[Reoxygenation in Yoshida sarcoma during different fractionated radiotherapy].
OBJECTIVE
Tumor reoxygenation is one of the most important factors determining the tumor control probability after radiotherapy. In experimental studies reoxygenation has been measured preferably after single dose irradiation. Only few data exist about changes in the hypoxic tumor fraction during fractionated radiotherapy.


METHODS
The changes in the pO2 during fractionated radiotherapy were studied in Yoshida sarcoma transplanted to Wistar rats. Tissue oxygenation was assessed using a polarographic electrode system at the beginning, in the middle and at the end of radiation therapy. Different fractionation schedules were used: 10 x 3 Gy, 6 x 5 Gy and 3 x 10 Gy.


RESULTS
In the statistical analysis significant changes emerged in the mean, median, 10%-percentile and 0 to 2.5 mm Hg and 0 to 5.0 mm Hg values dependent on time. The tumors were significantly more hypoxic at the end of therapy. This trend became more pronounced with decreasing dose per fraction.


CONCLUSIONS
The Yoshida sarcoma has no effective reoxygenation during fractionated radiotherapy.
Strnad
V
V
Klinik und Poliklinik für Strahlentherapie der Universität Erlangen-Nürnberg.
Kamprad
F
F
Jahns
J
J
Kirschner
M
M
Meyer
M
M
Madaj-Sterba
P
P
Riepl
M
M
Böhme
R
R
Sauer
R
R
D000818:Animals; D003627:Data Interpretation, Statistical; D004566:Electrodes; D010100:Oxygen / Q000378:metabolism*; D011048:Polarography; D011879:Radiotherapy Dosage; D051381:Rats; D017208:Rats, Wistar; D012517:Sarcoma, Yoshida / Q000378:metabolism* / Q000532:radiotherapy*
D010100:Oxygen
Reoxygenierung im Yoshida-Sarkom unter unterschiedlich fraktionierter Bestrahlung.