Schwoebel P R, Boone John M, Shao Joe
SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025, USA.
Phys Med Biol. 2014 May 21;59(10):2393-413. doi: 10.1088/0031-9155/59/10/2393. Epub 2014 Apr 17.
A prototype linear x-ray source to implement stationary source-stationary detector tomosynthesis (TS) imaging has been studied. Potential applications include human breast and small animal imaging. The source is comprised of ten x-ray source elements each consisting of a field emission cathode, electrostatic lens, and target. The electrostatic lens and target are common to all elements. The source elements form x-ray focal spots with minimum diameters of 0.3-0.4 mm at electron beam currents of up to 40 mA with a beam voltage of 40 kV. The x-ray flux versus time was quantified from each source. X-ray bremsstrahlung spectra from tungsten targets were produced using electron beam energies from 35 to 50 keV. The half-value layer was measured to be 0.8, 0.9, and 1.0 mm, respectively, for the 35, 40, and 45 kV tube potentials using the tungsten target. The suppression of voltage breakdown events, particularly during source operation, and the use of a modified form of the standard cold-cathode geometry, enhanced source reliability. The prototype linear source was used to collect tomographic data sets of a mouse phantom using digital TS reconstruction methods and demonstrated a slice-sensitivity profile with a full-width-half-maximum of 1.3 mm. Lastly, preliminary studies of tomographic imaging of flow through the mouse phantom were performed.
一种用于实现固定源-固定探测器断层合成（TS）成像的线性X射线源原型已得到研究。其潜在应用包括人体乳腺成像和小动物成像。该源由十个X射线源元件组成，每个元件都包括一个场发射阴极、静电透镜和靶。静电透镜和靶为所有元件共用。在高达40 mA的电子束电流和40 kV的束电压下，源元件形成最小直径为0.3 - 0.4 mm的X射线焦点。对每个源的X射线通量随时间的变化进行了量化。使用35至50 keV的电子束能量产生了来自钨靶的X射线轫致辐射光谱。使用钨靶时，对于35、40和45 kV的管电压，半值层分别测得为0.8、0.9和1.0 mm。对电压击穿事件的抑制，特别是在源运行期间，以及采用标准冷阴极几何结构的改进形式，提高了源的可靠性。该线性源原型用于使用数字TS重建方法收集小鼠体模的断层数据集，并展示了半高宽为1.3 mm的切片灵敏度分布。最后，对通过小鼠体模的血流进行了断层成像的初步研究。
