More and more patients were treated by surgery with metal implants in clinic.Metal artifacts in CT images caused by metal implants brought challenges for postoperative evaluation and diagnosis of tumor.It also led to the possibility of missed diagnosis and misdiagnosis.In recent decades,the improved methods based on filtered-backprojection and iterative reconstruction algorithms have great progresses in reducing effects of metal artifacts.The actuality of techniques for metal artifact reduction were reviewed in this article.

With the improvement of the complexity of medical image synthesis and the demand for the accuracy of clinical radiotherapy, deep learning algorithm plays an increasingly important role in pseudo CT image synthesis and analysis. This paper classifies and analyzes the pseudo CT image synthesis technology based on deep learning method in terms of the types of image modes, and describes the ongoing application in radiotherapy.

manual beam orientation selection, beam orientation optimization which is feasible in IMRT planning may significantly improve the efficiency and result.

In Chongqing Medical University,Introduction to Clinical Medicinewas first launched in 2002. In this article, based on the summary of 2014 to 2015, we summarized respectively from teaching material construction, evaluation system with combination of formative assessment and summative assess-ment, network support platform, teaching quality monitoring system, and student questionnaire survey and evaluation. Through the study of the course, 99.5% (836/840) of the students think their team conscious-ness and cooperation ability were improved, 94.2% (791/840) of the students consider this course can im-prove their innovative ability of self-learning, 87.0% (731/840) of the students think it is beneficial to the improvement of their self expression ability and more than 78.0% of the students think they have achieved the goal of early clinical contact, expanding knowledge, and enhancing the basic professional quality.

Objective To study the radioseusitization effect of gold nanoparticles modified by sodium glycididazole.Methods The sodium glycididazole was connected to gold nanoparticle,in dimension of about 18 nm,that had been modified with polyethylene glycol.The nanoparticle-swallowing efficiency of lung adenocarcinoma A549 cells was observed by a scanning electron microscope.Cells were divided into four groups:sodium glycididazole group,gold nanoparticles group,sodium glycididazole-gold nanoparticles group,and no drug control group.The radiosensitivity was detected by MTT and colony formation assays.Results Sodium glycididazole-gold nanoparticles could enter the cell cytoplasm and nucleus.The concentration of 0.003 mg/ml gold nanoparticles and sodium glycididazole-gold nanoparticles had no obvious cytotoxic effect.After irradiation of 2,4,6,8 Gy,the cell survival of the sodium glycididazole-gold nanoparticle group was significantly lower than that of the other three groups (F =4.8,14.5,5.7,7.6,P ＜0.05) and the D0 and Dq values of the sodium glycididazole-gold nanoparticle group were significantly lower than those of other three groups.Conclusion Sodium glycididazole-gold nanoparticles can enhance the radiosensitivity of lung adenocarcinoma cells.

Objective To investigate the effects of Trim34α on the activation of luciferase reporter gene containing NF-κB promoter induced by adaptor proteins TAB2. Methods The total RNA was isolated from HeLa cells. After amplification with RT-PCR, the target sequences were cloned into 5'-Flag-pcDNA3.1 (+) vector. The recombinant vector was confirmed by restriction enzyme digestion, colony PCR and sequencing. It was transfected into HEK293T cells to detected Trim34α expression by Western blot. Simultaneously, the effects of Trim34α on the NF-κB activation induced by TAB2 were determined by dual-luciferase reporter assay. Results Restriction enzyme digestion, colony PCR and sequencing confirmed the vector was constructed successfully, furthermore it expressed Trim34α protein in HEK293T cells. Moreover, trim34α could form high-molecular-weight oligomeric protein, and here we called it trimsome. Interestingly, dual-luciferase assay showed that Trim34α could effectively block TAB2-induced NF-κB activation. Conclusion Trim34α was involved in negative regulation of TAB2-induced NF-κB activation and could form high-molecular-weight oligomer.

Objective To investigate the impact on registration accuracy with the different registration ranges of CBCT images and CT images.Methods CBCT and CT scans were performed on the of 5 patients.The registration ranges of five patients' images of abdomen,head and chest performed CBCT and CT scanning were processed with four modes.Mode 1:the registration range of CT images was larger than the registration range of CBCT images,mode 2:the registration range of CT images and CBCT images were equally,mode 3:taking a 5 cm translation of CT images range from mode 2,mode 4:The CBCT range and CT range reduced 2 cm both sides simultaneously from mode 2.Using the registration program from Insight Segmentation and Registration Toolkit (ITK) to the four modes,the Mean Square Difference (MSD) metric values of four modes after registration were compared and the relationship between mode 2 and another three modes was analyzed by paired t test.Results For the MSD metric values,mode 3 was maximum,mode 2 and 4 were minimum,and mode 1 was centered.The difference between the mode 2 and mode 4 was not statistically significant(P ＞ 0.05).The difference between the mode 2 and mode 1 was statistically significant(t =-4.586,-4.164,-5.618,P ＜ 0.05).The difference between the mode 2 and mode 3 was statistically significant(t =-6.423,-8.109,-19.601,P＜0.05).Conclusion The registration ranges of CBCT and CT images has a certain extent of influence on the accuracy of image registration.The closer the registration range of CBCT and CT is,the higher the registration accuracy is.

Objective To establish a rabbit model of radiation-induced skeletal muscle injury in order to study the ultrastructural pathological changes and underlying mechanism.Methods 28 New Zealand rabbits were randomly divided into 2 groups with 16 rabbits in experimental group and 12 rabbits in control group.The experimental rabbits were irradiated on hip with a single dose of 80 Gy of 9 MeV electrons from a linear accelerator.1 month and 6 months after irradiation the pathological changes were respectively observed under light microscope and electron microscope.Results One month after irradiation,the morphologic changes including degeneration,necrosis of muscle cells,and hemorrhage between the muscle cells were observed under light microscope and the swelling of myofibrillae,blurring of light and shade band,vacuolar degeneration of mitochondria and amorphous areas of necrosis were observed under electron microscope.Six months after irradiation,the morphologic changes of nucleolus chips,fibrous connective tissue,thickening of vascular wall and vascular congestion between the muscle cells and the amorphous areas of necrosis in the experimental group were much more serious than those of 1 month after irradiation.In addition,the myofilaments were lost in degeneration areas and the sarcomere became shorten.Observation with electron microscope showed that the mitochondrial size and its morphological changes were varied and the amounts of collagen between myofibrillaes were increased 6 months after irradiation.Conclusions A rabbit model of high-dose irradiated skeleton muscle injury was successfully established with a single dose of 80 Gy of 9 MeV electrons from a linear accelerator.The degeneration and necrosis of muscle cells may be promoted by mitochondrial and vascular injury,degeneration of vessel and nerve fiber.

ObjectiveTo investigate the impact of metal plate on radiation dose distribution by Monte Carlo (MC) code. MethodsThe metal plates with 0. 4 thick were placed in water at 5 cm, all the plate irradiated with 6 MV X-ray were simulated by MC code, SSD =100 cm. The percentage depth dose with or without metal implants were compared. ResultsThe surface absorbed doses on incident plane of stainless steel plate and titanium plate were increased by 19. 6％ and 15.7％ respectively as compared water,the dose influence was less than 1.5％ more than 0. 3 cm outside the incidence plane. The doses on the exit surface of stainless steel plate and titanium plate were lowered by 8. 6％ and 8. 2％ when compared with water, the dose impacts of this places where were from the exit surface of stainless steel plate 、titanium plate more than 1.2 cm,0. 9 cm were less than 1.5％. The surface absorbed doses on incident plane of stainless steel plate were increased by 3.9％ respectively as titanium plate, the dose of the exit surface of stainless steel plate and titanium plate was similar. Conclusions MC method is a fast and accurate calculation method. The influence of metal plate on the radiotherapy dose distribution is significant. Under the such condition, the impact of stainless steel plate is much more than that of titanium alloy plate.

With the development of computer techniques and medical software in image analysis and visualization,medical image registration as a key step before image processing(e.g., image fusion)is important in research and medical diagnosis. Therefore, many studies have focused on medical registration methods and algorithms. Up to now, several registration methods have been applied in clinical practice. In this paper,we make a classification and analysis of registration methods clinically applied in radiotherapy. How to improve the accuracy,efficiency,and robustness of medical image registration remains an issue to be solved in the future.