ABSTRACT
To satisfy the daily demand of skin condition maintenance, make non-invasive real-time detection, and get proper quantitative evaluation of skin viscoelasticity parameters at the same time, a portable non-invasive detection system to acquire real-time skin tissue viscoelasticity is developed. The system relies mainly on a single-degree-of-freedom forced vibration model, with spring-damp-mass, and on dynamic micro indentation method. The experiment is conducted on two kinds of springs, and on pigskin tissues as well, the system's suitability, accuracy and stability are confirmed. The skin viscoelasticity detection in vivo is also carried out on 20 subjects with different ages, the differences of skin viscoelasticity in various parts of the body are investigated, and the correlations between age and skin viscoelasticity are clarified.
Subject(s)
Humans , Elasticity , Skin , Skin Physiological Phenomena , Time , ViscosityABSTRACT
Objective To retrospectively analyze the setup error in radiotherapy of somal tumors and body metastases using the ExacTrac X-ray portal image,and to evaluate the feasibility and effectiveness of 6D setup error correction in body radiotherapy.Methods The translational and rotational setup errors were calculated by registering the bony structures on the ExacTrac X-setup images to that of the digitally reconstructed setup images,and the corresponding residual errors were calculated together.Results The translational and rotational setup errors in the x (left-right),y (superior-inferior),z (anterior-posterior) and Rx (sagittal),Ry (transverse),Rz (coronal) directions were(2.27±2.02) mm,(4.49±2.52) mm,(2.27± 1.37) mm and (1.02 ± 0.73) °,(0.67 ± 0.68) °,(0.76 ± 0.84) °,respectively.The residual translational and rotational setup errors in the x(r),y(r),z(r) and Rx(r),Ry(r),Rz(r) directions were(0.27±0.48)mm,(0.37±0.45)mm,(0.22±0.30)mm and (0.17±0.33)°,(0.14±0.34)°,(0.16± 0.28) ° respectively.Conclusions Besides the translational setup errors,a certain amount of rotational setup errors exist in radiotherapy of somal tumors and body metastases.By using the 6D setup error correction of the ExacTrac system,a translational less than 0.4 mm and rotational setup errors less than 0.2° could be achieved.
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Objective:The purpose of this paper is to introduce a method of using compensate angles to eliminate rotation set-up errors without six-degree of freedom couch. Methods: To detect six-degree of freedom set-up errors, cone-beam computed tomography (CBCT) scans were acquired. These set-up errors were defined as a matrix to transform from accelerator coordinate system to patient coordinate system. Two independent vectors were defined to describe angles of gantry, collimator and couch in accelerator machine. Transformation of vectors were determined by transformation matrix and re-calculated back to the machine angles. Results:It was found that compensate angles can fully corrected the rotation angles in set-up with limited time consuming. It is feasible to implement compensate angles in routinely radiation procedure. Conclusion:With this method, it is possible to implement the complete corrections of set-up errors in radiotherapy without six-degree of freedom couch and it is convenient in operation as well.
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To restore gait function in paraplegic patients, hip-knee-ankle-foot orthoses are available. Orthoses maintain patient stability when standing and walking by restricting the degree of freedom the lower extremity joints. The disadvantages of orthoses include difficulties in standing and sitting movements, and the large burden placed on the upper extremities in walking. Usage of orthoses in daily living was therefore restricted. We are developing a gait assist robot, which we named WPAL (Wearable Power-Assist Locomotor). WPAL has a high degree of freedom and internal power for flexion-extension direction in each hip, knee, ankle joint. We compared WPAL with the conventional Primewalk orthosis as a preliminary investigation. (1) We compared independent standing ability and walking distance of a walker in WPAL and Primewalk orthosis. All three subjects achieved an independent level in standing and walking in WPAL, despite these users requiring assistance when using the Primewalk. Walking distances with the WPAL were several times greater when compared to walking distance with the Primewalk. (2) We performed a single case study using the patient who made the most entries into WPAL exercise. We compared heart rate, physiological cost index (PCI), modified Borg scale, lateral sway of trunk in 6 minutes walking on treadmill. His heart rate, PCI, and modified Borg scale were significantly lower and lateral sway was significantly smaller in WPAL gait. WPAL which has degree of freedom and internal power in the lower extremities is considered a step toward practical powered orthoses use in gait reconstruction for spinal cord injuries.
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Using three different types of the ankle joint, i.e., the fixed, single-axis, and multi axis type, the gait characteristics of transfemoral amputees were investigated to understand the biomechanics of ankle joint motion during gait of transfemoral amputees with a SNS (swing and stance phase) control prosthesis controlling the flexion-extension of knee in the stance phase unlike conventional swing control prostheses. The socket pressure was measured to explain the resulting gait characteristic of the transfemoral amputees for different ankle joint components. Based on the results from the gait characteristics, socket pressure, knee flexion-extension behavior, and ground reaction vector, the fixed type ankle joint could be considered as the most appropriate ankle joint for the transfemoral amputees using the SNS control prosthesis.
Subject(s)
Humans , Amputees , Ankle Joint , Ankle , Axis, Cervical Vertebra , Freedom , Gait , Knee , Prostheses and ImplantsABSTRACT
Using three different types of the ankle joint, i.e., the fixed, single-axis, and multi axis type, the gait characteristics of transfemoral amputees were investigated to understand the biomechanics of ankle joint motion during gait of transfemoral amputees with a SNS (swing and stance phase) control prosthesis controlling the flexion-extension of knee in the stance phase unlike conventional swing control prostheses. The socket pressure was measured to explain the resulting gait characteristic of the transfemoral amputees for different ankle joint components. Based on the results from the gait characteristics, socket pressure, knee flexion-extension behavior, and ground reaction vector, the fixed type ankle joint could be considered as the most appropriate ankle joint for the transfemoral amputees using the SNS control prosthesis.