Comparison of (18)F-fluorothymidine and (18)F-fluorodeoxyglucose PET/CT in delineating gross tumor volume by optimal threshold in patients with squamous cell carcinoma of thoracic esophagus.
OBJECTIVE
To determine the optimal method of using (18)F-fluorothymidine (FLT) positron emission tomography (PET)/computed tomography (CT) simulation to delineate the gross tumor volume (GTV) in esophageal squamous cell carcinoma verified by pathologic examination and compare the results with those using (18)F-fluorodeoxyglucose (FDG) PET/CT.


METHODS
A total of 22 patients were enrolled and underwent both FLT and FDG PET/CT. The GTVs with biologic information were delineated using seven different methods in FLT PET/CT and three different methods in FDG PET/CT. The results were compared with the pathologic gross tumor length, and the optimal threshold was obtained. Next, we compared the simulation plans using the optimal threshold of FLT and FDG PET/CT. The radiation dose was prescribed as 60 Gy in 30 fractions with a precise radiotherapy technique.


RESULTS
The mean +/- standard deviation pathologic gross tumor length was 4.94 +/- 2.21 cm. On FLT PET/CT, the length of the standardized uptake value 1.4 was 4.91 +/- 2.43 cm. On FDG PET/CT, the length of the standardized uptake value 2.5 was 5.10 +/- 2.18 cm, both of which seemed more approximate to the pathologic gross tumor length. The differences in the bilateral lung volume receiving > or =20 Gy, heart volume receiving > or =40 Gy, and the maximal dose received by spinal cord between FLT and FDG were not significant. However, the values for mean lung dose, bilateral lung volume receiving > or =5, > or =10, > or =30, > or =40, and > or =50 Gy, mean heart dose, and heart volume receiving > or =30 Gy using FLT PET/CT-based planning were significant lower than those using FDG PET/CT.


CONCLUSIONS
A standardized uptake value cutoff of 1.4 on FLT PET/CT and one of 2.5 on FDG PET/CT provided the closest estimation of GTV length. Finally, FLT PET/CT-based treatment planning provided potential benefits to the lungs and heart.
Han
Dali
D
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, Shandong Province 250117, China.
Yu
Jinming
J
Yu
Yonghua
Y
Zhang
Guifang
G
Zhong
Xiaojun
X
Lu
Jie
J
Yin
Yong
Y
Fu
Zheng
Z
Mu
Dianbin
D
Zhang
Baijiang
B
He
Wei
W
Huo
Zhijun
Z
Liu
Xijun
X
Kong
Lei
L
Zhao
Shuqiang
S
Sun
Xiangyu
X
D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D015224:Dideoxynucleosides; D019583:Dose Fractionation, Radiation; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006321:Heart / Q000528:radiation effects; D006801:Humans; D008168:Lung / Q000528:radiation effects; D008197:Lymph Node Excision; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D013116:Spinal Cord / Q000528:radiation effects; D014057:Tomography, X-Ray Computed / Q000379:methods*; D047368:Tumor Burden
D015224:Dideoxynucleosides; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C002854:alovudine