[Influence of radiation on the blood-brain barrier and optimum time of chemotherapy].
OBJECTIVE
A pilot study of the destructive effects of radiation on the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB) were carried out on 29 patients.


METHODS
(1) First BBB with localized and limited brain tumors was examined by 99mTc-GH imaging count/pixel, data was obtained from the unirradiated, irradiated, and tumor areas of before and after radiotherapy of 20-40 Gy respectively. (2) The BCSFB was studied quantitatively by observing the effect of methotrexate (MTX) permeation into the CSF before, during, and after brain irradiated after i.v. injection of MTX.


RESULTS
(1) the BBB in the unirradiated area outside the radiation portal was not changed, (2) the degree of destructive effect on the BBB in the irradiated normal area and on the BCSFB were directly proportional to radiation doses.


CONCLUSIONS
When the permeation of BBB and BCSFB irradiated, was enhanced the degree of destructive effect were enhanced proportionally with irradiation doses. It was that the BBB irradiated can be recovered at least partially after irradiation of 3 weeks proved. After a dose of 20 Gy irradiation, the BCSFB would gradually open. As compared with the pre-radiation data, the permeability of MTX increased by 1.05-1.3 times. So, it was advisable to give chemotherapy after 20 Gy irradiation.
Qin
D
D
Department of Radiotherapy, Cancer Hospital, CAMS and PUMC, Beijing 100021.
Zheng
R
R
Ma
J
J
Xiao
J
J
Tang
Z
Z
D000964:Antimetabolites, Antineoplastic / Q000493:pharmacokinetics*; D001812:Blood-Brain Barrier / Q000528:radiation effects*; D001921:Brain / Q000000981:diagnostic imaging; D001932:Brain Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000532:radiotherapy; D016371:Cranial Irradiation; D006801:Humans; D008727:Methotrexate / Q000493:pharmacokinetics*; D010865:Pilot Projects; D014055:Tomography, Emission-Computed
D000964:Antimetabolites, Antineoplastic; D008727:Methotrexate