Analysis of Vertical Ground Reaction Force Variables Using Foot Scans in Hemiplegic Patients

OBJECTIVE: To analyze the differences in the vertical ground reaction force (GRF) variables of hemiplegic patients compared with a control group, and between the affected and unaffected limbs of hemiplegic patients using foot scans. METHODS: Patients (n=20) with hemiplegia and healthy volunteers (n=20) underwent vertical force analysis. We measured the following: the first and second peak forces (F1, F2) and the percent stances at which they occurred (T1, T2); the vertical force impulse (VFI) and stance times. The GRF results were compared between the hemiplegic patients and control individuals, and between the affected and unaffected limbs of hemiplegic patients. Additionally, we analyzed the impulse of the unaffected limb according to the motor assessment scale (MAS), Brunnstrom stage, and a Timed Up and Go Test. RESULTS: The F1s and F2s of the affected and unaffected limbs were significantly less than those of the normal control individuals (p<0.05). The T1s of both the affected and unaffected limbs of the patients were greater than control individuals, whilst the T2s were lower (p<0.05). Greater impulses and stance times were recorded on both sides of the patients than in the limbs of the control individuals (p<0.05). The MAS, Brunnstrom stage and Timed Up and Go Test results were significantly correlated with the VFI of the unaffected limbs (p<0.05). CONCLUSION: The high impulse values of the unaffected limb were associated with complications during gait rehabilitation. Therefore, these results suggest that unaffected limbs should also be taken into consideration in these patients.

Changes in Activation of Abdominal Muscles at Selected Angles During Trunk Exercise by Using Ultrasonography

OBJECTIVE: To investigate the changes of activation of the abdominal muscles depending on exercise angles and whether the activation of rectus abdominis differs according to the location, during curl up and leg raise exercises, by measuring the thickness ratio of abdominal muscles using ultrasonography. METHODS: We examined 30 normal adults without musculoskeletal problems. Muscle thickness was measured in the upper rectus abdominis (URA), lower rectus abdominis (LRA), obliquus externus (EO), obliquus internus (IO), and transversus abdominis (TrA), at pre-determined angles (30degrees, 60degrees, 90degrees) and additionally at the resting angle (0degrees). Muscle thickness ratio was calculated by dividing the resting (0degrees) thickness for each angle, and was used as reflection of muscle activity. RESULTS: The muscle thickness ratio was significantly different depending on the angles in URA and LRA. For curl up-URA p=0 (30degrees90degrees), p=0.44 (30degrees90degrees), p=0.44 (30degrees>90degrees), respectively, by one-way ANOVA test-and for leg raise-URA p=0 (30degrees<60degrees), p=0 (60degrees<90degrees), p=0 (30degrees<90degrees) and LRA p=0.01 (30degrees<60degrees), p=0 (60degrees<90degrees), p=0 (30degrees<90degrees), respectively, by one-way ANOVA test-exercises, but not in the lateral abdominal muscles (EO, IO, and TrA). Also, there was no significant difference in the muscle thickness ratio of URA and LRA during both exercises. In the aspect of muscle activity, there was significant difference in the activation of RA muscle by selected angles, but not according to location during both exercises. CONCLUSION: According to this study, exercise angle is thought to be an important contributing factor for strengthening of RA muscle; however, both the exercises are thought to have no property of strengthening RA muscle selectively based on the location.

Dosimetric evaluation of Tomotherapy and four-box field conformal radiotherapy in locally advanced rectal cancer

PURPOSE: To report the results of dosimetric comparison between intensity-modulated radiotherapy (IMRT) using Tomotherapy and four-box field conformal radiotherapy (CRT) for pelvic irradiation of locally advanced rectal cancer. MATERIALS AND METHODS: Twelve patients with locally advanced rectal cancer who received a short course preoperative chemoradiotherapy (25 Gy in 5 fractions) on the pelvis using Tomotherapy, between July 2010 and December 2010, were selected. Using their simulation computed tomography scans, Tomotherapy and four-box field CRT plans with the same dose schedule were evaluated, and dosimetric parameters of the two plans were compared. For the comparison of target coverage, we analyzed the mean dose, V(n Gy), D(min), D(max), radical dose homogeneity index (rDHI), and radiation conformity index (RCI). For the comparison of organs at risk (OAR), we analyzed the mean dose. RESULTS: Tomotherapy showed a significantly higher mean target dose than four-box field CRT (p = 0.001). But, V(26.25 Gy) and V(27.5 Gy) were not significantly different between the two modalities. Tomotherapy showed higher D(max) and lower D(min). The Tomotherapy plan had a lower rDHI than four-box field CRT (p = 0.000). Tomotherapy showed better RCI than four-box field CRT (p = 0.007). For OAR, the mean irradiated dose was significantly lower in Tomotherapy than four-box field CRT. CONCLUSION: In locally advanced rectal cancer, Tomotherapy delivers a higher conformal radiation dose to the target and reduces the irradiated dose to OAR than four-box field CRT.

Deduction and Verification of Optimal Factors for Stent Structure and Mechanical Reaction Using Finite Element Analysis / 의학물리

Recently, along with technology development of endoscopic equipment, a stent has been developed for the convenience of operation, shortening of recovery times, and reduction of patient's pain. To this end, optimal factors are simulated for the stent structure and mechanical reaction and verified using finite element analysis. In order to compare to present commercialized product such as Zilver (Cook, Bloomington, Indiana, USA) and S.M.A.R.T (Cordis, Bridgewater Towsnhip, New Jersey, USA), mechanical impact factors were determined through Taguchi factor analysis, and flexibility and expandability of all the products including ours were tested using finite element analysis. Also, important factors were sought that fulfill the optimal condition using central composition method of response surface analysis, and optimal design were carried out based on the important factors. From the centra composition method of Response surface analysis, it is found that importat factors for flexibility is stent thickness (T) and unit area (W) and those for expandability is stent thickness (T). In results, important factors for optimum condition are 0.17 mm for stent thickness (T) and 0.09 mm2 for unit area (W). Determined and verified by finite element analysis in out research institute, a stent was manufactured and tested with the results of better flexibility and expandability in optimal condition compared to other products. Recently, As Finite element analysis stent mechanical property assessment for research much proceed. But time and reduce expenses research rarely stent of optimum coditions. In this research, Important factor as mechanical impact factor stent Taguchi factor analysis arrangement to find flexibility with expansibility as Finite element analysis. Also, Using to Center composition method of Response surface method appropriate optimized condition searching for important factor, these considering had design optimized. Production stent time and reduce expenses was able to do the more coincide with optimum conditions. These kind of things as application plan industry of stent development period of time and reduce expenses etc. be of help to many economic development.

The Verification of Computer Simulation of Nitinol Wire Stent Using Finite Element Analysis / 의학물리

Recently, the mathematical analysis of stent simulation has been improved, with the help of development of various tool which measure mechanical property and location of stent in artery. The most crucial part of the stent modeling is how to design ideal stent and to evaluate the interaction between stent and artery. While there has been great deal of researches on the evaluation of the expansion, stress distribution, deformation of the stent in terms of the various parameters, few verification through computer simulation has been performed about deformation and stress distribution of the stent. In this study, we have produced the corresponding results between experimental test using Universal Testing Machine and computer simulation for the ideal model of stent. Also, we have analyzed and compared stress distribution of stent in the cases of that with membrane and that without membrane. The results of this study would provide minimum change of plan and good quality for ideal stent replacing damaged artery through the analysis using computer simulation in the early stage of stent design.

The Verification of Computer Simulation of Nitinol Wire Stent Using Finite Element Analysis / 의학물리

Recently, the mathematical analysis of stent simulation has been improved, with the help of development of various tool which measure mechanical property and location of stent in artery. The most crucial part of the stent modeling is how to design ideal stent and to evaluate the interaction between stent and artery. While there has been great deal of researches on the evaluation of the expansion, stress distribution, deformation of the stent in terms of the various parameters, few verification through computer simulation has been performed about deformation and stress distribution of the stent. In this study, we have produced the corresponding results between experimental test using Universal Testing Machine and computer simulation for the ideal model of stent. Also, we have analyzed and compared stress distribution of stent in the cases of that with membrane and that without membrane. The results of this study would provide minimum change of plan and good quality for ideal stent replacing damaged artery through the analysis using computer simulation in the early stage of stent design.