Image quality of 4D in-treatment CBCT acquired during lung SBRT using FFF beam: a phantom study.
Image quality of 4D in-treatment CBCT acquired during lung SBRT using FFF beam: a phantom study.
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DOI：
10.1186/s13014-020-01668-3
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发表时间：
2020-09-25
期刊：
影响因子：
--
通讯作者：
Kim JS
中科院分区：
文献类型：
--
作者：
Kim J;Keum KC;Lee H;Hong CS;Park K;Kim JS
旋转射束输送可同时采集锥形束CT（CBCT），从而便于在放射治疗期间进一步验证患者的几何设置。然而，在立体定向体部放射治疗（SBRT）期间使用无滤片X射线束采集CBCT是具有挑战性的，其中递送高辐射剂量。本研究给出了SBRT输送过程中采集的四维（4D）治疗中CBCT图像质量的定量评价结果。使用Catphan 503和XSight肺跟踪体模评价兆伏（MV）散射和采集参数对图像质量的影响。在提供16个SBRT计划的同时采集体模的治疗中CBCT图像。计算治疗中CBCT图像的均匀性、对比度和对比噪声比（CNR），并与未进行SBRT输送的CBCT图像进行比较。此外，针对10个呼吸相位评价了XSight肺体模中移动目标的定位精度。由于MV治疗散射的影响，3D重建Catphan CBCT图像的CNR从6.3降至2.6。对于Catphan和XSight体模，CBCT图像质量均受治疗计划的管电流和监测单位（MU）的影响。XSight跟踪体模中的肺部目标在极端阶段最明显; SBRT计划中治疗中CBCT图像（40 mA管电流）中肺部目标的平均CNR在呼气末阶段为3.2，在吸气末阶段为3.0。肺部目标定位精度为亚毫米级的极端呼吸阶段。建议使用增加的管电流（例如40 mA）进行全弧采集，以补偿由于MV射束散射不平坦而导致的CBCT图像质量下降。还建议使用高MU治疗射束采集治疗中CBCT，以提高所得CBCT图像质量。
Rotational beam delivery enables concurrent acquisition of cone-beam CT (CBCT), thereby facilitating further geometric verification of patient setup during radiation treatment. However, it is challenging to acquire CBCT during stereotactic body radiation therapy (SBRT) using flattening-filter free X-ray beams, in which a high radiation dose is delivered. This study presents quantitative evaluation results of the image quality in four-dimensional (4D) in-treatment CBCT acquired during SBRT delivery. The impact of megavoltage (MV) scatter and acquisition parameters on the image quality was evaluated using Catphan 503 and XSight lung tracking phantoms. The in-treatment CBCT images of the phantoms were acquired while delivering 16 SBRT plans. The uniformity, contrast, and contrast-to-noise ratio (CNR) of the in-treatment CBCT images were calculated and compared to those of CBCT images acquired without SBRT delivery. Furthermore, the localizing accuracy of the moving target in the XSight lung phantom was evaluated for 10 respiratory phases. The CNR of the 3D-reconstucted Catphan CBCT images was reduced from 6.3 to 2.6 due to the effect of MV treatment scatter. Both for the Catphan and XSight phantoms, the CBCT image quality was affected by the tube current and monitor units (MUs) of the treatment plan. The lung target in the XSight tracking phantom was most visible for extreme phases; the mean CNRs of the lung target in the in-treatment CBCT images (with 40 mA tube current) across the SBRT plans were 3.2 for the end-of-exhalation phase and 3.0 for the end-of-inhalation phase. The lung target was localized with sub-millimeter accuracy for the extreme respiratory phases. Full-arc acquisition with an increased tube current (e.g. 40 mA) is recommended to compensate for degradation in the CBCT image quality due to unflattened MV beam scatter. Acquiring in-treatment CBCT with a high-MU treatment beam is also suggested to improve the resulting CBCT image quality.
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影响因子：
3.6
作者：
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通讯作者：
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影响因子：
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作者：
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作者：
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DOI：
10.1016/j.ijrobp.2011.05.042
发表时间：
2012-04-01
影响因子：
7
作者：
Malinowski, Kathleen T.;McAvoy, Thomas J.;D'Souza, Warren D.
通讯作者：
D'Souza, Warren D.