We recently designed and synthesized a Gluc(RGDyK)-bombesin (RGD-BBN) heterodimeric peptide exhibiting a dual integrin alpha(v)beta(3) and gastrin-releasing peptide receptor (GRPR) targeting property. In this study, we investigated whether Tc-99m-labeled RGD-BBN peptide could be used for the non-invasive detection of lung carcinoma by using small-animal single-photon emission computed tomography (SPECT)/CT. RGD-BBN peptide was conjugated with 6-hydrazinonicotinyl (HYNIC) and then radiolabeled with Tc-99m using tricine and TPPTS as the coligands (TPPTS = trisodium triphenylphosphine-3,3',3 ''-trisulfonate). The biodistribution, planar gamma imaging, and small-animal SPECT/CT studies of Tc-99m-HYNIC(tricine)(TPPTS)-RGD-BBN (Tc-99m-RGD-BBN) were performed in C57/BL6 mice bearing Lewis lung carcinoma (LLC) or bearing both inflammation and LLC. HYNIC-RGD-BBN possessed a dual integrin alpha(v)beta(3) and GRPR binding capacity. Tc-99m-RGD-BBN was prepared with a high radiochemical purity (>98%), and it exhibited specific tumor imaging with high contrast to the contralateral background. Tc-99m-RGD-BBN was superior to F-18-FDG for distinguishing lung carcinoma from inflammation. The uptake of Tc-99m-RGD-BBN in LLC xenografts was 2.69 +/- 0.66% ID/g at 1 h postinjection (p.i.) and was decreased to 1.99 +/- 0.61% ID/g at 2 h p.i. The inflammation uptake of Tc-99m-RGD-BBN was 1.20 +/- 0.32% ID/g at 1 h and 0.56 +/- 0.17% ID/g at 2 h p.i., respectively. High pancreas uptake (25.76 +/- 5.49%ID/g and 19.56 +/- 6.78% ID/g at 1 and 2 h p.i., respectively) was also found due to the high GRPR expression of this organ. Small-animal SPECT/CT using Tc-99m-RGD-BBN can specifically detect the LLC pulmonary metastases. Our results suggested that SPECT/CT with Tc-99m-RGD-BBN would provide an effective approach for the noninvasive detection of lung cancer.

本研究在仪器研发、应用开发方面的进展顺利，取得了多项重大技术突破，但是产业化方面的进展较慢，需要在以后的工作中做一些调整。在仪器研发方面，本年度主要进行了四个模态的整机连调、动物实验验证和工程样机的前期调研三方面工作。在四模态集成方面，研究组在2012年年底已成功完成了首台四模态分子影像原理样机，成功地获得了模型仿体与小动物的四模态同机融合影像，为下一代工程样机的开发积累了重要经验。在工程样机的前期调研和验证实验中，通过计算机模拟验证了SiPM、碲锌镉等新型元器件在工程样机中运用的合理性，解决了一些原理样机中暴露出的问题，提高了仪器的技术指标和稳定性，基本确定了各个成像模态的优化和改进方案，为研究中后期仪器的产业化打下坚实的基础。 在应用开发方面，研究组积极开展了多模态分子医学影像技术在癌症术后评估、新型糖尿病治疗药物、新型肿瘤放射性分子探针、脑间质途径给药、siRNA肿瘤治疗药物等方面的应用研究；从细胞生物学、生物化学、肿瘤学等多角度探索了多模态影像仪器的应用方向，建立了适合于四模态分子影像成像的小动物模型，拓宽了影像设备的应用领域；发表了多篇高水平的学术论文，申报并获得了多项专利授权，扩大了四模态仪器在国内外分子影像学术界的影响力。在产业化开发方面，研究组积极联合产业化单位开展相关工作，完成了一套面向于用户的分子影像信息管理系统，集成了软件算法、图像处理、数据分析、信息管理等多种功能。 Advances have been made in aspects of instrumentation development and application research,as well as several major technical breakthroughs have been achieved.However,the progress of industrialization was behind the schedule,thus required adjustments in our future work.In instrumentation development,the focus of this year's work was mainly on three projects,namely the integration of the four modalities,animal experiment validation and preliminary development of the next generation engineering prototype.In the section of the integration,the research group has successfully accomplished the first quad-modality imaging system in late 2012,as well as obtained phantom and small animal quad-modality fusion images,which contributed important experiences for the development of the prototype.In the preliminary research and validation of the next generation engineering prototype,the rationality of applying novel devices such as state-of-art SiPM and CZT have been verified,and basically determined the optimization scheme of the SPECT,PET and FMT.Some problems that revealed in the principle prototype were also solved,which improved the stability and technical indicators,and laid a solid foundation for the industrialization hereafter.In application development,the research group commenced to conduct researches on the applications of multi-modality molecular medical imaging in cancer postoperative evaluations,novel diabetes drugs,novel radioactive tumor probes,drug delivery via brain interstitial route,and siRNA tumor therapeutic drugs,and established the application of the multi-modality imaging equipment in different levels ranging from cell biological,biochemical to oncological.We also established animal models for the quad-modality molecular imaging,thus better exploited the functions of the imaging equipment and broadened the applications.Meanwhile,many patents and high level academic papers have been granted and published respectively,which enhanced the academic impact of the quad-modality instrumentation on international and domestic imaging community.In industrial development,the designated industrialization contractor has developed a user oriented system for information management in molecular imaging,which provides the user services like computation,storage-SCP,QR-SCP,as well as integrated many functions like software algorithm,image processing,data analysis,and information management.

Sonodynamic therapy (SDT) is a prospective therapy for many tumors by activation of sonosensitizers to produce reactive oxygen species (ROS) by ultrasound (US). However, limited generation of ROS and low drug delivery efficiency of sonosensitizers to the tumor tissue still hinder the application of SDT. Herein, an amphiphilic rose bengal (ARB) conjugate was designed to fabricate rose bengal microbubbles (RB-MBs) with high drug-loading contents (similar to 6.8%) and excellent contrast enhancement capability for US imaging, well suited for detecting tumor location and size. More importantly, RB-MBs could be successfully converted into RB-NPs by local US exposure, resulting in similar to 7.5 times higher drug accumulation at the tumor tissue through the sonoporation effect as compared to RB-NPs and RB-MBs without US sonication. Meanwhile, using RB as the MB shell facilitated US energy transfer by the US mediated collapse of MBs through either a sonoluminescence or pyrolysis process; thus, the ROS generation efficiency could be greatly enhanced, resulting in a significantly higher tumor inhibition rate for the RB-MBs + US (similar to 76.5%) in the HT-29 tumor model as compared to conventional MBs + US and RB-NPs + US (similar to 23.8% and similar to 49.2%), respectively. All these results suggested that this novel sonosensitizer delivery system of RB-MBs combined with US is a powerful strategy for remarkably enhancing SDT therapeutic efficacy with minimal side effects, showing great potential in cancer theranostics.

本项目在仪器研发、系统优化、应用开发及产业化方面进展顺利，取得了多项重大技术突破。在仪器研发方面，本年度项目组已经完成了CT/PET/SPECT/FMT四模态小动物四模态分子影像学工程样机的安装、调试工作。针对原理样机测试中暴露出的问题，对工程样机中各个模态进行了全面的优化设计，通过前期模拟，结果显示各项性能指标相比原理样机得到了很大的提升，为下一步仪器的精确化、智能化运行打下了基础；完善了多模态分子影像特征提取技术、影像特征约减技术，深入研究了不同模态之间分子影像特征的关联性，为多模态影像融合提供了保障。在应用开发方面，项目组进一步证实18F-CAP的特异性和有效性，进行了18F-CP-18、18F-FDG早期检测荷肺腺癌小鼠化疗后细胞凋亡的对照研究；利用小檗碱处理后的棕色脂肪，着重研究了小檗碱作用的靶器官，深入分析了其中的分子机制，进一步了解新型糖尿病治疗药物的作用机理；制备了放射性标记的RGD PET分子显像探针68Ga-3PRGD2,并对68Ga-3PRGD2在原位脑胶质瘤模型的PET和切伦科夫双模态成像进行了研究。项目组已在新型肿瘤放射性分子探针、脑间质途径给药、siRNA肿瘤治疗药物等领域发表多篇高水平的学术论文，获得了多项专利授权，进一步扩大了四模态仪器在国内外分子影像学术界的影响力。在产业化开发方面，项目组联合产业化单位在原有分子影像信息系统上开发了多模态分子影像数据挖掘模块，采用创新型的WEB平台，实现了数据的分布式采集以及挖掘后关联规则的异地共享。该模块目前可支持采用粗糙集和模糊—粗糙集算法，通过原始分子影像数据的离散化和模糊化处理，实现分子影像的数据挖掘，更好的推广了分子医学影像的应用产业化平台。 Advances have been made in aspects of instrumentation development,system optimization,application research and industrialization,and several major technical breakthroughs have been achieved.On instrumental development,the installation and debugging of the CT/PET/SPECT/FMT quadmodality small animal molecular imaging engineering prototype have been completed by the research group in this year.According to the problems revealed by the principal prototype,the design of all the modalities of the engineering prototype have been optimized,and through preliminary simulation,as suggested by the results,the performance is greatly enhanced comparing to the principle prototype,which laid a foundation for the further precise and intelligent performance of the equipment;multimodality imaging feature extraction and imaging feature reduction technologies have been improved and the correlation of the imaging features of different modalities has been studied,thus proved a support for the integration of the multimodality images.Regarding to the application development,the research group further verified the specificity and effectiveness of 18F-CAP,and conducted controlled studies with 18-F-CP-18,18-F-FDG on the early detection of the cell apoptosis of lung-tumor-bearing mice after chemotherapy;with the berberine treated brown fat,the target organs of berberine is studied and the mechanism behind this is thoroughly analyzed,and the mechanism of the new diabetes drug is thus understood;radioactive-labeled RDG PET tracers 68Ga-3PRGD2 is prepared and the dual modality PET and Cherenkov imaging with 68Ga-3PRGD2 of in situ brain glioma models.The research group has published many high level research papers in research areas of new radioactive molecular probes for cancer,brain interstitial drug delivery,siRNA cancer drugs,and obtained several patents,and enhanced the influence of the quadmodality equipment on the domestic and oversea molecular imaging academia.As for industrialization development,the research group together with the industrialization partner developed a multimodality molecular imaging data mining module based on the original molecular imaging information system,which employed the innovative WEB platform,and achieved the distributive acquisition of data and the remove sharing of the post-mining correlation rules.Currently,this module supports using rough sets and fuzzy rough set algorithms,and through the discrete and blurring treatment of the original molecular imaging data,the molecular imaging data mining can be achieved,thus better promotes the application and industrialization platform of molecular medical imaging.

本项目在仪器研发、系统优化、应用开发及产业化方面进展顺利，取得了多项重大技术突破。在仪器研发方面，本年度主要进行了四模态工程样机设备的优化设计、整体机架运动控制系统的加工调试以及四模态成像算法改进三项工作。针对原理样机测试中暴露出的问题，对工程样机中各个模态进行了全面的优化设计，通过前期模拟，结果显示各项性能指标相比原理样机得到了很大的提升；目前已完成工程样机整体机架的设计和安装、运动控制系统的调试工作，为下一步仪器的精确化、智能化运行打下了基础；完善了多模态分子影像特征提取技术、影像特征约减技术，深入研究了不同模态之间分子影像特征的关联性，为多模态影像融合提供了保障。在应用开发方面，项目组进一步证实18F-CAP的特异性和有效性，证实其PET/CT显像的时间点，完善评估机制；继续对小檗碱影响机体能量的代谢的机制作出了深入的研究，利用小檗碱处理后的棕色脂肪，深入分析了其中的分子机制，进一步了解新型糖尿病治疗药物的作用机理；通过动物模型系列实验研究获取具有靶向诊断的99mTc-RRL 的新型分子探针，为肿瘤新生血管诊断提供一种具有我国自主知识产权的新技术。项目组已在新型肿瘤放射性分子探针、脑间质途径给药、siRNA肿瘤治疗药物等领域发表多篇高水平的学术论文，获得了多项专利授权，进一步扩大了四模态仪器在国内外分子影像学术界的影响力。在产业化开发方面，项目组联合产业化单位在原有分子影像信息系统上开发了多模态分子影像数据挖掘模块，采用创新型的WEB平台，实现了数据的分布式采集以及挖掘后关联规则的异地共享。该模块目前可支持采用粗糙集和模糊—粗糙集算法，通过原始分子影像数据的离散化和模糊化处理，实现分子影像的数据挖掘，更好的推广了分子医学影像的应用产业化平台。 Advances have been made in aspects of instrumentation development,system optimization,application research and industrialization,as well as several major technical breakthroughs have been achieved.In instrumentation development,the focus of this year's work was mainly on three projects,namely,the optimization design of the four modalities engineering prototype,fabrication and adjustment of overall machine frame with controlling systems and the improvement of four modalities imaging algorithms.Aim at some problems exposed in testing the principle prototype,compressive optimization designs have been applied into various modalities of engineering prototype.The results showed that each performance index got a lot of promotions through previous simulations;At present,we have completed overall frame design and installation of engineering prototype,the adjustment of the motion control system,which laid a solid foundation for the precision and intellectualization of instrument for the next step;Multi-modality molecular imaging technologies of feature extraction and characteristics reducing have been consummated,relevance of molecular imaging characteristics in different modalities have been deeply researched,which provided the guarantee for multi-modality imaging functionally fusion.In application development,project team further confirmed the specificity and effectiveness of 18F-CAP and it’s timing of the PET/CT imaging,perfected the evaluation mechanism;In-depth study on the berberine affecting the body’s energy metabolism mechanism.Using brown fat after berberine processing,deeply analyze its molecular mechanisms,further understand the mechanism of the new type antidiabetic agentvagents;through experimental studies in animal models,researching new type of molecular probe 99mTc-RRL with function of targeting diagnosis and providing a new technology with independent intellectual property rights for tumor angiogenesis diagnosis.Meanwhile,many patents and high level academic papers have been granted and published respectively in new radioactive tumor probes,drug delivery via brain interstitial route,and siRNA tumor therapeutic drugs fields,which enhanced the academic impact of the quad-modality instrumentation on international and domestic imaging community.In industrial development,the project team and the designated industrialization contractor have developed a data mining module of molecular imaging,and realized the collection of distributed data,long-distance data sharing with association rules after data mining based on the original molecular imaging information system.Now,this module supports the rough sets and fuzzy rough sets algorithms,through discretization and fuzzing processing on the raw molecular imaging data,which realizes the data mining of the molecular imaging,and better promotes and popularizes the industrial platform of molecular imaging into application.

Colorectal cancer is a common malignant tumour with a low 5-year survival rate. A combination therapy with high selectivity and easy controllability is a pressing need for the effective treatment of such cancer. In this study, an indocyanine green derivative (Cy7)-conjugated lipid with a terminal carboxyl group was synthesized, which could self-assemble with a cerasome-forming lipid (CFL) into nanoparticles (NPs) by encapsulating doxorubicin (DOX) to achieve combined photothermal chemotherapy. The resulting Gly@Cy7-Si-DOX NPs with a surface covalent silicate framework showed excellent morphological stability and colloidal stability. Specifically, the conjugated Cy7 was covalently conjugated in the liposomal bilayer, resulting in high drug loading content, high photostability, and high photothermal conversion efficiency, which enabled the resulting nanoparticles to be an effective platform for photothermal therapy. Meanwhile, the encapsulated DOX leaked only slightly under physiological conditions due to the silicate surface of Gly@Cy7-Si-DOX NPs and exhibited controlled release in a weakly acidic environment or under near-infrared (NIR) light irradiation for chemotherapy. Gly@Cy7-Si-DOX NPs were efficiently taken up by tumour cells. Upon light irradiation, the released DOX entered the nuclei of tumour cells, as observed by confocal microscopy and flow cytometry. In vitro cell experiments indicated that both healthy cells and tumour cells were viable under treatment with only Gly@Cy7-Si-DOX NPs, indicating the encapsulated DOX was stably confined to the NPs, and cells were significantly killed when treated with both Gly@Cy7-Si-DOX NPs and NIR laser irradiation. After i.v. administration, Gly@Cy7-Si-DOX NPs accumulated at the tumour site, as monitored by near-infrared fluorescence imaging. A significant tumour inhibition rate (95.8%) was also achieved in a HT-29 colorectal cancer model when treated with Gly@Cy7-Si-DOX NPs plus irradiation. Therefore, the Gly@Cy7-Si-DOX NPs hold great promise for controllable combined colorectal cancer photothermal chemotherapy.

Objective: Accurate evaluation of the degree of hindlimb ischemia is challenging but essential for the diagnosis and treatment of peripheral vascular insufficiency. The aim of the study is to apply a multiparametric method for the quantitative estimation of mouse models with different degrees of hindlimb ischemia based on a dynamic fluorescence imaging-based strategy. Approach: An adjustable hydraulic occluder was placed around the thigh root of one hindlimb to induce six different degrees of hindlimb ischemia. Five parameters were extracted to quantitatively evaluate the degree of ischemia, including perfusion rate (PR) and perfusion vascular density (PVD) from a mathematical model of indocyanine green (ICG) pharmacokinetics, rising time (T rise), blood flow index (BFI) and mean fluorescence intensity (MFI) from time-series analysis of ICG hemodynamics. Main results: The results showed that the normalized PR and BFI decreased while the normalized T rise increased progressively with the degree of ischemia. The normalized PVD and MFI first increased and then decreased with the degree of ischemia. High correlation was observed between the degree of ischemia and the arterial oxygen saturation which was measured by an oximeter. Significance: The results of this work demonstrated that PR, BFI and T rise can be used for the quantitative and comprehensive evaluation of graded hindlimb ischemia. © 2018 Institute of Physics and Engineering in Medicine.

BACKGROUND: Optical imaging is one of the most common, low-cost imaging tools used for investigating the tumor biological behavior in vivo. This study explores the feasibility and sensitivity of a near infrared fluorescent protein mKate2 for a long-term non-invasive tumor imaging in BALB/c nude mice, by using a low-power optical imaging system.; METHODS: In this study, breast cancer cell line MDA-MB-435s expressing mKate2 and MDA-MB-231 expressing a dual reporter gene firefly luciferase (fLuc)-GFP were used as cell models. Tumor cells were implanted in different animal body compartments including subcutaneous, abdominal and deep tissue area and closely monitored in real-time. A simple and low-power optical imaging system was set up to image both fluorescence and bioluminescence in live animals.; RESULTS: The presence of malignant tissue was further confirmed by histopathological assay. Considering its lower exposure time and no need of substrate injection, mKate2 is considered a superior choice for subcutaneous imaging compared with fLuc. On the contrary, fLuc has shown to be a better option when monitoring the tumor in a diffusive area such as abdominal cavity. Furthermore, both reporter genes have shown good stability and sensitivity for deep tissue imaging, i.e. tumor within the liver. In addition, fLuc has shown to be an excellent method for detecting tumor cells in the lung.; CONCLUSIONS: The combination of mKate2 and fLuc offers a superior choice for long-term non-invasive real-time investigation of tumor biological behavior in vivo.

The objective of this study was to introduce, describe, and validate the performance of a novel preclinical silicon photomultiplier (SiPM)-based PET system (PKU-PET-II). Briefly, the detector assembly consisted of cerium-doped lutetium–yttrium oxyorthosilicate (LYSO) crystals, with dimensions of 2×2×15 mm3, that offered a 60 mm transaxial field of view (FOV) and 32 mm axial FOV, respectively. The compact front-end electronics readout and digital controller implemented architecture in the FPGA were noteworthy improvements in PKU-PET-II over its predecessor (PKU-PET-I). Based on the National Electrical Manufacturers Association (NEMA) NU 04-2008 standards, the design of the PKU-PET-II system was validated by a phantom experiment. The results presented spatial resolution (evaluated as full width at half maximum) with a system range from 1.68±0.07 to 2.31±0.03 mm at the FOV center and from 1.43±0.02 to 2.10±0.10 mm at the 1/4th axial FOV, respectively. The system's absolute sensitivity at the center position was 1.35% with the coincidence window of 6 ns and energy window of 300–700 keV. In addition, the NEMA image quality phantom and an animal study results validated the system imaging performance in preclinical imaging application. In conclusion, this SiPM-based, small-animal PET system (PKU-PET-II) provided higher-resolution, adequate sensitivity, and excellent image quality and has potential as a useful tool for real-time imaging of disease progression and development in vivo. © 2017

Targeted theranostic nano-system integrating functions of both diagnosis and therapy shows great potential for improving diagnosis and therapeutic efficacy. Herein, multifunctional nanoparticle based on activatable hyaluronic acid (HA) conjugating two near-infrared (NIR) dyes of Cy5.5 and IR825 was successfully designed and fabricated, and simultaneously used as a carrier for encapsulating perfluorooctylbromide (PFOB). In this system, PFOB showed good capability to absorb the X-rays, Cy5.5 on the outer surface acted as a fluorescent dye activatable by hyaluronidases (Hyals) in the tumor, and IR825 in the core as a photothermal agent. The obtained nanoparticles (NPs) of PFOB@IR825-HA-Cy5.5 can be utilized for triple X-ray computed tomography (CT), fluorescence and photoacoustic imaging. When PFOB@IR825-HA-Cy5.5 NPs were intravenously injected into the mice bearing HT-29 tumor, efficient tumor accumulation was clearly observed, as revealed by the triple modal imaging. An in vivo tumor treatment experiment was conducted by combination of PFOB@IR825-HA-Cy5.5 and near-infrared laser irradiation, achieving effective tumor ablation in mice. Therefore, PFOB@IR825-HA-Cy5.5 NPs is a safe, efficient, imageable photothermal nanoprobe, showing great potential for cancer theranostics. (C) 2017 Elsevier Ltd. All rights reserved.