A spherical detector configuration in truncated form, consisting of multiple layers of ring detector arrays, can substantially improve the reconstructed image quality in positron emission tomography since all inclined annihilation photon rays can now be used for reconstruction of the image. A new true three-dimensional reconstruction (n~) algorithm suitable for spherical and quasi-spherical forms of detector arrays is presented. In this algorithm each set of two-dimensional projection data is filtered with a 2-D filter function appropriate to the angular orientations, then back-projected onto the object space in every direction. An example of statistical image quality improvement for this algorithm over the conventional two-dimensional algorithm using only intraplane rays is presented using computer simulation.

There is a pressing need for functional testing platforms that use human, live tumor tissue to better predict traditional and immunotherapy responses. Such platforms should also retain as much of the native tumor microenvironment (TME) as possible, as many cancer drug actions rely on TME-dependent mechanisms. Present high-throughput testing platforms that have some of these features, e.g. based on patient-derived tumor organoids, require a growth step that alters the TME. On the other hand, micro-dissected tumor tissue "spheroids" that retain an intact TME have shown promising responses to immunomodulators acting on native immune cells. Here we demonstrate a microfluidic 96-well platform designed for drug treatment of hundreds of similarly-sized, cuboidal micro-tissues ("cuboids") produced from a single tumor sample. Four cuboids per well are automatically arrayed into the platform using hydrodynamic trapping. The microfluidic device, entirely fabricated in thermoplastics, features microvalves that fluidically isolate each well after the cuboid loading step. Since the platform effectively makes the most of scarce tumor tissue, we believe it could ultimately be applied to human biopsies for drug discovery and personalized oncology, altogether bypassing animal testing.