Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI, USA.
Med Phys. 2011 Oct;38(10):5500-8. doi: 10.1118/1.3634043.
To demonstrate the feasibility of Tetrahedron Beam Computed Tomography (TBCT) using a carbon nanotube (CNT) multiple pixel field emission x-ray (MPFEX) tube.
A multiple pixel x-ray source facilitates the creation of novel x-ray imaging modalities. In a previous publication, the authors proposed a Tetrahedron Beam Computed Tomography (TBCT) imaging system which comprises a linear source array and a linear detector array that are orthogonal to each other. TBCT is expected to reduce scatter compared with Cone Beam Computed Tomography (CBCT) and to have better detector performance. Therefore, it may produce improved image quality for image guided radiotherapy. In this study, a TBCT benchtop system has been developed with an MPFEX tube. The tube has 75 CNT cold cathodes, which generate 75 x-ray focal spots on an elongated anode, and has 4 mm pixel spacing. An in-house-developed, 5-row CT detector array using silicon photodiodes and CdWO(4) scintillators was employed in the system. Hardware and software were developed for tube control and detector data acquisition. The raw data were preprocessed for beam hardening and detector response linearity and were reconstructed with an FDK-based image reconstruction algorithm.
The focal spots were measured at about 1 × 2 mm(2) using a star phantom. Each cathode generates around 3 mA cathode current with 2190 V gate voltage. The benchtop system is able to perform TBCT scans with a prolonged scanning time. Images of a commercial CT phantom were successfully acquired.
A prototype system was developed, and preliminary phantom images were successfully acquired. MPFEX is a promising x-ray source for TBCT. Further improvement of tube output is needed in order for it to be used in clinical TBCT systems.
展示使用碳纳米管（CNT）多像素场发射 X 射线（MPFEX）管实现四面体束 CT（TBCT）的可行性。
多像素 X 射线源有助于创建新型 X 射线成像方式。在之前的一篇出版物中，作者提出了一种四面体束 CT（TBCT）成像系统，该系统由一个线性源阵列和一个与线性源阵列正交的线性探测器阵列组成。TBCT 有望减少与锥形束 CT（CBCT）相比的散射，并具有更好的探测器性能。因此，它可能会为图像引导放射治疗产生更好的图像质量。在这项研究中，使用 MPFEX 管开发了一种 TBCT 台式系统。该管有 75 个 CNT 冷阴极，在一个细长的阳极上产生 75 个 X 射线焦点，像素间距为 4 毫米。该系统采用了内部开发的使用硅光电二极管和 CdWO(4)闪烁体的 5 排 CT 探测器阵列。为管控制和探测器数据采集开发了硬件和软件。对原始数据进行了预处理，以进行束硬化和探测器响应线性度的校正，并使用基于 FDK 的图像重建算法进行了重建。
使用星型体模测量焦点光斑约为 1×2mm(2)。每个阴极在 2190V 栅极电压下产生约 3mA 的阴极电流。该台式系统能够进行 TBCT 扫描，但扫描时间较长。成功获取了商用 CT 体模的图像。
开发了原型系统，并成功获取了初步的体模图像。MPFEX 是 TBCT 的一种很有前途的 X 射线源。为了将其用于临床 TBCT 系统，需要进一步提高管的输出。
