全脑放射促进顺铂通过血脑屏障的研究

目的：通过检测顺铂（cis-diamminedichloroplatinum,DDP)在脑脊液中的浓变化，定量观察脑放射促进DDP透过血管屏障的作用。方法：20例非小细胞肺癌（non-smallcelllung cancer,NSCLC)脑转移患者接受脑放射，DDP20mg/m^2分别于脑放射前、脑放射10Gy、20Gy、30Gy及40Gy时静滴，于之后3h采集脑脊液与血标本。10例NSCLC无脑转移者于首次用DDP后3h采集脑脊液与血标本。采用石墨炉原子吸收光谱法检测DDP浓度。结果：脑转移可评价者20例，无脑转移者10例，脑转移者放疗前脑脊液中DDP浓度平均1.02mg/L，明显高于无脑转移者脑脊液中DDP浓度（平均0.33mg/L)；脑转移者全脑放疗10-30Gy，脑脊液中DDP浓度随脑放射剂量的增加而增加，全脑照射30Gy时浓度最高，平均2.36mg/L。结论：DDP可透过脑转移者受损的血脑屏障进入脑脊液中，并可以达到治疗浓度；全脑放射可以促进DDP透过血脑屏障，全脑放疗0-30Gy时DDP进入脑脊液中的浓度随放射剂量的增加而增加，39Gy时浓度最高；DDP可少量通过正常的血脑屏障，但未达有效治疗浓度。

Brain Irradiation Enhances Permeability of cis-Diamminedichloroplatinum into Blood-Brain Barrier

Objective：This study was designed to investigate the effect of brain irradiation on blood-brain barrier (BBB) quantitatively by measuring cis-diamminedichloroplatinum (DDP) concentration in cerebrospinal fluid (CSF). Methods：Twenty-two patients with brain metastases from non-small cell lung cancer (NSCLC) received brain irradiation (BI). During BI, DDP (20mg/m2) was given before radiotherapy and after cumulative doses of 10gray, 20gray, 30gray， and 40gray separately 3h prior to CSF collection and blood collection. Ten NSCLC patients without brain metastases were given the same dose DDP and the CSF and blood samples were collected. Samples were assayed for DDP levels by using flameless atomic absorption spectrophotometry. Results：There were 20 patients with and 10 without brain metastases assessable. The average DDP level in CSF was 1.02mg/L for patients with brain metastases before BI, which was significantly higher than the average level of 0.33mg/L for patients without brain metastases. The DDP level in CSF increased with the dose of BI and reached the highest level after 30gray irradiation(2.36mg/L). Conclusion：The BBB of patients with brain metastases is impaired in a certain degree and DDP could reach its therapeutic level in the CSF. The BBB would gradually open following BI, and DDP would reach the highest level after a dose of 30gray whole brain irradiation. In the CSF of patients with normal BBB, the DDP concentration is much lower than the therapeutic level.