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Intra-fractional dose rate effect in continuous and interrupted irradiation of the MCF-7 cell line: Possible radiobiological implications for breath-hold techniques in breast radiotherapy?

Authors :
Mosleh-Shirazi, Mohammad Amin
Kazempour, Somayeh
Fardid, Reza
Sharifzadeh, Sedigheh
Karbasi, Sareh
Source :
Journal of Cancer Research & Therapeutics; Apr-Jun2024, Vol. 20 Issue 3, p863-868, 6p
Publication Year :
2024

Abstract

Purpose: To investigate the effects of different dose rates (DRs) in continuous and interrupted irradiation on in-vitro survival of the MCF-7 cell line, towards finding possible radiobiological effects of breath-hold techniques in breast radiotherapy (RT), in which intra-fractional beam interruptions and delivery prolongation can occur. Materials and Methods: MCF-7 cells were irradiated continuously or with regular interruptions using 6 MV x-rays at different accelerator DRs (50-400 cGy/min) to deliver a 2 Gy dose. The interrupted irradiation was delivered in a 10 s on, 10 s off manner. Then, cell survival and viability were studied using colony and MTT assays, respectively. Results: Survival and viability with continuous and interrupted irradiation were similar (P > 0.5). A significant increase in survival at 50, 100, and 400 cGy/min compared to 200 and 300 cGy/min was observed, also a significant decreasing and then increasing trend from 50 to 200 cGy/min and 200 to 400 cGy/min, respectively (P < 0.04). Relative to 200 cGy/min, the survival fractions at 50, 100, 300, and 400 cGy/min were 1.24, 1.23, 1.05, and 1.20 times greater, respectively. Cell viability did not show significant differences between the DRs, despite following the same trend as cell survival. Conclusion: Our results suggest that for continuous irradiation of in-vitro MCF-7 cells, with increasing DR within the 50-400 cGy/min range, sensitivity increases and then decreases (inverse effect), also that up to doubling of treatment time in breath-hold techniques does not affect in-vitro radiobiological efficacy with 200-400 cGy/min accelerator DRs. Further confirmatory studies are required. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09731482
Volume :
20
Issue :
3
Database :
Complementary Index
Journal :
Journal of Cancer Research & Therapeutics
Publication Type :
Academic Journal
Accession number :
178742326
Full Text :
https://doi.org/10.4103/jcrt.jcrt_826_21