目的:评估PET/CT在寻找恶性肿瘤引起的老年患者非外伤性血性胸腔积液的原发灶中的应用价值。方法:回顾性分析43例非外伤性血性胸腔积液老年患者的PET/CT检查结果,以病理或临床随访结果作为最后诊断标准,进行对比分析。结果:43例进行PET/CT检查的非外伤性血性胸腔积液老年患者中,确诊为恶性肿瘤者41例,占95.35%,其中PET/CT检出恶性肿瘤病灶40例,占肿瘤患者的97.56%;PET/CT检出恶性肿瘤原发灶33例,原发灶检出率为80.49%。结论:PET/CT对于老年患者非外伤性单纯血性胸腔积液的诊断及恶性肿瘤原发灶的确定有重要价值。 OBJECTIVE: To evaluate the value of PET / CT in the search for the primary tumor of non-traumatic bloody pleural effusion in elderly patients caused by malignant tumors. Methods: A retrospective analysis of 43 cases of non-traumatic bloody effusion in elderly patients with PET / CT examination results, pathological or clinical follow-up results as the final diagnostic criteria for comparative analysis. Results: Among the 43 cases of non-traumatic bloody pleural effusion diagnosed in PET / CT, 41 cases were diagnosed as malignant tumors, accounting for 95.35%. Among them, 40 cases of malignant tumors were detected by PET / CT, accounting for 97.56 %; PET / CT detected 33 cases of primary malignant tumor, primary detection rate was 80.49%. Conclusion: PET / CT is of great value in the diagnosis of non-traumatic simple bloody pleural effusion in elderly patients and the determination of the primary tumor of malignant tumors.