Oraya Therapeutics, Inc., Newark, California 94560, USA.
Med Phys. 2010 Feb;37(2):600-6. doi: 10.1118/1.3291648.
Validation of the targeting and dose delivery of the IRay low voltage age-related macular degeneration treatment system.
Ten human cadaver eyes were obtained for this study and mounted in the IRay system. Using gel and vacuum, an I-Guide immobilization device was coupled to the eyes and radiochromic film was affixed to the posterior aspect of the globes. Three narrow x-ray beams were delivered through the pars plana to overlap on the predicted nominal fovea. A needle was placed through the center of the film's beam spot and into the eye to register the film and the inner retina. The process was performed three times for each of the ten eyes (30 simulated treatments; 90 individual beams). The globes were dissected to assess the targeting accuracy by measuring the distances from the needles to the fovea. The dose to the fovea was calculated from the radiochromic film.
X-ray targeting on the retina averaged 0.6 +/- 0.4 mm from the fovea. Repeated treatments on the same eye showed a reproducibility of 0.4 +/- 0.4 mm. The optic nerve was safely avoided, with the 90% isodose edge of the beam spot between 0.4 and 2.6 mm from the edge of the optic disk. Measured dose matched that prescribed.
This study provides confidence that the IRay, with an average accuracy of 0.6 mm and a precision of 0.4 mm, can reliably treat most AMD lesions centered on the fovea. With the exception of motion, all sources of error are included.
验证 IRay 低压治疗年龄相关性黄斑变性系统的靶向和剂量传递。
本研究共使用 10 个人体尸体眼球，并将其安装在 IRay 系统中。使用凝胶和真空，将 I-Guide 固定装置连接到眼球上，并将放射色胶片贴在眼球的后表面。通过平坦部输送三个窄的 X 射线束，使光束在预测的名义黄斑区重叠。将一根针穿过胶片光束点的中心并进入眼球，以记录胶片和视网膜内层。对每个眼球进行了三次该过程（30 次模拟治疗；90 个单独的光束）。通过测量针到黄斑的距离，将眼球解剖以评估靶向准确性。从放射色胶片计算黄斑的剂量。
X 射线在视网膜上的靶向平均距离黄斑 0.6 +/- 0.4 毫米。同一眼球的重复治疗显示出 0.4 +/- 0.4 毫米的重现性。视神经安全避开，光束点的 90%等剂量边缘位于视神经盘边缘 0.4 至 2.6 毫米之间。测量的剂量与规定的剂量相符。
这项研究表明，IRay 的平均精度为 0.6 毫米，精度为 0.4 毫米，可以可靠地治疗大多数以黄斑为中心的 AMD 病变。除了运动之外，所有误差源都包括在内。
