Synchrotron radiation(SR)represents a unique and innovative anti-cancer treatment due to its unique physical features,including high flux density,and tunable and collimated radiation generation.The aim of this work is to assess the dosimetric properties of SR in Shanghai Synchrotron Radiation Facility(SSRF)for potential applications to clinical radiation oncology.The experiments were performed with 34 and 50 keV X-rays on the BL13W biomedical beamline of SSRF and the 6 MV X-rays from ARTISTE linac for the dosimetry study.The percentage depth dose(PDD)and the surface dose of the SR X-rays and the 6 MV photon beams were performed in solid water phantom with Gafchromic EBT3 films.All curves are normalized to the maximum calculated dose.The depth of full dose buildup is about 10μm deeper for the monoenergetic X-ray beams of 34 and 50 keV.The beam transmits through the phantom,with a linear attenuation coefficient.The profile in the horizontal plane shows that the dose distribution is uniform within the facula,while the vertical profile shows a Gaussian distribution of the dose.The penumbra is less than 0.2 mm in the horizontal profile.Gafchromic EBT film may be a useful and convenient tool for dose measurement and quality control for the high space and density resolution.It is therefore important to gain a thorough understanding about the physical features of SR before this novel technology can be applied to clinical practice.
Alzheimers disease(AD)is a chronic neurodegenerative disease.The symptoms include memoryand spatial learning dificulties,language disorders,and loss of motivation,which get worse overtime,eventually ending in death.No ffective treatments are available for AD,currently.Currenttreatments only attenuate symptoms temporarily and are associated with severe side ffects.Nearinfra-red(NIR)light has been studied for a long time.We investigated the effect of NIR on ADusing a transgenic mouse model,which was obtained by co-injecting two vectors carrying ADmutations in amyloid precursor protein(APP)and presenilin-i(PSEN1)into C57BL/6J mice.The irradiation equipment consisted of an accommodating box and an LED array.The wave-length of NIR light emitted from LED was between 1040 nm and 1090 nm.The power densitydelivered at the level of the mice was approximately 15 mW/cm^(2),Firstly,we treated the micewith NIR for 40 days,Then,the irradiation was suspended for 28 days.Finally,another 15 daystreatment was brought to mice.We conducted Morris water maze and immunofluorescenceanalysis to evaluate the effects of treatment.Immunofuorescence analysis was based on mea-suring the quantity of plaques in mouse brain slices,Our results show that NIR light improvesmemory and spatial learning ability and reduces plaques moderately.NIR light represents apotential treatment for AD.
Photodynamic therapy(PDT)has been commonly used in treating many diseases,such as cancer and infectious diseases.We investigated the different effects of PDT on three main pathogenic bacteria of periodontitis-Prevotella melaninogenica(P.m.),Porphyromonas gingitvalis(P.g.)and Aggregatibacter actinomycetercomitans(A.a-).The portable red light-ermitting diode(LED)phototherapy device was used to assess the exogenous PDT effects with different light doses and photosensitizer concentrations(Toluidine blue O,TBO).The portable blue LED phototherapy device was used to assess the endogenous PDT effects with the use of endogenous photosensit izers(porphyrin)under dfferent light doses.We found out that both exogenous and endogenous PDT were able to restrict the growth of all the three bacteria significantly.Moreover,the optimal PDT conditions for these bacteria were obtained through this in vitro screening and could guide the clinical PDT on periodontitis.
Although conventional radiotherapy remains to be one of the most useful treatments for cancer, it is not the best strategy to maximize the effects on the tumors and minimize the damage to the surrounding tissues due to its physical and biological characteristics. Synchrotron radiation (SR) with uniquely physical and biological advantages may represent an innovative approach for cancer treatment. In recent years, SR-based photon activation therapy, stereotactic synchrotron radiation therapy and micro-beam radiation treatment have been developed, and the results of in vitro and in vivo experiments are very promising. It is necessary to understand the physical and radiobiological principle of those novel strategies before the approach is applied to the clinic. In this paper, we summarize the advances of SR in terms of physical, radiobiological advantages and its potential clinical applications. With the successful operation of shanghai synchrotron radiation, good opportunities in China have been provided for investigations on the treatment of cancer with synchrotron radiation.
Photodynamic therapy(PDT)takes advantage of photosensitizers(PSs)to generate reactive oxygen species(ROS)for cell killing when excited by light.It has been widely used in clinic for therapy of multiple cancers.Currently,all the FDA-approved PSs,including porphyrin,are all small organic molecules,suffering from aggregation-caused quenching(ACQ)issues in biological environment and lacking tumor targeting capability.Nanoparticles(NPs)with size between 20 nm and 200 nm possess tumor targeting capability due to the enhanced permeability and retention(EPR)effect.It is urgent to develop a new strategy to form clinical-approved-PSs-based NPs with improved ROS generation capability.In this study,we report a strategy to overwhelm the ACQ of porphyrin by doping it with a type of aggregation-induced emission(AIE)luminogen to produce a binary NPs with high biocompatibility,and enhanced fluorescence and ROS generation capability.Such NPs can be readily synthesized by mixing a porphyrin derivative,Ce6 with a typical AIE luminogen,TPE-Br.Here,our experimental results have demonstrated the feasibility and effectiveness of this strategy,endowing it a great potential in clinical applications.
在光声成像中,超声信号通常需要采用接触传感器探测,这使其在很多应用中受到很大的限制,如脑功能成像。为了替代接触探测器实现非接触的光声层析成像(NCPAT),激光干涉技术被用于远程获取超声信号。本文搭建了非接触光声层析成像系统,系统采用波长为532 nm、能量17.5 m J/cm^2的激光作为光声激发源,激光外差干涉仪作为光声信号的远程探测系统,对实际生物组织模型进行了旋转几何的光声信号探测。利用激光外差干涉仪探测到的光声信号,进行反投影算法的图像重建。实验结果表明在具有组织散射特性的模型中,激光外差干涉仪在2.25 MHz带宽(峰值下15 d B强度的信号宽带)下,NCPAT成像系统可以识别500μm直径的黑色微球,并实现了在强散射介质中多层结构的光学对比成像。这将扩展光声和超声在体成像在生物医学领域的应用范围。
