Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan; Department of Radiation Oncology, Shandong Cancer Hospital, Shandong University, Jinan, China.
Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan.
Int J Radiat Oncol Biol Phys. 2014 May 1;89(1):145-51. doi: 10.1016/j.ijrobp.2014.01.044.
To study changes in functional activity on ventilation (V)/perfusion (Q) single-photon emission computed tomography (SPECT) during radiation therapy (RT) and explore the impact of such changes on lung dosimetry in patients with non-small cell lung cancer (NSCLC).
Fifteen NSCLC patients with centrally located tumors were enrolled. All patients were treated with definitive RT dose of ≥60 Gy. V/Q SPECT-CT scans were performed prior to and after delivery of 45 Gy of fractionated RT. SPECT images were used to define temporarily dysfunctional regions of lung caused by tumor or other potentially reversible conditions as B3. The functional lung (FL) was defined on SPECT by 2 separate approaches: FL1, a threshold of 30% of the maximum uptake of the patient's lung; and FL2, FL1 plus B3 region. The impact of changes in FL between initiation of RT and delivery of 45 Gy on lung dosimetry were analyzed.
Fourteen patients (93%) had larger FL2 volumes than FL1 pre-RT (P<.001). Dysfunctional lung became functional in 11 patients (73%) on V SPECT and in 10 patients (67%) on Q SPECT. The dosimetric parameters generated from CT-based anatomical lung had significantly lower values in FL1 than FL2, with a median reduction in the volume of lung receiving a dose of at least 20 Gy (V20) of 3%, 5.6%, and mean lung dose of 0.95 and 1.55 on V and Q SPECT respectively.
Regional ventilation and perfusion function improve significantly during RT in centrally located NSCLC. Lung dosimetry values vary notably between different definitions of functional lung.
研究放射治疗（RT）过程中通气（V）/灌注（Q）单光子发射计算机断层扫描（SPECT）的功能活动变化，并探讨这些变化对非小细胞肺癌（NSCLC）患者肺剂量学的影响。
纳入 15 例中央型肿瘤的 NSCLC 患者。所有患者均接受≥60Gy 的根治性 RT 剂量。在接受 45Gy 分割 RT 前后进行 V/Q SPECT-CT 扫描。SPECT 图像用于定义因肿瘤或其他潜在可逆转情况引起的暂时性肺功能障碍区域，即 B3。通过 2 种独立的方法在 SPECT 上定义功能性肺（FL）：FL1，为患者肺部最大摄取量的 30%的阈值；FL2，为 FL1 加 B3 区域。分析从 RT 开始到 45Gy 时 FL 变化对肺剂量学的影响。
14 例患者（93%）在 RT 前的 FL2 体积大于 FL1（P<.001）。11 例患者（73%）在 V SPECT 上，10 例患者（67%）在 Q SPECT 上的功能障碍肺变为功能性。基于 CT 解剖学肺生成的剂量学参数在 FL1 中的值明显低于 FL2，至少 20Gy 剂量的肺体积（V20）中位数降低 3%，5.6%，V 和 Q SPECT 上的平均肺剂量分别降低 0.95 和 1.55。
中央型 NSCLC 中，RT 过程中区域通气和灌注功能显著改善。功能性肺的不同定义之间，肺剂量学值有明显差异。
