Ikoro N C, Johnson D A, Antich P P
Med Phys. 1987 Jan-Feb;14(1):93-7. doi: 10.1118/1.596113.
Clinical dosimetry data are presented for the lower-energy x-ray beam of a Varian Clinac 1800 linear accelerator. This beam has comparable characteristics to single energy linear accelerators with the same stated 6-MV x-ray energy. The nominal beam energy was found to be 5.3 +/- 0.3 MV on the central axis. Beam quality expressed in terms of half-value layer in water was found to vary by less than 10% over the entire field. The surface doses are only slightly, but consistently, larger than those reported in the literature for other 6-MV linacs. Dosimetric results presented include central axis percentage depth dose (% DD) and tissue-maximum ratio (TMR), surface and buildup doses, output factors, and inverse square law applicability. The flatness and symmetry characteristics are within the manufacturer's specifications for both large and small fields.
给出了瓦里安Clinac 1800直线加速器低能X射线束的临床剂量学数据。该射线束与标称6兆伏X射线能量相同的单能直线加速器具有相似的特性。在中心轴上测得标称射线能量为5.3±0.3兆伏。以水中半价层表示的射线质在整个射野内变化小于10%。表面剂量仅比文献中报道的其他6兆伏直线加速器略高，但较为稳定。给出的剂量学结果包括中心轴百分深度剂量（%DD）和组织最大剂量比（TMR）、表面剂量和建成剂量、输出因子以及平方反比定律适用性。对于大射野和小射野，平坦度和对称性特性均在制造商的规格范围内。
