Single-dose compared with fractionated-dose radiation of the OM431 choroidal melanoma cell line.
OBJECTIVE
To compare single-dose and fractionated-dose radiotherapeutic effects on choroidal melanoma cells.


METHODS
We determined the effects of gamma radiation on OM431 cell survival by exposing cells to either a single 9-Gy dose or two 4.5-Gy fractionated doses at intervals of 20 minutes to eight hours. The effects of single dosing and fractionated dosing at six hours were compared at doses of 2 to 12 Gy.


RESULTS
Tumor cell repair was most rapid during the first two hours. Maximum repair had occurred by six hours after radiation. Cell survival curves showed doses greater than 3 Gy of single-dose gamma radiation resulted in a greater number of cells killed than did equivalent fractionated doses.


CONCLUSIONS
Ocular melanoma in vitro is relatively radioresistant to low-dose fractionated radiotherapy. High single-dose radiotherapy would be more effective but would also result in more damage to normal tissue unless more focused modalities of radiotherapy are used.
Logani
S
S
Department of Ophthalmology, University of California Los Angeles, School of Medicine, USA.
Cho
A S
AS
Ali
B H
BH
Withers
H R
HR
McBride
W H
WH
Kozlov
K L
KL
Hall
M O
MO
Lee
D A
DA
Straatsma
B R
BR
D002470:Cell Survival / Q000528:radiation effects; D002830:Choroid Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D003037:Cobalt Radioisotopes; D004261:DNA Replication / Q000528:radiation effects; D004273:DNA, Neoplasm / Q000528:radiation effects; D005720:Gamma Rays; D006801:Humans; D008545:Melanoma / Q000473:pathology / Q000532:radiotherapy*; D011829:Radiation Dosage; D014407:Tumor Cells, Cultured
D003037:Cobalt Radioisotopes; D004273:DNA, Neoplasm