Romanelli Pantaleo, Fardone Erminia, Bucci Domenico, Battaglia Giuseppe, Bräuer-Krisch Elke, Requardt Herwig, Le Duc Geraldine, Bravin Alberto
Cyberknife Radiosurgery Center, Centro Diagnostico Italiano, via Saint Bon, 20147 Milano, Italy; AB Medica, 31 via Nerviano, 20020 Lainate, Milano, Italy.
European Synchrotron Radiation Facility (ESRF), 71 avenue des Martyrs, 38043 Grenoble, France.
Phys Med. 2015 Sep;31(6):642-6. doi: 10.1016/j.ejmp.2015.05.007. Epub 2015 May 29.
Microplanar X-ray beams (microbeams) originated by synchrotron sources have been delivered to the visual brain cortex regions in rodents to create microscopically narrow lesions. The effects of microbeams mimic those generated by microsurgical subpial transections (also known as multiple subpial transections) but are obtained in a low-invasive way.
Image-guided atlas-based microbeam cortical transections have been generated on seven 1 month-old Wistar rats. An array of 10 parallel beams of 25 microns in thickness and spaced of 200 micron center-to-center was centered on the visual cortex and deposited an incident dose of 600 Gy.
The procedure was well tolerated by rats. After recovery, rats showed regular behavior, no sign of gross visual impairment and regular weight gain. After 3 months, rats were sacrificed and brains histologically examined. Cortical transections resembling those obtained through a surgical incision were found over the irradiated region. Remarkable sparing of the cortical columns adjacent to the transections was observed. No sign of radionecrosis was evident at least at this time point.
The visual brain cortex transected by synchrotron-generated microbeams showed an incision-like path of neuronal loss while adjacent non irradiated columns remained intact. These preliminary findings, to be further investigated also using other techniques, suggest that microbeam radiosurgery can affect the cortex at a cellular level providing a potential novel and attractive tool to study cortical function.
由同步加速器源产生的微平面X射线束（微束）已被输送到啮齿动物的视觉脑皮质区域，以形成微观上狭窄的损伤。微束的作用类似于显微外科软膜下横切术（也称为多次软膜下横切术）所产生的作用，但以低侵入性方式获得。
在7只1月龄的Wistar大鼠上进行了基于图像引导图谱的微束皮质横切术。一组10条平行束，厚度为25微米，中心间距为200微米，以视觉皮质为中心，入射剂量为600戈瑞。
该过程大鼠耐受性良好。恢复后，大鼠行为正常，无明显视力损害迹象，体重正常增加。3个月后，处死大鼠并对大脑进行组织学检查。在照射区域发现了类似于手术切口的皮质横切。观察到横切相邻的皮质柱有明显的保留。至少在这个时间点没有放射性坏死的迹象。
由同步加速器产生的微束横切的视觉脑皮质显示出类似切口的神经元丢失路径，而相邻未照射的柱保持完整。这些初步发现，还需使用其他技术进一步研究，表明微束放射外科可以在细胞水平上影响皮质，为研究皮质功能提供了一种潜在的新颖且有吸引力的工具。
