的是建立使用飛行時間(Time-Of-Flight, TOF)與點擴散函數技術(Point-Spread-Function, PSF)影像重建技術後，在沒有罹癌且已知異常的受檢者器官組織中之2-deoxy-2-[18F]fluoro-D-glucose (FDG) (18F-FDG)的生理攝取分布。並比較使用TOF與PSF影像重建技術前後對標準攝取值(Standardized Uptake Value, SUV)的影響。
材料與方法：本回溯性研究收集從104年1月至104年6月間為了健康檢查而進行全身FDG- Positron Emission Tomography (PET) / Computed Tomography (CT)掃描，經篩選後總共有107位受檢者(男性50位，女性57位) 符合條件。FDG-PET/CT影像使用兩種影像重建技術進行比較，分別為只使用Ordered Subset Expectation Maximization (OSEM)與使用OSEM+TOF+PSF，再利用影像後處理軟體圈選不同器官和組織感興趣區域(Region of Interest, ROI)，獲得18F-FDG PET/CT的最大和平均標準攝取值。利用配對樣本T-檢定(Paired Sample T-test)、相關係數與散佈圖觀察分析只使用OSEM與使用OSEM+TOF+PSF的FDG-PET / CT影像之間標準攝取值的差異與相關性。
結果：顯著攝取FDG的器官組織（平均SUVmax >2.5）包括小腦（6.57±1.32）、軟顎（2.84±0.66）、腭扁桃體（3.48±1.16）、舌扁桃體（3.04±0.94）、舌下腺(2.71±0.82)、心肌(4.63±3.55)、肝臟(3.34±0.43)、直腸括約肌(2.97±0.67)和睪丸(2.88±0.50)。對於腭扁桃體、舌下腺和睪丸， FDG攝取與年齡呈負相關。本研究所測量器官組織中只使用OSEM與同時使用OSEM+TOF+PSF的SUV皆為正相關，且除了肝臟外，其餘皆有統計學上顯著性差異。大多數器官組織使用OSEM+TOF+PSF比只使用OSEM所測量到的SUV值會顯著偏高，但因部分體積效應(Partial-Volume Effect)影響下口咽、舌、膽囊與攝護腺反之。
結論：了解整個身體的FDG生理攝取對於提高影像判讀的精確度是有價值的，但在臨床應用上使用不同影像處理技術，應小心謹慎。

關鍵字

飛行時間 ； 點擴散函數 ； 標準攝取值

並列摘要

Purpose：The purpose of this study was to establish the physiologic distribution of 2-deoxy-2-[18F]fluoro-D-glucose (FDG) (18F-FDG) on Positron Emission Tomography (PET)/Computed Tomography (CT) images reconstructed by Time-Of-Flight (TOF) and Point-Spread-Function (PSF) image reconstruction techniques in patients without cancer history and known abnormalities in organ and tissue. In addition, the effects of using or not using TOF and PSF image reconstruction techniques on standardized uptake values (SUV) were compared.
Materials and Method：We retrospectively included a total of 107 patients (50 males and 57 females) who underwent whole body 18F-FDG PET/ CT between January 2015 and June 2015. By drawing regions of interest (ROIs) in different organs and tissue on 18F-FDG PET images reconstructed using two construction techniques, i.e. , Ordered Subset Expectation Maximization (OSEM) and OSEM + TOF + PSF, we explored the effects of TOF and PSF on maximum and average SUVs. By paired sample T-test, the correlation coefficient and the scatter plot were used to analyze the differences and correlations of the SUV in FDG-PET/CT images between OSEM and OSEM + TOF + PSF reconstructed images.
Results：Organs or tissue with significant FDG uptake (i.e. mean SUVmax >2.5) included the cerebellum (6.57±1.32), soft palate (2.84±0.66), palatine tonsils (3.48±1.16), lingual tonsils (3.04±0.94), sublingual glands (2.71±0.82), myocardium (4.63±3.55), liver (3.34±0.43), rectum sphincter (2.97±0.67) and testes (2.88±0.50). FDG uptake in the palatine tonsils, sublingual glands, and testes negatively correlated with age. The SUV values obtained from OSEM reconstructed images positively correlated with that from OSEM + TOF + PSF, besides, the SUV values, except in the liver, were significantly different. The images reconstructed by combination of PSF and TOF had higher SUV in most organs and tissue than by OSEM. However, SUVs of oropharynx, tongue, gallbladder, prostate on OSEM + TOF + PSF images were lower than those on OSEM images. Partial-volume effect may be the cause.
Conclusion：For improving the accuracy of interpretation, it is valuable to know the physiological uptake of FDG over the whole body. Since different image reconstruction technologies greatly affect the SUV values, their clinical application should be careful.

並列關鍵字

point-spread function ； time-of-flight ； standardized uptake values

參考文獻

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