Dose-rate effects between 0.3 and 30 Gy/h in a normal and a malignant human cell line

Journal Article · Tue Aug 30 04:00:00 EDT 1994 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/0360-3016(94)90522-3· OSTI ID:90911

Amdur, R J; Bedford, J S ^[1]

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1. Colorado State Univ., Fort Collins, CO (United States)

This study used continuous {open_quotes}intermediate{close_quotes} dose rate irradiation (0.3-30 Gy/h) to compare the capacity for and repair of sublethal radiation damage in different cell lines growing in tissue culture. Two human cell lines were studied; one was derived from normal human fibroblasts (AG1522) and the other from a squamous cell carcinoma of the uterine cervix (HTB-35). Dose-response curves for clonogenic survival were determined following irradiation of plateau-phase cultures at five different dose rates: 22.6, 6.12, 3.65, 1.04, and 0.38 Gy/h. Subculture following irradiation was delayed for 8-24 h to allow for the full repair of {open_quotes}potentially lethal damage.{close_quotes} A significant dose-rate effect was seen in both cell lines. For irradiation at the highest dose rate, survival at 2 Gy (SF2) and the {alpha}/{beta} ratio were similar for the two cell lines (approximately 0.7 and 8.0 Gy, respectively) but the half-time of repair of sublethal damage was estimated to be approximately five times longer in the normal human fibroblast line (154 min) than in the carcinoma (31 min) cell line. These results indicate that measuring the dose-rate effect between 0.3 and 30 Gy/h is a useful way to identify and quantify differences in sublethal damage repair between cell lines. To the extent that in vitro and in vivo repair parameters are similar, and that representative tumor biopsy specimens can be examined in this way, this approach may provide a prospective way of determining the dose rate (brachytherapy) or fractionation schedule that will optimize the therapeutic ratio. 32 refs., 1 fig.

• Sponsoring Organization: USDOE
• OSTI ID: 90911
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 1 Vol. 30; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BETA RATIO
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL REPAIR
BIOPSY
CARCINOMAS
DOSE RATES
DOSE-RESPONSE RELATIONSHIPS
FIBROBLASTS
IRRADIATION
TISSUE CULTURES