Spectral performance for iodine quantification of a dual-source, dual-kV photon counting detector CT.

Background: Multi-energy CT (MECT) enables quantification of material concentrations by measuring linear attenuation coefficient line integrals with multiple x-ray spectra. Photon counting detector (PCD)-CT utilizes a detector-based approach for MECT that can suffer from substantial spectral overlap, resulting in amplified material quantification noise. Dual-source dual-kV approaches for MECT are currently utilized in some energy-integrating detector (EID)-CT systems and can potentially be utilized with PCD-CT for improved spectral separation.

Use of Neurophysiological Monitoring during MR Imaging-Guided Ablation Procedures at 1.5 T: Workflow and Safety Considerations.

Purpose: To evaluate the feasibility of intraoperative neurophysiological monitoring (IONM) during magnetic resonance (MR) imaging-guided ablations and identify strategies to reduce IONM electrode radiofrequency (RF) heating during MR imaging.

Materials And Methods: Ex vivo experiments with a porcine tissue phantom simulating a typical high RF heating risk IONM setup during an MR imaging-guided ablation procedure on the shoulder were performed using a 1.5-T scanner.

Simultaneous photon counting and charge integrating for pulse pile-up correction in paralyzable photon counting detectors.

In photon counting detectors (PCDs), electric pulses induced by two or more x-ray photons can pile up and result in count losses when their temporal separation is less than the detector dead time. The correction of pulse pile-up-induced count loss is particularly difficult for paralyzable PCDs since a given value of recorded counts can correspond to two different values of true photon interactions. In contrast, charge (energy) integrating detectors work by integrating collected electric charge induced by x-rays over time and do not suffer from pile-up losses.

Photon counting-energy integrating hybrid flat panel detector systems for image-guided interventions: an experimental proof-of-concept.

Current C-arm x-ray systems equipped with scintillator-based flat panel detectors (FPDs) lack sufficient low-contrast detectability and spectral, high-resolution capabilities much desired for certain interventional procedures. Semiconductor-based direct-conversion photon counting detectors (PCDs) offer these imaging capabilities, although the cost of full field-of-view (FOV) PCD is still too high at the moment. The purpose of this work was to present a hybrid photon counting-energy integrating FPD design as a cost-effective solution to high-quality interventional imaging.

Benefits of using removable filters in dual-layer flat panel detectors.

Existing dual-layer flat panel detectors (DL-FPDs) use a thin scintillator layer to preferentially detect low-energy x-rays, followed by a permanent Cu filter to absorb residual low-energy x-rays, and finally, a thicker scintillator layer to preferentially detect high-energy x-rays. The image outputs of the two scintillator layers can be jointly processed for dual-energy (DE) planar and cone-beam CT imaging. In clinical practice, a given FPD is often used for not only DE imaging but also routine single-energy (SE) imaging.

A C-arm photon counting CT prototype with volumetric coverage using multi-sweep step-and-shoot acquisitions.

Existing clinical C-arm interventional systems use scintillator-based energy-integrating flat panel detectors (FPDs) to generate cone-beam CT (CBCT) images. Despite its volumetric coverage, FPD-CBCT does not provide sufficient low-contrast detectability desired for certain interventional procedures. The purpose of this work was to develop a C-arm photon counting detector (PCD) CT system with a step-and-shoot data acquisition method to further improve the tomographic imaging performance of interventional systems.

An experimental method to correct low-frequency concentric artifacts in photon counting CT.

Large-area photon counting detectors (PCDs) are usually built by tiling multiple semiconductor panels that often have slightly different spectral responses to input x-rays. As a result of this spectral inconsistency, experimental PCD-CT images of large, human-sized objects may show high-frequency ring artifacts and low-frequency band artifacts. Due to the much larger width of the bands compared with the rings, the concentric artifact problem in PCD-CT images of human-sized objects cannot be adequately addressed by conventional CT ring correction methods.

Development of an Integrated C-Arm Interventional Imaging System With a Strip Photon Counting Detector and a Flat Panel Detector.

Modern interventional x-ray systems are often equipped with flat-panel detector-based cone-beam CT (FPD-CBCT) to provide tomographic, volumetric, and high spatial resolution imaging of interventional devices, iodinated vessels, and other objects. The purpose of this work was to bring an interchangeable strip photon-counting detector (PCD) to C-arm systems to supplement (instead of retiring) the existing FPD-CBCT with a high quality, spectral, and affordable PCD-CT imaging option. With minimal modification to the existing C-arm, a 51×0.

Anomalous edge response of cadmium telluride-based photon counting detectors jointly caused by high-flux radiation and inter-pixel communication.

This work reports an edge enhancing effect experimentally observed in cadmium telluride (CdTe)-based photon counting detector (PCD) systems operated under the charge summing (CS) mode and irradiated by high-flux x-rays. Experimental measurements of the edge spread functions (ESFs) of a PCD system (100m pixel size, 88 ns deadtime) were performed at different input flux levels from 4.5 × 10count per second (cps) mmto 1.

Accuracy of weighted CTDI in estimating average dose delivered to CTDI phantoms: An experimental study.

Purpose: The concept of the weighted computed tomography dose index ( ) was proposed in 1995 to represent the average CTDI across an axial section of a cylindrical phantom. The purpose of this work was to experimentally re-examine the validity of the underlying assumptions behind for modern MDCT systems.

Methods: To enable experimental mapping of in the axial plane, in-house 16 and 32 cm cylindrical phantoms were fabricated to allow the pencil chamber to reach any arbitrary axial location within the phantoms.

Drosophila strain specific response to cisplatin neurotoxicity.

Drosophila melanogaster has recently been developed as a simple, in vivo, genetic model of chemotherapy-induced peripheral neuropathy. Flies treated with the chemotherapy agent cisplatin display both a neurodegenerative phenotype and cell death in rapidly dividing follicles, mimicking the cell specific responses seen in humans. Cisplatin induces climbing deficiencies and loss of fertility in a dose dependent manner.