Polymer gel dosimetry in proton beams

聚合物凝胶剂量法是一种新型的用于质量保证的三维（3D）剂量测定工具，它利用链聚合与辐射剂量成正比。本研究的目的是在临床质子剂量测定中对聚合物凝胶进行剂量测定。在本研究中，我们使用内部程序从2张和4张获得的MR图像中计算R2图像。我们将两个图像的编程R2图像与四个图像的图像进行了比较。从两个图像得到的R2图像与从四个图像得到的图像是相同的。我们可以从两个图像中使用R2图像来减少扫描时间。并利用x射线CT扫描仪对质子束进行了剂量读数法测量，实现了对质子束的薄片数据采集。此外，我们使用体绘制构建了聚合物凝胶的三维图像。因此，通过薄片的收集，我们可以获得更详细的三维数据。然而，我们发现在薄切片厚度和小体素时，体素周围的信噪比（SNR）下降。

Polymer gel dosimetry which utilizes chain polymerization that is proportional to radiation dose is a new three-dimensional(3D) dosimetric tool for quality assurance. The purpose of this study was to carry out dosimetry of polymer gels in clinical proton dosimetry. In this study, we caluculated R2 iamges from two and four acquired MR images using an in-house program. We comared the programmed R2 image from two iamges with that from four images. The R2 image from two images was same as that from four images. We can use the R2 image from two images for reduction of scan time. And we performed dose reading method using an X-ray CT scanner for proton beam measurements, in which data collection of thin slices is possible. In addition, we constructed 3D images of polymer gels using volume rendering. As a result, through the collection of thin slices, we could acquire more detailed 3D data. However, we found that at thin slice thicknesses and small voxel, the signal to noise ratio(SNR) around voxels deteriorated.