Mm In Y-axis Research Articles

Is Ranawat triangle method accurate in estimating hip joint center in Japanese population?

BackgroundLittle information has been available regarding the usefulness of Ranawat triangle method in estimating anatomical hip joint center in the Japanese population. In this study, we aimed to determine the accuracy of the method in estimating hip joint center. MethodsUsing digitally reconstructed radiographs of 123 normal hips (123 patients), we measured the hip joint center coordinates (Cx, Cy) with reference to the ipsilateral lowest point of the teardrop, the pelvic width, and the pelvic height. Using these measurement values, we performed the following analyses: (1) the relationship of hip joint center location with pelvic dimensions; (2) accuracy of Ranawat method in estimating hip joint center; (3) alternative methods to estimate hip joint center using pelvic height. ResultsThe mean Cx and Cy were 32 ± 3.0 mm and 13 ± 2.1 mm, respectively. Pelvic height was positively correlated with Cx (r = 0.51, p < 0.001) and Cy (r = 0.69, p < 0.001), but the correlations of pelvic width with Cx and Cy were negligible. The mean estimation error of the Ranawat method was −6.7 ± 2.6 mm in x-axis and 6.6 ± 1.9 mm in y-axis, respectively. The hip joint center was estimated within a 5 mm error in both axes in only 8 hips (6.5%). Thus, we developed two estimating methods using pelvic height, modified Ranawat method and pelvic height ratio method, and the estimation errors of these methods were within 5 mm in both axes in 118 hips (96%) and 116 hips (94%), respectively. ConclusionsRanawat method showed poor accuracy in estimating anatomical hip joint center and is not recommended for clinical use. Our alternative methods may be useful for surgeons planning the position of the acetabular component in total hip arthroplasty.

Design and development of a 5R 2DOF parallel robot arm for handling paper pot seedlings in a vegetable transplanter

This paper presents a complete mechatronic approach in designing and developing a robotic arm for handling paper pot seedlings in a transplanter for the purpose of inclusion of automation and possible reduction of heavy mechanical components in pot seedling transplanters by utilizing microcontrollers and embedded systems. The robot arm developed was of two degrees of freedom (DOF), five revolute joints (5R) with parallel arm structure using 3D printed parts, commercially available embedded microcontrollers and sensors. The gripper which was connected to the parallel robot arm performed pick and place operations at a desired path. For achieving the preferred maximum and minimum reach of the gripper, a suitable method for synthesizing the link length has been discussed. A complete logical technique to program microcontrollers was developed which enabled smooth actuation of both the independent input links simultaneously. Parabolic blends were utilized at the beginning and at the end of the robot input joint trajectory for minimizing dynamic vibrations during continuous operation. The developed robot arm was flexible to change the number of pickup points in a row, pickup and drop co-ordinates within the workspace envelope. Finally, the robot arm was tested and evaluated for picking and placing 15 numbers (4 replications, 60 runs) of actual paper pots filled with vermicompost, soil and sand. Each pot weighed approximately 80 g with a moisture content of approximately 5%. The robot arm took 2.1 to 2.4 s to pick and drop a pot seedling from a distance of 116.6 mm with a maximum power consumption of 20.47 W. Experimental results showed that no pots were missed in picking and dropping, no visual cracks and damage appeared on the pots. The repeatability of the robot arm was 2.1 mm in X-axis and 3.4 mm in Y-axis.

The Development of Walking Pattern and Stabilization of Humanoid Soccer Robot DARDROID (DARWIN-ODROID)

One of the main problems on humanoid robot is motion, which is related to the stability of the robot when walking. This problem can be solved by using static walking and dynamic walking method, and the application of zero moment point and inverse kinematics supported by inertial measurement unit (IMU) with also the application of Kalman filter method and Proportional Derivative (PD) controller. The PD controller uses feedback from IMU to improve the servo position obtained from the calculation of zero moment point and inverse kinematics during the robot walking. This research would be done by comparing results from previous research and direct examination of a humanoid robot to get its stability margin and velocity. The result of humanoid robot stability margin is 5.367 mm in X-axis and 10.567 mm in Y-axis, and its minimum velocity 0.0524 m/s and maximum velocity 0.0633 m/s on grass with altitude 3 cm and minimum velocity 0.0933 m/s and maximum velocity 0.1048 m/s on grass with altitude 1.5 cm.

Planning target volume margin based on the image-guided radiotherapy in nasopharyngeal carcinoma

Objective To analyze set-up errors for irradiation of nasopharyngeal carcinoma by using kilo-voltage cone beam computed tomography (kV-KBCT) scanning, and to calculate the external margin from planning target volume (PTV) of nasopharyngeal carcinoma. Methods A total of 150 nasopharyngeal carcinoma patients in Meizhou People's Hospital from December 2014 to November 2016 were treated by image-guided radiation therapy (IGRT), kV-KBCT, CT image scanning matcthed by bone and grey alignment. PTV of nasopharyngeal carcinoma was also calculated. Results According to PTV formula, the external distance before radiotherapy guided by grey alignment was 0.5 mm in X-axis, 0.4 mm in Y-axis, 0.8 mm in Z-axis. While the distance was 0.1 mm in X-axis, 0.5 mm in Y-axis, 1.7 mm in Z-axis guided by bone alignment. After radiotherapy, the external distance guided by grey alignment was 0.4 mm in X-axis, 0.5 mm in Y-axis, 0.9 mm in Z-axis. While the distance was 0.1 mm in X-axis, 0.9 mm in Y-axis, 2.0 mm in Z-axis guided by bone alignment. There was no significant difference in set-up errors of 3 directions and 2 aligned ways before and after treatment. Conclusions The PTV within 3 mm is safe when IGRT is used for directing radiotherapy of nasopharyngeal carcinoma, and kV-KBCT is an effective image equipment. Key words: Nasopharyngeal neoplasms; Radiotherapy, computer-assisted; Cone-beam computed tomography; Set-up errors

Impact of movement frequency on gross tumor volume of moving tumors based on three-and four-dimensional CT scans

Objective To investigate the impact of movement frequency on gross tumor volume (GTV) of moving tumors and coordinate position of the central point based on three-and four-dimensional CT scans. Methods The respiratory motion platform from Modus and 8 phantoms with different shapes and volumes were used to simulate the movement of lung tumors. Three-and four-dimensional CT scans were performed at movement frequencies of 10, 15, and 20 times/min. GTV (GTV10, GTV15, and GTV20) and IGTV (IGTV10, IGTV15, and IGTV20) were delineated, and the coordinate position of the central point was obtained. The Friedman test was performed for GTV10, GTV15, GTV20, IGTV10, IGTV15, IGTV20, and the coordinate position of the central point. Results GTV10, GTV15, and GTV20 at the three movement frequencies were 12.41±14.26 cm3, 10.38±11.18 cm3, and 12.50±15.23 cm3, respectively (P=0.687), and the positional values were -8.2±96.2 mm, -8.6±96.1 mm, and -8.6±95.7 mm in x-axis (P=0.968), 108.2±25.0 mm, 110.4±22.5 mm, and 109.0±24.2 mm in y-axis (P=0.028), and 65.2±13.7 mm, 65.4±13.4 mm, and 65.4±13.2 mm in z-axis (P=0.902). IGTV10, IGTV15, and IGTV20 at the three movement frequencies were 17.78±19.42 cm3, 17.43±19.56 cm3, and 17.44±18.80 cm3, respectively (P=0.417), and the positional values were -7.7±95.9 mm, -7.9±95.6 mm, and -7.9±95.1 mm in x-axis (P=0.325), 109.4±24.5 mm, 109.6±24.1 mm, and 109.2±24.3 mm in y-axis (P=0.525), and 65.5±13.3 mm, 65.6±13.4 mm, and 65.5±13.3 mm in z-axis (P=0.093). Conclusions During simulated positioning of thoracic tumors, respiratory movement frequency has no significant impact on target volume established by four-dimensional CT scan. There are no significant differences in three-dimensional target volume established at different respiratory frequencies, but respiratory frequency has a significant impact on the position of the central point of the target volume in y-axis. Key words: Respiratory movement; Target volume; Tomography, X-ray computed; Body phantom

P-0089 The Position Difference of Liver Cancer in Free-Breathing Condition Between 3DCT and 4DCT Simulation

IntroductionTo investigate the position difference of liver cancer in free-breathing condition between 3DCT and 4DCT simulation. Methods12 patients with liver cancer after TACE were scanned at free breath condition by simulation 4DCT and 3DCT. Gross tumor volume (GTV), normal tissues and skin markers of end expiration, end inspiration and T20 of 4DCT and 3DCT were contoured. The three dimensional position variation of them were measured and their correlation were analyzed. Resultsthe targets position of end expiration and end inspiration were different from 3DCT. The target movement range of liver cancer in three dimensional direction was different, that was 8.44±6.52mm in z-axis, 3.78±3.07mm in y-axis, 1.11±1.27mm in x-axis. There was statistical significant correlation for movement range of GTV with that of liver, gallbladder, right diaphragmatic dome and right skin marker. ConclusionCorresponding to target position of T20, there was great difference between individual GTV position of 3DCT and 4DCT.

A study on position variation of liver cancer and interested structures during respiration by 4DCT and 3DCT.

e13529 Background: The movement of liver cancer targets could be infected by respiration.The aim of this study was to investigate the position difference of liver cancer in free-breathing condition between 3DCT and 4DCT simulation, and to investigate the correlation of position movement of primary tumor with normal tissues and skin markers. Methods: 12 patients with liver cancer after TACE were scanned at free breath condition by simulation 4DCT and 3DCT. A coordinate system was created based on image of T20 (maximum intensity projection) reconstructed from 4DCT, gross tumor volume (GTV), normal tissues and skin markers of end expiration, end inspiration and T20 of 4DCT and 3DCT were contoured. The three dimensional position variation of them were measured and their correlation were analyzed. Results: Corresponding to target position of T20, the targets position of end expiration and end inspiration were different from 3DCT in x-axis(χ2=2.552, p=0.579), y-axis(χ2=6.938, p=0.031), z-axis(χ2=10.606, p=0.005). The target movement range of liver cancer in three dimensional direction was different, that was 8.44±6.52mm in z-axis, 3.78±3.07mm in y-axis, 1.11±1.27mm in x-axis,. 9.88±6.43mm in three dimensional vector. There was statistical significant correlation for movement range of GTV with that of liver, gallbladder, right diaphragmatic dome and right skin marker(r=0.738-0.922, p=0.037-0.001), but there was no significant correlation for movement range of GTV with that of kidney, pancreas, spleen, and middle skin marker. Conclusions: Corresponding to target position of T20, there was great difference between individual GTV position of 3DCT and 4DCT. What's more, it was not all of the movement of abdominal normal tissues correlated to the movement of GTV. These uncertain factors may infer dose mapping of GTV and abdominal risk organs.

18F-FDG-PET and MRI in patients with malignancies of the liver and pancreas

Summary Purpose: To evaluate the accuracy of retrospective rigid image registration and fusion between F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) of the upper abdomen. Patients, material, methods: Image fusion of PET and MRI was performed in 30 patients with suspected malignancy of the liver or pancreas. Using a commercially available image fusion tool capable of rigid manual point-based registration, PET-Images were retrospectively registered and fused by matching eight homologous points in the 3D spoiled gradient echo (GRE) MRI sequences acquired in portal venous phase and in the CT-component of PET/CT. Two separate observers (R1, R2) assessed accuracy of image registration by determining the distances in the x-, y- and z-axis as well as the absolute distance between anatomical landmarks which differed from the landmarks chosen for registration. Quality of fusion was graded using a three point grading scale (1 poorly fused; 2 satisfactory fused; 3 correctly fused) and compared to hybrid PET/CT fusion. Results: Mean time of registration per patient was less than 2 minutes. Objective registration assessment showed errors between 2.4–6.3 mm in x-axis: mean 3.6 mm (R1); 4.6 mm (R2), 2.3–9.3 mm in y-axis (mean 5.1 mm; 5.5 mm) and 3.3–12.0 mm in z-axis (mean 5.9 mm; 5.9 mm.) The mean error in absolute distance between points was 6.0–16.8 mm (mean 9.9 mm; 10.6 mm). In visual assessment, most fusions were graded to be satisfactory or correctly fused: R1, R2: grade 3, 11/30 (36.7%), 22/30 (73.3%); grade 2, 13/30 (43.3%), 8/30 (26.7%); grade 1, 6/30 (20%), 0/30 (0%). Fusions were mostly comparable to hybrid PET/ CT fusions. All of the fusions were defined as diagnostically relevant by both observers. Conclusion: Retrospective rigid image fusion of FDGPET and MRI of the upper abdomen using the CT-component of PET/CT for registration is feasible without adaptation in image acquisition protocols and shows sub-centimeter registration errors in most cases.