Polemi Andrew M, Niestroy Justin, Stolin Alexander, Jaliparthi Gangadhar, Wojcik Randy, Majewski Stan, Williams Mark B
Dept. of Biomedical Engineering, University of Virginia, 415 Lane Road, Charlottesville, VA USA 22908.
Dept. of Physics, University of Virginia, 382 McCormick Rd., Charlottesville, VA USA 22908.
Proc SPIE Int Soc Opt Eng. 2016 Aug 28;9969. doi: 10.1117/12.2246561. Epub 2016 Oct 3.
A new low profile gamma camera is being developed for use in a dual modality (x-ray transmission and gamma-ray emission) tomosynthesis system. Compared to the system's current gamma camera, the new camera has a larger field of view (20×25 cm) to better match the system's x-ray detector (23×29 cm), and is thinner (7.3 cm instead of 10.3 cm) permitting easier camera positioning near the top surface of the breast. It contains a pixelated NaI(Tl) array with a crystal pitch of 2.2 mm, which is optically coupled to a 4×5 array of Hamamatsu H8500C position sensitive photomultiplier tubes (PSPMTs). The manufacturer-provided connector board of each PSPMT was replaced with a custom designed board that a) reduces the 64 channel readout of the 8×8 electrode anode of the H8500C to 16 channels (8X and 8Y), b) performs gain non-uniformity correction, and c) reduces the height of the PSPMT-base assembly, 37.7 mm to 27.87 mm. The X and Y outputs of each module are connected in a lattice framework, and at two edges of this lattice, the X and Y outputs (32Y by 40X) are coupled to an amplifier/output board whose signals are fed via shielded ribbon cables to external ADCs. The camera uses parallel hole collimation. We describe the measured camera imaging performance, including intrinsic and extrinsic spatial resolution, detection sensitivity, uniformity of response, energy resolution for 140 keV gamma rays, and geometric linearity.
一种新型的低剖面伽马相机正在被开发用于双模态（X射线透射和伽马射线发射）断层合成系统。与该系统当前的伽马相机相比，新相机具有更大的视野（约20×25厘米），以便更好地匹配系统的X射线探测器（约23×29厘米），并且更薄（7.3厘米而非10.3厘米），从而允许在乳房顶表面附近更轻松地定位相机。它包含一个像素化的碘化钠（铊）阵列，晶体间距为2.2毫米，该阵列与滨松H8500C位置灵敏光电倍增管（PSPMT）的4×5阵列进行光学耦合。每个PSPMT制造商提供的连接板被一个定制设计的板所取代，该板a）将H8500C的8×8电极阳极的64通道读出减少到16通道（8X和8Y），b）进行增益不均匀性校正，c）将PSPMT底座组件的高度从37.7毫米降低到27.87毫米。每个模块的X和Y输出以晶格框架连接，在该晶格的两条边上，X和Y输出（32Y×40X）耦合到一个放大器/输出板，其信号通过屏蔽带状电缆馈送到外部ADC。相机使用平行孔准直。我们描述了测量的相机成像性能，包括固有和外在空间分辨率、探测灵敏度、响应均匀性、140keV伽马射线的能量分辨率以及几何线性度。
