Kandarakis I, Cavouras D, Nikolopoulos D, Episkopakis A, Kalivas N, Liaparinos P, Valais I, Kagadis G, Kourkoutas K, Sianoudis I, Dimitropoulos N, Nomicos C, Panayiotakis G
Department of Medical Instruments Technology, Technological Educational Institution (TEI) of Athens, Agiou Spyridonos, Aigaleo, 12210 Athens, Greece.
Appl Radiat Isot. 2006 Apr;64(4):508-19. doi: 10.1016/j.apradiso.2005.11.016. Epub 2006 Jan 4.
The aim of this study was to examine the angular distribution of the light emitted from radiation-excited scintillators in medical imaging detectors. This distribution diverges from Lambert's cosine law and affects the light emission efficiency of scintillators, hence it also affects the dose burden to the patient. In the present study, the angular distribution was theoretically modeled and was used to fit experimental data on various scintillator materials. Results of calculations revealed that the angular distribution is more directional than that predicted by Lambert's law. Divergence from this law is more pronounced for high values of light attenuation coefficient and thick scintillator layers (screens). This type of divergence reduces light emission efficiency and hence it increases the incident X-ray flux required for a given level of image brightness.
本研究的目的是研究医学成像探测器中辐射激发闪烁体发出的光的角分布。这种分布偏离了朗伯余弦定律，影响闪烁体的发光效率，因此也影响患者的剂量负担。在本研究中，对角分布进行了理论建模，并用于拟合各种闪烁体材料的实验数据。计算结果表明，角分布比朗伯定律预测的更具方向性。对于高值的光衰减系数和厚的闪烁体层（屏），与该定律的偏差更为明显。这种类型的偏差会降低发光效率，因此会增加给定图像亮度水平所需的入射X射线通量。
