Halogenated pyrimidine sensitization of low dose rate irradiation in human malignant glioma.
OBJECTIVE
To determine the potential advantage of combining halogenated pyrimidine radiosensitization and continuous low dose rate irradiation in human malignant glioma.


METHODS
An established glioma line (U-251) was incubated with 5-bromo-2-doxyuridine (BrdUrd) at clinically achievable concentrations at three dose rates of interest--100 cGy/min (typical of external beam therapy), 43 cGy/hr (typical of temporary afterloaded implants), and 12 cGy/hr (typical of permanent implants).


RESULTS
After exposure to 1 microM BrdUrd, the greatest enhancement ratio was seen at the 12 cGy/hr dose rate, implying a BrdUrd induced inverse dose rate effect independent of a G2M block. Under these conditions, the mean inactivation dose after 1 microM BrdUrd exposure was equivalent for 100 cGy/min and 12 cGy/hr.


CONCLUSIONS
These results support the use of halopyrimidines as sensitizers of temporary afterloaded and permanent implants.
McLaughlin
P W
PW
Dept. of Radiation Oncology, University of Michigan Medical Center, Ann Arbor 48109.
Mancini
W R
WR
Stetson
P L
PL
Greenberg
H S
HS
Nguyen
N
N
Seabury
H
H
Heidorn
D B
DB
Lawrence
T S
TS
D001973:Bromodeoxyuridine / Q000627:therapeutic use*; D004307:Dose-Response Relationship, Radiation; D005910:Glioma / Q000532:radiotherapy*; D006801:Humans; D066298:In Vitro Techniques; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use*; D011879:Radiotherapy Dosage; D015996:Survival Rate; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000528:radiation effects
D011838:Radiation-Sensitizing Agents; D001973:Bromodeoxyuridine