Ertl A, Hartl R F, Zehetmayer M, Kitz K, Griffitt W
Department of Neurosurgery, University of Vienna, Austria.
Phys Med Biol. 1996 Dec;41(12):2679-86. doi: 10.1088/0031-9155/41/12/007.
We developed a new TLD array for precise dose measurement and verification of the spatial dose distribution in small radiation targets. It consists of a hemicylindrical, tissue-equivalent rod made of polystyrene with 17 parallel moulds for an exact positioning of each TLD. The spatial resolution of the TLD array was evaluated using the Leskell spherical phantom. Dose planning was performed with KULA 4.4 under stereotactic conditions on axial CT images. In the Leksell gamma unit the TLD array was irradiated with a maximal dose of 10 Gy with an unplugged 14 mm collimator. The doses delivered to the TLDs were rechecked by diode detector and film dosimetry and compared to the computer-generated dose profile. We found excellent agreement of our measured values, even at the critical penumbra decline. For the 14 mm and 18 mm collimator and for the 11 mm collimator combination we compared the measured and calculated data at full width at half maximum. This TLD array may be useful for phantom or tissue model studies on the spatial dose distribution in confined radiation targets as used in stereotactic radiotherapy.
我们开发了一种新型热释光剂量计（TLD）阵列，用于精确剂量测量以及验证小型辐射靶区的空间剂量分布。它由一个半圆柱形、聚苯乙烯材质的组织等效棒组成，带有17个平行模具，用于每个TLD的精确定位。使用Leksell球形体模评估TLD阵列的空间分辨率。在立体定向条件下，于轴向CT图像上使用KULA 4.4进行剂量规划。在Leksell伽马刀装置中，使用未插塞的14毫米准直器，以最大10 Gy的剂量照射TLD阵列。通过二极管探测器和胶片剂量测定法重新检查输送至TLD的剂量，并与计算机生成的剂量分布图进行比较。我们发现，即使在关键的半值层下降区域，测量值之间也具有极佳的一致性。对于14毫米和18毫米准直器以及11毫米准直器组合，我们比较了半高宽处的测量数据和计算数据。这种TLD阵列可能有助于针对立体定向放射治疗中受限辐射靶区的空间剂量分布进行体模或组织模型研究。
