Publications by authors named "H Tsukada"

639 Publications

Visually Navigated Bronchoscopy using three cycle-Consistent generative adversarial network for depth estimation.

Med Image Anal 2021 Jul 18;73:102164. Epub 2021 Jul 18.

National Center for Image-guided Therapy, Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States.

[Background] Electromagnetically Navigated Bronchoscopy (ENB) is currently the state-of-the art diagnostic and interventional bronchoscopy. CT-to-body divergence is a critical hurdle in ENB, causing navigation error and ultimately limiting the clinical efficacy of diagnosis and treatment. In this study, Visually Navigated Bronchoscopy (VNB) is proposed to address the aforementioned issue of CT-to-body divergence. [Materials and Methods] We extended and validated an unsupervised learning method to generate a depth map directly from bronchoscopic images using a Three Cycle-Consistent Generative Adversarial Network (3cGAN) and registering the depth map to preprocedural CTs. We tested the working hypothesis that the proposed VNB can be integrated to the navigated bronchoscopic system based on 3D Slicer, and accurately register bronchoscopic images to pre-procedural CTs to navigate transbronchial biopsies. The quantitative metrics to asses the hypothesis we set was Absolute Tracking Error (ATE) of the tracking and the Target Registration Error (TRE) of the total navigation system. We validated our method on phantoms produced from the pre-procedural CTs of five patients who underwent ENB and on two ex-vivo pig lung specimens. [Results] The ATE using 3cGAN was 6.2 +/- 2.9 [mm]. The ATE of 3cGAN was statistically significantly lower than that of cGAN, particularly in the trachea and lobar bronchus (p < 0.001). The TRE of the proposed method had a range of 11.7 to 40.5 [mm]. The TRE computed by 3cGAN was statistically significantly smaller than those computed by cGAN in two of the five cases enrolled (p < 0.05). [Conclusion] VNB, using 3cGAN to generate the depth maps was technically and clinically feasible. While the accuracy of tracking by cGAN was acceptable, the TRE warrants further investigation and improvement.
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http://dx.doi.org/10.1016/j.media.2021.102164DOI Listing
July 2021

Differences in in vitro microglial accumulation of the energy metabolism tracers [F]FDG and [F]BCPP-EF during LPS- and IL4 stimulation.

Sci Rep 2021 Jun 24;11(1):13200. Epub 2021 Jun 24.

Department of Biofunctional Imaging, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan.

The positron emission tomography probes 2-deoxy-2-[F]fluoro-D-glucose ([F]FDG) and 2-tert-butyl-4-chloro-5-{6-[2-(2-[F]fluoroethoxy)-ethoxy]-pyridin-3-ylmethoxy}-2H-pyridazin-3-one ([F]BCPP-EF) are designed to evaluate glycolysis and oxidative phosphorylation, respectively, and are both used to estimate neuronal activity. However, previous studies have shown a discrepancy in these probes' accumulation in the compromised region, possibly due to the presence of activated microglia acting like deleterious or neuroprotective phenotypes. Hence, we evaluated lipopolysaccharide (LPS)- and interleukin 4 (IL4)-stimulated microglial uptake of [C]2DG and [F]BCPP-EF to give a new insight into the hypothesis that different uptake of [F]FDG and [F]BCPP-EF can be ascribed to the different metabolic pathways activated during microglial activation. LPS or IL4 stimulation increased the proinflammatory or anti-inflammatory marker gene expression in microglial cells. In LPS-stimulated cells, [C]2DG uptake and glycolysis related gene expression were elevated, and [F]BCPP-EF uptake was reduced. In IL4-stimulated cells, [F]BCPP-EF uptake was increased, and [C]2DG uptake was decreased. The expression of genes involved in glycolysis and mitochondrial complex I subunits was not changed by IL4 stimulation. The uptake of [C]2DG and [F]BCPP-EF differs in LPS- and IL4-stimulated polarized microglial cells. The present results suggest that the in vivo accumulation of metabolic tracers [F]FDG and [F]BCPP-EF can be influenced by the different aspects of neuroinflammation.
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http://dx.doi.org/10.1038/s41598-021-92436-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8225620PMC
June 2021

Radiocaesium in the environment of Fukushima.

Authors:
H Tsukada

Ann ICRP 2021 Jun 14:1466453211006808. Epub 2021 Jun 14.

Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima-shi, Fukushima 960-1296, Japan; e-mail:

It has been 10 years since the accident at Fukushima Daiichi nuclear power plant in 2011. Large quantities of I, Cs, and Cs were released into the environment, and 80% of Cs still remains. In addition to the decrease by attenuation, the transfer of Cs to plants, animals, and humans is decreasing due to movement and changing fractions with elapsed time. The activity concentration of Cs in the atmosphere has decreased drastically, and the internal radiation dose due to inhalation is negligible. The activity concentration of Cs in agricultural plants is decreasing due to decontamination of soil, application of potassium, and lower levels in irrigation water. The activity concentration of Cs in wild animals is decreasing, and shows seasonal variation in wild boars. The activity concentration of Cs in offshore seawater has decreased to 0.01 Bq l. Therefore, the radiation dose is <1 mSv of the additional radiation dose.
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http://dx.doi.org/10.1177/01466453211006808DOI Listing
June 2021

Head-to-head comparison of (R)-[C]verapamil and [F]MC225 in non-human primates, tracers for measuring P-glycoprotein function.

Eur J Nucl Med Mol Imaging 2021 Jun 11. Epub 2021 Jun 11.

Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, the Netherlands.

Purpose: P-glycoprotein (P-gp) function is altered in several brain disorders; thus, it is of interest to monitor the P-gp function in vivo using PET. (R)-[C]verapamil is considered the gold standard tracer to measure the P-gp function; however, it presents some drawbacks that limit its use. New P-gp tracers have been developed with improved properties, such as [F]MC225. This study compares the characteristics of (R)-[C]verapamil and [F]MC225 in the same subjects.

Methods: Three non-human primates underwent 4 PET scans: 2 with (R)-[C]verapamil and 2 with [F]MC225, at baseline and after P-gp inhibition. The 30-min PET data were analyzed using 1-Tissue Compartment Model (1-TCM) and metabolite-corrected plasma as input function. Tracer kinetic parameters at baseline and after inhibition were compared. Regional differences and simplified methods to quantify the P-gp function were also assessed.

Results: At baseline, [F]MC225 V values were higher, and k values were lower than those of (R)-[C]verapamil, whereas K values were not significantly different. After inhibition, V values of the 2 tracers were similar; however, (R)-[C]verapamil K and k values were higher than those of [F]MC225. Significant regional differences between tracers were found at baseline, which disappeared after inhibition. The positive slope of the SUV-TAC was positively correlated to the K and V of both tracers.

Conclusion: [F]MC225 and (R)-[C]verapamil show comparable sensitivity to measure the P-gp function in non-human primates. Moreover, this study highlights the 30-min V as the best parameter to measure decreases in the P-gp function with both tracers. [F]MC225 may become the first radiofluorinated tracer able to measure decreases and increases in the P-gp function due to its higher baseline V.
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http://dx.doi.org/10.1007/s00259-021-05411-2DOI Listing
June 2021

Technical validation of multi-section robotic bronchoscope with first person view control for transbronchial biopsies of peripheral lung.

IEEE Trans Biomed Eng 2021 May 4;PP. Epub 2021 May 4.

This study aims to validate the advantage of the new engineering method to maneuver multi-section robotic bronchoscope with first person view control in transbronchial biopsy. Six physician operators were recruited and tasked to operate a manual and a robotic bronchoscope to the peripheral area placed in patient-derived lung phantoms. The metrics collected were the furthest generation count of the airway the bronchoscope reached, force incurred to the phantoms, and NASA-Task Load Index. The furthest generation count of the airway the physicians reached using the manual and the robotic bronchoscopes were 6.6 +/- 1.2th and 6.7 +/- 0.8th. Robotic bronchoscopes successfully reached the 5th generation count into the peripheral area of the airway, while the manual bronchoscope typically failed earlier in the 3rd generation. More force was incurred to the airway when the manual bronchoscope was used (0.24 +/- 0.20 [N]) than the robotic bronchoscope was applied (0.18 +/- 0.22 [N], p<0.05). The manual bronchoscope imposed more physical demand than the robotic bronchoscope by NASA-TLX score (55 +/- 24 vs 19 +/- 16, p<0.05). These results indicate that a robotic bronchoscope facilitates the advancement of the bronchoscope to the peripheral area with less physical demand to physician operators. The metrics collected in this study would expect to be used as a benchmark for the future development of robotic bronchoscopes.
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http://dx.doi.org/10.1109/TBME.2021.3077356DOI Listing
May 2021
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