Optimization of the intensity gain of multiple-focus phased-array heating patterns

A new technique for enhancing the intensity gain at the focal points in multiple-focus patterns is introduced. The new technique is shown to be effective in reducing the interference typically associated with multiple-focus patterns. This reduction in interference patterns allows multiple-focus scanning to generate highly localized heating. Simulation results indicate that multiple-focus scanning not only provides an alternative to single-focus scanning, but also achieves better localization in the heating pattern. The maximization of intensity gain of multiple-focus heating patterns significantly reduces the pre-focal-depth high-temperature regions that can be caused by single-focus scanning. This is shown by computer simulation of a two-dimensional cylindrical-section array (CSA2D) as a heating applicator. Two series of simulations are presented in which different scan trajectories were used to therapeutically heat a small deep-seated target volume. In every case the heating pattern was generated using single-focus scanning and multiple-focus scanning (with and without intensity gain maximization). Multiple-focus scanning with gain maximization offers the best localization of heating to the target volume of the three methods.     

mfERG对原发性青光眼的诊断价值及其与视野视盘的相关性

目的评价应用多焦视网膜电图（multiple-focus clectroretinogram,mfERG）二阶kernel反应（second order kernel,SOK）对原发性青光艰视功能损害的诊断价值并研究其与视野视盘的相关性。方法检查原发性青光眼42眼。其中早期青光眼15眼，中期16眼，晚期11眼，高眼压症16眼，并检测33眼正常眼作为正常对照组。记录各组SOK成分参数P1波振幅和峰时，N1波振幅和峰时；同时检测平均视野缺损（MD）和杯盘比（CD）应用SPSS 10.0软件进行ANOVE和多元逐步回归统计学处理。结果P1波振幅和峰时在正常对照组与中、晚期青光眼组间有显著性差异；N1波振幅在正常对照组与中、晚期和高眼压症组间有显著性差异；P1波振幅和峰时、N1波振幅在晚期青光眼组与其他各组间均有显著性差异。正常对照组与早期青光眼组鼻上象限P1波峰时有显著性差异；与高眼压症组鼻上象限P1波振幅，鼻下、颞下象限N1波振幅有显著性差异，高眼压症组、早期、中期、晚期青光眼组P1波振幅的异常检出率为50．0％、66．7％、56.3％、100.0％；N1波振幅为：62．5％、53．3％、50．0％、81．8％；P1波峰时为：31．3%、60．0%、100．0％、90．9％；N1波峰时为：50．0％、53．3％、31．3％、45．5％．MD值的大小对P1波振幅、峰时和N1波振幅大小的影响。统计学上有显著性意义（P=0．003，P=0．018，P=0．002）。结论mfERG提供了评价青光眼视功能损害的一种敏感性的方法，但尚未发现具有典型特征性的mfERG改变。因而在临床上应该是多种指标联合检测，以提高诊断的敏感性、准确性。