PDF(Pubmed)
Abstract：
OBJECTIVE: To investigate the dependence of signal-to-noise ratio (SNR) and calculated average dose per volume of spiral breast-CT (B-CT) on breast size and breast density and to provide a guideline for choosing the optimal tube current for each B-CT examination.
METHODS: Three representative B-CT datasets (small, medium, large breast size) were chosen to create 3D-printed breast phantoms. The phantoms were filled with four different agarose-oil-emulsions mimicking differences in breast densities. Phantoms were scanned in a B-CT system with systematic variation of the tube current (6, 12.5, 25, 32, 40, 50, 64, 80, 100, 125 mA). Evaluation of SNR and the average dose per volume using Monte Carlo simulations were performed for high (HR) and standard (STD) spatial resolution.
RESULTS: SNR and average dose per volume increased with increasing tube current. Artifacts had negligible influence on image evaluation. SNR values ≥ 35 (HR) and ≥ 100 (STD) offer sufficient image quality for clinical evaluation with SNR being more dependent on breast density than on breast size. For an average absorbed dose limit of 6.5 mGy for the medium and large phantoms and 7 mGy for the small phantom, optimal tube currents were either 25 or 32 mA.
CONCLUSIONS: B-CT offers the possibility to vary the X-ray tube current, allowing image quality optimization based on individual patient\'s characteristics such as breast size and density. This study describes the optimal B-CT acquisition parameters, which provide diagnostic image quality for various breast sizes and densities, while keeping the average dose at a level similar to digital mammography.
CONCLUSIONS: • Image quality optimization based on breast size and density varying the tube current using spiral B-CT.
METHODS: Three representative B-CT datasets (small, medium, large breast size) were chosen to create 3D-printed breast phantoms. The phantoms were filled with four different agarose-oil-emulsions mimicking differences in breast densities. Phantoms were scanned in a B-CT system with systematic variation of the tube current (6, 12.5, 25, 32, 40, 50, 64, 80, 100, 125 mA). Evaluation of SNR and the average dose per volume using Monte Carlo simulations were performed for high (HR) and standard (STD) spatial resolution.
RESULTS: SNR and average dose per volume increased with increasing tube current. Artifacts had negligible influence on image evaluation. SNR values ≥ 35 (HR) and ≥ 100 (STD) offer sufficient image quality for clinical evaluation with SNR being more dependent on breast density than on breast size. For an average absorbed dose limit of 6.5 mGy for the medium and large phantoms and 7 mGy for the small phantom, optimal tube currents were either 25 or 32 mA.
CONCLUSIONS: B-CT offers the possibility to vary the X-ray tube current, allowing image quality optimization based on individual patient\'s characteristics such as breast size and density. This study describes the optimal B-CT acquisition parameters, which provide diagnostic image quality for various breast sizes and densities, while keeping the average dose at a level similar to digital mammography.
CONCLUSIONS: • Image quality optimization based on breast size and density varying the tube current using spiral B-CT.
摘要：
目的：研究信噪比（SNR）和计算的螺旋乳腺CT（B-CT）每体积平均剂量对乳腺大小和乳腺密度的依赖性，并为每次B-CT检查选择最佳管电流提供指导。
方法：三个代表性的B-CT数据集（小型，中等,选择大乳房尺寸）来创建3D打印的乳房模型。幻影中充满了四种不同的琼脂糖油乳液，模仿了乳房密度的差异。在B-CT系统中扫描体模，管电流有系统变化（6、12.5、25、32、40、50、64、80、100、125mA）。对于高(HR)和标准(STD)空间分辨率进行使用蒙特卡罗模拟的SNR和每体积平均剂量的评估。
结果：SNR和每体积平均剂量随管电流的增加而增加。伪影对图像评价的影响可忽略不计。SNR值≥35（HR）和≥100（STD）为临床评估提供了足够的图像质量，SNR更依赖于乳腺密度而不是乳腺大小。对于中型和大型体模的平均吸收剂量限值为6.5mGy，小型体模的平均吸收剂量限值为7mGy，最佳管电流为25或32mA。
结论：B-CT提供了改变X射线管电流的可能性，允许基于个体患者的特征（如乳房大小和密度）优化图像质量。这项研究描述了最佳的B-CT采集参数，提供各种乳房大小和密度的诊断图像质量，同时将平均剂量保持在类似于数字乳房X线照相术的水平。
结论：•使用螺旋B-CT基于乳房大小和密度改变管电流的图像质量优化。
方法：三个代表性的B-CT数据集（小型，中等,选择大乳房尺寸）来创建3D打印的乳房模型。幻影中充满了四种不同的琼脂糖油乳液，模仿了乳房密度的差异。在B-CT系统中扫描体模，管电流有系统变化（6、12.5、25、32、40、50、64、80、100、125mA）。对于高(HR)和标准(STD)空间分辨率进行使用蒙特卡罗模拟的SNR和每体积平均剂量的评估。
结果：SNR和每体积平均剂量随管电流的增加而增加。伪影对图像评价的影响可忽略不计。SNR值≥35（HR）和≥100（STD）为临床评估提供了足够的图像质量，SNR更依赖于乳腺密度而不是乳腺大小。对于中型和大型体模的平均吸收剂量限值为6.5mGy，小型体模的平均吸收剂量限值为7mGy，最佳管电流为25或32mA。
结论：B-CT提供了改变X射线管电流的可能性，允许基于个体患者的特征（如乳房大小和密度）优化图像质量。这项研究描述了最佳的B-CT采集参数，提供各种乳房大小和密度的诊断图像质量，同时将平均剂量保持在类似于数字乳房X线照相术的水平。
结论：•使用螺旋B-CT基于乳房大小和密度改变管电流的图像质量优化。
