18F-FDG PET/CT是大多数淋巴瘤准确初期分期的成像选择。霍奇金病、弥漫性大B细胞和滤泡性淋巴瘤显示亲和性FDG的摄取，而少数非霍奇金淋巴瘤亚型，如MALT淋巴瘤、边缘区和小淋巴细胞淋巴瘤显示低或中度亲和性。作为经验准则，缓慢恶化的淋巴瘤显示较低的FDG活性。PET/CT在检测大或正常大小的淋巴结中的淋巴结受累具有更高的灵敏度。相比于CT，它在检测外淋巴结系统疾病，尤其是脾脏和骨髓中的疾病具有更高的灵敏度。在霍奇金淋巴瘤中，PET/CT导致了高达25%的分期升级，为强化治疗铺平了道路。在霍奇金病的骨髓侵犯检测中，PET/CT具有优秀的阴性预测值（NPV>95％），该方法可使骨髓穿刺活检不再绝对必要：阴性PET可以排除霍奇金淋巴瘤患者的骨髓侵犯，但这在非霍奇金淋巴瘤中并非普遍适用。PET/CT在检测并非是先前怀疑或隐匿部位的侵袭性非霍奇金淋巴瘤的初始分期中优于其他成像方法。18F-FDG PET/CT通过在化疗开始2-3个周期后进行中期PET来进行早期治疗评估霍奇金病。中期PET为阴性且未发现高代谢病变的患者可以继续相同有效的治疗或转为较不积极的治疗。另一方面，未显示PET反应的患者可能需要接受更加积极的治疗以根除高代谢的活动疾病。随机对照试验已经证明，中期PET/CT对于最终治疗反应的高阴性预测值和增加的无进展生存率在霍奇金淋巴瘤中具有高度的准确性。通过应用特定的客观评估标准：德维尔得分法，中期和术后PET/CT的报告和解读准确性得到了提高。德维尔得分为4-5，活动淋巴瘤较肝脏活动更强烈。病变中的18F-FDG摄取，等于或低于纵膈血池，被解释为阴性：得分为1-2。中期PET在非霍奇金淋巴瘤中的作用也受到研究，尤其是目前应用更有效的治疗方法的情况下。与CT相比，PET/CT在淋巴瘤的术后评估中具有优异的阴性预测值和较高的诊断准确性。治疗后，相当比例的患者在CT上显示出残余的解剖病灶，例如残余纵膈软组织;然而，在个别情况中，这些病变对应活动性疾病。PET/CT在评估残余组织方面具有高度的诊断准确性，并可区分PET阴性的纤维化或坏死组织与PET阳性的活动残余病变。该方法在巨大疗法前干细胞移植的评估中也具有很高的阴性预测值：良好的PET反应与更好的无进展生存率和总生存率相关。总之，PET/CT已经成为淋巴瘤患者中的一个成熟方法，并被纳入临床决策和指南的算法中，改变了治疗决策。

18F-FDG PET/CT is the imaging modality of choice for the accurate initial staging of most lymphomas. Hodgkin's, Diffuse Large B-cell and follicular lymphomas show avid FDG uptake, while a minority of Non-Hodgkin lymphoma subtypes namely MALT, marginal and small lymphocytic lymphoma demonstrate low or moderate avidity. As a rule of thumb, indolent lymphomas show lower FDG activity than aggressive ones. PET/CT has increased sensitivity in the detection of nodal involvement even in small or normal-sized nodes. It shows higher sensitivity than CT in the detection of extra-nodal disease, most often in the spleen and bone marrow. PET/CT leads to upstaging in up to 25% of Hodgkin lymphomas, paving the way to intensified therapy. It has excellent Negative Predictive Value (NPV>95%) in the detection of bone marrow involvement in Hodgkin's rendering bone marrow biopsy not absolutely necessary: a negative PET rules out bone marrow disease in Hodgkin's patients, yet this does not universally apply in Non-Hodgkin lymphomas. PET/CT is superior to other imaging modalities in the initial stating of aggressive Non-Hodgkin lymphomas detecting disease in previously not suspected or occult sites. 18F-FDG PET/CT is applied in the early therapeutic evaluation of Hodgkin's by means of interim PET performed after 2-3 initial cycles of chemotherapy. Patients with negative interim PET and no hypermetabolic disease identified may continue with the same effective treatment or switch to less aggressive therapy. On the other hand, patients who do not show PET response may be subjected to more intensified treatment to eradicate hypermetabolic active disease. Randomized controlled trials have proven that interim PET/CT shows high NPV for final treatment response and for increased progression free survival in Hodgkin's. The accuracy in reporting and interpretating interim and post-treatment PET/CT has increased by applying specific objective criteria: Deauville 5-score scale. Deauville's uptake scores of 4-5, more intense than liver activity, correspond to active lymphomatous disease. 18F-FDG uptake in lesions, equal or lower than mediastinal blood-pool, is interpreted as negative: Deauville scores of 1-2. Role of interim PET is also investigated in Non-Hodgkin Lymphomas, especially nowadays with more effective treatments being applied. PET/CT is highly recommended for post-treatment assessment of lymphomas with excellent NPV and superior diagnostic accuracy compared with CT. After treatment, a significant proportion of patients show residual anatomic lesions on CT f.e. residual mediastinal soft-tissue; yet, in the minority of cases, these lesions correspond to active disease. PET/CT has high diagnostic accuracy in the assessment of residual tissue and may distinguish between PET-negative fibrotic or necrotic tissue and PET-positive, active residual disease. The modality also has high NPV in the evaluation of megatherapy before stem cell transplantation: a favorable PET response is associated with better progression free survival and overall survival. To sum up, PET/CT has evolved as an established method in lymphoma patients being incorporated into clinical algorithms and guidelines altering therapeutic decisions.