Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, USA.
Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, USA.
J Appl Clin Med Phys. 2024 Oct;25(10):e14484. doi: 10.1002/acm2.14484. Epub 2024 Aug 13.
To investigate the feasibility of standardizing RT simulation CT scanner protocols between vendors using target-based image quality (IQ) metrics.
A systematic assessment process in phantom was developed to standardize clinical scan protocols for scanners from different vendors following these steps: (a) images were acquired by varying CTDI and using an iterative reconstruction (IR) method (IR: iDose and model-based iterative reconstruction [IMR] of CT-Philips Big Bore scanner, SAFIRE of CT-Siemens biograph PETCT scanner), (b) CT exams were classified into body and brain protocols, (c) the rescaled noise power spectrum (NPS) was calculated, (d) quantified the IQ change due to varied CTDI and IR, and (e) matched the IR strength level. IQ metrics included noise and texture from NPS, contrast, and contrast-to-noise ratio (CNR), low contrast detectability (d'). Area under curve (AUC) of the receiver operation characteristic curve of d' was calculated and compared.
The level of change in the IQ ratio was significant (>0.6) when using IMR. The IQ ratio change was relatively low to moderate when using either iDose in CTp (0.1-0.5) or SAFIRE in CT (0.1-0.6). SAFIRE-2 in CT showed a closer match to the reference body protocol when compared to iDose-3 in CT. In the brain protocol, iDose-3 in CT could be matched to the low to moderate level of SAFIRE in CT. The AUC of d' was highest when using IMR in CT with lower CTDI, and SAFIRE in CT performed better than iDose in CT CONCLUSION: It is possible to use target-based IQ metrics to evaluate the performance of the system and operations across various scanners in a phantom. This can serve as an initial reference to convert clinical scanned protocols from one CT simulation scanner to another.
使用基于目标的图像质量（IQ）指标来研究在不同供应商之间标准化 RT 模拟 CT 扫描仪协议的可行性。
在体模中开发了一种系统评估过程，以遵循以下步骤标准化来自不同供应商的扫描仪的临床扫描协议：（a）通过改变 CTDI 和使用迭代重建（IR）方法（IR：CT-Philips Big Bore 扫描仪的 iDose 和基于模型的迭代重建 [IMR]、CT-Siemens biograph PETCT 扫描仪的 SAFIRE）获取图像，（b）将 CT 检查分为身体和大脑协议，（c）计算重新缩放的噪声功率谱（NPS），（d）量化由于 CTDI 和 IR 变化导致的 IQ 变化，（e）匹配 IR 强度水平。IQ 指标包括 NPS 的噪声和纹理、对比度和对比噪声比（CNR）、低对比度检测能力（d'）。计算并比较了 d'的受试者工作特征曲线的曲线下面积（AUC）。
使用 IMR 时，IQ 比的变化水平显着（>0.6）。当在 CTp 中使用 iDose 时（0.1-0.5）或在 CT 中使用 SAFIRE 时（0.1-0.6），IQ 比的变化相对较低至中等。与 CT 中的 iDose-3 相比，CT 中的 SAFIRE-2 显示出与参考身体协议更接近的匹配。在大脑协议中，CT 中的 iDose-3 可以与 CT 中的 SAFIRE 的低至中等水平相匹配。当在 CT 中使用具有较低 CTDI 的 IMR 并且在 CT 中使用 SAFIRE 时，d'的 AUC 最高。结论：使用基于目标的 IQ 指标评估系统在体模中的性能并在各种扫描仪之间进行操作是可行的。这可以作为将临床扫描协议从一个 CT 模拟扫描仪转换为另一个的初始参考。
