From the *Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; †CDPI Clinics-Abdominal and Pelvic Imaging, Rio de Janeiro Federal University, Rio de Janeiro, Brazil; ‡Institute of Medical Statistics; and §Department of Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
Clin Nucl Med. 2014 Mar;39(3):e197-201. doi: 10.1097/RLU.0b013e3182a23d37.
Image quality (IQ) of PET in voluminous body regions can be limited, which impairs the assessment of small metastatic lesions. Time-of-flight (TOF) reconstruction algorithm may deliver an increase of spatial resolution. The purpose of this study was to evaluate the impact of TOF on IQ, lesion detection rate, lesion volume (V) and SUVmax in F choline PET/CT of prostate cancer patients with biochemical recurrence compared to standard PET/CT reconstruction (standard).
During a period of 9 months, 32 patients with prostate cancer (mean [SD] age, 71 [7.8] years) and biochemical recurrence were included in this prospective institutional review board-approved study. Each patient underwent a state-of-the-art 3-dimensional F choline PET/CT. A total of 76 lesions were assessed by 2 board-certified nuclear medicine physicians and a third-year resident. Lesion volume and SUVmax of local recurrence, lymph nodes, and organ metastases were compared between TOF and standard. Image quality and lesion demarcation were rated according to a 5-point Likert-type scale. Interobserver agreement was assessed.
Eight additional lesions were detected using TOF (SUVmax, 3.64 [0.95]; V, 0.58 cm [0.50]). Image quality was reduced (IQ standard, 1.28; TOF, 1.77; P < 0.01) in calculated TOF images, although quality of lesion demarcation was improved (lesion demarcation: standard, 1.66; TOF, 1.26; P < 0.01). SUVmax was significantly increased in TOF images (SUVmax standard, 6.9 [4.1]; TOF, 8.1 [4.1]; P < 0.01), whereas V did not show significant differences (V standard, 5.3 [10.4] cm; TOF, 5.4 [10.3] cm; P = 0.41). Interobserver agreement was good for combined ratings (1 + 2 and 3 + 4).
Application of TOF seems to be of additional value to detect small metastatic lesions in patients with prostate cancer and biochemical recurrence, which may have further clinical implications for secondary treatment.
在体积较大的身体部位，正电子发射断层扫描（PET）的图像质量（IQ）可能会受到限制，从而影响对小转移病灶的评估。飞行时间（TOF）重建算法可能会提高空间分辨率。本研究旨在评估 TOF 对前列腺癌患者生化复发时氟[18F]胆碱 PET/CT 中 IQ、病灶检出率、病灶体积（V）和最大标准摄取值（SUVmax）的影响，并与标准 PET/CT 重建（标准）进行比较。
在 9 个月的时间内，这项前瞻性机构审查委员会批准的研究纳入了 32 例前列腺癌（平均[标准差]年龄 71[7.8]岁）和生化复发患者。每位患者均接受了最新的 3 维氟[18F]胆碱 PET/CT 检查。由 2 名核医学医师和 1 名三年级住院医师对总共 76 个病灶进行了评估。比较了局部复发、淋巴结和器官转移的 TOF 和标准的病灶体积和 SUVmax。根据 5 分李克特量表对图像质量和病灶边界进行评分。评估了观察者间的一致性。
使用 TOF 额外检测到 8 个病灶（SUVmax：3.64[0.95]；V：0.58 cm[0.50]）。虽然病灶边界的质量得到改善（病灶边界：标准 1.66；TOF 1.26；P <0.01），但计算的 TOF 图像的图像质量降低（IQ 标准 1.28；TOF 1.77；P <0.01）。TOF 图像中的 SUVmax 显著增加（SUVmax 标准 6.9[4.1]；TOF 8.1[4.1]；P <0.01），而 V 无显著差异（V 标准 5.3[10.4] cm；TOF 5.4[10.3] cm；P =0.41）。联合评分（1+2 和 3+4）的观察者间一致性良好。
TOF 的应用似乎对检测前列腺癌生化复发患者的小转移病灶具有附加价值，这可能对继发性治疗具有重要的临床意义。
