School of Biomedical Engineering, College of Biomedical & Health Science, Research Institute of Biomedical Engineering, Konkuk University, 322 Danwol-dong, Chungju-si, Chungcheongbuk-do, 380-701, Korea.
Sensors (Basel). 2012;12(5):6404-14. doi: 10.3390/s120506404. Epub 2012 May 14.
A T-shaped fiber-optic phantom-dosimeter system was developed using square scintillating optical fibers, a lens system, and a CMOS image camera. Images of scintillating light were used to simultaneously measure the transverse and longitudinal distributions of absorbed dose of a 6 MV photon beam with field sizes of 1 × 1 and 3 × 3 cm(2). Each optical fiber has a very small sensitive volume and the sensitive material is water equivalent. This allows the measurements of cross-beam profile as well as the percentage depth dose of small field sizes. In the case of transverse dose distribution, the measured beam profiles were gradually become uneven and the beam edge had a gentle slope with increasing depth of the PMMA phantom. In addition, the maximum dose values of longitudinal dose distribution for 6 MV photon beam with field sizes of 1 × 1 and 3 × 3 cm(2) were found to be at a depth of approximately 15 mm and the percentage depth dose of both field sizes were nearly in agreement at the skin dose level. Based on the results of this study, it is anticipated that an all-in-one phantom-dosimeter can be developed to accurately measure beam profiles and dose distribution in a small irradiation fields prior to carrying out stereotactic radiosurgery.
一种 T 型光纤型体模剂量仪系统，采用方形闪烁光纤、透镜系统和 CMOS 图像相机开发而成。闪烁光的图像用于同时测量 6MV 光子束的横向和纵向吸收剂量分布，射野大小为 1×1cm2 和 3×3cm2。每根光纤都有一个非常小的灵敏体积，灵敏材料是水当量。这使得能够测量小射野的横向射束轮廓和百分深度剂量。在横向剂量分布的情况下，随着 PMMA 体模深度的增加，测量的射束轮廓逐渐变得不均匀，射束边缘有一个平缓的斜率。此外，发现 1×1cm2 和 3×3cm2 射野的 6MV 光子束的纵向剂量分布的最大剂量值在大约 15mm 的深度处，并且两个射野的百分深度剂量在皮肤剂量水平几乎一致。基于这项研究的结果，可以预期可以开发出一种一体式体模剂量仪，以便在进行立体定向放射外科之前准确测量小照射野中的射束轮廓和剂量分布。
