Determination of the compound biological effectiveness (CBE) factors based on the ISHIYAMA-IMAHORI deterministic parsing model with the dynamic PET technique

動的PET技術に基づく石山-今堀決定論的モデルによるCBEファクターの算出法

石山 新太郎; 今堀 良夫*; 伊丹 純*; Koivunoro, H.*

Ishiyama, Shintaro; Imahori, Yoshio*; Itami, Jun*; Koivunoro, H.*

ボロン薬剤BPAを投与したがん患者PETデータからCBEファクターを求めるための決定論的石山-今堀モデル(I-Iモデル)を提案している。本論文では、実際のがん患者にBPAを投与後の動的PETデータからシグモイド関数近似を行い、I-Iモデル中のNth/Nmax値を一義的に求められることを示すことで様々な重篤度の患者33ケースで個別にCBEファクターを求めることを示した。

In defining the biological effects of the neutron capture reaction, we have proposed a deterministic parsing model (ISHIYAMA-IMAHORI model) to determine the Compound Biological Effectiveness (CBE) factor in Borono-Phenyl-Alanine (BPA)-mediated Boron Neutron Capture Therapy (BNCT). To determine the CBE factor, we derived new calculation formula founded on the deterministic parsing model with three constants, CBE0, F, n and the eigen value Nth/Nmax. where, Nth and Nmax are the threshold value of boron concentration of N and saturation boron density. In order to determine Nth and Nmax in the formula, sigmoid logistic function was employed for B concentration data, Db(t) obtained by dynamic PETtechnique, where, A, a and t0 are constants. From the application of sigmoid function to dynamic PET data, it is concluded that the Nth and Nmax for tissue and tumor are identified with the parameter constants in the sigmoid function in tion as: th b at 0 and max N = D t = N = x.