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Objective To explore the feasibility of our method on assessing the three-dimensional facial morphological features based on three-dimensional surface imaging techniques.Methods According to the admission criteria,three-dimensional facial images of 34 attractive young Chinese women and 172 healthy reference young women were selected from the three-dimensional facial images database of our department.For those images,anthropometric facial measurements including facial height,width,the degree of convexity and concavity were computed using three-dimensional surface imaging techniques combined with three-dimensional coordinate system.The variance between attractive group and reference group was analyzed and the facial morphological features of each group were preliminarily summarized.Results Both groups met the criteria of mesoprosopy,not the "vertical facial trisection and rule of fifths".The attractive group had a relatively narrow anterior facial frame,a more rounded and full upper face compared with the reference group.They also had smaller intercan thai width compared with the reference group.Moreover,the attractive group showed more prominent nose,more full and prominent medial cheek.In addition,the attractive group shared less protruded upper lips and less retruded chin compared with the reference group.Conclusions Assessing facial morphology using three-dimensional surface imaging techniques is a convenient and feasible method.The evaluation of sagittal facial convexity and concavity is an indispensable part of facial morphology features assessment.
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The hand coordinate systems for measuring vibration exposures and biodynamic responses have been standardized, but they are not actually used in many studies. This contradicts the purpose of the standardization. The objectives of this study were to identify the major sources of this problem, and to help define or identify better coordinate systems for the standardization. This study systematically reviewed the principles and definition methods, and evaluated typical hand coordinate systems. This study confirms that, as accelerometers remain the major technology for vibration measurement, it is reasonable to standardize two types of coordinate systems: a tool-based basicentric (BC) system and an anatomically based biodynamic (BD) system. However, these coordinate systems are not well defined in the current standard. Definition of the standard BC system is confusing, and it can be interpreted differently; as a result, it has been inconsistently applied in various standards and studies. The standard hand BD system is defined using the orientation of the third metacarpal bone. It is neither convenient nor defined based on important biological or biodynamic features. This explains why it is rarely used in practice. To resolve these inconsistencies and deficiencies, we proposed a revised method for defining the realistic handle BC system and an alternative method for defining the hand BD system. A fingertip-based BD system for measuring the principal grip force is also proposed based on an important feature of the grip force confirmed in this study.
Subject(s)
Hand Strength , Hand , VibrationABSTRACT
Objective To investigate the development and application of thoracic-abdominal tumor precise positioning puncture devices.Methods Based on the principle of locating and pendulum,as well as the isocenter multi-angle non-coplanar light principle on the chest and abdomen precise radiation therapy,the thoracic-abdominal tumor precise positioning puncture devices was developed with the use of tumor center spatial location method and radiotherapy positioning coordination system transfer method of radiation oncology treatment planning system (TPS).Results The device was applied to puncture chest tumor,reaching 100％ accuracy rate of one time biopsy.The average error in the space between tumor center (pre-puncture points) and actual puncture point (the actual arrival at the needle tip) was 2.59 mm,and the average displacement in the space distance of skin marker was 0.56 mm.Conclusion Using the newly developed thoracic-abdominal tumor precise positioning puncture devices can reduce the dependence on doctor's experience and the technique,as well can significantly improve the accuracy rate of puncture.As a result,it is a promising device which can be put in application.
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Objective In order to avoid potential injuries imposed to human body, it can be feasible to use the musculoskeletal models which can be reconstructed from the cadaver color cryosection (CCC) images, computerized tomography (CT) images, magnetic resonance (MR) images or other images to analyze the dynamic properties of muscles in vivo during human movement. Methods We reconstruct the lower limb musculoskeletal model and define the uniform joint coordinate system (JCS) on the model and the subject. The coordinate transformation of the muscle attachment points both on the model and the subject is described in detail. Results The length and the moment arm of the biceps femoris (short head) during knee flexion are calculated and analyzed. Conclusion This method plays an important role in improving the kinematics and dynamic simulation and the muscle force estimation.
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Objective In order to avoid potential injuries imposed to human body,it could be feasible to use the musculoskeletal models which can be reconstructed from the cadaver color cryosection(CCC)images,computerized tomography(CT)images,magnetic resonance(MR)images or other images to analyze the dynamic properties of muscles in vivo during human movement.Mothod We reconstruct the lower limb musculoskeletal model and define the uniform ioint coordinate system(JCS)on the model and the subject.The coordinate transformation of the muscle attachment points both on the model and the subject is described in detail.Results The length and the moment arm of the biceps femoris(short head)during knee flexion are calculated and analyzed.Conclusion This method plays an important role in improving the kinematics and dynamic simulation and the muscle force estimation.
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Objective In order to avoid potential injuries imposed to human body,it could be feasible to use the musculoskeletal models which can be reconstructed from the cadaver color cryosection(CCC)images,computerized tomography(CT)images,magnetic resonance(MR)images or other images to analyze the dynamic properties of muscles in vivo during human movement.Mothod We reconstruct the lower limb musculoskeletal model and define the uniform ioint coordinate system(JCS)on the model and the subject.The coordinate transformation of the muscle attachment points both on the model and the subject is described in detail.Results The length and the moment arm of the biceps femoris(short head)during knee flexion are calculated and analyzed.Conclusion This method plays an important role in improving the kinematics and dynamic simulation and the muscle force estimation.
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Objective In order to avoid potential injuries imposed to human body,it could be feasible to use the musculoskeletal models which can be reconstructed from the cadaver color cryosection(CCC)images,computerized tomography(CT)images,magnetic resonance(MR)images or other images to analyze the dynamic properties of muscles in vivo during human movement.Mothod We reconstruct the lower limb musculoskeletal model and define the uniform ioint coordinate system(JCS)on the model and the subject.The coordinate transformation of the muscle attachment points both on the model and the subject is described in detail.Results The length and the moment arm of the biceps femoris(short head)during knee flexion are calculated and analyzed.Conclusion This method plays an important role in improving the kinematics and dynamic simulation and the muscle force estimation.
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Developments in computer technology have made possible the 3-dimensional (3-D) evaluation of hard and soft tissues in orthodontic diagnosis, treatment planning and post-treatment results. In this study, Korean adults with normal occlusion (male 30, female 30) were scanned by a 3-D laser scanner, then 3-D facial images formed by the Rapidform 2004 program (Inus Technology Inc., Seoul, Korea.). Reference planes in the facial soft tissue 3-D images were established and a 3-D coordinate system (X axis-left/right, Y axis-superior/inferior, Z axis-anterior/posterior) was established by using the soft tissue nasion as the zero point. Twenty-nine measurement points were established on the 3-D image and 43 linear measurements, 8 angular measurements, 29 linear distance ratios were obtained. The results are as follows; there were significant differences between males and females in the nasofrontal angle (male: 142 degrees, female: 147 degrees) and transverse nasal prominence (male: 112 degrees, female: 116 degrees) (p < 0.05). The transverse upper lip prominence was 107 degrees in males, 106 degrees in females and the transverse mandibular prominence was 76 degrees in both males and females. Li-Me' was 0.4 times the length of Go-Me' (mandibular body length) and the mouth height was also 0.4 times the width of the mouth width. The linear distance ratio from the coronal reference plane of FT, Zy, Pn, ULPm, Li, Me' was -1/-1/1/0.5/0.5/-0.6 respectively. The 3-D facial model of Korean adults with normal occlusion were be constructed using coordinate values and linear measurement values. These data may be used as a reference in 3-D diagnosis and treatment planning for malocclusion and dentofacial deformity patients and applied for 3-D analysis of facial soft tissue changes before and after orthodontic treatment and orthognathic surgery.
Subject(s)
Adult , Female , Humans , Male , Dentofacial Deformities , Diagnosis , Imaging, Three-Dimensional , Lip , Malocclusion , Mouth , Orthognathic Surgery , SeoulABSTRACT
The purpose of this study was to redefine the cephalometric landmarks in three-dimensional (3D) images, which are used in orthodontic cephalometric radiography, and to evaluate the reproducibility of each landmark for 3D cephalometric analysis. Eighteen CT scans were taken at the Department of Diagnostic Radiology at Seoul National University Dental Hospital and manipulated with V works 4.0 (Cybermed Inc., Seoul, Korea). The coordinate system was established using 7 reference points, with no more than 4 points on the same plane. These 7 points were generated as a volume model, the voxel size of which was 4 by 4 by 2 (threshold value = 639). The cephalometric landmarks were selected at the multiplanar reformation (MPR) window on the volume mode of V works 4.0. The selected landmarks were exported to V surgery (Cybermed Inc., Seoul, Korea) for the calculation of coordinate values. All the data were taken twice with a lapse of 2 weeks by one investigator. The reproducibility of each landmark was 0.17 ~ 1.21 mm in the x axis, 0.30 ~ 1.53 mm in the y axis, and 0.27 ~ 1.81 mm in the z axis. In all three axes, the range of error was similar. These error ranges were acceptable with regards to the pixel space and slice thickness. The most reproducible points were I points which were selected on the basis of the volume model. The least reproducible points were J points that were defined by sutures.
Subject(s)
Humans , Axis, Cervical Vertebra , Head , Neck , Radiography , Research Personnel , Seoul , Sutures , Tomography, X-Ray ComputedABSTRACT
The three-dimensional (3D) changes of bone, soft tissue and the ratio of soft tissue to bony movement was investigated in 8 skeletal Class III patients treated by mandibular setback surgery. CT scans of each patient at pre- and post-operative states were taken. Each scan was segmented by a threshold value and registered to a universal three-dimensional coordinate system, consisting of an FH plane, a mid-sagittal plane, and a coronal plane defined by PNS. In the study, the grid parallel to the coronal plane was proposed for the comparison of the changes. The bone or soft tissue was intersected by the projected line from each point on the gird. The coordinate values of intersected point were measured and compared between the pre- and post-operative models. The facial surface changes after setback surgery occurred not only in the mandible, but also in the mouth corner region. The soft tissue changes of the mandibular area were measured relatively by the proportional ratios to the bone changes. The ratios at the mid-sagittal plane were 77 ~ 102% (p < 0.05). The ratios at all other sagittal planes had similar patterns to the mid-sagittal plane, but with decreased values. And, the changes in the maxillary region were calculated as a ratio, relative to the movement of a point representing a mandibular movement. When B point was used as a representative point, the ratios were 14 ~ 29%, and when Pog was used, the ratios were 17 ~ 37% (p < 0.05). In case of the 83rd point of the grid, the ratios were 11 ~ 22% (p < 0.05).