Jones A Kyle, Ahmad Moiz, Raza Shaan M, Chen Stephen R, Siewerdsen Jeffrey H
University of Texas MD Anderson Cancer Center, Department of Imaging Physics, Houston, Texas, United States.
University of Texas MD Anderson Cancer Center, Department of Interventional Radiology, Houston, Texas, United States.
J Med Imaging (Bellingham). 2024 Jul;11(4):043503. doi: 10.1117/1.JMI.11.4.043503. Epub 2024 Aug 22.
We aim to compare the imaging performance of a cone-beam CT (CBCT) imaging system with noncircular scan protocols (sine-on-sphere) to a conventional circular orbit.
A biplane C-arm system (ARTIS Icono; Siemens Healthineers) capable of circular and noncircular CBCT acquisition was used, with the latter orbit (sine-on-sphere, "Sine Spin") executing a sinusoidal motion with tilt amplitude over the half-scan orbit. A test phantom was used for the characterization of image uniformity, noise, noise-power spectrum (NPS), spatial resolution [modulation transfer function (MTF) in axial and oblique directions], and cone-beam artifacts. Findings were interpreted using an anthropomorphic head phantom with respect to pertinent tasks in skull base neurosurgery.
The noncircular scan protocol exhibited several advantages associated with improved 3D sampling-evident in the NPS as filling of the null cone about the spatial frequency axis and reduction of cone-beam artifacts. The region of support at the longitudinal extrema was reduced from 16 to at a radial distance of 6.5 cm. Circular and noncircular orbits exhibited nearly identical image uniformity and quantum noise, demonstrating cupping of and overall noise of . Although both the radially averaged axial MTF ( ) and 45 deg oblique MTF ( ) were lower for the noncircular orbit compared with the circular orbit at the default full reconstruction field of view (FOV), there was no difference in spatial resolution for the medium reconstruction FOV (smaller voxel size). Differences in the perceptual image quality for the anthropomorphic phantom reinforced the objective, quantitative findings, including reduced beam-hardening and cone-beam artifacts about structures of interest in the skull base.
Image quality differences between circular and noncircular CBCT orbits were quantitatively evaluated on a clinical system in the context of neurosurgery. The primary performance advantage for the noncircular orbit was the improved sampling and elimination of cone-beam artifacts.
我们旨在比较采用非圆形扫描协议（球面上的正弦扫描）的锥形束CT（CBCT）成像系统与传统圆形轨道的成像性能。
使用了一台能够进行圆形和非圆形CBCT采集的双平面C形臂系统（ARTIS Icono；西门子医疗），后者的轨道（球面上的正弦扫描，“正弦旋转”）在半扫描轨道上执行具有倾斜幅度的正弦运动。使用测试体模来表征图像均匀性、噪声、噪声功率谱（NPS）、空间分辨率[轴向和斜向的调制传递函数（MTF）]以及锥形束伪影。使用一个仿真人头体模针对颅底神经外科的相关任务对结果进行解读。
非圆形扫描协议展现出与改进的三维采样相关的几个优势——在NPS中表现为零锥在空间频率轴上的填充以及锥形束伪影的减少。在径向距离为6.5厘米处，纵向极值处的支撑区域从16减少到了 。圆形和非圆形轨道表现出几乎相同的图像均匀性和量子噪声，显示出 的杯状伪影和 的总体噪声。尽管在默认的全重建视野（FOV）下，非圆形轨道的径向平均轴向MTF（ ）和45度斜向MTF（ ）均低于圆形轨道，但在中等重建FOV（较小体素尺寸）下空间分辨率并无差异。仿真人头体模的感知图像质量差异强化了客观、定量的结果，包括颅底感兴趣结构周围的束硬化和锥形束伪影减少。
在神经外科的背景下，在临床系统上对圆形和非圆形CBCT轨道之间的图像质量差异进行了定量评估。非圆形轨道的主要性能优势在于采样的改进和锥形束伪影的消除。
