OBJECTIVE: To evaluate the feasibility and accuracy of cone-beam CT (CBCT) images for radiotherapy dose calculation in pelvic tumors. METHODS: An improved volumetric density coverage method was used to establish CT value-relative electron density (RED) curves for CBCT images. The planning CT plans were transferred to the CBCT images, and the constructed density curves were applied to calculate doses for CBCT plans while maintaining the optimization parameters unchanged. Dose calculation deviations between the two plans were analyzed. RESULTS: The mean differences in dosimetric parameters for the target volume and organs at risk (OAR) between the two plans were less than 1% and 1.5%, respectively. The target conformity index (CI), homogeneity index (HI), and gamma passing rates were highly consistent, with no statistically significant differences. CONCLUSION CBCT images corrected by this method can be used for dose calculation in pelvic tumor radiotherapy planning.
Cone-Beam Computed Tomography/methods* ; Humans ; Radiotherapy Planning, Computer-Assisted/methods* ; Radiotherapy Dosage ; Pelvic Neoplasms/diagnostic imaging*

Objective To investigate the effects on one hand of training the other with isometric wrist extension and flexion training and its underlying mechanism.Methods Twenty healthy young girls were recruited and randomized into a training group and a control group with 10 subjects in each,using a random number table.The subjects in the training group were accepted isometric training of the wrist extensors and flexors on the right side once every other day,4 days a week for 6 weeks according to a pre-programmed protocol,while those in the control group had no intervention.Peak torque and surface electromyography (sEMG) were recorded and assessed before and after 6 weeks of training.Results In the training group,the average peak torque of right wrist flexion and extension were both significantly higher than before training (within-group comparison) and higher than in the control group (between-group comparison) after 6 weeks of training.The average peak torques of the left wrist in the training group in flexion and extension were (12.9±2.0) Nm and (6.4 ± 1.3) Nm after training,both significantly higher than before the training and stronger than the control group.In the sEMG traces during wrist extension,after training the ascend velocity of the right extensor carpi ulnaris and the integrated area of the left extensor carpi ulnaris in the training group were significantly smaller than before training and in the control group.Conclusion Unilateral isometric resistance training of the wrist muscles can transfer to the contralateral side,probably by altering muscle recruitment.

Objective To investigate the extent of cross-education between the pronation and supination muscles of the right and left forearms after unilateral isometric training.Methods Twenty healthy young girls were randomized into a training group and a control group using a random number table.The training group underwent isometric training of their right forearms for six weeks,while the control group continued ordinary life without exercises.Pronation peak torque (PPT) and supination peak torque (SPT) were assessed before and after the training for both groups.Results The differences in PPT or SPT between the training group and the control group were not significant before the training program.When the training had been completed,however,the average PPT and SPT on right side of those trained of course had increased significantly compared to before training or to the control group.More significantly,the average PPT and SPT on the left side in the training group were also significantly better than before training or in the control group after training.Conclusion Unilateral isometric training of the forearm pronation and supination muscles for six weeks can significantly increase muscle strength bilaterally,indicating good cross-education.