High resolution imaging with focused kV x-rays for small animal radio-neuromodulation.
High resolution imaging with focused kV x-rays for small animal radio-neuromodulation.
复制标题
使用聚焦 kV X 射线进行高分辨率成像，用于小动物放射神经调节。
作者：
Shi,Linxi;Bennett,NRobert;Nguyen,Eric;MacDonald,Carolyn;Wang,Adam;Liu,Wu
背景小尺寸辐射器的高精度放射治疗在许多涉及小型浅靶标的治疗应用中具有潜力，小动物放射神经调节就是一个有趣的例子。基于多毛细管 X 射线透镜新颖用途的聚焦 kV 技术可以将 X 射线束聚焦到直径 <0.2 毫米，非常适合此类用途。目的此类应用还需要高分辨率 CT 图像来进行治疗计划和设置。在这项工作中，我们证明了使用 X 射线透镜生成的虚拟焦点来执行高分辨率 CBCT 采集的可行性。方法在 X 射线桌面系统上建立了 X 射线透镜的实验来生成虚拟焦点。首先比较了使用和不使用 X 射线镜头的泛场图像。获取虚拟焦点的针孔图像，并将其与没有透镜的传统焦点获取的图像进行比较。使用线对分辨率模型评估有和没有透镜的平面成像分辨率。通过重建 0.15 毫米线体模型并比较其半峰全宽 (FWHM) 来估计两种设置的空间分辨率。还对啮齿动物头部进行了 CBCT 扫描，以进一步证明使用 X 射线镜头提高了分辨率。结果所提出的 X 射线镜头成像装置在探测器上的曝光区域有限，为 5 cm x 5 cm，适合将无线电神经调节引导到啮齿动物大脑中的小目标。与测量的 X 射线焦点为 0.395 mm FWHM 的传统成像采集相比，测量的虚拟焦点尺寸为 0.175 mm。镜头焦斑尺寸的减小使得平面成像分辨率几乎翻倍，3D 空间分辨率提高了 26%。啮齿动物头部的真实 CBCT 采集模仿了放射神经调节的成像采集步骤，并进一步显示了精细结构可视化的改进。结论这项工作表明，聚焦 kV X 射线技术能够产生 <0.2 mm 的小焦点，这大大提高了小动物成像的 X 射线成像分辨率。
BackgroundHigh precision radiotherapy with small irradiator size has potential in many treatment applications involving small shallow targets, with small animal radio‐neuromodulation as an intriguing example. A focused kV technique based on novel usage of polycapillary x‐ray lenses can focus x‐ray beams to <0.2 mm in diameter, which is ideal for such uses.PurposeSuch an application also requires high resolution CT images for treatment planning and setup. In this work, we demonstrate the feasibility of using a virtual focal spot generated with an x‐ray lens to perform high‐resolution CBCT acquisition.MethodThe experiment with x‐ray lens was set up on an x‐ray tabletop system to generate a virtual focal spot. The flood field images with and without the x‐ray lens were first compared. A pinhole image was acquired for the virtual focal spot and compared with the one acquired with the conventional focal spot without the lens. The planar imaging resolution with and without the lens were evaluated using a line pair resolution phantom. The spatial resolution of the two settings were estimated by reconstructing a 0.15‐mm wire phantom and comparing its full width half maximum (FWHM). A CBCT scan of a rodent head was also acquired to further demonstrate the improved resolution using the x‐ray lens.ResultThe proposed imaging setup with x‐ray lens had a limited exposure area of 5 cm by 5 cm on the detector, which was suitable for guiding radio‐neuromodulation to a small target in rodent brain. Compared to conventional imaging acquisition with a measured x‐ray focal spot of 0.395 mm FWHM, the virtual focal spot size was measured at 0.175 mm. The reduction in focal spot size with lens leads to an almost doubled planar imaging resolution and a 26% enhancement in 3D spatial resolution. A realistic CBCT acquisition of a rodent head mimicked the imaging acquisition step for radio‐neuromodulation and further showed the improved visualization for fine structures.ConclusionThis work demonstrated that the focused kV x‐ray technique was capable of generating small focal spot size of <0.2 mm, which substantially improved x‐ray imaging resolution for small animal imaging.