ABSTRACT
Objective:Based on the framework of reference point contract theory,the experimental economics methodwas used to explore the medical institution managers' motivation and reflection of the profit allocation in vertical integrated?medical service system.Methods:Z-tree software was applied to design the experimental program.40 undergraduate students majoring in health management were recruited as the subjects.Sharing rates and effort levels were collected and calculated by Excel 2007 and SPSS 17.0.Results:The median of sharing rate hospital managers allocated to community health centers?was 35.00％.The median of effort level that community health center directors chose was 8.00.The proportion of sharing rates equal to or less than 50.00％ accounted for 98％.The proportion of the highest effort level was 23.50％.The correlation between sharing rate and effort level was significant(P＜0.05).Conclusion:In the process of establishing vertical integration of medical service system,sharing rates and effort levels were closely related while the community health centers' effort was shading.
ABSTRACT
Objective To compare the errors of final isocenter marking method and reference point marking method for CT simulation positioning in intensity-modulated radiotherapy (IMRT).Methods From 2009 to 2012,327 patients with head and neck cancer for IMRT underwent CT simulation positioning using the Philips Brilliance CT Big Bore scanner and Philips Tumor LOC workstation and were divided into final isocenter marking group (n =208) and reference point marking group (n =119) according to positioning methods.Target volume delineation and treatment plan design were performed on the Varian Eclipse treatment planning system (TPS).Before treatment,kilovoltage cone-beam CT scans and registration were performed with the Varian EX on-board imager system to obtain beam position errors in the right-left (RL),superior-inferior (SI),and anterior-posterior (AP) directions,and then comparisons of errors between the two groups were made by independent-samples t test.Finally,the TPS was used to measure the changes in the doses to the organs at risk after moving isocenters in the RL,SI,and AP directions among 5 patients with nasopharyngeal carcinoma.Results The mean beam position errors in the three directions were less in the final isocenter marking group than in the reference point marking group (P =0.02,0.01,0.03).After moving isocenters in the three directions,the target dose was reduced and the dose to the normal tissue around the target tumor was increased significantly.The error in the AP direction had the maximum influence on the spinal cord and brainstem.Conclusions Final isocenter marking method leads to less beam position error than reference point marking method in CT simulation positioning.Small isocenter motion can cause large changes in the doses to the organs at risk.
ABSTRACT
Subject(s)
Humans , Congenital Abnormalities , Dentofacial Deformities , Maxilla , Molar , Orthognathic Surgery , Osteotomy , Osteotomy, Le Fort , Vertical DimensionABSTRACT
Objective: To study the changes and rules of the reference point potentials of electrocardiograms (ECGs) before and after pacing. Methods: The head-chest lead and routine lead ECGs of the patients with permanent pacemaker implantation were recorded with and without right ventricular pacing; the Q, R and S wave amplitudes were compared between the 2 ECGs. Results: Without right ventricular pacing, the amplitudes of Q and S wave of routine lead were higher than those of the headchest lead; the amplitude of R wave was lower than that of the head-chest lead. With right ventricle pacing, the amplitudes of Q, R, and S waves of routine lead were lower than those of head-chest lead (all P<0.01). Conclusion: The transduction direction of the cardiac excitement has great influence on the potentials of the reference point.
ABSTRACT
Objective: To explore the rule of voltage change in the reference point of electrocardiograms ( ECG). Methods: The r and R′ waves on the head-chest lead and routine lead ECGs in 21 patients with right bundle branch block in whole synchronization were compared, and the correlation of voltage change in reference point with the direction of cardiac muscular stimulation of ECGs was analyzed. Results: The swing of wave r in head-chest leads was significantly higher than that of routine leads([0.16±0.19] vs [0.11±0.13] mV, P<0.01), and the swing of wave R′ in head-chest leads was significantly lower than that of the routine leads( [0.25±0.21] vs [0.35±0.23] mV, P<0.01). Conclusion: Voltage change in reference point of ECG varies with the direction of cardiac muscular stimulation.
ABSTRACT
Objective: To explore the position change of the setup reference markers on the sternum due to the change of hands grip position. Methods: Six hands grip positions were simulated for 8 patients and the set-up reference points marked on the sternum skin were compared while the hands grasped different positions of the hands. Results: The setup markers on the sternum were deviated by all five hands grip positions. The maximum deviated distance was 14mm. Conclusion: The change of the hands grip position can affect the position of setup reference markers on the sternum of the patients and thus the isocenter of plan may be aligned to the wrong area.
ABSTRACT
Researches on brain functions using MRI or PET generally involve the process that normalizes spatially the results of functional images into a standard brain template in order to find out a common activation area of multiple subjects. So far MNI305, which is Western people's standard brain template, has been commonly used. However, the brain may be different morphologically and structurally among human races, so the use of MNI305 may produce inaccurate results. Furthermore, because the size and shape of the brain vary according to gender and age, if brain temperatures are developed considering these factors, brain activation areas may be identified more precisely. This study collected MR brain images from 121 men and women in their 20s (23.0 +/-2.6 years on the average) and 99 men and women in their 40s (47.5 +/-3.7 years on the average). After eight reference points were defined using the method proposed by Nowinski, the image that had the least error from the mean distances among the reference points was selected as the representative brain image. All images were affine-transformed into the representative brain image, and average brain templates were created by age and gender through averaging the brightness of images. The results of this study may be utilized in Korean brain probability maps to be developed in the future for more precise research on the functions of Koreans' brain.
Subject(s)
Female , Humans , Male , Brain , Racial Groups , Magnetic Resonance ImagingABSTRACT
During thalamotomy, we have to use the various kinds of brain reference points. From 1989 to 1992, the authors performed streotactic thalamotomy or pallidotomy in 169 patients suffering from tremor. We measured and estimated the important intracerebral reference points. These data were very meaningful for stereotactic functional neurosurgery in the Korean medical community because it is obtained from Korean people. We have also estimated the average location of targets for tremor submission.