y. duan

This paper compares the cavitation of a pump-jet propulsor under different launch conditions and discusses the effects of cavitation on the performance and noise of the pump-jet propulsor rotor blade. At the same time, the load and deformation of the rotor blade under the conditions of cavitation are studied via the one-way fluid-structure interaction (FSI) approach. The results show that the cavitation of the pump-jet propulsor decreases with increasing launch depth and speed. The performance decreases with increasing launch speed at large depths, whereas the performance improves with increasing launch speed at small depths due to the improvement of the cavitation on the rotor blades. Increasing launch speed and depth increase the noise caused by the rotor of the pump-jet propulsor, and the increase in flow rate caused by the improvement of cavitation also increases the noise level. Moreover, increasing launch depth increases the overall load of the blade and produces a larger deformation, while the speed affects the distribution of the load on the blade. In addition, with the improvement of cavitation caused by increasing launch speed, the deformation of the blade decreases.

The study aimed to elucidate the clinical application significance of prospective ECG-gated dual-source CT in central venous (CV) imaging.

Eighty patients who took CT imaging of CV (CTV) check using dual-source Force CT were enrolled. The control group (helical pitch, 0.8; rotation speed, 0.5 s) and the experimental group (rotation speed, 0.25 s). For both groups, image quality and radiation dose were computed.

Cases in the experimental group required longer scanning durations than those in the contro lgroup. In respect to the experimental group, the image quality scores of the superior vena cava and left and right brachiocephalic veins of the patients sharply increased relative to those in the control group. Individuals in the experimental group also presented better image quality scores in left and right subclavian veins, left and right jugular veins, however, this difference was not statistically significant. Lastly, no increase in the radiation dose was bited with the application of prospective ECG gating.

The clinical use of prospective ECG-gated technology significantly reduced cardiovascular pulsing artifact interference on the central vein, especially the superior vena cava segment, and remarkably improved the image quality without increasing the radiation dose to patients.

To investigate the performance of Auto-Planning intensity modulated radiation therapy (IMRT) plans for patients with central lung cancer and to determine whether Auto-Planning improves the quality of IMRT plans.

Thirty patients treated with IMRT for central lung cancer were replanned with the Pinnacle3 Auto-Planning module. The dose distribution at the target, organ at risk (OAR) sparing, dose falloff in the five rings outside of target, monitor units (MUs), planning time, and dosimetric verification in terms of the γ passing rate were evaluated. A Wilcoxon signed-rank test was performed to assess differences between groups (p<0.05).

The target homogeneity in the Auto-Planning were significantly better than that in the manual plans, the target conformity in both groups were similar. The Auto-Planning plans yielded lower V5, V10, V13, V20, V30, V40 values, mean lung dose of total lung (p<0.01), and Dmax of spinal cord (p<0.01) and V30 of heart (p<0.01). No significant difference was found for the V40 of the heart (p=0.203). The Auto-Planning module reduced the Dmean, D2 and D5 values in all rings outside of PTV. The planning time was 52.5% shorter for Auto-Planning plans than for manual plans (p<0.01), and 4.4% additional MUs were required with Auto-Planning. No difference was observed for the γ passing rate.

Auto-Planning for central lung cancer could improve homogeneity of target volumes, significantly delivery lower dose to OARs and steeper dose falloff outside of tumors while reducing the planning time.