Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg, 413 90 Göteborg, Sweden; Department of Medical Physics, County Hospital Ryhov, 551 85 Jönköping, Sweden.
Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg, 413 90 Göteborg, Sweden; Department of Therapeutic Radiation Physics, Sahlgrenska University Hospital, 413 46 Göteborg, Sweden.
Phys Med. 2019 Jan;57:191-199. doi: 10.1016/j.ejmp.2018.12.030. Epub 2019 Jan 12.
Evaluate the performance of three commercial deformable image registration (DIR) solutions on computed tomography (CT) image-series of the thorax.
DIRs were performed on CT image-series of a thorax phantom with tumor inserts and on six 4-dimensional patient CT image-series of the thorax. The center of mass shift (CMS), dice similarity coefficient (DSC) and dose-volume-histogram (DVH) parameters were used to evaluate the accuracy. Dose calculations on deformed patient images were compared to calculations on un-deformed images for the gross tumor volume (GTV) (D, D), lung (V, V), heart and spinal cord (D).
Phantom structures with constant volume and shifts ≤30 mm were reproduced with visually acceptable accuracy (DSC ≥ 0.91, CMS ≤ 0.9 mm) for all software solutions. Deformations including volume changes were less accurate with 9/12 DIRs considered visually unacceptable. In patients, organs were reproduced with DSC ≥ 0.83. GTV shifts ≤1.6 cm were reproduced with visually acceptable accuracy by all software while larger shifts resulted in failures for at least one of the software. In total, the best software succeeded in 18/25 DIRs while the worst succeeded in 12/25 DIRs. Visually acceptable DIRs resulted in deviations ≤3.0% of the prescribed dose and ≤3.6% of the total structure volume in the evaluated DVH-parameters.
The take home message from the results of this study is the importance to have a visually acceptable registration. DSC and CMS are not predictive of the associated dose deviation. Visually acceptable DIRs implied dose deviations ≤3.0%.
评估三种商业变形图像配准（DIR）解决方案在胸部计算机断层扫描（CT）图像序列上的性能。
对带有肿瘤植入物的胸部体模和 6 例胸部 4 维患者 CT 图像序列进行 DIR。使用质心位移（CMS）、骰子相似系数（DSC）和剂量-体积-直方图（DVH）参数来评估准确性。对变形后的患者图像进行剂量计算，并与未变形图像进行比较，以获得大体肿瘤体积（GTV）（D、D）、肺（V、V）、心脏和脊髓（D）的剂量。
对于所有软件解决方案，具有恒定体积和位移≤30mm 的幻影结构都以可接受的视觉精度（DSC≥0.91，CMS≤0.9mm）再现。包括体积变化在内的变形在 9/12 个 DIR 中被认为视觉上不可接受。在患者中，器官的 DSC 再现值≥0.83。所有软件均能以可接受的视觉精度再现 GTV 位移≤1.6cm，而较大的位移则至少导致一种软件失败。在总共 25 个 DIR 中，最好的软件成功了 18 次，而最差的软件成功了 12 次。视觉上可接受的 DIR 导致处方剂量偏差≤3.0%和评估的 DVH 参数中总结构体积偏差≤3.6%。
本研究结果的重要启示是需要进行视觉上可接受的配准。DSC 和 CMS 不能预测相关的剂量偏差。视觉上可接受的 DIR 意味着剂量偏差≤3.0%。
