An autopsy case of a young man with a single overdose of dextromethorphan.

Dextromethorphan (DXM) is an over-the-counter antitussive that is commonly used worldwide. Recently, DXM has become popular among young individuals because of its euphoric, hallucinogenic, and dissociative properties. Despite an increasing number of patients with DXM addiction, fatal cases of DXM poisoning are rare, and patients with fatalities often ingest DXM along with other drugs. Here, we report an autopsy case in which DXM was detected without multidrug ingestion. A man in his early twenties was found dead at home; no external injuries or obvious internal lesions were found during the autopsy. The toxicological analyses revealed extremely high concentrations of DXM, and no drugs other than DXM were detected. To the best of our knowledge, this is the first case report to describe a death caused by a single overdose of DXM in Japan. Public awareness regarding the risks associated with a massive ingestion of DXM should be increased.

Respiratory motion tracking of spine stereotactic radiotherapy in prone position.

PURPOSE: The CyberKnife system is a specialized device for non-coplanar irradiation; however, it possesses the geometric restriction that the beam cannot be irradiated from under the treatment couch. Prone positioning is expected to reduce the dose to normal lung tissue in spinal stereotactic body radiotherapy (SBRT) owing to the efficiency of beam arrangement; however, respiratory motion occurs. Therefore, the Xsight spine prone tracking (XSPT) system is used to reduce the effects of respiratory motion. The purpose of this study was to evaluate the motion-tracking error of the spine in the prone position. MATERIALS AND METHODS: Data from all 25 patients who underwent spinal SBRT at our institution between April 2020 and February 2022 using CyberKnife (VSI, version 11.1.0) with the XSPT tracking system were retrospectively analyzed using log files. The tumor motion, correlation, and prediction errors for each patient were examined. Furthermore, to assess the potential relationships between the parameters, the relationships between the tumor-motion amplitudes and correlation or prediction errors were investigated using linear regression. RESULTS: The tumor-motion amplitudes in each direction were as follows: superior-inferior (SI), 0.51 ± 0.39 mm; left-right (LR), 0.37 ± 0.29 mm; and anterior-posterior (AP), 3.43 ± 1.63 mm. The overall mean correlation and prediction errors were 0.66 ± 0.48 mm and 0.06 ± 0.07 mm, respectively. The prediction errors were strongly correlated with the tumor-motion amplitudes, whereas the correlation errors were not. CONCLUSIONS: This study demonstrated that the correlation error of spinal SBRT in the prone position is sufficiently small to be independent of the tumor-motion amplitude. Furthermore, the prediction error is small, contributing only slightly to the tracking error. These findings will improve the understanding of how to compensate for respiratory-motion uncertainty in the prone position.

Fiducial marker position affects target volume in stereotactic lung irradiation.

PURPOSE: Real-time tracking systems of moving respiratory targets such as CyberKnife, Radixact, or Vero4DRT are an advanced robotic radiotherapy device used to deliver stereotactic body radiotherapy (SBRT). The internal target volume (ITV) of lung tumors is assessed through a fiducial marker fusion using four-dimensional computed tomography (CT). It is important to minimize the ITV to protect normal lung tissue from exposure to radiation and the associated side effects post SBRT. However, the ITV may alter if there is a change in the position of the fiducial marker with respect to the tumor. This study investigated the relationship between fiducial marker position and the ITV in order to prevent radiation exposure of normal lung tissue, and correct target coverage. MATERIALS AND METHODS: This study retrospectively reviewed 230 lung cancer patients who received a fiducial marker for SBRT between April 2015 and September 2021. The distance of the fiducial marker to the gross tumor volume (GTV) in the expiratory (dex ) and inspiratory (din ) CT, and the ratio of the ITV/V(GTVex ), were investigated. RESULTS: Upon comparing each lobe, although there was no significant difference in the ddiff and the ITV/V(GTVex ) between all lobes for dex  < 10 mm, there was significant difference in the ddiff and the ITV/V(GTVex ) between the lower and upper lobes for dex ≥ 10 mm (p < 0.05). Moreover, there was significant difference in the ddiff and the ITV/V(GTVex ) between dex ≥10 mm and dex  < 10 mm in all lung regions (p < 0.05). CONCLUSION: The ITV that had no margin from GTVs increased when dex was ≥10 mm for all lung regions (p < 0.05). Furthermore, the increase in ITV tended to be greater in the lower lung lobe. These findings can help decrease the possibility of adverse events post SBRT, and correct target coverage.

Highly Crystalline Ni-Co Layered Double Hydroxide Fabricated via Topochemical Transformation with a High Adsorption Capacity for Nitrate Ions.

Layered double hydroxide (LDH) has emerged as promising candidates for removing harmful oxoanions (i.e., SO42-, HPO42-, and NO3- ions) from wastewater because of their intrinsic ability to accommodate anionic species in the interlayer space. Highly crystalline [Ni0.67Co0.33(OH)2]Cl0.29·0.53H2O (Ni-Co LDH) particles with an exceptionally high anion-exchange capacity of 58.8 mg g-1 and a distribution coefficient (Kd) of 2396 mL g-1 for NO3- ions were successfully prepared by the flux method and a topochemical strategy. Layered Na0.97Ni0.67Co0.33O2 (NNCO) was prepared using a high-temperature flux and used as a starting material for topotactic transformation consisting of oxidative hydrolysis with KOH and NaClO and subsequent reduction with H2O2 and NaCl. During the transformation from NNCO to Ni-Co LDH, a drastic change in the valences of the Ni and Co belonging to the host layer and in the cationic and anionic species occurs in interlayer space; the valences of the Ni and Co in NNCO were increased from Ni2+,3+ and Co2+,3+ to Ni3+ and Co2+,3+,4+ by an oxidative hydrolysis reaction with simultaneous intercalation of K+ ions and deintercalation of Na+ ions, and subsequently decreased from Ni3+ and Co2+,3+,4+ to Ni2+ and Co2+,3+ by a reduction reaction with simultaneous intercalation of anionic species such as CO32- and Cl- ions and deintercalation of Na+ and K+ ions. Through synchrotron powder X-ray diffraction analysis and Rietveld refinement, the resultant Ni-Co LDH was clearly shown to exhibit high crystallinity with less compositional deviation even after topochemical transformation in comparison with the one prepared by traditional coprecipitation and solid-state methods. Furthermore, the adsorption isotherm for NO3- ions elucidated that homogeneous adsorption sites are consistently constructed in the crystal structure, which could be found from the fitting to a Langmuir curve, with the R2 value being 0.98. This work opens up a new route for the fabrication of excellent not only ion-exchangeable but also ion-conductive inorganic materials for direct utilization in environmental and energy-storage processes.

Retrospective assessment of a single fiducial marker tracking regimen with robotic stereotactic body radiation therapy for liver tumours.

AIM: To investigate tumour motion tracking uncertainties in the CyberKnife Synchrony system with single fiducial marker in liver tumours. BACKGROUND: In the fiducial-based CyberKnife real-time tumour motion tracking system, multiple fiducial markers are generally used to enable translation and rotation corrections during tracking. However, sometimes a single fiducial marker is employed when rotation corrections are not estimated during treatment. MATERIALS AND METHODS: Data were analysed for 32 patients with liver tumours where one fiducial marker was implanted. Four-dimensional computed tomography (CT) scans were performed to determine the internal target volume (ITV). Before the first treatment fraction, the CT scans were repeated and the marker migration was determined. Log files generated by the Synchrony system were obtained after each treatment and the correlation model errors were calculated. Intra-fractional spine rotations were examined on the spine alignment images before and after each treatment. RESULTS: The mean (standard deviation) ITV margin was 4.1 (2.3) mm, which correlated weakly with the distance between the fiducial marker and the tumour. The mean migration distance of the marker was 1.5 (0.7) mm. The overall mean correlation model error was 1.03 (0.37) mm in the radial direction. The overall mean spine rotations were 0.27° (0.31), 0.25° (0.22), and 0.23° (0.26) for roll, pitch, and yaw, respectively. The treatment time was moderately associated with the correlation model errors and weakly related to spine rotation in the roll and yaw planes. CONCLUSIONS: More caution and an additional safety margins are required when tracking a single fiducial marker.

Left- and right-circularly polarized light-sensing based on colored and mechano-responsive chiral nematic liquid crystals.

A liquid crystal host-guest system composed of achiral organic molecules (host) and colored chiral metal complexes (guest) was fabricated to sense both right- and left-handed circularly polarized light (r- and l-CPL), depending on the guest (dopant) concentration. The CPL-sensing can be reversibly turned on and off upon mechanical stress and heating.

"Colored" inorganic dopants for inducing liquid crystal chiral nematic and blue phases: monitoring of dopant-host interaction by Raman spectroscopy.

A new ruthenium complex that effectively induces chiral nematic and blue phases upon doping with a nematic liquid crystal was developed. The red-colored dopant exhibits strong Raman scattering in solution and nematics even at low concentrations. Further measurements at various concentrations strongly suggested homogeneous dispersion of the dopant in chiral nematics.