Dosimetric properties of radiophotoluminescent glass detector in low-energy photon beams
Dosimetric properties of radiophotoluminescent glass detector in low-energy photon beams
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DOI：
10.1118/1.4747261
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发表时间：
2012-10-01
期刊：
影响因子：
3.8
通讯作者：
Tabushi, Katsuyoshi
中科院分区：
文献类型：
--
作者：
Kadoya, Noriyuki;Shimomura, Kouhei;Tabushi, Katsuyoshi
目的：一种辐射光致发光玻璃棒剂量计（RGD）最近已上市。它越来越多地用于放射治疗中的剂量测定，以测量吸收剂量，包括患者体表散射的低能光子，并用于邮政剂量测定审计。在这篇文章中，ROD的剂量学特性，包括剂量响应的能量依赖性，可重复性，由ROD获得的每种能量的数据的变化，以及低能量光子的角度依赖性，进行了讨论。的RGD（GD-301，Asahi Techno Glass Corporation，静冈，日本）在Photon Factory用同步加速器辐射产生的单色低能光子束照射，高能加速器研究组织（KEK）GD-301的尺寸为直径1.5 mm，长度8.5 mm，有效剂量读出体积为直径1 mm，深度0.6 mm，位于距离探测器末端0.7 mm处。研究了用塑料保持器辐照和不用塑料保持器辐照的RGDs的剂量响应的能量依赖性、重现性和变异性。RGD的响应不仅通过常规的单场照射，而且通过双侧照射获得。用13、17、40和80 keV的光子束，在0 ° ~ 90 °范围内，用常规单场照射测量了RGD的角度依赖性。对于小于25 keV的能量范围内，所有的剂量响应曲线急剧下降的比例的质量能量吸收系数的ROD的空气。至于通过RGD获得的数据的再现性和变化，方差系数随着光子能量的降低而增加。此外，双侧照射的变化小于单野照射。关于RGD的角度依赖性，对于13和17 keV的能量，响应随着照射角度的增加而减小，并且最小值分别为93.5%和86%。我们的研究结果显示了RGD的剂量学特性，包括剂量响应的能量依赖性，可重复性，变化，和角度的依赖性，在低能量光子，并建议在低能量光子的吸收剂量的准确性是由读出方法和辐射光致发光中心的分布在ROD的影响。(C)2012年美国医学物理学家协会。[http：//dx.doi.org/10.1118/1.4747261]
Purpose: A radiophotoluminescent glass rod dosimeter (RGD) has recently become commercially available. It is being increasingly used for dosimetry in radiotherapy to measure the absorbed dose including scattered low-energy photons on the body surface of a patient and for postal dosimetry audit. In this article, the dosimetric properties of the ROD, including energy dependence of the dose response, reproducibly, variation in data obtained by the ROD for each energy, and angular dependence in low-energy photons, are discussed.Methods: An RGD (GD-301, Asahi Techno Glass Corporation, Shizuoka, Japan) was irradiated with monochromatic low-energy photon beams generated by synchrotron radiation at Photon Factory, High Energy Accelerator Research Organization (KEK). The size of GD-301 was 1.5 mm in diameter and 8.5 mm in length and the active dose readout volume being 1 mm diameter and 0.6 mm depth located 0.7 mm from the end of the detector. The energy dependence of the dose response and reproducibility and variation were investigated for RGDs irradiated with a plastic holder and those irradiated without the plastic holder. Response of the RGD was obtained by not only conventional single field irradiation but also bilateral irradiation. Angular dependence of the RGD was measured in the range of 0 degrees-90 degrees for 13, 17, 40, and 80 keV photon beams by conventional single field irradiation.Results: The dose responses had a peak at around 40 keV. For the energy range of less than 25 keV, all dose response curves steeply decreased in comparison with the ratio of mass energy absorption coefficient of the ROD to that of air. As for the reproducibility and variation in data obtained by the RGD, the coefficient of variance increased with decrease in photon energy. Furthermore, the variation for bilateral irradiation was less than that for single field irradiation. Regarding angular dependence of the RGD, for energies of 13 and 17 keV, the response decreased with increase in the irradiation angle, and the minimum values were 93.5% and 86%, respectively.Conclusions: Our results showed the dosimetric properties of the RGD, including the energy dependence of the dose response, reproducibly, variation, and angular dependence in low-energy photons and suggest that the accuracy of the absorbed dose in low-energy photons is affected by the readout method and the distribution of radiophotoluminescence centers in the ROD. (C) 2012 American Association of Physicists in Medicine. [http://dx.doi.org/10.1118/1.4747261]