The function of Chinese herbal medicine in the reconstruction of periodontal tissue during orthodontic tooth movement / 中国组织工程研究

BACKGROUND:Orthodontic tooth movement is based on the periodontal tissue remodeling. In the exogenous factors accelerating orthodontic tooth movement, Chinese herbal medicine has become a research hotspot because of its wide resources, low cost, easy to extract, mild effect, smal toxic, less side effects and drug resistance. OBJECTIVE: To summarize the role of Chinese herbal medicine in the periodontal tissue remodeling during orthodontic tooth movement. METHODS:A computer-based retrieval of CNKI, Wanfang and PubMed databases was performed for articles related to Chinese herbal medicine for improving orthodontic tooth movement published before 2014. The keywords were “Chinese herbal medicine, orthodontic tooth movement, periodontal tissue remodeling” in Chinese and English, respectively. RESULTS AND CONCLUSION:Erigeron breviscapus, Salvia, teasel, Drynaria, baicalin, evening primrose oil as Chinese herbs are most widely used in the promotion of periodontal tissue remodeling, characterized as wide resources, low cost, easy to extract, mild effect, low toxicity, less drug resistance. In the clinical orthodontic treatment, it is hoped to accelerate orthodontic tooth movement and shorten the treatment time. Therefore, under the appropriate corrective force, Chinese herbs can be used properly to improve periodontal tissue repair and remodeling, which can improve the microcirculation of periodontal tissue, increase the local blood flow, promote bone formation and repress bone resorption.

A positioning method of ultrasound probe in MR system / 中国医疗器械杂志

This paper provides a method of positioning the ultrasound probe in MR system. Machining 6 slots or cylinder perpendicular to the ultrasound probe surface on the edge of ultrasound probe as markers, 12 central cylinder ends are chosen as positioning points. By calculating these positioning points' coordinates in MR's coordinate system, the coordinate transformation between the ultrasound and MR coordinate system can be computed. Furthermore, by taking advantage of redundant information, calculating errors can be reduced and the precision can be improved.

Framework design of MRI guided phased HIFU system and software development / 中国医疗器械杂志

This paper introduced a new structure of MRI guided P-HIFU therapy system and software implementation based on the current P-HIFU system and interface provided by MRI vendor. The tests showed that the system's software can achieve the appropriate form of treatment need.

The development of phase signal generator for the phased HIFU system based on FPGA / 中国医疗器械杂志

The FPGA-based phased-signal generator described in this paper meets the requirement of massive output channels and high resolution of HIFU. After experimental measurements, this phased-signal generator can output 256 channels of phase signals and each channel has a phase resolution of 2nS. The phased-signal generator also has many other advantages such as simple implementation method and high reliability.

Experimental study of a novel radiofrequency ablation system / 中华物理医学与康复杂志

Objective To determine the power-time-ablation scope correlogram of a water-cooled single needle electrode radiofrequency (RF) ablation system and to establish a theoretical basis for its practical application.Methods RF ablations were performed using a water-cooled single needle electrode radiofrequency ablation system developed by the authors using fresh ox liver as well as liver and muscles of healthy adult New Zealand white rabbits.The temperature of the ablation area was monitored using a multichannel thermometric system.The maximum ablation scope was determined by detecting the rim at which the temperature was no less than 50 °C.The specific absorption rate (SAR) of the isolated liver tissue was calculated.Results In the treatment voltage range of 100-130V,the process was smooth and steady.No impedance variation was obvious.The maximum diameter of a single ablation was 51 cm.With the treatment voltage at 140-170 V,a larger ablation area could be reached in less time,but eventually the impedance began to increase while the ablation area was no longer expanded.When the treatment voltage reached the range of 180-200 V the impedance almost always increased rapidly out of limits,and the treatment system stopped automatically.The measured SAR value was consistent with the theoretical value.Pathology confirmed that both liver tissue and muscle tissue manifested typical coagulative necrosis.Conclusions The power amplifier,cooling,thermometric and control sections of the RF ablation system worked stably,and the practical ablation effect met the design and clinical treatment requirements.

Development and application of the phased HIFU system software / 中国医疗器械杂志

This paper introduces HIFU system software based on a phased-array HIFU device. Combined with the database and computer graphics technology, this HIFU system software can be used to develop the therapy planning semi-automatically, implement the pilot project efficiently and accelerate the clinical studies.

Measurement and analysis of phased-array focused ultrasound field of two-foci pattern / 中国医疗器械杂志

This paper introduces the simulation and measurement results of the phased-array focused ultrasound field of two-foci pattern.

Development and New Clinical Applications of Ultrasound Microbubble Contrast Agents / 中国医学物理学杂志

Objective: Several generations of ultrasound contrast agents have been developed. Now the application of targeted microbubble is an important research field. Methods: Ultrasound microbubble contrast agents can be divided into two types: ordinary and special ones. First generation microbubble products are air bubbles. They lack a stabilizing shell and have large size. The second ones are stabilized by a sheU and have a smaller size ,instable gas cores consisting of air. The third ones have a stable shell and gas cores with perfiuorocarbons. Researches on new applications of targeted microbubble involve the targeted molecular imaging such as thrombus and inflammation imaging, thrombolytic therapy, drug/gene therapy and so on. Results: The stability of microbubble is increased gradually. Microbubble is injected intravenously and reaches the targeted tissue. At low ultrasound beam power imaging contrast can be improved. Low frequency ultrasound (1 MHz) can cause transient perfora-tion of cell membrane by cavitation effects and thereby improve drug/gene delivery efficiency. Conclusions: Ultrasound-target-ed microbubble has shown its advantages over other methods in the clinical diagnosis and treatment. While the bio-effects are not fully understood. And physical parameters affecting drug or gene delivery efficiency should be optimized.

Digital image analysis of trabecular microstructure / 生物医学工程学杂志

Trabecular microstructure is an important factor that influences the bone biomechanical properties. In this paper, studies on digital image analysis of trabecular microstructure are reviewed with special emphases on the serials parameters as well as on the measurement methods of trabecular microstructure characteristic. The future researches and advances are also prospected.

Development of a cryosurgery & radiofrequency alternating tumor ablation device / 中国医疗器械杂志

The combination of the cryosurgery using LN2 and intelligent RF ablation therapeutic instrument based on the theory of local destruction is introduced in this paper, and this alternating therapy is believed to have a better controlling effect on tumor ablation. In heating period, a fuzzy algorithm is used to control the RF power to realize a more smoothly heating process to the target area.

System design of small intellectualized ultrasound hyperthermia instrument in the LabVIEW environment / 生物医学工程学杂志

Small-scale intellectualized medical instrument has attracted great attention in the field of biomedical engineering, and LabVIEW (Laboratory Virtual Instrument Engineering Workbench) provides a convenient environment for this application due to its inherent advantages. The principle and system structure of the hyperthermia instrument are presented. Type T thermocouples are employed as thermotransducers, whose amplifier consists of two stages, providing built-in ice point compensation and thus improving work stability over temperature. Control signals produced by specially designed circuit drive the programmable counter/timer 8254 chip to generate PWM (Pulse width modulation) wave, which is used as ultrasound radiation energy control signal. Subroutine design topics such as inner-tissue real time feedback temperature control algorithm, water temperature control in the ultrasound applicator are also described. In the cancer tissue temperature control subroutine, the authors exert new improvments to PID (Proportional Integral Differential) algorithm according to the specific demands of the system and achieve strict temperature control to the target tissue region. The system design and PID algorithm improvement have experimentally proved to be reliable and excellent, meeting the requirements of the hyperthermia system.

A Non-rigid Medical Image Registration Algorithm Based on Modally Controlled Free Form Deformation / 航天医学与医学工程

Objective To register pre-operative MRI/CT images with intra-operative ultrasound images based on vessels visible in both of the modalities. Method A non-rigid registration method of multimodal medical images based on Free Form Deformation(FFD) was proposed. When the images were aligned, the centerline points of the vessels in one image aligned with the intensity ridge points in the other image. Rigid transformation was adopted in global registration while local deformation was described by a Free Form Deformation based on a modally controlled B-spline. The method applied an optimization strategy combining the genetic algorithm with the conjugated gradients algorithm to minimize the objective function. Result Two experiments were designed on phantom and clinical data to evaluate the method. The results demonstrated that the registration method was consistent accurate. The average standard deviation of the final transformation parameters was sub-voxel, sub-millimeter, and within 0.010 radians. Conclusion The results show that the method has good registration accuracy and convergence rate. It can be applied efficiently in the ultrasound-image-guided surgery system.

Ultrasound-mediated gene delivery / 生物医学工程学杂志

Recently there have been increasing interests in ultrasound-mediated gene delivery techniques. This paper reviews the general concept of sonoporation, the effect of contrast agents, and the in vitro and in vivo applications of such techniques. Factors which contribute to the efficiency of gene delivery were also discussed. The technology is promising and has great potential in targeted drug delivery and gene delivery applications.

A multi-modal image registration method for use in thermotherapy of tumor / 生物医学工程学杂志

In the interactive image-guided thermotherapy, we need the real time image and location of the target tumor. But the current mono-modal imaging technique can not do it. We present a method to register a preoperative 3D MRI volume to a set of intra-operative ultrasound images for the target localization of the liver tumor in the thermotherapy. The registration method is a genetic algorithm based on the features such as liver surface vessels and liver surface.

Temperature control in a combined therapeutic system for tumor / 生物医学工程学杂志

Tumor combined therapeutic system, a kind of medical instrument to restrain and kill tumor, is based on radio frequency heating technique and biological heating effect theory. It can be used solely or in combination with chemotherapy and actinotherapy for tumor hyperthermia. Combined with hardware measurement and adjustment, as well as application of the improved PID algorithm to the system of temperature control, the required accurate temperature control which directly influences the curative effect is realized. The experimental results presented in this paper demonstrated that the equipment works stably and reliably, and it is of good usefulness.

3D display of sequential 2D medical images / 生物医学工程学杂志

A detailed review is given in this paper on various current 3D display methods for sequential 2D medical images and the new development in 3D medical image display. True 3D display, surface rendering, volume rendering, 3D texture mapping and distributed collaborative rendering are discussed in depth. For two kinds of medical applications: Real-time navigation system and high-fidelity diagnosis in computer aided surgery, different 3D display methods are presented.

An improved PID algorithm for temperature control used by tumor combined therapeutic instrument / 生物医学工程学杂志

The development of a multi-functional tumor combined therapeutic instrument based on improved PID algorithm is introduced. It is based on the theory of 1 + 1 = 3 or 1 + 1 + 1 > 3 curative effect enhancement by tumor combined therapy, and it can be used solely, or with the combination of chemotherapy or actinotheraphy or both for tumor hyperthermia. By adopting improved PID temperature control algorithm, the problem of temperature control precision reduction due to process characteristics changing with different heaters was solved, thus ensuring homogeneous and smooth radio frequency heating by different heaters to intracavity tumor foci. These experiments demonstrated that the new algorithm has strong adaptability and anti-disturbance capability, the equipment works stably and reliably, and it can control therapeutic temperature precisely (+/- 0.1 degree C), which indicates a good value in clinical application.

Study on multi-pole RF ablation system / 生物医学工程学杂志

Radio frequency ablation has become a valuable method in treating cancers or tumors for its wide adaptability, better efficacy, convenience and safety. This paper introduces the research and development of a multipolar RF tumor therapy system based on the technology of destroying hypoxic cell. This is an intellectualized tumor curing system.