Generating realistic radiographs from CT is mainly limited by the native spatial resolution of the latter. Here we present a general approach for synthesizing high-resolution digitally reconstructed radiographs (DRRs) from an arbitrary resolution CT volume. Our approach is based on an upsampling framework where tissues of interest are first segmented from the original CT volume and then upsampled individually to the desired voxelization (here ∼1 mm → 0.2 mm). Next, we create high-resolution 2D tissue maps by cone-beam projection of individual tissues in the desired radiography direction. We demonstrate this approach on a coronary artery calcium (CAC) patient CT scan and show that our approach preserves individual tissue volumes, yet enhances the tissue interfaces, creating a sharper DRR without introducing artificial features. Lastly, we model a dual-layer detector to synthesize high-resolution dual-energy (DE) anteroposterior and lateral radiographs from the patient CT to visualize the CAC in 2D through material decomposition. On a general level, we envision that this approach is valuable for creating libraries of synthetic yet realistic radiographs from corresponding large CT datasets.
We demonstrate measured radiation detection results from a 50 × 50 μm2 pixel size direct-conversion amorphous selenium (a-Se)/CMOS hybrid detector. We are interested in investigating a monolithic hybrid CMOS detector composed of an a-Se photoconductor thin film integrated on a CMOS active pixel readout array. In this work, we attempt to verify the fabrication process of a-Se as a photoconductive layer for integration with an existing CMOS ASIC. For this initial investigation, the RD53B-ATLAS was used to validate the deposition of a-Se for integration with CMOS technology.
Computed tomography (CT) is a non-invasive means of localizing a region of interest within an object, which enables the investigation of soil distributions and localized flow processes within soil pore systems. CT scanning allows for cross-sectional successions that provide visibility within the environment of plant samples. Knowledge of the characteristics of the soil pore system is essential for evaluating various processes that take place between root-soil interactions. In this study, we investigate the potential application of a high-resolution amorphous selenium (a-Se) direct conversion detector on complementary metal-oxide-semiconductor (CMOS) readouts for micro-CT scanning of a soil matrix to image the status of aggregation and networks of pore spaces within intact soil. The combination of the intrinsic high spatial resolution of a-Se and small pixel CMOS readouts provide detailed visualization in the soil aggregates of the plant samples. The x-ray energy and plant soil thickness were varied during the investigation for imaging the root-soil. A 10 μm spatial resolution and noise limited performance of eight photons/pixel at 20 keV were achieved. High attenuation of x-rays in thick soil poses challenges however fine details are observable in thinner samples and care should be taken when choosing soil thickness and container material.
Single exposure dual energy Dual-Layer (DL) Flat-Panel Detectors (FPD) are an approach to acquisition technology for x-ray imaging applications. It provides the advantages of enabling dual energy exposures in a single shot, avoiding motion artifacts created by respiratory or cardiac motion, and creating spectral separation to improve tissue specificity. We are investigating the effect of the top layer detector of a DL FPD by comparing two configurations (indirect vs. direct top layer conversion). We are interested in replacing the top layer scintillator detector for a direct conversion detector, made of amorphous selenium (a-Se), to improve image quality. Due to the photoconductive properties of a-Se, we will demonstrate that our design may improve the spatial resolution and high-frequency response of the x-ray image. The merit of developing these detectors lies in the possibility of opportunistic screening for quantifying coronary artery calcium (CAC), determining bone mineral density (i.e., osteoporosis), and characterizing renal stones through improvements to high-contrast visualization. In this work, we simulate the a-Se top layer detector to optimize the design parameters (e.g., the layer thickness and pixel pitch) for direct conversion to maintain spectral separation compared to that provided by a 200 µm cesium iodide (CsI) indirect conversion layer and improve image quality.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.