Application of Imaging Plate to Quality Control of Heavy Ion Therapy

本研究的目的是从根本上研究成像平板(IP)在重离子放射治疗质量控制中的应用。2002财年，我们将IP作为重离子放射治疗质量控制的工具，对重离子摄影的图像质量进行了评估。重离子激电的特征曲线与X射线相似，均为直线。在2003财政年度，我们讨论了用激电法和增强屏-II CCD摄像系统测量剩余区分布的方法。这两种方法得出的结果相似。此外，利用投影角度下剩余射程分布的起伏得到的一维维纳谱估计了重离子CT图像的电子密度分辨率。这一结果与密度分辨率体模的结果一致。2004财年，我们对IP重离子散射照相的图像质量进行了评估。实验中使用的是方波图(模型1，KYOKKO)。结果表明，由于重离子与材料的散射产生了边缘增强，成像分辨率能够优于传统的重离子照相。

The aim of this research project is to fundamentally study applications of imaging plate (IP) to quality control of the heavy ion radiation therapy.In fiscal year 2002, we evaluated the image quality of the heavy ion radiography with IP as a tool for quality control of the heavy ion radiation therapy. Characteristic curves of IP for heavy ions were straight lines, similarly to X-rays. The lateral straggling of heavy ion passing through the material was approximately represented as a Gaussian distribution.In fiscal year 2003, we discussed the measurement methods of residual rage distribution with the IP and the intensifying screen-II CCD camera system. The two methods lead to similar results. Furthermore, the electron density resolution of heavy ion CT image was estimated by the 1 dimensional Wiener spectrum obtained from the fluctuation of residual range distribution for a projection angle. The result is consistent with the one obtained form the density resolution phantom. Therefore, it was considered that the measurement with the IP was useful.In fiscal year 2004, we evaluated the image quality of the heavy ion scattering radiography with IP. A square wave chart (Model No.1, KYOKKO) was used in the experiment. As a result, the image resolution was able to be superior to the conventional heavy ion radiography due to an edge enhancement arose from the scattering of heavy ions with the material.