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目的:采用X线衰减校正提高前瞻性、多中心研究中99mTc-3PRGD2肺癌SPECT图像定量分析的精确性。方法:经病理确诊的肺癌患者27例,其中肺腺癌23例、鳞癌4例。患者静脉注射99mTc-3PRGD2后40分钟顺序进行全身和局部断层扫描。采用迭代图像重建方法,对获得的99mTc-3PRGD2SPECT图像进行X线衰减校正(CTAC)和非衰减校正重建(NAC)。测量CTAC和NAC病灶所在层面的总计数,感兴趣区域(ROI)病灶的总计数、最大计数和平均计数。分别以病灶ROI内最大计数的38%、42%和48%作为阈值测量CTAC和NAC图像病灶最大长径。结果:经过CTAC后病灶所在层面总计数增加2.09倍,ROI区域病灶的总计数增加3.32倍,病灶最大计数和平均计数与本底比值分别提高了65.9%和70.3%。以病灶ROI最大计数42%作为阈值,CTAC后的病灶最大长径为(5.65±2.77)cm,与CT测量结果一致。结论:采用X线衰减校正是提高99mTc-3PRGD2定量分析的有效方法。
OBJECTIVE: To improve the accuracy of quantitative analysis of SPECT images of 99m Tc-3 PRGD2 lung cancer in prospective, multicenter studies using X-ray attenuation correction. Methods: Twenty-seven patients with pathologically diagnosed lung cancer were diagnosed as pulmonary adenocarcinoma and squamous cell carcinoma. Patients underwent 99mTc-3PRGD2 intravenously followed by systemic and local tomography 40 minutes after the injection. X-ray attenuation correction (CTAC) and non-attenuation-corrected reconstruction (NAC) were performed on the obtained 99mTc-3PRGD2SPECT images using an iterative image reconstruction method. The total counts of CTAC and NAC lesions, the total count, maximum count and average count of ROI lesions were measured. The maximal diameters of CTAC and NAC lesions were measured by using the thresholds of 38%, 42% and 48% of the maximum counts in the lesion ROI respectively. Results: After CTAC, the total count of lesion increased 2.09 times, the total number of lesions in ROI increased 3.32 times, the maximum count and average count of lesions increased 65.9% and 70.3% respectively. With the maximum of 42% of the maximum ROI of the lesion as the threshold, the maximum long axis of the lesion after CTAC was (5.65 ± 2.77) cm, which was consistent with the CT measurement. Conclusions: The use of X-ray attenuation correction is an effective method to improve quantitative analysis of 99mTc-3PRGD2.