Journal of Computing and Information Science in Engineering
The rapid development of digitization and 3D printing is creating an ever-increasing demand for m... more The rapid development of digitization and 3D printing is creating an ever-increasing demand for methods for the automated generation of 3D models from real components. Thanks to the progress and widespread use of computer vision, it is now possible to merge classical engineering tasks with image processing techniques. Computer-aided design can therefore be automated using information from image data. In this study, we present a novel method for automated digitization of 3D structures using AprilTag fiducial system and Solid Geometry Library. The proposed design process is implemented in matlab. AprilTags are used to realize 3D coordinate measurements to digitally capture the 3D dimensions of real components. Based on these data, 3D replica models are generated with the Solid Geometry Library toolbox, which enables the automated design of 3D surface models in matlab. The mathematical background of this procedure is described. The capability of the proposed method is demonstrated on 3...
Einleitung: Durch die weite Nutzung von Navigationssytemen in der HNO-Chirurgie gibt es Ansätze f... more Einleitung: Durch die weite Nutzung von Navigationssytemen in der HNO-Chirurgie gibt es Ansätze fortgeschrittenere Systeme, wie das Navigated Control System, einzuführen. Das Navigated Control System nutzt Informationen eines bildgestützten Navigationssystems zur intraoperativen Kontrolle[for full text, please go to the a.m. URL]
International journal of computer assisted radiology and surgery, 2018
The minimally invasive closure of the left atrial appendage is a promising alternative to anticoa... more The minimally invasive closure of the left atrial appendage is a promising alternative to anticoagulation for stroke prevention in patients suffering from atrial fibrillation. One of the challenges of this procedure is the correct positioning and the coaxial alignment of the tip of the catheter sheath to the implant landing zone. In this paper, a novel preoperative planning system is proposed that allows patient-individual shaping of catheters to facilitate the correct positioning of the catheter sheath by offering a patient-specific catheter shape. Based on preoperative three-dimensional image data, anatomical points and the planned implant position are marked interactively and a patient-specific catheter shape is calculated if the standard catheter is not considered as suitable. An approach to calculate a catheter shape with four bends by maximization of the bending radii is presented. Shaping of the catheter is supported by a bending form that is automatically generated in the pl...
This paper presents a finite position synthesis (f.p.s.) procedure of a spatial single-degree-of-... more This paper presents a finite position synthesis (f.p.s.) procedure of a spatial single-degree-of-freedom linkage that we call origami-evolved, spherically constrained spatial revolute–revolute (RR) chain here. This terminology is chosen because the linkage may be found from the mechanism equivalent of an origami folding pattern, namely, known as the Miura-ori folding. As shown in an earlier work, the linkage under consideration has naturally given slim shape and essentially represents two specifically coupled spherical four-bar linkages, whose links may be identified with spherical and spatial RR chains. This provides a way to apply the well-developed f.p.s. theory of these linkage building blocks in order to design the origami-evolved linkage for a specific task. The result is a spherically constrained spatial RR chain, whose end effector may reach three finitely separated task positions. Due to an underspecified spherical design problem, the procedure provides several free design ...
The concept presented in this paper describes two new approaches to integrate transfer support fu... more The concept presented in this paper describes two new approaches to integrate transfer support functions into wheelchairs. The goal is to relieve caregivers and nurses in their daily task of lifting patients from and to the wheelchair without the need of an additional external lift device, such as commonly used lifting cranes or lifting belts. The contributions of this paper are (i) the design of two different mechanical linkages, which realize two types of transfer motions, (ii) the selection of a passive actuator for weight compensation and simulation of the force induced by it (static design), as well as (iii) the experimental evaluation of the simulation using rapid prototyping functional models of the concepts. The results are two different design concepts, each of which can realize a particular, smooth transfer motion.
International journal of oral and maxillofacial surgery, 2001
Up to now it has only been possible to monitor the alignment of orbital floor fractures postopera... more Up to now it has only been possible to monitor the alignment of orbital floor fractures postoperatively with a computed tomography (CT) examination with coronal sectioning. If this showed an incorrect positioning, renewed surgery and anaesthetics were often required. The purpose of this study was the implementation and definition of the spectrum of indications for intraoperative CT examinations while keeping patient radiation exposure to a minimum. Thirty-two orbital fracture cases were examined pre- and intraoperatively using the mobile computer tomograph Tomoscan M in coronal sectioning. In this patient collective, 12 cases showed an isolated orbital floor fracture and twenty cases an orbital floor fracture associated with a zygomatic fracture. The technical prerequisite for these examinations was the construction of a suitable radiolucent operating table which permitted coronal sections to be made with the CT-Gantry tilted. The authors aimed to reduce radiation exposure by optimi...
2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2007
This article presents a novel microfluidic module system for the synthesis of radiopharmaceutical... more This article presents a novel microfluidic module system for the synthesis of radiopharmaceutical products. As a main function a piezo-actuated diaphragm valve is produced with rapid prototyping procedures. A system for the automatic characterization of microvalves is described. The built microvalve is characterized by a very high throughput and low leakage rate even for gaseous media. The valve as other passive modules like mixer elements can be easily combined to a microfluidic system. The system makes the application of radiopharmaceutical products more effective and less costly intensive.
2010 IEEE International Conference on Robotics and Biomimetics, 2010
This paper gives an overview of a project, which is focused on the development of a convenient de... more This paper gives an overview of a project, which is focused on the development of a convenient device for continuous blood pressure (BP) monitoring with wireless communication interface. The reliability of long-term automatically monitoring is the main focus for current paper. 18 healthy subjects were tested with the continuous BP monitor against a brand of community-based BP monitor. Accuracy assessment
In this article, a new concept for navigated laser surgery is presented. Mechanically rotating in... more In this article, a new concept for navigated laser surgery is presented. Mechanically rotating instruments such as drills or mills for bone treatment have the disadvantage of damaging the surrounding bone by the generated frictional heat. Cooling of the instrument cannot avoid this damage completely. Laser systems are an alternative solution for bone removal. Areas of application for bone treatment laser systems are the dental implantology and the osteotomy. The goal of the approach presented here was to combine the advantages of laser treatment with the precision and safety of navigated control. During the use of medical laser systems, the tissue is not only removed exactly in the focus of the laser. It is removed inside of a remove range around the focus. The amount of removed bone cannot be determined only by performance adjustment and the position of the laser because the size of the remove range is unknown. The new approach is to use a position- and orientation-dependent power-controlled laser. Therefore, a calibration of the laser parameters has to be accomplished. The position and orientation of the laser handpiece is measured by an optical measurement system. The laser parameters and the tissue properties are determined by a calibration procedure. On the basis of a preoperative planning, the laser remove range is adjusted by modulation of the laser power. Near to border areas or sensitive structure, the laser power is decreased. Therewith, a precise and safe bone removal according to a preoperative planning without damaging the bone by frictional heat is possible. The inaccuracies as result of simplifications by the calibration procedure have to be verified.
A new concept was developed based on the experience gained in dental rehabilitation with implanta... more A new concept was developed based on the experience gained in dental rehabilitation with implantation in the oral maxillofacial region. Despite the use of cooling systems, mechanically rotating instruments may damage the surrounding tissue due to the frictional heat generated. An alternative approach for bone removal is laser application. A preoperative plan was prepared. Laser ablation was performed in accordance with the data set on bovine bone using a navigation system. This new concept allows precise bone removal and adjustment of the laser power according to the preoperative plan. The power of the laser automatically decreases as it approaches the border of the planned cavity or important anatomical structures. The advantage of this approach is precise and safe bone removal without damaging the bone by frictional heat.
Journal of Computing and Information Science in Engineering
The rapid development of digitization and 3D printing is creating an ever-increasing demand for m... more The rapid development of digitization and 3D printing is creating an ever-increasing demand for methods for the automated generation of 3D models from real components. Thanks to the progress and widespread use of computer vision, it is now possible to merge classical engineering tasks with image processing techniques. Computer-aided design can therefore be automated using information from image data. In this study, we present a novel method for automated digitization of 3D structures using AprilTag fiducial system and Solid Geometry Library. The proposed design process is implemented in matlab. AprilTags are used to realize 3D coordinate measurements to digitally capture the 3D dimensions of real components. Based on these data, 3D replica models are generated with the Solid Geometry Library toolbox, which enables the automated design of 3D surface models in matlab. The mathematical background of this procedure is described. The capability of the proposed method is demonstrated on 3...
Einleitung: Durch die weite Nutzung von Navigationssytemen in der HNO-Chirurgie gibt es Ansätze f... more Einleitung: Durch die weite Nutzung von Navigationssytemen in der HNO-Chirurgie gibt es Ansätze fortgeschrittenere Systeme, wie das Navigated Control System, einzuführen. Das Navigated Control System nutzt Informationen eines bildgestützten Navigationssystems zur intraoperativen Kontrolle[for full text, please go to the a.m. URL]
International journal of computer assisted radiology and surgery, 2018
The minimally invasive closure of the left atrial appendage is a promising alternative to anticoa... more The minimally invasive closure of the left atrial appendage is a promising alternative to anticoagulation for stroke prevention in patients suffering from atrial fibrillation. One of the challenges of this procedure is the correct positioning and the coaxial alignment of the tip of the catheter sheath to the implant landing zone. In this paper, a novel preoperative planning system is proposed that allows patient-individual shaping of catheters to facilitate the correct positioning of the catheter sheath by offering a patient-specific catheter shape. Based on preoperative three-dimensional image data, anatomical points and the planned implant position are marked interactively and a patient-specific catheter shape is calculated if the standard catheter is not considered as suitable. An approach to calculate a catheter shape with four bends by maximization of the bending radii is presented. Shaping of the catheter is supported by a bending form that is automatically generated in the pl...
This paper presents a finite position synthesis (f.p.s.) procedure of a spatial single-degree-of-... more This paper presents a finite position synthesis (f.p.s.) procedure of a spatial single-degree-of-freedom linkage that we call origami-evolved, spherically constrained spatial revolute–revolute (RR) chain here. This terminology is chosen because the linkage may be found from the mechanism equivalent of an origami folding pattern, namely, known as the Miura-ori folding. As shown in an earlier work, the linkage under consideration has naturally given slim shape and essentially represents two specifically coupled spherical four-bar linkages, whose links may be identified with spherical and spatial RR chains. This provides a way to apply the well-developed f.p.s. theory of these linkage building blocks in order to design the origami-evolved linkage for a specific task. The result is a spherically constrained spatial RR chain, whose end effector may reach three finitely separated task positions. Due to an underspecified spherical design problem, the procedure provides several free design ...
The concept presented in this paper describes two new approaches to integrate transfer support fu... more The concept presented in this paper describes two new approaches to integrate transfer support functions into wheelchairs. The goal is to relieve caregivers and nurses in their daily task of lifting patients from and to the wheelchair without the need of an additional external lift device, such as commonly used lifting cranes or lifting belts. The contributions of this paper are (i) the design of two different mechanical linkages, which realize two types of transfer motions, (ii) the selection of a passive actuator for weight compensation and simulation of the force induced by it (static design), as well as (iii) the experimental evaluation of the simulation using rapid prototyping functional models of the concepts. The results are two different design concepts, each of which can realize a particular, smooth transfer motion.
International journal of oral and maxillofacial surgery, 2001
Up to now it has only been possible to monitor the alignment of orbital floor fractures postopera... more Up to now it has only been possible to monitor the alignment of orbital floor fractures postoperatively with a computed tomography (CT) examination with coronal sectioning. If this showed an incorrect positioning, renewed surgery and anaesthetics were often required. The purpose of this study was the implementation and definition of the spectrum of indications for intraoperative CT examinations while keeping patient radiation exposure to a minimum. Thirty-two orbital fracture cases were examined pre- and intraoperatively using the mobile computer tomograph Tomoscan M in coronal sectioning. In this patient collective, 12 cases showed an isolated orbital floor fracture and twenty cases an orbital floor fracture associated with a zygomatic fracture. The technical prerequisite for these examinations was the construction of a suitable radiolucent operating table which permitted coronal sections to be made with the CT-Gantry tilted. The authors aimed to reduce radiation exposure by optimi...
2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2007
This article presents a novel microfluidic module system for the synthesis of radiopharmaceutical... more This article presents a novel microfluidic module system for the synthesis of radiopharmaceutical products. As a main function a piezo-actuated diaphragm valve is produced with rapid prototyping procedures. A system for the automatic characterization of microvalves is described. The built microvalve is characterized by a very high throughput and low leakage rate even for gaseous media. The valve as other passive modules like mixer elements can be easily combined to a microfluidic system. The system makes the application of radiopharmaceutical products more effective and less costly intensive.
2010 IEEE International Conference on Robotics and Biomimetics, 2010
This paper gives an overview of a project, which is focused on the development of a convenient de... more This paper gives an overview of a project, which is focused on the development of a convenient device for continuous blood pressure (BP) monitoring with wireless communication interface. The reliability of long-term automatically monitoring is the main focus for current paper. 18 healthy subjects were tested with the continuous BP monitor against a brand of community-based BP monitor. Accuracy assessment
In this article, a new concept for navigated laser surgery is presented. Mechanically rotating in... more In this article, a new concept for navigated laser surgery is presented. Mechanically rotating instruments such as drills or mills for bone treatment have the disadvantage of damaging the surrounding bone by the generated frictional heat. Cooling of the instrument cannot avoid this damage completely. Laser systems are an alternative solution for bone removal. Areas of application for bone treatment laser systems are the dental implantology and the osteotomy. The goal of the approach presented here was to combine the advantages of laser treatment with the precision and safety of navigated control. During the use of medical laser systems, the tissue is not only removed exactly in the focus of the laser. It is removed inside of a remove range around the focus. The amount of removed bone cannot be determined only by performance adjustment and the position of the laser because the size of the remove range is unknown. The new approach is to use a position- and orientation-dependent power-controlled laser. Therefore, a calibration of the laser parameters has to be accomplished. The position and orientation of the laser handpiece is measured by an optical measurement system. The laser parameters and the tissue properties are determined by a calibration procedure. On the basis of a preoperative planning, the laser remove range is adjusted by modulation of the laser power. Near to border areas or sensitive structure, the laser power is decreased. Therewith, a precise and safe bone removal according to a preoperative planning without damaging the bone by frictional heat is possible. The inaccuracies as result of simplifications by the calibration procedure have to be verified.
A new concept was developed based on the experience gained in dental rehabilitation with implanta... more A new concept was developed based on the experience gained in dental rehabilitation with implantation in the oral maxillofacial region. Despite the use of cooling systems, mechanically rotating instruments may damage the surrounding tissue due to the frictional heat generated. An alternative approach for bone removal is laser application. A preoperative plan was prepared. Laser ablation was performed in accordance with the data set on bovine bone using a navigation system. This new concept allows precise bone removal and adjustment of the laser power according to the preoperative plan. The power of the laser automatically decreases as it approaches the border of the planned cavity or important anatomical structures. The advantage of this approach is precise and safe bone removal without damaging the bone by frictional heat.
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Papers by Tim Lueth