Background: This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding window IMRT in terms of dosimetric end points and delivery time for head and neck cancer. Materials and Methods: 22 patien...Background: This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding window IMRT in terms of dosimetric end points and delivery time for head and neck cancer. Materials and Methods: 22 patients with head and neck cancer were selected for a planning comparative study. All patients went to CT-simulation in supine position. PTVs were delineated for two dose level of prescription 70 Gy to the boost-PTV70Gy and 54 Gy to the elective-PTV54Gy in 35 equal fraction/day. Simultaneous Integrated Boost (SIB) technique plan was generated for all patients and optimized with both techniques, Rapid Arc and IMRT with similar planning objectives. Dose of all plans of both techniques were calculated for 6MV photon using AAA implemented in Eclipse treatment planning system (10.0.39) with calculating grid size of 2.5 mm. Results: Comparison of Rapid Arc and IMRT plans in every patient showed significantly higher conformity index (CI95%) (p = 0.021) and sparing of the all OARs with Rapid Arc. The average homogeneity Index (HI95%) of lower prescribed dose target PTV54Gy which is in proximity to Higher dose prescribed target PTV70Gy was improved significantly with rapid Arc (p = 0.0001). D1% of spinal cord dose reduced significantly (p = 0.047) with Rapid Arc and the average mean dose of both left-parotid (21.26 ± 8.5 Gy), right-parotid (22.37 ± 7.44 Gy) were received lesser than with IMRT (22.78 ± 11.2 Gy and 24.1 ± 7.96 Gy) respectively. A significantly less monitor unit (MU) was required to deliver the plan (p < 0.00001) with significantly lesser treatment time (p < 0.00001). Conclusion: Rapid Arc technique was superior to IMRT in sparing the OARs without compromising target coverage and delivered the plan with lesser monitor unit and treatment time.展开更多
As a deposition technology, gas metal arc welding （GMAW） has shown new promise for rapid prototyping of metallic parts. During the process of metal forming using the arc of GMA W, low heat input and stable droplet t...As a deposition technology, gas metal arc welding （GMAW） has shown new promise for rapid prototyping of metallic parts. During the process of metal forming using the arc of GMA W, low heat input and stable droplet transition are critical to high quality figuration. The effects of various processing parameters on figuration quality were studied in the experiment of GMA W rapid prototyping using the wire of ERSO-6 , including welding voltage, wire feeding rate, welding speed and so on. The optimal parameters for ERSO-6 are obtained. Simultaneously, it is verified that the rapid prototyping parts with favorable structures and quality can be achieved under the conditions of low heat input and stable droplet transition.展开更多
As a deposition technology, robotic metal active gas （MAG） welding has shown new promise for rapid prototyping （ RP） of metallic parts. During the process of metal forming using robotic MAG welding, sectional prof...As a deposition technology, robotic metal active gas （MAG） welding has shown new promise for rapid prototyping （ RP） of metallic parts. During the process of metal forming using robotic MAG welding, sectional profile of single-puss welded bead is critical to formed accuracy and quality of metal pans. In this paper, the experiments of single-pass welded bead for rapid prototyping using robotic MAG welding were carried out. The effect of some edge detectors on the cross-sectional edge of welded bead was discussed and curve fitting was applied using least square fitting. Consequently, the mathematical model of welded bead profile was developed. The experimental results show that good shape could be obtained under suitable welding parameters. Canny operator is suitable to edge detection of welded bead profile, and the mathematical model of welded bead profile developed is approximately parabola.展开更多
Metal device rapid prototyping with welding is one of the research interests at present. A controlled inertial droplet transfer MAG welding (CIDTMAGW) process was developed for the 3D steel device rapid prototyping wi...Metal device rapid prototyping with welding is one of the research interests at present. A controlled inertial droplet transfer MAG welding (CIDTMAGW) process was developed for the 3D steel device rapid prototyping with metal deposition. In this process, by using a special designed wire feeder, a controlled inertia is imposed on the droplet formed on the wire tip and combines with the arc force to make it detached. Thus, according to the requirements of rapid prototyping, the arc heat and the droplet detaching force can be separately controlled to attain a stable and satisfactory metal deposition process. A CIDTMAGW system and a testing manipulator for the 3D steel device rapid prototyping are presented. The required software is completed as well. The experiments proved that the geometric formation of the rapid prototyping device with welding deposition is well agreed the data of the device CAD modeling. The surface of the deposited device is comparatively smooth.展开更多
文摘Background: This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding window IMRT in terms of dosimetric end points and delivery time for head and neck cancer. Materials and Methods: 22 patients with head and neck cancer were selected for a planning comparative study. All patients went to CT-simulation in supine position. PTVs were delineated for two dose level of prescription 70 Gy to the boost-PTV70Gy and 54 Gy to the elective-PTV54Gy in 35 equal fraction/day. Simultaneous Integrated Boost (SIB) technique plan was generated for all patients and optimized with both techniques, Rapid Arc and IMRT with similar planning objectives. Dose of all plans of both techniques were calculated for 6MV photon using AAA implemented in Eclipse treatment planning system (10.0.39) with calculating grid size of 2.5 mm. Results: Comparison of Rapid Arc and IMRT plans in every patient showed significantly higher conformity index (CI95%) (p = 0.021) and sparing of the all OARs with Rapid Arc. The average homogeneity Index (HI95%) of lower prescribed dose target PTV54Gy which is in proximity to Higher dose prescribed target PTV70Gy was improved significantly with rapid Arc (p = 0.0001). D1% of spinal cord dose reduced significantly (p = 0.047) with Rapid Arc and the average mean dose of both left-parotid (21.26 ± 8.5 Gy), right-parotid (22.37 ± 7.44 Gy) were received lesser than with IMRT (22.78 ± 11.2 Gy and 24.1 ± 7.96 Gy) respectively. A significantly less monitor unit (MU) was required to deliver the plan (p < 0.00001) with significantly lesser treatment time (p < 0.00001). Conclusion: Rapid Arc technique was superior to IMRT in sparing the OARs without compromising target coverage and delivered the plan with lesser monitor unit and treatment time.
文摘As a deposition technology, gas metal arc welding （GMAW） has shown new promise for rapid prototyping of metallic parts. During the process of metal forming using the arc of GMA W, low heat input and stable droplet transition are critical to high quality figuration. The effects of various processing parameters on figuration quality were studied in the experiment of GMA W rapid prototyping using the wire of ERSO-6 , including welding voltage, wire feeding rate, welding speed and so on. The optimal parameters for ERSO-6 are obtained. Simultaneously, it is verified that the rapid prototyping parts with favorable structures and quality can be achieved under the conditions of low heat input and stable droplet transition.
文摘As a deposition technology, robotic metal active gas （MAG） welding has shown new promise for rapid prototyping （ RP） of metallic parts. During the process of metal forming using robotic MAG welding, sectional profile of single-puss welded bead is critical to formed accuracy and quality of metal pans. In this paper, the experiments of single-pass welded bead for rapid prototyping using robotic MAG welding were carried out. The effect of some edge detectors on the cross-sectional edge of welded bead was discussed and curve fitting was applied using least square fitting. Consequently, the mathematical model of welded bead profile was developed. The experimental results show that good shape could be obtained under suitable welding parameters. Canny operator is suitable to edge detection of welded bead profile, and the mathematical model of welded bead profile developed is approximately parabola.
文摘Metal device rapid prototyping with welding is one of the research interests at present. A controlled inertial droplet transfer MAG welding (CIDTMAGW) process was developed for the 3D steel device rapid prototyping with metal deposition. In this process, by using a special designed wire feeder, a controlled inertia is imposed on the droplet formed on the wire tip and combines with the arc force to make it detached. Thus, according to the requirements of rapid prototyping, the arc heat and the droplet detaching force can be separately controlled to attain a stable and satisfactory metal deposition process. A CIDTMAGW system and a testing manipulator for the 3D steel device rapid prototyping are presented. The required software is completed as well. The experiments proved that the geometric formation of the rapid prototyping device with welding deposition is well agreed the data of the device CAD modeling. The surface of the deposited device is comparatively smooth.
