Image quality evaluation of in-treatment four-dimensional cone-beam computed tomography in volumetric-modulated arc therapy for stereotactic body radiation therapy
Image quality evaluation of in-treatment four-dimensional cone-beam computed tomography in volumetric-modulated arc therapy for stereotactic body radiation therapy
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DOI：
10.1016/j.ejmp.2019.11.003
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发表时间：
2019-12-01
影响因子：
3.4
通讯作者：
Toya, Ryo
中科院分区：
文献类型：
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作者：
Shimohigashi, Yoshinobu;Doi, Yasuhiro;Toya, Ryo
在这项研究中，在肺部和肝脏立体定向放射治疗（SBRT）的体积调制弧形疗法（VMAT）中定量评估了使用不同处方剂量（PD）获得的治疗中四维锥形束计算机断层扫描（In-4D-CBCT）的图像质量。为了评估图像质量，我们使用了动态胸部模型和三维 (3D) 腹部模型； In-4D-CBCT 图像是使用各种 PD（从 5 到 12 Gy）获取的。将具有各种 PD 的 In-4D-CBCT 与参考图像（4D-CBCT 之前）进行比较。使用信噪比（SNR）、对比度噪声比（CNR）和Dice相似系数（DSC）来评估图像质量。将不同 PD 的基准标记位置与参考图像的位置进行比较。对于动态胸部模型，随着 PD 从 6 Gy 增加到 12 Gy，4D-CBCT 前和 In-4D-CBCT 在 SNR 和 CNR 方面的差异减小。中位 DSC 范围为 0.7 至 0.74，显示出良好的相似性。对于3D腹部体模，随着PD从5Gy增加到6Gy，4D-CBCT前和In-4D-CBCT在SNR和CNR方面的差异减小；相反，随着PD从7Gy增加到8Gy，它也增加。所有 PD 的基准标记位置均在 1.0mm 以内。我们的结论是，与参考图像相比，In-4D-CBCT 的图像质量有所下降；然而，在目标体积相似性和基准标记位置的准确性方面，它足以准确地评估肺和肝脏 SBRT 的 VMAT 中的分次内肿瘤位置。
In this study, the image quality of in-treatment four-dimensional cone-beam computed tomography (In-4D-CBCT) obtained with various prescription doses (PDs) were quantitatively evaluated in volumetric-modulated arc therapy (VMAT) for stereotactic body radiation therapy (SBRT) of the lungs and liver. To assess image quality, we used a dynamic thorax phantom and three-dimensional (3D) abdominal phantom; In-4D-CBCT images were acquired with various PDs (from 5 to 12 Gy). The In-4D-CBCT with various PDs were compared with the reference images (pre-4D-CBCT). The image quality was evaluated using the signal-to-noise ratio (SNR), the contrast-to-noise ratio (CNR), and the Dice similarity coefficient (DSC). The fiducial marker positions with various PDs were compared with those of the reference images. For the dynamic thorax phantom, the difference between pre- and In-4D-CBCT in terms of SNR and CNR decreased, as the PD increased from 6 to 12 Gy. The median DSC ranged from 0.7 to 0.74, and showed good similarity. For the 3D abdominal phantom, the difference between pre- and In-4D-CBCT in terms of SNR and CNR decreased as the PD increased from 5 to 6 Gy; conversely, it increased as the PD increased from 7 to 8 Gy. The fiducial marker positions were within 1.0mm for all PDs. We concluded that the image quality of In-4D-CBCT degraded compared with the reference image; however, it was sufficiently accurate for assessing the intra-fractional tumor position in VMAT for SBRT of the lungs and liver both in terms of the target volume similarity and accuracy of the fiducial marker position.