Estimating radiation exposure of the brain of a physician with a protective flap in interventional radiology: A phantom study.

PURPOSE: The efficiency of protective equipment for the brain has not been verified at the left anterior oblique (LAO) position, which is commonly used in clinical procedures. The purpose of this study was to investigate radiation exposure of the brain in interventional radiology (IR) and the shielding ability of a new protective flap. METHODS: We made a flap that combined a protective cap with a left lateral face shield. The flap was made of tungsten-containing rubber (TCR). An anthropomorphic head phantom was placed at the physician's position, and air kerma rates (µGy/min and µGy/15s) were measured by electronic dosimeter at three locations: the surface of the left side of the head, and the left and right temporal lobes with the protective cap and the flap in fluoroscopy and cine modes. The X-ray tube was at the lower left side of the physician, and its angles were LAO60 and LAO60CAU40. The tube voltage (95-125 kV), tube current (4.7-732 mA), and air kerma rate (27.8-1078 mGy/min) were automatically adjusted by the X-ray system. We obtained the cap and the flap shielding efficiencies. RESULTS: In cine mode at LAO60CAU40, the shielding efficiencies on the surface of the left side of the head and left temporal lobe with the cap were 92.6% and 5.1%, respectively, and the corresponding shielding efficiencies with the flap were 92.5% and 86.1%, respectively. The flap can reduce radiation exposure of the brain more than the cap alone. CONCLUSIONS: At the left anterior oblique in interventional radiology, the flap can reduce exposure to the brain.

Learning Self-Prior for Mesh Inpainting Using Self-Supervised Graph Convolutional Networks.

This study presents a self-prior-based mesh inpainting framework that requires only an incomplete mesh as input, without the need for any training datasets. Additionally, our method maintains the polygonal mesh format throughout the inpainting process without converting the shape format to an intermediate, such as a voxel grid, a point cloud, or an implicit function, which are typically considered easier for deep neural networks to process. To achieve this goal, we introduce two graph convolutional networks (GCNs): single-resolution GCN (SGCN) and multi-resolution GCN (MGCN), both trained in a self-supervised manner. Our approach refines a watertight mesh obtained from the initial hole filling to generate a completed output mesh. Specifically, we train the GCNs to deform an oversmoothed version of the input mesh into the expected completed shape. To supervise the GCNs for accurate vertex displacements, despite the unknown correct displacements at real holes, we utilize multiple sets of meshes with several connected regions marked as fake holes. The correct displacements are known for vertices in these fake holes, enabling network training with loss functions that assess the accuracy of displacement vectors estimated by the GCNs. We demonstrate that our method outperforms traditional dataset-independent approaches and exhibits greater robustness compared to other deep-learning-based methods for shapes that less frequently appear in shape datasets.

REDUCTION OF THE COMPUTED TOMOGRAPHY DOSE TO THE GONADS OF ADOLESCENT AND YOUNG ADULT MALES THROUGH USE OF A TUNGSTEN-CONTAINING RUBBER SHEET.

This study aims to measure the shielding effect of a novel tungsten rubber sheet (TRS) on the exposure of male gonads to ionizing radiation during upper abdominal and abdominal plus pelvic computed tomography (CT) examinations. The air kerma at the gonad with and without shielding was measured using an anthropomorphic body phantom. Gonads were shielded using: (1) 360° wrap with TRS (0.5-mm thick) and (2) 180° wrap with TRS. The air kerma at a position of male gonads in a pelvic scan was 21.8 mGy, even when the gonads were in the off-axis range. The TRS reduced the dose to the male gonads in abdominal plus pelvic CT examinations by 61% and 38% for the 360° and 180° TRS wrap, respectively.

Accelerated polymer-polymer click conjugation by freeze-thaw treatment.

Herein, we report a unique technique to accelerate polymer-SNA conjugation based on copper-free click chemistry: gradual freeze-thawing of the reaction solution substantially increases the conjugation rate possibly because of the reactant concentration at the microenvironment scale. This technique was applied to the conjugation between a small interfering RNA (siRNA) and PEG in an aqueous buffer at/below room temperature.

Radiation dose reduction to the eye lens in head CT using tungsten functional paper and organ-based tube current modulation.

PURPOSE: We investigated whether a tungsten functional paper (TFP) shield and/or organ-based tube current modulation (TCM) can reduce the dose to the eye lens. MATERIALS AND METHODS: All scans were performed using our routine head examination protocol (spiral acquisition, 120 kVp, noise Index 3.5) with an anthropomorphic head phantom. The dose reduction rate was measured by the following methods with a scintillation fiber optic dosimeter: (a) without any dose reduction techniques (Original scan), (b) TFP shield, (c) TCM, and (d) TFP shield plus TCM. Image noise and CT number were obtained and compared between the three groups. In addition, image noise in method (d) was measured with varying distances between the TFP shield and eye lens. RESULTS: The reduction rates using TFP shield, TCM, and TFP shield plus TCM compared with those for the Original scan were 17.8 %, 13.6 %, and 27.7 %, respectively. Image noise (mean ± standard deviation) in the anterior region for the Original scan, TFP shield, TCM, and TFP shield plus TCM were 4.1 ± 0.2, 4.6 ± 0.2, 4.4 ± 0.3, and 5.0 ± 0.2, while the CT numbers were 19.3 ± 0.8, 23.8 ± 0.8, 19.6 ± 0.8, and 24.1 ± 0.8, respectively. Increasing the distance between the TFP and the eye significantly decreased the CT number when using TFP shield plus TCM (p < .05). CONCLUSION: TFP shield plus TCM reduced the dose to the eye lens in head CT while maintaining image quality with an air gap between the TFP and skin surface.

Machine learning-driven electronic identifications of single pathogenic bacteria.

A rapid method for screening pathogens can revolutionize health care by enabling infection control through medication before symptom. Here we report on label-free single-cell identifications of clinically-important pathogenic bacteria by using a polymer-integrated low thickness-to-diameter aspect ratio pore and machine learning-driven resistive pulse analyses. A high-spatiotemporal resolution of this electrical sensor enabled to observe galvanotactic response intrinsic to the microbes during their translocation. We demonstrated discrimination of the cellular motility via signal pattern classifications in a high-dimensional feature space. As the detection-to-decision can be completed within milliseconds, the present technique may be used for real-time screening of pathogenic bacteria for environmental and medical applications.

Diplatinum(II)-coordinated polyoxotungstate: synthesis, molecular structure, and photocatalytic performance for hydrogen evolution from water under visible-light irradiation.

The synthesis and molecular structure of a monomeric diplatinum(II) complex composed of mono-lacunary α-Keggin polyoxometalate is described. The polyoxometalate, Cs(3)[α-PW(11)O(39){cis-Pt(NH(3))(2)}(2)]·8H(2)O (Cs-1), afforded by a stoichiometric reaction of mono-lacunary Keggin polyoxotungstate with cis-diamminedichloroplatinum(ii) in water, followed by crystallization from water, was obtained as analytically pure, homogeneous, yellow crystals. The compound Cs-1 was characterized by elemental analysis, thermogravimetric/differential thermal analysis (TG/DTA), Fourier transform infrared (FTIR) and UV-visible spectroscopy, solution (1)H and (31)P nuclear magnetic resonance (NMR), and X-ray crystallography. The single-crystal X-ray structure analysis revealed that the two cis-platinum(ii) moieties, [cis-Pt(NH(3))(2)](2+), were coordinated each to two oxygen atoms in a mono-vacant site of [α-PW(11)O(39)](7-) with asymmetric configuration, resulting in an overall C(1) symmetry. Furthermore, hydrogen evolution from an EDTA·2Na (ethylenediamine tetraacetic acid disodium salt) aqueous solution under visible-light irradiation (≥400 nm) was achieved by using polyoxoanion 1 and titanium dioxide.