The compound biological effectiveness (CBE) value of boronophenylalanine (BPA) for hepatocytes was experimentally determined for the purpose of boron neutron capture therapy (BNCT) for liver tumors. In this study, the critical reevaluation of previous value was performed. In previous experimental studies, the contribution of β component of dose was ignored in the response curve to X-ray. X-ray dose cell survival curves were estimated by combining the α/β values obtained in the ordinary micronucleus (MN) assay with the curve of MN-negative cell fraction (MN(−)F) to dose. This curve was compared to the boron neutron capture reaction (BNCR) dose curve. As a result, the CBE value was 4 at doses close to 0 Gy, decreasing to about 1.0 at doses close to 4.5 Gy. The new value is smaller than the previous value 4.2. This indicates that the bioequivalent dose to normal liver is lower than previously expected. Therefore, higher doses can be given to the tumor.

硼中苯丙氨酸（BPA）对肝细胞的复合生物有效性（CBE）值是通过实验确定用于肝肿瘤的硼中子俘获治疗（BNCT）的目的。在这项研究中，对以前的值进行了重新评估。在先前的实验研究中，剂量X成分的贡献在X射线反应曲线中被忽略。X射线剂量细胞存活曲线是通过将在普通微核（MN）分析中获得的α/β值与MN阴性细胞分数（MN（-）F）对剂量的曲线相结合来估算的。将该曲线与硼中子俘获反应（BNCR）剂量曲线进行比较。结果，在接近0 Gy的剂量下，CBE值为4，在接近4.5 Gy的剂量下降低至约1.0。新值小于以前的值4.2。这表明对正常肝脏的生物等效剂量低于以前的预期。因此，可以给肿瘤更高剂量。