High resolution Cerenkov light imaging of induced positron distribution in proton therapy
High resolution Cerenkov light imaging of induced positron distribution in proton therapy
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DOI：
10.1118/1.4898592
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发表时间：
2014-11-01
期刊：
影响因子：
3.8
通讯作者：
Komori, Masataka
中科院分区：
文献类型：
--
作者：
Yamamoto, Seiichi;Toshito, Toshiyuki;Komori, Masataka
目的：在质子治疗中，对质子照射期间或照射后不久由碎片产生的正电子分布进行成像是监测质子范围的有效方法。虽然正电子发射断层扫描（PET）通常用于这种成像，但其空间分辨率有限。切伦科夫光成像是一种新的分子成像技术，它利用高灵敏度光学相机检测高速电子产生的可见光子。由于其固有的空间分辨率远高于PET，作者可以用切伦科夫光成像技术测量更精确的质子诱导正电子分布信息。为此，他们对质子治疗中诱导的正电子分布进行了切伦科夫光成像。方法：首先，作者评估了实际成像设置中Na-22点源的切伦科夫光成像系统的空间分辨率。然后使用点扫描质子治疗系统用两种不同能量的质子照射透明丙烯酸模型（100x100x100mm(3)）。采用高灵敏度电子倍增电荷耦合器件（EM-CCD）相机对每个模体进行切伦科夫光成像。结果：该装置的切伦科夫光空间分辨率为0.76 +/- 0.6 mm FWHM。他们获得了两种不同质子能量的幻影中正电子分布的高分辨率切伦科夫光图像，并制作了参考图像和切伦科夫光图像的融合图像。从切伦科夫光图像得到的幻影中正电子分布的深度与模拟结果几乎相同。切伦科夫光图像上的兴趣区域（roi）的衰减曲线表明，切伦科夫光图像可以用来估计正电子的放射性核素成分的半衰期。结论：高分辨率Cerenkov光成像质子诱导正电子分布是可行的。作者认为质子诱导正电子的切伦科夫光成像在质子治疗中是有前景的。(C) 2014年美国医学物理学家协会。
Purpose: In proton therapy, imaging of the positron distribution produced by fragmentation during or soon after proton irradiation is a useful method to monitor the proton range. Although positron emission tomography (PET) is typically used for this imaging, its spatial resolution is limited. Cerenkov light imaging is a new molecular imaging technology that detects the visible photons that are produced from high-speed electrons using a high sensitivity optical camera. Because its inherent spatial resolution is much higher than PET, the authors can measure more precise information of the proton-induced positron distribution with Cerenkov light imaging technology. For this purpose, they conducted Cerenkov light imaging of induced positron distribution in proton therapy.Methods: First, the authors evaluated the spatial resolution of our Cerenkov light imaging system with a Na-22 point source for the actual imaging setup. Then the transparent acrylic phantoms (100x100x100 mm(3)) were irradiated with two different proton energies using a spot scanning proton therapy system. Cerenkov light imaging of each phantom was conducted using a high sensitivity electron multiplied charge coupled device (EM-CCD) camera.Results: The Cerenkov light's spatial resolution for the setup was 0.76 +/- 0.6 mm FWHM. They obtained high resolution Cerenkov light images of the positron distributions in the phantoms for two different proton energies and made fused images of the reference images and the Cerenkov light images. The depths of the positron distribution in the phantoms from the Cerenkov light images were almost identical to the simulation results. The decay curves derived from the region-of-interests (ROIs) set on the Cerenkov light images revealed that Cerenkov light images can be used for estimating the half-life of the radionuclide components of positrons.Conclusions: High resolution Cerenkov light imaging of proton-induced positron distribution was possible. The authors conclude that Cerenkov light imaging of proton-induced positron is promising for proton therapy. (C) 2014 American Association of Physicists in Medicine.