With the rapid development of nanotechnology, nano oncology medicine that is formed through the combination of nano science and oncology medicine has become an important field emerging in nano science. Because of its unique optical properties, the gold nanorod (GNR), that is a rod-shaped nano materials, has shown great potential applications in the biomedical field, especially, in GRNs thermotherapy, radio-sensitizing effect therapy and targeting therapy of the tumor. Being a newly-developed therapy, gold nanorods combined with internal radiotherapy has already obtained excellent durative effect in targeting therapy of tumor. This paper aims to make a comprehensive review about its mechanism and its clinical application and research situation in recent years.

BACKGROUND:Gold nanorods have unique optical properties, good histocompatibility, easily control ed surface modification, which have a broad application prospect in the field of biology and medicine. OBJECTIVE:To summarize the optical and thermal properties of gold nanoparticles, and to review the mechanism and research advances of gold nanoparticles, especial y gold nanorods in tumor sensitize radiotherapy. METHODS:A computer-based search of PubMed and CNKI databases was undertaken with the keywords of“gold nanoparticles, radiotherapy sensitivity”in English and Chinese, respectively. The included articles were related to nanoparticles used in vitro and in vivo for clinic study as wel as gold nanoparticles-related tumor sensitize radiotherapy. RESULTS AND CONCLUSION:Gold nanoparticles exhibit unique properties of surface plasmon resonance properties. Compared with the traditional spherical gold nanoparticles, gold nanorods are capsule-like gold nanoparticles containing two absorption peaks that are a transverse surface plasmon resonance absorption peak and a longitudinal surface plasmon resonance absorption peak corresponding to the dimensional characteristics of their horizontal axis and vertical axis, respectively. By regulation of the ratio of horizontal axis and vertical axis, we can realize the manipulation of the longitudinal surface plasmon resonance absorption peak location. Thus, the longitudinal surface plasmon resonance absorption peak can be changed from visible region to the near-infrared region which is the most ideal optical transmission through for al of biological tissues. As a kind of novel radiotherapy sensitization agent, gold nanorods have the properties of low toxicity, high efficiency, high yield. Its sensitization effect is not only related to the exposure dose, own concentration and size, surface modified compounds, but also related to the types of radiation and celllines. However, for radiotherapy sensitization of gold nanorods how to avoid the limits of radioactive ray species, choose appropriate trim and maximize the use of gold nanorods stil need a further research.

0.05),(5.45 ? 0.58)% and (11.60 ? 0.87)%,(P 0.05)of the control team and test team. Conclusions 125Ⅰ seeds implantation can induce tumor cell apoptosis, beginning at 72 h and reached peak at 2 w and kept the high level here afterword. The apoptosis rate descended rapidly along with the increase of distance away from the 125Ⅰ seedling.

Objective To develop a cancer cell targeting probe based on silica-coated gold nanorods and investigate its optics properties and its targeting effect on human hepatocellular carcinoma HepG2 cells in vitro.Methods Preparation of gold nanorods (GNRs) by seeded growth method,and then the spherical core-shell silica-coated gold nanorods were successfully prepared by a sol-gel method,finally the GNRs@SiO2 was conjugated with folate (GNRs@SiO2-FA).The characteristics of GNRs@SiO2-FA were studied using transmission electron microscopy,and UV spectra.The cells were divided into 2 groups randomly,adding GNRs@SiO2-FA and GNRs solution respectively at the gold concentration of 40.0 × 10-6,20.0 ×10-6,10.0 × 10-6,5.0 × 10-6,2.5 × 10-6,and the MTT method was applied to detect the absorbance (A value) and study the cytotoxicity of GNRs@SiO2-FA and GNRs.The cells were divided into 2 groups randomly,and incubated with the same concentration of GNRs@SiO2-FA and GNRs@SiO2 solution respectively,at 2,4,8,16,24 h,and the targeting of GNRs@SiO2-FA cellular uptake were detected by ICPMS by observing the process of GNRs@SiO2-FA into the cells by transmission electron microscopy (TEM).The data represented by (-x) ± s ; single factor analysis of variance were compared between the 2 groups ; and the differences were significant when P ＜ 0.05.Results UV spectrum confirmed the successful preparation of GNRs@SiO2-FA.The A value of the same concentration group was variance analysised,and the differences between the 2 groups was statistically significant (all P ＜ 0.01) with the gold element concentration from high to low:F =191.876,265.419,77.987,52.061,18.745.The ICP-MS confirmed GNRs@SiO2-FA could specifically bind with HepG2 cells.GNRs@SiO2 group gold element content at 2,4,8,16,24 h was (256.7±3.3),(602.8±2.4),(1067.1±3.6),(1998.5±4.3),(2078.5±1.3) mg/kg and GNRs@SiO2-FA group was(693.1 ±2.0),(1432.0 ±2.6),(2331.3 ±3.5),(2484.5 ±5.0),(2589.7 ±2.1)mg/kg,and the 2 groups was statistically significant (F =3278.070,34287.199,85434.870,18333.454,42412.973,P ＜0.01).TEM results showed that a small amount of nano probes were in the cytoplasm after cultured with GNRs@SiO2-FA cells 1 h,and that,a lot of probe were in the cytoplasm,4-24 h later,but there was no probe in the nucleus.Conclusion The prepared Folate-conjugated gold nanorods has good performance on biocompatibility and targeting.

Objective To explore the possible mechanism of the apoptosis of hepatoma cell line HepG2 induced by the combination use of GNRs@SiO2-FA and 125I seeds and to discuss its relationship with Bcl-2 and Bax protein expressions so as to provide theoretical basis for clinical treatment of hepatic cancer with interstitial brachytherapy by using 125I seeds. Methods In vitro cultured HepG2 cells were randomly divided into 4 groups: blank control group (not treated), simple GNRs@SiO2-FA group, simple 125I seeds group, and combination group (GNRs@SiO2-FA plus 125I seeds). The apoptosis of HepG2 cells was determined by flow cytometry. The expression of Bax mRNA and Bcl-2 mRNA of HepG2 cells were tested by RT-PCR. The apoptosis-related genes (Bax and Bcl-2) and the tumor proliferation cell nuclear antigen (Ki67) proteins expression on HepG2 cells were examined with immunohistochemistry method. Results The flow cytometry examination showed that the apoptosis rate of HepG2 cells in the simple GNRs@SiO2-FA group and simple 125I seeds group was higher than that in blank control group (P<0.05), and the apoptosis rate of the combination group was significantly higher than that of the simple GNRs@SiO2-FA group and the simple 125I seeds group (P< 0.05). The expression level of Bax mRNA in the combination group was higher than that in the simple GNRs@SiO2-FA group and simple 125I seeds group, while the expression level of Bcl-2 mRNA in the combination group was obviously lower than that in the simple GNRs@SiO2-FA group and simple 125I seeds group. Bax protein was expressed on cytoplasm, Bcl-2 protein was expressed on cytoplasm and cell membrane, while Ki67 protein was expressed on nucleus. All of them presented as brown finely granular precipitations. Statistically significant differences in the amount of Bax, Bcl-2 and Ki67 protein expression existed between each other among the four groups (P< 0.05). The positive expression rate of Bax protein in the combination group was significantly higher than that of the simple GNRs@SiO2-FA group and the simple 125I seeds group, while the positive expression rate of Bcl-2 and Ki67 protein was significantly lower than that of the simple GNRs@SiO2-FA group and the simple 125I seeds group, and the differences were statistically significant (P < 0.05). Conclusion The combination use of GNRs@SiO2-FA and 125I seeds can more effectively induce the apoptosis of HepG2 cells. This effect may be accomplished through increasing the expression of Bax protein and inhibiting the expression of Bcl-2 and Ki67 proteins.

Objective To establish the rabbit model with hepatic VX-2 tumor and to investigate the intake of folate-conjugated silica-coated gold nanorods (GNRs@SiO2-FA) in experimental rabbits. Methods Under CT-guidance, animal model with VX-2 liver cancer was established in 27 rabbits by using puncture inoculation method. CT scanning and sonography were employed to observe the tumor growth. After two weeks, the rabbits were randomly and equally divided into blank control group (n=9, injection of saline), portal vein injection group (n=9, injection of GNRs@SiO2-FA) and intra-tumoral injection group (n=9, injection of GNRs@SiO2-FA). Every three rabbits from each group were sacrificed each time at 24 h, 48 h and 72 h after the treatment. The tumor tissue and the major organs were collected and sent for pathological examination. The cellular uptake of GNRs@SiO2-FA was studied by confocal laser scanning microscopy. Results The rabbit model of VX-2 liver cancer was successfully established. CT and sonography examination indicated that the tumor was rich in blood supply. Confocal laser scanning microscopy revealed that GNRs@SiO2-FA could specifically bind with tumor cells within 24 hours after injection, then the GNRs@SiO2-FA entered into the tumor cells and gathered in the tumor cytoplasm. Conclusion GNRs@SiO2-FA has highly targeted effect on the liver cancer cells in experimental animals, which has very important application prospect in targeting hyperthermia therapy and in 125I seed implantation therapy.

BACKGROUND: As a new radiotherapy for malignant tumor, brachytherapy of radioactive seed implantation enables the inter-tissue implantation of radioactive seeds to be applied further with the appearance of seed implantation treatment planning system (TPS), and the gradual consummation of ultrasound and CT-guided precise positioning system.OBJECTIVE: To evaluate the methods, feasibility, safety and efficacy of CT-guided iodine-125 (125I) implantation for malignant tumors.DESIGN: A controlled observation before and after implantation.SETTING: The First People's Hospital of Hefei City.PARTICIPANTS: Twenty-one patients with malignant tumors, who were not suitable for surgical treatments of operation,were selected from the First People's Hospital of Hefei City from January 2004 to March 2005. There were 26 lesions, including 9 lesions of primary unresectable carcinoma and 17 lesions of metastasis tumors.METHODS: Under CT guidance, 125I seeds were implanted into malignant tumor according to TPS, the radioactivity quantum were 22, 26, 30 and 33 MBq per granule. Larger radiation 125I wes suitable for the implantation in the center of a lesion and smaller ones were for the margin of the lesion and the peripheral region of some important organisms such as vessels and nerves. The interval between larger seeds was about 1.5 cm whereas the interval between smaller ones was about 1.0 cm.MAIN OUTCOME MEASURES: The seed distribution, existence of complication and changes of the size of lesion after implantation were observed.RESULTS: ① The seeds were implanted successfully in all the 21 cases. No complication was observed. The practical distribution of the implanted seeds was basically the same as the scheduled scheme before implantation. All the 21 patients were involved in the analysis of results. ② The number of seeds implanted in one lesion was 5 to 40 (mean 14).Pain relief was obtained in all 10 cases of malignant tumors of bone after implantation. Follow-up CT reexamination demonstrated that 18 lesions were obviously diminished, necrosis was found in 4 lesions and remaining 4 lesions had no significant changes in size. ③ The average sizes of 14 lesions in 11 patients at 5-7 months after implantation were obviously smaller than those before implantation (1.84 cm vs 3.41 cm, t =5.7237, P ＜ 0.001). The average sizes of 12 lesions in 10 patients at 8-10 months after implantation were also obviously smaller than those before implantation (1.96 cm vs 3.43 cm, t =5.577 8, P ＜ 0.002).CONCLUSION: CT-guided 125I implantation is a safe, effective and feasible method for the treatment of malignant tumor.

Objective To evaluate the role and technical advantages of CT in 125Ⅰseed implantation in the treatment of tumors. Methods CT-guided 125Ⅰ seed implantation in 45 cases of cancer patients treated 57 times in 51 lesions,CT were used to evaluate the progress of lesions after 125Ⅰ seed implantation 1,2,6 months. Results All procedures were once successful and the total effective rate was 74.5% without any serious complications. Fifty CT examinations immediately after implantation showed satisfactorily seeds distribution but seven cases less satisfactorily that include particles overlap,the location is too close to the lesion edge,the larger the radiation cold spots,etc. Follow-up CT reexamination in 1,2 and 6 months demonstrated that CT examinations showed satisfactorily seeds distribution but accurate seeds number,which could be solved by combined with MPR images and the positioning piece. Conclusions CT-guided 125Ⅰ seed implantation treatment of tumors was a safe,reliable and effective minimally invasive treatment. CT in the preoperative treatment of seed implants planning,precise intraoperative guidance,quality assurance and efficacy of postoperative assessment had a greater role and application advantages.

Objective To explore the application value of a special fence in percutaneous transhepatic cholangial drainage(PTCD)under the guidance of C-arm CT.Methods A total of 43 patients who underwent PTCD were randomly divided into observation group and control group.The intervention operation in the observation group was guided by C-arm CT and located by special fence;in the control group,the intervention operation was only performed under digital subtraction angiography(DSA)fluoroscopy.Respectively,the differences in operation time,number of puncture needles and number of complications between the two groups were compared.Results The operation time,puncture times and complications in the observation group were(39.33±12.96)min,(1.67±0.80)times and 3 cases respectively;in the control group were(86.77±22.70)min,(3.41±1.26)times and 13 cases respectively;There were significant differences between the two groups(P<0.05).Conclusion The application of special fence in PTCD under the guidance of C-arm CT can short the operation time,reduce the number of punctures and reduce complications,which has important clinical application value.

Objective:To explore the imaging changes of lung lesions in patients with imported COVID-19 when reaching the discharge standard.Methods:The clinical and CT imaging data of 60 cured patients with imported COVID-19 and discharged from January to February 2020 in Anhui Province were retrospectively collected. At the initial diagnosis, 5 cases were mild, 53 were ordinary, and 2 were severe. The clinical characteristics of the patients and the characteristics of chest CT images at discharge were analyzed.Results:Fever (57 cases) and cough (55 cases) were the main symptoms in 60 patients. In 5 mild patients, 3 cases were negative in the whole course of CT examination, 2 cases were negative in the first time and abnormal in the second time. The first CT imaging features of 55 patients (53 common type and 2 severe type) were mainly bilateral lung involvement (51 cases), multiple lesions (33 cases), more common under the pleura (40 cases), and ground glass opacities were the most common (55 cases). The features of chest CT in clinical outcomes were that the ground glass shadow in the lung gradually faded and was completely absorbed (19 cases); the scope of ground glass shadow in the lung expanded and progressed to crazy-paving, consolidation shadow, and the lesion gradually absorbed again followed by fibrous cord shadows (27 cases); ground-glass opacities in the lungs quickly progressed to a consolidation and then slowly absorbed. Most of the lesions were accompanied by more residual fibrous cord shadows (4 cases). In 2 severe patients, the lesions in the lungs were larger ground glass, and a large amount of fibrous foci remained after slow absorption.Conclusions:Chest CT plays an important role in the diagnosis and treatment of imported COVID-19, and the degree of lung involvement seen on CT images is in good agreement with clinical outcome.