Study on Small Field Dosimetery for Stereotactic Irradiation using a Radiophotoluminescent Glass Dosimeter

我们研究立体定向放射外科（SRS）和立体定向放射治疗（SRT）的小场剂量学，使用放射光致发光玻璃剂量计。在这项研究中，我们得到了以下结果：辐射光致发光玻璃棒剂量计（GRD）的剂量学特性及其在小场剂量测量中的应用我们研究了高能光子光束中GRD的剂量学特性，包括信号的均匀性和可重复性、剂量线性以及能量和方向依赖性。结果表明，GRD比热释光剂量计（TLD）性能优越；(1)无限重复读数；(2)信号均匀性和再现性好；(3)衰减小；(4)剂量线性好；(5)能量和方向依赖性小。我们还将GRD应用于基于线性加速器的放射外科系统、伽玛刀和电子刀的高能光子束的小场剂量测定。结果表明，GRD是一种非常有用的小场剂量测定方法，特别是小于10mm的圆准直场。用于小场剂量测量的放射光致发光玻璃板剂量计（GPD）的研制与应用我们与旭硝子玻璃公司合作开发了一种用于高能光子光束小场剂量测量的新型装置原型GPD系统。GPD的尺寸为30毫米见方，厚度为1毫米，材料与GRD相同。GPD系统可以同时测量剂量谱和吸收剂量。在这一点上，该装置比GRD、薄膜剂量计和其他探测器有优势。GPD可以测量高分辨率，这是由冷却型电荷耦合器件（CCD）相机的像素大小决定的。GPD也可以读出0.1-100 Gy的范围。在0.1 Gy和1 Gy的情况下，在1个标准差下，读数的准确度分别为0.8%和0.5%。我们将GPD应用于小场剂量测定，并检验了其实用性。通过与薄膜和各种探测器的比较，以及EGSnrc Monte Garlo模拟，发现GPD系统是一种非常有用的小场剂量测定探测器。本研究的另一个目的是将更宽的玻璃板探测器应用于调强放射治疗（IMRT）剂量测定。少

We investigate small field dosimetry for Stereotactic radiosurgery(SRS) and stereotactic radiotherapy(SRT), using a radiophotoluminescent glass dosimeter. We obtained the following results in this study.1.Dosimetric properties of a radiophotoluminescent glass rod dosimeter(GRD) and the application of the GRD to small field dosimetryWe investigated dosimetric properties of a GRD regarding the uniformity and reproducibility of signal, dose linearity, and energy- and directional dependence, for high-energy photon beams. It was found that the GRD is superior to a thermoluminescent dosimeter(TLD) ; (1)unlimited repeatable reading, (2)excellent signal uniformity and reproducibility, (3)little fading, (4)excellent dose linearity, (5)little energy- and directional dependence. We also applied the GRD to the small field dosimetry in high-energy photon beams from a linear accelerator-based radiosurgery system, Gamma-Knife, and Cyber-Knife. It was found that the GRD is a very useful detector for s … More mall field dosimetry, in particular, below 10 mm circular collimator fields.2.Development and the application of a radiophotoluminescent glass plate dosimeter(GPD) for small field dosimetryWe developed a prototype GPD system as a new device for small field dosimetry in high-energy photon beams, with Asahi Techno Glass Company. The size of the GPD is 30 mm square by 1 mm thick and it is made of the same material as a GRD. The GPD system can measure both the dose profiles and the absorbed dose simultaneously. This device has an advantage over the GRD, a film dosimeter, and other detectors at this point. The GPD can measure with high resolution, which is determined by a pixel size of a cooling type charge-coupled device(CCD) camera. The GPD can also read out with a range of 0.1-100 Gy. The accuracy of readout is about 0.8% and 0.5% on 1 standard deviation for 0.1 and 1 Gy, respectively. We applied the GPD to small field dosimettry and examined the usefulness. It was found the GPD system is a very useful detector for small field dosimetry, by comparing it to film and various detectors, and EGSnrc Monte Garlo simulations. Another purpose of this study is to apply more wide glass plate detectors to intensity modulated radiation therapy(IMRT) dosimetry. Less