乳腺癌放疗误差主要由摆位误差和呼吸运动组成，通过准确测量摆位误差为乳腺癌计划靶区体积（PTV）外扩范围提供临床参考依据，提高治疗精度。测量2021年6月至10月采用发泡胶固定的31例乳腺癌患者的摆位误差。每一例患者在治疗前三次以及治疗后的每周进行一次锥形束CT（CBCT）扫描，将获取的CBCT图像与治疗计划CT进行骨性配准，并记录配准结果得到摆位误差值，分析摆位误差，并据此计算PTV外放边界的大小。结果显示：31例患者共行131次CBCT扫描，X（左右）、Y（头脚）和Z（腹背）方向的系统误差和随机误差的标准差分别是1.40 mm和0.67 mm、1.89 mm和0.56 mm、1.68 mm和1.16 mm；摆位误差的绝对值最大分别为4.9 mm、6.4 mm、8.7 mm；5.0 mm内误差在X、Y、Z方向分别占100%、98.47%、93.89%；X、Y、Z方向摆位误差小于3 mm的发生率分别为88.55%、79.39%、75.57%。经公式计算，得到本科室治疗乳腺癌临床靶区体积（CTV）到PTV外扩理论边界三个方向分别为3.98 mm、5.11 mm、5.02 mm。结果提示：发泡胶固定的乳腺癌调强放疗中，基于经验PTV外放边界的大小不能准确反映实际的摆位误差，需要基于CBCT测量和分析摆位误差、计算PTV外扩边界、指导临床靶区勾画范围具有实际的临床意义。

We investigate the temperature dependence of the emission spectrum of a laser-induced semiconductor (Ge and Si) plasma. The change in spectral intensity with the sample temperature indicates the change of the laser ablation mass. The reflectivity of the target surface is reduced as the sample is heated, which leads to an increase in the laser energy coupled to the surface of the sample and eventually produces a higher spectral intensity. The spectral intensities are enhanced by a few times at high temperatures compared with the cases at low temperatures. The spectral intensity of Ge is enhanced by 1.5 times at 422.66 nm, and 3 times at 589.33 nm when the sample temperature increases from 50°C to 300°C. We can obtain the same emission intensity by a more powerful laser or by less pulse energy with a higher sample temperature. Based on experimental observations we conclude that the preheated sample can improve the emission intensity of laser-induced semiconductor plasma spectroscopy.

The ultrafast dynamic process in semiconductor Ge irradiated by the femtosecond laser pulses is numerically simulated on the basis of van Driel system. It is found that with the increase of depth, the carrier density and lattice temperature decrease, while the carrier temperature first increases and then drops. The laser fluence has a great influence on the ultrafast dynamical process in Ge. As the laser fluence remains a constant value, though the overall evolution of the carrier density and lattice temperature is almost independent of pulse duration and laser intensity, increasing the laser intensity will be more effective than increasing the pulse duration in the generation of carriers. Irradiating the Ge sample by the femtosecond double pulses, the ultrafast dynamical process of semiconductor can be affected by the temporalinterval between the double pulses.11474129), the Research Fund for the Doctoral Program of Higher Education in China (grant no. 20130061110021) and the Project 2015091 Supported by Graduate Innovation Fund of Jilin University.

Our experiments show that external focusing and initial laser energy strongly influences filament generated by the femtosecond Ti–sapphire laser in air. The experimental measurements show the filament length can be extended both by increasing the laser energy and focal length of focusing lens. On the other hand, the plasma fluorescence emission can be enhanced by increasing the laser energy with fixed focal length or decreasing the focal length. In addition, the collapse distance measured experimentally are larger than the calculated ones owing to the group-velocity-dispersion effect. In addition, we find that the line widths of the spectral lines from N2 is independent of filament positions, laser energies and external focusing.11504129), the Research Fund for the Doctoral Program of Higher Education (No. 20130061110021), and the Graduate Innovation Fund of Jilin University (No. 2015091).