Haider T K, el-Khatib E E
Physics Department, University of British Columbia, Vancouver, Canada.
Med Phys. 1994 May;21(5):663-6. doi: 10.1118/1.597319.
An alternate method to measure the phantom scatter factor in small fields is provided for high energy photon beams. The measurement technique is based on the density scaling theorem described by O'Connor [Phys. Med. Biol. 1, 352-369 (1957)]. The phantom scatter factor (Sp) is measured in balsa and cedar wood to give effective field sizes in 3 x 3 to 0.5 x 0.5 cm2 water. The extrapolated zero area phantom scatter factor from the average data of balsa and cedar is 0.45. This indicates that the variation of output is largely due to a sharp decrease in the phantom scatter factor for small field sizes.
对于高能光子束，提供了一种测量小射野中模体散射因子的替代方法。该测量技术基于奥康纳描述的密度缩放定理[《物理医学与生物学》1, 352 - 369(1957)]。在轻木和雪松木中测量模体散射因子，以给出3×3至0.5×0.5平方厘米水中的有效射野尺寸。从轻木和雪松的平均数据外推得到的零面积模体散射因子为0.45。这表明输出的变化在很大程度上是由于小射野尺寸下模体散射因子的急剧下降。
