Performance evaluation of a 71Ga(n,γ)72Ga reaction-based epithermal neutron flux detector at an AB-BNCT device.

The 71Ga(n,γ)72Ga reaction-based epithermal neutron flux detectors are novel instruments developed to measure the epithermal neutron flux of boron neutron capture therapy (BNCT) treatment beams. In this study, a spherical epithermal neutron flux detector using 71Ga(n,γ)72Ga reaction was prototyped. The performance of the detector was experimentally evaluated at an accelerator-based BNCT (AB-BNCT) device developed by Lanzhou University, China. Based on the experimental results and related analysis, we demonstrated that the detector is a reliable tool for the quality assurance of BNCT treatment beams.

A physically constrained Monte Carlo-Neural Network coupling algorithm for BNCT dose calculation.

BACKGROUND: In boron neutron capture therapy (BNCT)-a form of binary radiotherapy-the primary challenge in treatment planning systems for dose calculations arises from the time-consuming nature of the Monte Carlo (MC) method. Recent progress, including the use of neural networks (NN), has been made to accelerate BNCT dose calculations. However, this approach may result in significant dose errors in both the tumor and the skin, with the latter being a critical organ in BNCT. Furthermore, owing to the lack of physical processes in purely NN-based approaches, their reliability for clinical dose calculations in BNCT is questionable. PURPOSE: In this study, a physically constrained MC-NN (PCMC-NN) coupling algorithm is proposed to achieve fast and accurate computation of the BNCT three-dimensional (3D) therapeutic dose distribution. This approach synergizes the high precision of the MC method with the speed of the NN and utilizes physical conservation laws to constrain the coupling process. It addresses the time-consuming issue of the traditional MC method while reducing dose errors. METHODS: Clinical data were collected from 113 glioblastoma patients. For each patient, the 3D dose distributions for both the coarse and detailed dose grids were calculated using the MC code PHITS. Among these patients, the data from 14 patients were allocated to the test set, 9 to the validation set, and the remaining to the training set. A neural network, 3D-Unet, was built based on the coarse grid dose and patient CT information to enable fast and accurate computation of the 3D detailed grid dose distribution of BNCT. RESULTS: Statistical evaluations, including relative deviation, dose deviation, mean absolute error (MAE), and mean absolute percentage error (MAPE) were conducted. Our findings suggested that the PCMC-NN algorithm substantially outperformed the traditional NN and interpolation methods. Furthermore, the proposed algorithm significantly reduced errors, particularly in the skin and GTV, and improved computational accuracy (hereinafter referred to simply as 'accuracy') with a MAPE range of 1.6%-4.0% and a maximum MAE of 0.3 Gy (IsoE) for different organs. The dose-volume histograms generated by the PCMC-NN aligned well with those obtained from the MC method, further validating its accuracy. CONCLUSIONS: The PCMC-NN algorithm enhanced the speed and accuracy of BNCT dose calculations by combining the MC method with the NN algorithm. This indicates the significant potential of the proposed algorithm for clinical applications in optimizing treatment planning.

Squamous cell carcinoma of ascending colon with pMMR/MSS showed a partial response to PD-1 blockade combined with chemotherapy: A case report.

Primary colon squamous cell carcinoma (SCC) is extremely rare and associated with a poor prognosis. Moreover, there is no treatment guideline for this disease. Proficient mismatch repair/microsatellite-stable (pMMR/MSS) colorectal adenocarcinoma is refractory to immune monotherapy. Although the combination of immunotherapy with chemotherapy in pMMR/MSS colorectal cancer (CRC) is currently under investigation, the clinical activity of this approach in colorectal SCC remains unknown. In this article, we report the case of a pMMR/MSS CRC patient with ascending colon SCC who had high programmed cell death-ligand 1 (PD-L1) expression and the a missense mutation in codon 600 of the B-Raf proto-oncogene (BRAF V600E) mutation. The patient exhibited a significant response to the combination of immunotherapy and chemotherapy. After eight cycles of treatment with the combination of sintilimab and mFOLFOX6 (oxaliplatin, fluorouracil, and leucovorin), computed tomography-guided microwave ablation of the liver metastasis was performed. The patient achieved excellent durable response and continues to experience a good quality of life. The present case indicates that programmed cell death 1 blockade combined with chemotherapy may be an effective therapy for patients with pMMR/MSS colon SCC and high PD-L1 expression. Furthermore, PD-L1 expression may be a biomarker for immunotherapy in patients with colorectal SCC.

Controllable in situ growth of novel octahedral TiO2 nanoparticles on nickel/titanium alloy fiber substrate for selective solid-phase microextraction of ultraviolet filters in water samples.

The nature and fabrication of fiber coatings with good adsorption capacity and selectivity play a decisive role in solid-phase microextraction (SPME). In this work, a novel SPME fiber was fabricated through hydrothermal in situ growth of octahedral TiO2 nanoparticles (TiO2NPs) on a superelastic nickel/titanium alloy (NiTi) wire substrate in acid solution. The resulting fiber coatings were characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. Acid types, acid concentration as well as hydrothermal temperature and time were found to be effective route to manipulate the morphologies and composition of TiO2-based nanoflakes grown on the NiTi fiber substrates. At the concentration of 0.4 mol L-1 HCl as well as hydrothermal temperature of 150 °C and hydrothermal time of 12 h, TiO2NPs were in situ grown on the NiTi wire substrates. The obtained NiTi wire with the TiO2NPs coating (NiTi@TiO2NPs fiber) was employed to investigate the adsorption of some representative aromatic analytes in water samples coupling with high-performance liquid chromatography with UV detection (HPLC/UV). The results clearly demonstrate that the fiber exhibits good extraction selectivity for ultraviolet filters (UVFs). In view of good extraction selectivity for the selected UVFs, the key experimental parameters were optimized. Under the optimum conditions, the calibration curves were linear in the ranges of 0.05-100 µg L-1 with the correlation coefficients greater than 0.998. Limits of detection (LODs) were 0.007 to 0.064 µg L-1. Furthermore, the intra-day and inter-day repeatability of the proposed method with the single fiber varied from 4.3% to 6.1% and from 4.5% to 6.8%, respectively. The fiber-to-fiber reproducibility ranged from 5.8% to 8.2%. The developed SPME-HPLC/UV method was applied to selective preconcentration and sensitive determination of target UVFs from real water samples. Moreover, the fabricated fiber showed precisely controllable growth and 150 extraction and desorption cycles.

Selective and efficient solid-phase microextraction of polycyclic aromatic hydrocarbons in water by robust two-dimensional zinc oxide nanosheets grown on a superelastic nickel-titanium alloy fiber prior to determination by HPLC-UV.

Oriented zinc oxide nanosheets (ZnONSs) were directly grown on pretreated nickel-titanium alloy (NiTi) fiber substrates without a traditional seeding layer of ZnO by electrochemical deposition for the first time. The fiber coatings were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. Direct growth of ZnONSs on the NiTi fiber substrate was dependent on the type of zinc salt. The adsorption performance of the ZnONSs coatings was evaluated using representative aromatic compounds as model analytes together with high performance liquid chromatography with ultraviolet detection. The as-prepared fiber shows higher extraction capability for the selected polycyclic aromatic hydrocarbons (PAHs) than for ultraviolet filters in water samples, and better extraction selectivity for PAHs. For this purpose, the important experimental parameters were optimized for the extraction of PAHs. Under the optimized conditions, the calibration curves are linear in the range of 0.03-200 µg L-1 with correlation coefficients greater than 0.999. Limits of detection ranged from 0.011 µg L-1 to 0.082 µg L-1. Intra-day and inter-day relative standard deviations (RSDs) of the developed method with a single fiber ranged from 2.69% to 4.18% and from 4.44% to 5.40%, respectively. RSDs for the fiber-to-fiber reproducibility varied between 5.57% and 7.66%. The developed method was successfully applied for selective preconcentration and determination of trace PAHs in five real water samples. Relative recoveries varied from 84.5% to 104% with RSDs between 1.65% and 8.30%. Furthermore, the as-prepared fiber is highly stable.

Modulating the selectivity of solid-phase microextraction fibers based on morphological, compositional, and size-depended control of bimetallic oxide nanostructures grown on nickel-titanium alloy substrates.

Nickel-titanium oxide nanotubes (NiTiONTs), nanoparticles, and nanopores were in situ grown on NiTi fiber substrates by controlling anodization parameters. The adsorption performance of different bimetallic oxide nanostructures was evaluated using typical aromatic compounds including chlorophenols, phthalic acid esters, ultraviolet filters (UVFs), and polycyclic aromatic hydrocarbons (PAHs) coupled to HPLC-UV. The results clearly indicate that these NiTiO nanostructures show good extraction capability for UVFs and PAHs. The extraction performance of UVFs and PAHs greatly depends on the surface morphologies and sizes of the grown NiTiO nanostructures along with their elemental compositions. Compared with NiTiO nanoparticle and nanopore coatings, the longer well-aligned NiTiONT coating exhibits better extraction capability and selectivity for PAHs than for UVFs. Therefore, the extraction parameters of the NiTi@NiTiONT fiber for PAHs were investigated and optimized. Under optimized conditions, the proposed method was linear in the range 0.05-200 µg L-1 with correlation coefficients above 0.999. Limits of detection were between 0.008 and 0.124 µg L-1. Relative standard deviations (RSDs) of the intra-day and the inter-day analyses with the single fiber varied from 4.09 to 6.33%. RSDs for fiber-to-fiber reproducibility of the proposed method with five fibers prepared in different batches were between 5.75 and 7.43%. The applicability of the proposed method was investigated by the enrichment and determination of target PAHs in environmental water samples and relative recoveries of 84.5 ± 6.5 - 116 ± 7.8% were achieved. Notably, the prepared fiber was stable up to 250 times. Graphical abstract.

Template-directed fabrication of zeolitic imidazolate framework-67-derived coating materials on nickel/titanium alloy fiber substrate for selective solid-phase microextraction.

Novel solid-phase microextraction fibers were fabricated by electrochemical deposition of cobalt on the pretreated nickel/titanium alloy (NiTi) fiber substrate and subsequent in situ growth of zeolitic imidazolate framework-67 (ZIF-67) followed by annealing treatment. The Co@ZIF-67 coating was used as a precursor and template for controlled fabrication of the Co@ZIF-67-derived coatings including Co@ZIF-67-Co3O4 and carbonaceous composite coatings. . The extraction performance of the Co@ZIF-67-derived coatings was evaluated using typical aromatic compounds coupled to high-performance liquid chromatography with UV detection. The results clearly demonstrate that the extraction selectivity is subject to the surface elemental composition of the ZIF-67-derived coatings. In view of long-term stability and good extraction selectivity, the Co@ZIF-67-C coating was selected for the enrichment and determination of polycyclic aromatic hydrocarbons (PAHs). Under the optimized conditions, the calibration curves were linear in the range of 0.05-100 µg•L-1 with the correlation coefficients above 0.998. Limits of detection were 0.005-0.042 µg•L-1. Furthermore, the intra-day and inter-day repeatability of the proposed method with the single fiber varied from 2.3% to 5.8% and from 3.3% to 6.9%, respectively. The fiber-to-fiber reproducibility ranged from 4.1% to 8.5%. The proposed method was suitable for selective enrichment and determination of target PAHs from real water samples. Moreover, the fabricated fiber showed precisely controllable growth and 150 extraction and desorption cycles.