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Journal of the Korean Society for Therapeutic Radiology 1986;4(2): 89-98. |
| Dose-Response Curves of Mouse Jejunal Crypt Cells by Multifrationated Irrdiation |
| Seong Eon Hong, Chi Yul Ahn |
| Department of Radiology, College of Medicine, Kyung Hee University, Korea. |
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| ABSTRACT |
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Using as assay for jejunal crypt stem cell survival, dose-response curves for the reproductive capacity of crypt stem cells mouse jejunum exposed to multifractionated gamma-ray irradiation(single, 2, 3, 4, 5, 6, 7, 8, 10,12, and 16 fractions) were analyzed and single-dose survival curve of these cells was constructed. The following conclusion were drawn: 1) Survival curves for higher numbers of dose fractions were displaced to higher dose, and characterized by increasingly shallower slopes. 2) The single-dose survival curve had broad shoulder, Dq=460 cGy, remaining near-exponential over initial dose range 0 to 300 cGy, with initial slope 1Do=474 cGy 3) At fractionated dose in the range of 180 to 450 cGy, the average recovered dose per fraction interval was approximately 50% of the dose per fraction. 4) The value of a/b ratio by using of linear regression analysis for the reciprocal dose plots was 8.3Gy which lied in the range of 6-14Gy for early-reacting tissues. 5) The linear-quadratic model for dose-response formula offers valid approximations for all doses to be used in radiotherapy, only two parameters to be determined, and considerable convenience in practical applications. |
| Key Words:
Radiation, Fractionation, jejunal crypt |
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