Performance of a plastic scintillation fiber dosimeter based on different photoelectric devices

The photoelectric device of a scintillation dosimeter converts photons produced by radiation into an electrical signal.Its features directly determine the overall performance of the dosimeter.For a plastic scintillation fiber dosimeter(PSFD)with a current readout mode,systematic studies of the stability and light-dose response were performed for the photomultiplier tube(PMT),silicon photomultiplier(SiPM),avalanche photodiode(APD),and photodiode(PD).The temperature stability,long-term stability,repeatability,signal-to-noise ratio(SNR),and current dose response of the PSFD with the abovementioned photoelectric devices were studied using a pulsed LED light source and the Small Animal Radiation Therapy platform.An exponential relationship between the dark/ne current and temperature was obtained for all the devices.I is shown that the APD is the most sensitive device to temperature,with a current dependence on temperature reaching 6.5%C^(-1)at room temperature,whereas for the other devices this dependence is always<0:6%C^(-1).In terms of long-term stability,the net current of PD can change by up to 4%when working continuously for 8 h and 2%when working intermittently for 32 h,whereas for the other devices,the changes are all<1%.For the dose response,the PMT and SiPM exhibit excellent linear responses and SNRs within the range of 0.1-60 Gy/min For the PSFD with a current readout mode,the performance of the PMT and SiPM is concluded to be better than that of the other devices in the study.In particular,the SiPM,which has a compact size,low bias voltage,and antimagnetic interference,has great advantages for further applications.

Evaluation of CdZnTe spectrometer performance in measuring energy spectra during interventional radiology procedure

Interventional radiology has been beneficial for patients for over 30 years of age with the combination of diagnostic and therapeutic methods. The radiation affecting occupationally exposed workers should be evaluated by means of the energy spectra and flux of X-rays in the treatment room. The present study aims to obtain the energy spectra of interventional procedures and study the capability of some detectors to evaluate the dose in interventional procedures. These measurements were taken by silicon-drift, CdTe, and CdZnTe detectors. The energy spectra were corrected by the energy-response curve of each detector. The energy-response curves of silicon-drift and CdTe detectors provided by the manufacturers specification were used. The energy response of the CdZnTe detector was measured by 133Ba and 152Eu γ sources. The experimental data were compared with the simulation results, and their perfect agreement provides a way to correct the energy or dose response, which can be used for the personal dosimeter developed by our group. Moreover, the measured energy spectra can be used in individual radiation protection. The present study shows that the CdZnTe detector is a good candidate detector in interventional procedures.

Production of high-energy neutron beam from deuteron breakup

The deuteron breakup on heavy targets has been investigated in the framework of an improved quantum molecular dynamics model,focusing on the production of neutrons near zero degrees.The experimental differential cross sections of neutron production in the 102 MeV d+C reactions were reproduced by simulations.Based on the consistency between the model prediction and experiment,the feasibility of producing a neutron beam through the breakup of deuteron on a carbon target was demonstrated.Because of the nucleon Fermi motion inside the deuteron,the energy spectrum of the inclusive neutron near 0°in the laboratory exhibits considerable energy broadening in the main peak,whereas the long tail on the low-energy side is suppressed.By coincidentally measuring the accompanying deuteron breakup proton,the energy of the neutron can be tagged with an intrinsic uncertainty of approximately 5%(1σ).The tagging efficiency of the accompanying proton on the forward-emitted neutron can reach 90%,which ensures that the differential cross section in the(d,np)channel remains two orders higher than that in(p,n)after considering the measurement of accompanying protons.This enables the application of a well-defined energy neutron beam in an event-by-event scheme.

Comparison of neutron energy spectrum unfolding methods and evaluation of rationality criteria

The neutron energy spectrum was measured using a Bonner sphere spectrometer at six locations inside the containment vessel of a nuclear reactor at the Qinshan nuclear power plant. The structures of the neutron spectra obtained by the maximum entropy, iteration, and genetic algorithm methods were consistent with one another and could be interpreted as the spectral superposition of different energy regions. The characteristic parameters of the neutron spectrum, including the fluence rate,average energy, and neutron ambient dose equivalent rate H^(*)(10), were in good agreement among the three methods. In addition, an LB6411 neutron ambient dose equivalent meter was employed to obtain the H^(*)(10) directly for comparison.These findings indicate that neutron spectrum unfolding methods can be used to overcome the problems associated with the response functions of dosimeters to provide more accurate H^(*)(10) values. In this study, the following three evaluation criteria were systematically addressed to ensure the accuracy of the unfolded spectra: count rates of the inverse solutions,neutron spectrum structures, and comparison of key parameters.

Synthesis of novel nanomaterials and their application in efficient removal of radionuclides

With the development of nuclear energy, large amounts of radionuclides are inevitably released into the natural environment. It is necessary to eliminate radionuclides from wastewater for the protection of environment. Nanomaterials have been considered as the potential candidates for the effective and selective removal of radionuclides from aqueous solutions under complicated conditions because of their high specific surface area, large amounts of binding sites, abundant functional groups, pore-size controllable and easily surface modification. This review mainly summarized the recent studies for the synthesis, fabrication and surface modification of novel nanomaterials and their applications in the efficient elimination and solidification of radionuclides,and discussed the interaction mechanisms from batch experiments, spectroscopy analysis and theoretical calculations. The sorption capacities with other materials, advantages and disadvantages of different nanomaterials are compared, and at last the perspective of the novel nanomaterials is summarized.

Single-cell RNA sequencing reveals the cell landscape of a radiation-induced liver injury mouse model

The mechanisms of radiation-induced liver injury(RILI)has not been fully elucidated so far.In the present study,a RILI mouse model was constructed by exposing the liver to a single dose of 30 Gy X-rays.Liver injuries consisting of liver function damage and histopathological variations were confirmed after 2 weeks.And then the cellular atlas of RILI liver was generated by profiling 9,641 cells isolated from X-ray irradiated mice livers and control ones from RILI mice model using single-cellRNAsequencing(scRNA-seq).Seven cell types were identified,including B cells,natural killer cells,T cells,macrophages/Küpffer cells/Dendritic cells(DC),neutrophils,endothelial cells,and hepatocyte.Although there was no significant difference of overall cell typing was observed between the Control and RILI groups,hepatocytes and macro/Küpffer/DC cell types were chosen for further functional exploration.Gene expression profiles and bioinformatics analysis of hepatocytes revealed that multiple metabolic related pathways were enriched in livers exposed to IR.These scRNA-seq data were confirmed in RILI liver samples via adipose staining.Besides,obviously varied M1-/M2-macrophages polarization was observed in RILI liver,which was in accordance with the enzyme linked immunosorbent assay(ELISA)results of IR-induced M2 to pro-inflammatory M1 macrophages transformation in mouse macrophage cell line Raw264.7.In addition,we predicted that several genes were found to differentially expressed during the process of macrophage polarization from M2 to M1 subtype.Overall,our study provides a cellular landscape of RILI at single-cell resolution that indicates the characteristics of hepatocytes and macrophages,which will contribute to investigate the novel therapeutic or preventive management for RILI.

Visualized uranium rapid monitoring system based on self-enhanced electrochemiluminescence-imaging of amidoxime functionalized polymer nanoparticles

The development of uranyl ion detection technology has exhibited its significance in public security and environmental fields for the radioactivity and chemical toxicity of uranyl ion.The WHO standard of uranyl ion makes it necessary to develop highly sensitive uranyl rapid warning system in drinking water monitoring.Herein,a visualized rapid warning system for trace uranyl ion is carried out based on electrochemiluminescence(ECL) imaging technology to give an ultra-low limit of detection(LOD) and high selectivity.Amidoxime,a bi-functional group with both uranyl ion capturing and co-reactive functions,is modified on a conjugated polymer backbone with strong ECL signal to be prepared into three-in-one polymer nanoparticles(PNPs) with self-enhanced ECL property.The captured uranyl ion can enhance the ECL signal of PNPs via resonance energy transfer process to give the LOD as 0.5 ng/L,which is much lower than the known luminescent uranyl sensors.Furthermore,ECL imaging technology is introduced into realizing visualized uranyl rapid warning,and can be successfully applied on natural water samples.This study provides a novel strategy for uranyl rapid warning,and shows its potential meaning in public security and environmental fields.

Physical dosimetric reconstruction of a case of large area back skin injury due to overexposure in an interventional procedure

To estimate the physical dose of skin and key organs in a case of overexposure during a cardiac interventional procedure.Methods The female patient aged 50 suffered from owerexposure during ardiac interventional therapy in a hospital,Xinxiang city,Henan province,China in January 2020.The mesh-type phantom for the patient was constructed based on the adult mesh-type reference computational phantoms(MRCPs)released by the International Comission on Radiological Protection Publication 145 (ICRP145)and phantom deformation technology.Models of exposure scenario were constructed and simulated with particle and heavy ion transport code system(PHTTS)according to exposure conditions.Resuts:The maximum absorbed dose of key organs/tissues under iradiation in posteroanterior(PA)and 30°left anterior oblique directions(LOA)was 632.4 and 305.6 mGy,respectively.The let lung,heart,and left mammary gland received a larger dose under both iradiation conditions.The ratio of the absorbed dose with and without shielding was a lculated,and the relative difference in most organs was<1%between two directions.The iso-dose curve of the back skin revealed the ditribution of the absorbed dose(0.1-5.2 Gy).The dose estimate of key tssues/organs was higher than the conventional level,especially the local skin,up to 5.2 Gy.Concusions The interventional procedure in this ase resulted in a higher dose.Monte Carlo codes combined with the MRCPs can be employed to estimate physical dose to individuals in concrete irradia tion scenarios.

Respiratory flora:The potential biomarker of radiation-induced pulmonary injury

Radiation-induced pulmonary injury is a major dose-limiting toxicity that occurs due to thoracic radiotherapy.And the most widely used high-throughput technology,16S ribosomal RNA sequencing,is adopted for bacterial classification and identification of airway microbiome analysis.In this study,we provide novel insights into the composition pattern and predicted function of the lung microbiome in RIPI rats.Certain genus and species change in a dose-dependent manner,which might be capable of serving as novel bacterial biomarkers,as well as the potential targets for the future diagnosis or treatment of RIPI.In summary,our findings provide a vital reference for RIPI study,and will contribute to investigate the novel therapeutic or preventive management for RIPI.

Fluorescent Nile blue-functionalized poly(N-isopropylacrylamide)microgels responsive to temperature and polyamines

Fluorescent poly(N-isopropylacrylamide-co-Nile blue)(pNIPAm-co-NB)microgels were synthesized that exhibited fluorescence intensity changes in a water temperature-dependent fashion.NB is well known to exhibit fluorescence intensity that depends on the hydrophobicity of the environment,while pNIPAm-based microgels are well known to transition from swollen(hydrophilic)to collapsed(relatively hydrophobic)at temperatures greater than 32℃;hence,we attribute the above behavior to the hydrophobicity changes of the microgels with increasing temperature.This phenomenon is ultimately due to NB dimers(relatively quenched fluorescence)being broken in the hydrophobic environment of the microgels leading to relatively enhanced fluorescence.We went on to show that the introduction of cucurbit[7]uril(CB[7])into the pNIPAm-co-NB microgels enhanced their fluorescence allowing them to be used for polyamine(e.g.,spermine[SPM])detection.Specifically,CB[7]forms a host–guest interaction with NB in the microgels,which prevents NB dimerization and enhances their fluorescence.When SPM is present,it forms a host–guest complex that is favored over the CB[7]-NB host–guest interaction,which frees the NB for dimerization and leads to fluorescence quenching.As a result,we could generate an SPM sensor capable of SPM detection down to~0.5µmol/L in complicated matrixes such as serum and urine.

A Pretargeting Strategy Enabled by Bioorthogonal Reactions Towards Advanced Nuclear Medicines: Application and Perspective

Pretargeting is an innovative and promising approach in nuclear medicine for targeted-imaging/therapy through the following bioorthogonal reactions.It requires two reactive participants,one of which is a targeting vector and the other is a small radiolabeled probe capable of specifically coupling through bioorthogonal reactions with the targeting vector accumulated in the disease site.Compared to the conventional direct targeting approach,such a two-step scheme conceptually can achieve a higher imaging contrast and an improved therapeutic effect owing to the suppressed non-specific targeting.In this review,we will first give a brief introduction on pretargeting systems and the history of bioorthogonal reactions,and then focus on some important works about radionuclide delivering through the bioorthogonal reaction based pretargeting strategy.Finally,we will discuss the steps forward in respect to the future clinical translation and truly hope that this methodology would continue to make contributions to nuclear medicines.

Inorganic imaging nanoprobes for breast cancer diagnosis

Breast cancer is one of the most prevalent cancers worldwide,and early diagnosis and screening are vital to its successful treatment.Although medical imaging methods can assist in the early detection of breast cancer,imaging methods that are currently used for clinical diagnosis have drawbacks,such as low sensitivity and accuracy.Contrast agents are often used in diagnostic imaging to address these drawbacks.Nanocontrast agents have attracted considerable attention in recent years due to their unique physicochemical characteristics.Among these agents,inorganic nanoprobes have been substantially developed through improvements in synthesis techniques and pairings with other organic molecules.This paper mainly summarizes the specific applications of inorganic nanoprobes in the magnetic resonance imaging,fluorescence imaging,radionuclide imaging,and bimodal/multimodal imaging of breast cancer.

Mechanisms underlying FLASH radiotherapy, a novel way to enlarge the differential responses to ionizing radiation between normal and tumor tissues

Different from conventional radiotherapy(CONV-RT),FLASH radiotherapy(FLASH-RT)delivers a single high dose at a mean dose rate40 Gy/s in milliseconds to achieve similar tumor control to CONV-RT while sparing normal tissues from detrimental injury.It provides an intriguing perspective in improving clinical outcomes for tumor patients as well as a novel way to enhance the differential responses between normal and tumor tissues.However,its mechanisms remain largely unclear.In this paper,we review the currently available publications on FLASH-RT and parse the probable mechanisms of three major aspects including the production of reactive oxygen species,DNA damage response,and immunoreaction.Experiments specifically designed to disclose the intrinsic difference between normal and malignant cells in response to FLASH-RT and CONV-RT are necessary to prove these hypotheses.

Nuclear DNA damages generated by reactive oxygen molecules (ROS) under oxidative stress and their relevance to human cancers, including ionizing radiation-induced neoplasia part II: Relation between ROS-induced DNA damages and human cancer

Oxidative stress(OS)occurs when the production of reactive oxygen species(ROS)overrides the body’s natural defence.When the cell nucleus represents the target,macromolecular damage may result in mutations.Cancer is a disease of mutations,and DNA damages that are not repaired or mis-repaired during cell proliferation are necessary but not sufficient for cancer development.A role of ROS for cancer initiation depends on the likelihood of interaction between reactive electrophilic molecules and nuclear DNA.As described in part one of this presentation,the physico-chemical properties of the ROS involved in OS and of the ensuing DNA lesions are of major importance.Current knowledge dictates that emphasis should be shifted from oxidative DNA damages of low genotoxicity towards pro-mutagenic lesions induced by reaction products of nitrogen monoxide and complex highly reactive carbonyls,e.g.from the peroxidation of lipids.Based on the determination of pro-mutagenic DNA adducts in human tissues there is compelling evidence for a causal relation between OS and cancers of the liver,colon/rectum,cervix,pancreas and stomach.However,modulation by the simultaneous presence of an ubiquitous high background of potent pro-carcinogenic DNA adducts,which are not generated by ROS should be taken into account.Ionizing radiation is established human carcinogenic agent,and generate some of the same oxidative ROS as those involved in OS.However,the cancer spectrum from whole body radiation exposure differs in some important respects from that associated with OS.The scientific support for a causal link between exposure to non-ionizing electromagnetic radiation and human cancer is judged to be insufficient.As exemplified by diabetes,a common shortcoming when assessing the role of OS in disease is the failure to distinguish between cause and effect-i.e.could the indicators of harmful oxidative stress be the result of the pathological condition in question,rather than its cause.

Nuclear DNA damages generated by reactive oxygen molecules (ROS) under oxidative stress and their relevance to human cancers, including ionizing radiation-induced neoplasia part I: Physical, chemical and molecular biology aspects

Oxidative stress(OS)occurs when the production of reactive oxygen species(ROS)overpowers the body’s natural defence,causing macromolecular damage.The role of OS in cancer initiation will depend on the likelihood of interaction between short lived ROS and nuclear DNA.For this reason,a description of the physico-chemical properties of the various ROS that have been suggested to be involved is included.DNA damages that are not repaired or mis-repaired during cell proliferation are necessary but not sufficient for cancer initiation.The characteristics of DNA pro-mutagenic lesions and their potential role in cancer induction will be assessed,while stressing quantitative aspects as well as the importance of DNA repair.A low level of a specific DNA adduct can be compensated for by its persistence and high pro-mutagenic potency.Because ionizing radiations generate some of the same oxidative ROS as those involved in OS,the cancer spectrum from whole body radiation exposure should be compared with that associated with OS.A causal link between electromagnetic radiations and human cancer lacks adequate scientific support.Current knowledge dictates that emphasis should be shifted from oxidative damages of low genotoxicity towards pro-mutagenic lesions induced by reaction products of nitrogen monoxide and complex highly reactive carbonyls,e.g.from the peroxidation of lipids.A common shortcoming when assessing the role of OS in disease is the failure to distinguish between cause and effect-i.e.could the indicators of harmful OS be the result of the pathological condition in question,rather than its cause?Further,little attention has been paid to exposure in food to some of the same ROS(e.g.reactive carbonyl compounds),as are generated endogenously by OS.Nor have the simultaneous presence of an ubiquitous high background of potent pro-carcinogenic DNA adducts which are not generated by ROS been taken into account.

Chromate separation by selective crystallization

A new paradigm to remove toxic chromate anions from aqueous solution by crystallization of chromatewater clusters with imine-linked guanidinium cationic ligands is introduced.The guanidium-based cationic ligand was easily prepared through the imine condensation of an alde hyde and aminoguanidine hydrochloride.The cationic imine-linked guanidinium liga nd(BBIG-CI)showed a high re moval capacity(292.5 mg/g)in the solutions.Rapid decontamination of chromate anions from the wastewater by this cationic ligand was resulted from an instantaneous crystallization.The produced guanidium chromate salts have an extremely low solubility(Ksp,BBIG=8.19×10^9).Such superior removal performance of these mate rials was attributed to the cha rge-assisted hydrogen bonding between the cationic ligand and chromate-water hydrate anions,which was revealed by the single-crystal X-ray diffraction analysis and density functional theory(DFT)calculations.In addition,the succes s ful recove ry of the guanidium-based ligand makes it more attractive for real-world applications.

Angular distribution measurement for ^12C fragmentation via ^12C ＋ ^12C scattering at 100 MeV/u

The angular distributions and energy spectra of^(11)B,^(10)B,and^9Be fragments of^(12)C in the angular range from 1.0°~to 7.5°~at 100 Me V/u were obtained via^(12)C+^(12)C scattering.Detailed comparisons are presented between the experimental data and the modified antisymmetrized molecular dynamics(AMD-FM),binary intranuclear cascade model(BIC)and Liege intranuclear cascade model(INCL++).The experimental angular distributions and energy spectra are well reproduced by the AMD-FM calculations but fail to be reproduced by the physical models installed in the Geant4 program,including the BIC and INCL++models.

Photoacoustic and magnetic resonance imaging-based gene and photothermal therapy using mesoporous nanoagents

The integration of photothermal therapy(PTT)with gene therapy(GT)in a single nanoscale platform demonstrates great potential in cancer therapy.Porous iron oxide nanoagents(PIONs)are widely used as magnetic nanoagents in the drug delivery field and also serve as a photothermal nanoagent for photothermal therapy.However,the therapeutic efficacy of PIONs-mediated GT has not been studied.The long noncoding RNA(lncRNA)CRYBG3(LNC CRYBG3),a lncRNA induced by heavy ion irradiation in lung cancer cells,has been reported to directly bind to globular actin(G-actin)and cause degradation of cytoskeleton and blocking of cytokinesis,thus indicating its potential for use in GT by simulating the effect of heavy ion irradiation and functioning as an antitumor drug.In the present study,we investigated the possibility of combining PIONs-mediated PTT and LNC CRYBG3-mediated GT to destroy non-small cell lung cancer(NSCLC)cells both in vitro and in vivo.The combination therapy showed a high cancer cell killing efficacy,and the cure rate was better than that achieved using PTT or GT alone.Moreover,as a type of magnetic nanoagent,PIONs can be used for magnetic resonance imaging(MRI)and photoacoustic imaging(PAI)both in vitro and in vivo.These findings indicate that the new combination therapy has high potential for cancer treatment.

High stearic acid diet modulates gut microbiota and aggravates acute graft-versus-host disease

Dear Editor,Acute graft-versus-host disease(aGVHD)is the leading cause of transplantation-related mortality,and limits therapeutic benefits of allogeneic bone marrow transplantation(allo-BMT).New insight is needed into the development of aGVHD.Most nutritional metabolites contribute to host health and immune homeostasis.