Venkada Manickam G, Rawat Sheh, Choudhury Ps, Rajesh T, Rao Sa, Khullar Pooja, Kakria Anjali
Department of Radiation, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India.
Indian J Nucl Med. 2012 Apr;27(2):95-100. doi: 10.4103/0972-3919.110691.
To compare quantitatively Gross tumor volume (GTV), both primary and nodal areas of head and neck cancers, delineated on [18F]-2fluoro, 2deoxy d-glucose-positron emission tomography/computed tomography ([18F]-FDG-PET-CT) scan to those delineated on Contrast-enhanced CT scan (CECT scan).
A total of 26 consecutive patients with squamous cell cancers of head and neck were included in this study. The primary sites were oropharynx (n = 7), hypopharynx (n = 6), paranasal sinus (n = 6), nasopharynx (n = 4), oral cavity (n = 2), and one with unknown primary and secondary neck node. All patients underwent routine staging work-up. FDG-PET and CECT scans were performed with dedicated PET-CT scanner in single session as a part of the radiotherapy treatment planning for Intensity modulated radiotherapy/Image-guided radiotherapy.
All patients had abnormal increased uptake in PET-CT scans. PET-CT resulted in changes of CT-based staging in 8 of 26 patients (up-staged in 7 and down-staged in 1). The mean primary and nodal GTV volumes on PET-CT and CT were significantly different (primary: PET-GTV: 48.43 ± 53.21 cc vs. CT 54.78 ± 64.47 cc, P < 0.001; nodes: PET-GTV: 12.72 ± 15.46 cc vs. 11.04 ± 14.87 cc, P < 0.001). The mismatch between two target volumes was statistically significant (P = 0.03 for GTV primary, P = 0.04 for GTV node).
Accuracy of delineation of GTV can be improved along with functional imaging using [18F]-FDG. These metabolically active volumes are significantly smaller than CT-based volumes and could be missed during conventional CT-based target delineations of GTVs.
定量比较在[18F]-2-氟-2-脱氧-D-葡萄糖正电子发射断层扫描/计算机断层扫描（[18F]-FDG-PET-CT）上勾画的头颈部癌原发灶和区域淋巴结的大体肿瘤体积（GTV）与在增强CT扫描（CECT扫描）上勾画的GTV。
本研究共纳入26例连续的头颈部鳞状细胞癌患者。原发部位包括口咽（n = 7）、下咽（n = 6）、鼻窦（n = 6）、鼻咽（n = 4）、口腔（n = 2），另有1例原发灶不明但有颈部继发淋巴结转移。所有患者均接受常规分期检查。作为调强放疗/图像引导放疗的放疗治疗计划的一部分，使用专用PET-CT扫描仪在单次检查中进行FDG-PET和CECT扫描。
所有患者的PET-CT扫描均显示摄取异常增加。PET-CT导致26例患者中有8例基于CT的分期发生改变（7例分期上调，1例分期下调）。PET-CT和CT上的原发灶和区域淋巴结GTV平均体积有显著差异（原发灶：PET-GTV：48.43±53.21立方厘米，CT为54.78±64.47立方厘米，P<0.001；区域淋巴结：PET-GTV：12.72±15.46立方厘米，CT为11.04±14.87立方厘米，P<0.001）。两个靶体积之间的差异具有统计学意义（原发灶GTV的P = 0.03，区域淋巴结GTV的P = 0.04）。
使用[18F]-FDG的功能成像可提高GTV勾画的准确性。这些代谢活跃体积明显小于基于CT的体积，在基于传统CT的GTV靶区勾画过程中可能会被遗漏。
