Metal-enhanced fluorescence of graphene oxide by palladium nanoparticles in the blue-green part of the spectrum

Graphene oxide（GO） has a wide fluorescence bandwidth,which makes it a prospective candidate for numerous applications.For many of these applications,the fluorescence yield of GO should be further increased.The sp2-hybridized carbons in GO confine the π-electrons.Radiative recombination of electron-hole pairs in such sp2 clusters is the source of fluorescence in this material.Palladium nanoparticles are good catalysts for sp2 bond formations.We report on the preparation of GO,palladium nanoparticles and their nanocomposites in two different solvents.It is shown that palladium nanoparticles can considerably enhance the intrinsic fluorescence of GO in the blue-green part of the visible light spectrum.Fluorescence enhancement has been attributed to the catalytic role of palladium nanoparticles in increasing the number of sp2 bonds of GO with the molecules of the surrounding media.It is shown that palladium nanoparticles could be the nanoparticle of choice for fluorescence enhancement of GO because of their catalytic role in sp2 bond formation.

An ultra-sensitive dual-mode imaging system using metal-enhanced fluorescence in solid phantoms

In this study, we developed a highly sensitive dual-mode imaging system using gold nanoparticles （GNPs） conjugated to various fluorophores in solid phantoms. The system consists of fluorescence-lifetime imaging microscopy （FLIM） for surface imaging, diffusion reflection （DR） for deep-tissue imaging （up to 1 cm）, and metal-enhanced fluorescence （MEF）. We detected quenching in the fluorescent intensity （FI） for the conjugation of both gold nanospheres （GNS） and gold nanorods （GNRs） to Fluorescein, which has an excitation peak at a wavelength shorter than the surface plasmon resonance （SPR） of both types of GNPs. Enhanced FI was detected in conjugation to Rhodamine B （RhB） and Sulforhodamine B （SRB）, both with excitation peaks in the SPR regions of the GNPs. The enhanced FI was detected both in solution and in solid phantoms by the FLIM measurements. DR measurements detected the presence of GNRs within the solid phantoms by recording the dropped rates of light scattering in wavelengths corresponding to the absorption spectra of the GNRs. With the inclusion of MEF, this promising dual-mode imaging technique enables efficient and sensitive molecular and functional imaging.

Durable metal-enhanced fluorescence flexible platform by in-situ growth of micropatterned Ag nanospheres

Here, we demonstrate an in-situ growth of micropatterned silver nanospheres(Ag NS) array on transparent polyimide(PI), namely PI-Ag substrate, applied as a flexible platform for metal-enhanced fluorescence(MEF). The scheme proposed here can easily control the grid formation of Ag NSs and the particle size inside, thus achieving patterned fluorescence imaging and MEF efficiency optimization. Meanwhile, the magnitude of enhanced intensity, relying on the distance between Ag NSs and emissive molecules, was systematically investigated by exploring diverse polyethyleneimine(PEI) spacer thickness. Consequently,an optimal enhancement factor of 7.9 and a pattern of grid fluorescence imaging was obtained with an insertion of 10 nm PEI on the PI-Ag(25 nm) platform. Moreover, owing to robust adhesion between Ag NSs and PI film by in-situ growth, this flexible PI-Ag MEF platform maintained a stable MEF efficiency even after taking mechanical bending for 1000 cycles. This new surface-confined micropatterned Ag NSs PI film provides a promising candidate in design flexible MEF platforms for future analytical and clinical sensing applications.

pH-Dependent Metal-Enhanced Fluorescence from CdTe@PAA Nanospheres near the Au Nanoparticles in Aqueous Solution

Metal-enhanced fluorescence of semiconductor nanocrystals （NCs） is the current investigation focus. In this work, we directly observed metal-enhanced fluorescence of CdTe@PAA nanaospheres in aqueous solution. The enhanced magnitude of photoluminescence （PL） was closely related to solution pH values, and the maximal PL enhancement is about 9 times compared with the ones without Au NPs. Furthermore, based on the results of absorptions and fluorescence lifetimes of CdTe@PAA-Au mixed solution at different pH values, we studied the mechanisms and physics processes of pH-dependent enhanced PL induced by Au NPs. The pH-dependent PL of CdTe@PAA-Au mixed solutions are due to the constantly changing distances between Au NPs and CdTe@PAA nanaospheres with pH. In the CdTe@PAA-Au mixed solutions, CdTe@PAA nanospheres in close proximity to the Au NPs are exposed to the increased electric fields in between and around the NPs, effectively resulting in significant increases in their absorption cross section. This lends itself to a subsequent increase in the excitation and eventually in the fluorescence emission from the CdTe@PAA nanospheres.

Clinical application of indocyanine green fluorescence imaging in laparoscopic cholecystectomy with common bile duct exploration and J-Tube drainage

BACKGROUND Intraoperative and postoperative biliary injuries remain significant complications of laparoscopic common bile duct exploration(LCBDE).Indocyanine green(ICG)has been shown to significantly reduce injuries caused by intraoperative operational errors.We found that the J-tube can reduce postoperative strictures and injuries to the common bile duct.At this moment,we aim to analyze and compare the complications,efficacy,short-term outcomes,and feasibility of these two adjunctive tools for LCBDE.AIM To evaluate the efficacy of ICG fluorescence imaging In LCBDE and J-tube drainage for patients with common bile duct stones.METHODS We retrospectively collected the clinical case data of patients who were treated at the Hepatobiliary Surgery Department of the Third People’s Hospital of Nantong,affiliated with Nantong University,from January 2016 to January 2021 due to gallbladder stones with choledocholithiasis and who underwent LCBDE combined with a primary suture and either J-tube or T-tube drainage.The patients were divided into groups:Traditional white-light laparoscopy+T-tube group(WL+T-tube),traditional WL+J-tube group,fluorescent laparoscopy+T-tube group(ICG+T-tube)and fluorescent laparoscopy+J-tube group(ICG+J-tube).The preoperative and postoperative clinical case data,laboratory examination data,and intraoperative and postoperative complications(including postoperative bile leakage,electrolyte disturbances,biliary peritonitis,and postoperative infections)and other relevant indicators were compared.RESULTS A total of 198 patients(112 males and 86 females)were included in the study,with 74 patients in the WL+T-tube,47 in the WL+J-tube,42 in the ICG+T-tube,and 35 in the ICG+J-tube.Compared with the other groups,the ICG+J had significantly shorter operation time(114 minutes,P=0.001),less blood loss(42 mL,P=0.02),shorter postoperative hospital stays(7 days,P=0.038),and lower surgical costs(China yuan 30178,P=0.001).Furthermore,patients were subdivided into two groups based on whether a T-tube or J-tube was placed during the surgery.By the third postoperative day,the aspartate transaminase,glutamic pyruvic transaminase,total bilirubin,and direct bilirubin levels were lower in the J-tube group than in the T-tube group(P<0.001).At last,follow-up observations showed that the incidence of biliary strictures at three months postoperatively was significantly lower in the J-tube group than in the T-tube group(P=0.002).CONCLUSION ICG fluorescence imaging in laparoscopic cholecystectomy with common bile duct exploration and J-tube drainage facilitates rapid identification of biliary anatomy and variations,reducing intraoperative bile duct injury,blood loss,surgery duration,and postoperative bile duct stenosis rates,supporting its clinical adoption.

Metal-enhanced fluorescence of lanthanide chelates near silver nanostructured films

Metal-enhanced fluorescence(MEF)from lanthanide chelates in close proximity to silver films was studied.Different thicknesses of silver films(20 and 50 nm)were deposited onto quartz substrates using magnetron sputtering,while silver island films were prepared using a previously published procedure.Obviously enhanced emissions from the lanthanide chelates were observed on the silver films.The effect of using different concentrations of aqueous solutions polyvinyl alcohol(PVA)on MEF was also investigated.Fluorescence close to a 20-nm-thick silver film showed that the enhancement of emission is a function of the thickness of the PVA film,reaching a maximum(～2.5-fold increase in intensity)at 83 nm.In conclusion,the MEF induced by the silver films is caused by an electric field effect arising from surface plasmon resonance.

NIR-II fluorescence imaging in liver tumor surgery: A narrative review

In liver tumor surgery,the recognition of tumor margin and radical resection of microcancer focis have always been the crucial points to reduce postoperative recurrence of tumor.However,naked-eye inspection and palpation have limited effectiveness in identifying tumor boundaries,and traditional imaging techniques cannot consistently locate tumors in real time.As an intraoperative real-time navigation imaging method,NIRfluorescence imaging has been extensively studied for its simplicity,reliable safety,and superior sensitivity,and is expected to improve the accuracy of liver tumor surgery.In recent years,the research focus of NIRfluorescence has gradually shifted from the-rst near-infrared window(NIR-I,700–900 nm)to the second near-infrared window(NIR-II,1000–1700 nm).Fluorescence imaging in NIR-II reduces the scattering effect of deep tissue,providing a preferable detection depth and spatial resolution while signi-cantly eliminating liver autofluorescence background to clarify tumor margin.Developingfluorophores combined with tumor antibodies will further improve the precision offluorescence-guided surgical navigation.With the development of a bunch offluorophores with phototherapy ability,NIR-II can integrate tumor detection and treatment to explore a new therapeutic strategy for liver cancer.Here,we review the recent progress of NIR-IIfluorescence technology in liver tumor surgery and discuss its challenges and potential development direction.

A novel fluorescence sensor for milk clotting enzyme chymosin using peptide as substrate and covalent organic framework nanosheet as fluorescence quencher

Chymosin is one of the critical enzymes in cheese making.Herein,we proposed a novel fluorometric assay for chymosin determination.Firstly,covalent organic frameworks(COF)were synthesized and exfoliated to 2-dimensional COF nanosheets(COF NS)by ultrasound treatment.Gold nanoparticles(Au NPs)were loaded with COF NS to prepare AuNPs/COF NS(Au@COF NS).Secondly,rhodamine B(RhB)modified substrate peptide(Pep)for chymosin was linked with Au@COF NS to construct a Pep-Au@COF NS nanocomposite.For the sensing principle,fluorescence of RhB was quenched by Au@COF NS and the fluorescence intensity was weak due to the fluorescence resonance energy transfer between COF NS and RhB of Pep.However,in the presence of chymosin,the RhB was released by specific cleavage of the substrate peptide by chymosin and resulted in the recovery of fluorescence.The increased fluorescence intensity was proportional to the increase of chymosin concentration and thus a“turn on”fluorescent sensor for chymosin was constructed.The sensor showed a linear range in the concentration of 0.05-60.00μg/mL for the detection of chymosin with a detection limit of 20 ng/mL.The sensor was used to quantify chymosin in rennet product with good selectivity,which has the potential applications in cheese manufacturing.

Efficacy of multi-color near-infrared fluorescence with indocyanine green:A new imaging strategy and its early experience in laparoscopic cholecystectomy

BACKGROUND Near-infrared fluorescence imaging via using intravenous indocyanine green(ICG)has a wide range of applications in multiple surgical scenarios.In lapa-roscopic cholecystectomy(LC),it facilitates intraoperative identification of the biliary system and reduces the risk of bile duct injury.However,the usual single color fluorescence imaging(SCFI)has limitations in manifesting the fluorescence signal of the target structure when its intensity is relatively low.Moreover,sur-geons often experience visual fatigue.We hypothesized that a novel imaging stra-tegy,named multi-color fluorescence imaging(MCFI),could potentially address these issues by decreasing hepatic and background fluorescence pollution and improving biliary visualization.AIM To investigate the novel imaging strategy MCFI in LC.METHODS This was a single-center retrospective study conducted at Peking Union Medical College Hospital,Beijing,China.Patients who underwent LC from June 2022 to March 2023 by the same surgical team were enrolled.Demographic features,clinical and surgical information were collected.The clarity,visual comfort,and effectiveness of different imaging strategies were subjectively evaluated by surgeons.RESULTS A total of 155 patients were included,60 patients were in the non-ICG group in which only bright light illuminance without ICG was applied,60 patients were in the SCFI group,and 35 patients were in the MCFI group.No statist-ically significant differences were found in demographics or clinical history.Post-surgical complications were minimal in all 3 groups with no significant differences observed.MCFI improved the clarity of imaging and visual comfort.Clarity of imaging and visual comfort were improved with MCFI.CONCLUSION MCFI improves biliary visualization and reduces liver fluorescence contamination,which supports its routine use in LC.MCFI may also be a better choice than SCFI in other clinical settings.

Self-confocal NIR-II fluorescence microscopy for multifunctional in vivo imaging

Fluorescence imaging in the second near-infrared window(NIR-II,900–1880 nm)with less scattering background in biological tissues has been combined with the confocal microscopic system for achieving deep in vivo imaging with high spatial resolution.However,the traditional NIR-IIfluorescence confocal microscope with separate excitation focus and detection pinhole makes it possess low confocal e±ciency,as well as di±cultly to adjust.Two types of upgraded NIR-IIfluorescence confocal microscopes,sharing the same pinhole by excitation and emission focus,leading to higher confocal e±ciency,are built in this work.One type is-ber-pinhole-based confocal microscope applicable to CW laser excitation.It is constructed forfluorescence intensity imaging with large depth,high stabilization and low cost,which could replace multiphotonfluorescence microscopy in some applications(e.g.,cerebrovascular and hepatocellular imaging).The other type is air-pinhole-based confocal microscope applicable to femtosecond(fs)laser excitation.It can be employed not only for NIR-IIfluorescence intensity imaging,but also for multi-channelfluorescence lifetime imaging to recognize different structures with similarfluorescence spectrum.Moreover,it can be facilely combined with multiphotonfluorescence microscopy.A single fs pulsed laser is utilized to achieve up-conversion(visible multiphotonfluorescence)and down-conversion(NIR-II one-photonfluorescence)excitation simultaneously,extending imaging spectral channels,and thus facilitates multi-structure and multi-functional observation.

Research on a deconvolution algorithm for laser-induced fluorescence diagnosis based on the maximum entropy principle

Laser-induced fluorescence(LIF)spectroscopy is employed for plasma diagnosis,necessitating the utilization of deconvolution algorithms to isolate the Doppler effect from the raw spectral signal.However,direct deconvolution becomes invalid in the presence of noise as it leads to infinite amplification of high-frequency noise components.To address this issue,we propose a deconvolution algorithm based on the maximum entropy principle.We validate the effectiveness of the proposed algorithm by utilizing simulated LIF spectra at various noise levels(signal-to-noise ratio,SNR=20–80 d B)and measured LIF spectra with Xe as the working fluid.In the typical measured spectrum(SNR=26.23 d B)experiment,compared with the Gaussian filter and the Richardson–Lucy(R-L)algorithm,the proposed algorithm demonstrates an increase in SNR of 1.39 d B and 4.66 d B,respectively,along with a reduction in the root-meansquare error(RMSE)of 35%and 64%,respectively.Additionally,there is a decrease in the spectral angle(SA)of 0.05 and 0.11,respectively.In the high-quality spectrum(SNR=43.96 d B)experiment,the results show that the running time of the proposed algorithm is reduced by about98%compared with the R-L iterative algorithm.Moreover,the maximum entropy algorithm avoids parameter optimization settings and is more suitable for automatic implementation.In conclusion,the proposed algorithm can accurately resolve Doppler spectrum details while effectively suppressing noise,thus highlighting its advantage in LIF spectral deconvolution applications.

Near-Infrared Fluorescence Imaging Contrast Agents for Clinical Research: Limitations and Alternatives

Introduction: Near-infrared fluorescence imaging is a technique that will establish itself in the short term at the international level because it is recognized for its potential to improve the performance of surgical interventions, its moderate investment and operating costs and its portability. Although the technology is now mature, there is currently the problem of the availability of contrast agents to be injected IV. The aim of this methodology article is to propose an alternative solution to the need for contrast agents for clinical research, particularly in oncology. Methodology: They consist of coupling a fluorescent marker in the form of an NHS derivative, such as IR DYE manufactured in compliance with GMP, with therapeutic monoclonal antibodies having marketing authorization for molecular imaging. For a given antibody, the marking procedure must be the subject of a validation file on the final preparation filtered on a sterilizing membrane at 0.22 μm. Once the procedure has been validated, it would be unnecessary to repeat the tests before each clinical research examination. A check of the marking by thin-layer chromatography (TLC) and place it in a sample bank at +4˚C for 1 month of each injected formulation would be sufficient for additional tests if necessary. Conclusion: Molecular near-infrared fluorescence imaging is experiencing development, the process of which could be accelerated by greater availability of clinical contrast agents. Alternative solutions are therefore necessary to promote clinical research in this area. These methods must be shared to make it easier for researchers.

Isomeric fluorescence sensors for wide range detection of ionizing radiations

In order to achieve a wider range of ionizing radiations detection,novel fluorescence sensing materials have been developed that utilize the fluorescence enhancement phenomenon caused by the intramolecular photoinduced electron transfer(PET)effect.Two perylene diimide isomers PDI-P and PDI-B were designed and synthesized,and their molecular structures were characterized by high-resolution Fourier transform mass spectrometry(HRMS),nuclear magnetic resonance hydrogen and carbon spectroscopy(~1H and~(13)C NMR).The interaction between ionizing radiation and fluorescent molecules was simulated by HCl titration.The results show that combining PDIs and HCl can improve fluorescence through the retro-PET process.Despite the similarities in chemical structures,the fluorescent enhancement multiple of PDI-B with aromatic amine as electron donor is much higher than that of PDI-P with alkyl amine.In the direct irradiation experiments of ionizing radiation,the emission enhancement multiples of PDI-P and PDI-B are 2.01 and 45.4,respectively.Furthermore,density functional theory(DFT)and time-dependent density functional theory(TDDFT)calculations indicate that the HOMO and HOMO-1 energy ranges of PDI-P and PDI-B are 0.54 e V and 1.13 e V,respectively.A wider energy range has a stronger driving force on electrons,which is conducive to fluorescence quenching.Both femtosecond transient absorption spectroscopy(fs-TAS)and transient fluorescence spectroscopy(TFS)tests show that PDI-B has shorter charge separation lifetime and higher electron transfer rate constant.Although both isomers can significantly reduce LOD during PET process,PDI-B with aromatic amine has a wider detection range of 0.118—240 Gy due to its larger emission enhancement,which is a leap of three orders of magnitude.It breaks through the detection range of gamma radiation reported in existing studies,and provides theoretical support for the further study of sensitive and effective new materials for ionizing radiation detection.

Application of a neural network model with multimodal fusion for fluorescence spectroscopy

In energy-dispersive X-ray fluorescence spectroscopy,the estimation of the pulse amplitude determines the accuracy of the spectrum measurement.The error generated by the amplitude estimation of the pulse output distorted by the measurement system leads to false peaks in the measured spectrum.To eliminate these false peaks and achieve an accurate estimation of the distorted pulse amplitude,a composite neural network model is proposed,which embeds long and short-term memory(LSTM)into the UNet structure.The UNet network realizes the fusion of pulse sequence features and the LSTM model realizes pulse amplitude estimation.The model is trained using simulated pulse datasets with different amplitudes and distortion times.For the pulse height estimation,the average relative error of the trained model on the test set was approximately 0.64%,which is 27.37% lower than that of the traditional trapezoidal shaping algorithm.Offline processing of a standard iron source further validated the pulse height estimation performance of the UNet-LSTM model.After estimating the amplitude of the distorted pulses using the model,the false peak area was reduced by approximately 91% over the full spectrum and was corrected to the characteristic peak region of interest(ROI).The corrected peak area accounted for approximately 1.32%of the characteristic peak ROI area.The results indicate that the model can accurately estimate the height of distorted pulses and has substantial corrective effects on false peaks.

In vivo fluorescence flow cytometry reveals that the nanoparticle tumor vaccine OVA@HA-PEI effectively clears circulating tumor cells

Tumor vaccine therapy offers significant advantages over conventional treatments,including reduced toxic side effects.However,it currently functions primarily as an adjuvant treatment modality in clinical oncology due to limitations in tumor antigen selection and delivery methods.Tumor vaccines often fail to elicit a sufficiently robust immune response against progressive tumors,thereby limiting their clinical efficacy.In this study,we developed a nanoparticle-based tumor vaccine,OVA@HA-PEI,utilizing ovalbumin(OVA)as the presenting antigen and hyaluronic acid(HA)and polyethyleneimine(PEI)as adjuvants and carriers.This formulation significantly enhanced the proliferation of immune cells and cytokines,such as CD3,CD8,interferon-,and tumor necrosis factor-,in vivo,effectively activating an immune response against B16–F10 tumors.In vivofluorescenceflow cytometry(IVFC)has already become an effective method for monitoring circulating tumor cells(CTCs)due to its direct,noninvasive,and long-term detection capabilities.Our study utilized a laboratory-constructed IVFC system to monitor the immune processes induced by the OVA@HA-PEI tumor vaccine and an anti-programmed death-1(PD-1)antibody.The results demonstrated that the combined treatment of OVA@HA-PEI and anti-PD-1 antibody significantly improved the survival time of mice compared to anti-PD-1 antibody treatment alone.Additionally,this combination therapy substantially reduced the number of CTCs in vivo,increased the clearance rate of CTCs by the immune system,and slowed tumor progression.Thesefindings greatly enhance the clinical application prospects of IVFC and tumor vaccines.

Initial Experience of NIR-II Fluorescence Imaging-Guided Surgery in Foot and Ankle Surgery

Optical imaging in the second near-infrared(NIR-II;900-1880 nm)window is currently a popular research topic in the field of biomedical imaging.This study aimed to explore the application value of NIR-II fluorescence imaging in foot and ankle surgeries.A lab-established NIR-II fluorescence surgical navigation system was developed and used to navigate foot and ankle surgeries which enabled obtaining more high-spatial-frequency information and a higher signal-to-background ratio(SBR)in NIR-II fluorescence images compared to NIR-I fluorescence images;our result demonstrates that NIR-II imaging could provide higher-contrast and larger-depth images to surgeons.Three types of clinical application scenarios(diabetic foot,calcaneal fracture,and lower extremity trauma)were included in this study.Using the NIR-II fluorescence imaging technique,we observed the ischemic region in the diabetic foot before morphological alterations,accurately determined the boundary of the ischemic region in the surgical incision,and fully assessed the blood supply condition of the flap.NIR-II fluorescence imaging can help surgeons precisely judge surgical margins,detect ischemic lesions early,and dynamically trace the perfusion process.We believe that portable and reliable NIR-II fluorescence imaging equipment and additional functional fluorescent probes can play crucial roles in precision surgery.

Pay attention to the application of indocyanine green fluorescence imaging technology in laparoscopic liver cancer resection

Traditional laparoscopic liver cancer resection faces challenges,such as difficultiesin tumor localization and accurate marking of liver segments,as well as theinability to provide real-time intraoperative navigation.This approach falls shortof meeting the demands for precise and anatomical liver resection.The introductionof fluorescence imaging technology,particularly indocyanine green,hasdemonstrated significant advantages in visualizing bile ducts,tumor localization,segment staining,microscopic lesion display,margin examination,and lymphnode visualization.This technology addresses the inherent limitations oftraditional laparoscopy,which lacks direct tactile feedback,and is increasinglybecoming the standard in laparoscopic procedures.Guided by fluorescenceimaging technology,laparoscopic liver cancer resection is poised to become thepredominant technique for liver tumor removal,enhancing the accuracy,safetyand efficiency of the procedure.

A ratiometric fluorescent probe for hypoxanthine detection in aquatic products based on the enzyme mimics and fluorescence of cobalt-doped carbon nitride

A ratiometric fluorescent probe for hypoxanthine(Hx)detection was established based on the mimic enzyme and fluorescence characteristics of cobalt-doped graphite-phase carbon nitride(Co doped g-C_(3)N_(4)).In addition to emitting strong fluorescence,the peroxidase activity of Co doped g-C_(3)N_(4)can catalyze the reaction of O-phenylenediamine and H_(2)O_(2)to produce diallyl phthalate which can emit yellow fluorescence at 570 nm.Through the decomposition of Hx by xanthine oxidase,Hx can be indirectly detected by the generating hydrogen peroxide based on the measurement of fluorescent ratio I(F_(570)/F_(370)).The linear range was 1.7-272.2 mg/kg(R^(2)=0.997),and the detection limit was 1.52 mg/kg(3σ/K,n=9).The established method was applied to Hx detection in bass,grass carp,and shrimp,and the data were verified by HPLC.The result shows that the established probe is sensitive,accurate,and reliable,and can be used for Hx detection in aquatic products.

Simultaneous fluorescence and Compton scattering computed tomography based on linear polarization X-ray

Purpose To propose a method for simultaneous fluorescence and Compton scattering computed tomography by using linearly polarized X-rays.Methods Monte Carlo simulations were adopted to demonstrate the feasibility of the proposed method.In the simulations,the phantom is a polytetrafluoroethylene cylinder inside which are cylindrical columns containing aluminum,water,and gold(Au)-loaded water solutions with Au concentrations ranging between 0.5 and 4.0 wt%,and a parallel-hole collimator imaging geometry was adopted.The light source was modeled based on a Thomson scattering X-ray source.The phantom images for both imaging modalities were reconstructed using a maximumlikelihood expectation maximization algorithm.Results Both the X-ray fluorescence computed tomography(XFCT)and Compton scattering computed tomography(CSCT)images of the phantom were accurately reconstructed.A similar attenuation contrast problem for the different cylindrical columns in the phantom can be resolved in the XFCT and CSCT images.The interplay between XFCT and CSCT was analyzed,and the contrast-to-noise ratio(CNR)of the reconstruction was improved by correcting for the mutual influence between the two imaging modalities.Compared with K-edge subtraction imaging,XFCT exhibits a CNR advantage for the phantom.Conclusion Simultaneous XFCT and CSCT can be realized by using linearly polarized X-rays.The synergy between the two imaging modalities would have an important application in cancer radiation therapy.

Application value of indocyanine green fluorescence imaging in guiding sentinel lymph node biopsy diagnosis of gastric cancer: Meta-analysis

BACKGROUND Gastric cancer is a common malignant tumor of the digestive system worldwide,and its early diagnosis is crucial to improve the survival rate of patients.Indocyanine green fluorescence imaging(ICG-FI),as a new imaging technology,has shown potential application prospects in oncology surgery.The meta-analysis to study the application value of ICG-FI in the diagnosis of gastric cancer sentinel lymph node biopsy is helpful to comprehensively evaluate the clinical effect of this technology and provide more reliable guidance for clinical practice.AIM To assess the diagnostic efficacy of optical imaging in conjunction with indocya-nine green(ICG)-guided sentinel lymph node(SLN)biopsy for gastric cancer.METHODS Electronic databases such as PubMed,Embase,Medline,Web of Science,and the Cochrane Library were searched for prospective diagnostic tests of optical imaging combined with ICG-guided SLN biopsy.Stata 12.0 software was used for analysis by combining the"bivariable mixed effect model"with the"midas"command.The true positive value,false positive value,false negative value,true negative value,and other information from the included literature were extracted.A literature quality assessment map was drawn to describe the overall quality of the included literature.A forest plot was used for heterogeneity analysis,and P<0.01 was considered to indicate statistical significance.A funnel plot was used to assess publication bias,and P<0.1 was considered to indicate statistical significance.The summary receiver operating characteristic(SROC)curve was used to calculate the area under the curve(AUC)to determine the diagnostic accuracy.If there was interstudy heterogeneity(I2>50%),meta-regression analysis and subgroup analysis were performed.analysis were performed.RESULTS Optical imaging involves two methods:Near-infrared(NIR)imaging and fluorescence imaging.A combination of optical imaging and ICG-guided SLN biopsy was useful for diagnosis.The positive likelihood ratio was 30.39(95%CI:0.92-1.00),the sensitivity was 0.95(95%CI:0.82-0.99),and the specificity was 1.00(95%CI:0.92-1.00).The negative likelihood ratio was 0.05(95%CI:0.01-0.20),the diagnostic odds ratio was 225.54(95%CI:88.81-572.77),and the SROC AUC was 1.00(95%CI:The crucial values were sensitivity=0.95(95%CI:0.82-0.99)and specificity=1.00(95%CI:0.92-1.00).The Deeks method revealed that the"diagnostic odds ratio"funnel plot of SLN biopsy for gastric cancer was significantly asymmetrical(P=0.01),suggesting significant publication bias.Further meta-subgroup analysis revealed that,compared with fluorescence imaging,NIR imaging had greater sensitivity(0.98 vs 0.73).Compared with optical imaging immediately after ICG injection,optical imaging after 20 minutes obtained greater sensitivity(0.98 vs 0.70).Compared with that of patients with an average SLN detection number<4,the sensitivity of patients with a SLN detection number≥4 was greater(0.96 vs 0.68).Compared with hematoxylin-eosin(HE)staining,immunohistochemical(+HE)staining showed greater sensitivity(0.99 vs 0.84).Compared with subserous injection of ICG,submucosal injection achieved greater sensitivity(0.98 vs 0.40).Compared with 5 g/L ICG,0.5 and 0.05 g/L ICG had greater sensitivity(0.98 vs 0.83),and cT1 stage had greater sensitivity(0.96 vs 0.72)than cT2 to cT3 clinical stage.Compared with that of patients≤26,the sensitivity of patients>26 was greater(0.96 vs 0.65).Compared with the literature published before 2010,the sensitivity of the literature published after 2010 was greater(0.97 vs 0.81),and the differences were statistically significant(all P<0.05).CONCLUSION For the diagnosis of stomach cancer,optical imaging in conjunction with ICG-guided SLN biopsy is a therapeut-ically viable approach,especially for early gastric cancer.The concentration of ICG used in the SLN biopsy of gastric cancer may be too high.Moreover,NIR imaging is better than fluorescence imaging and may obtain higher sensitivity.