Evidence for Two Forms of Substructure in the Cell Survival Curve: Mechanisms and Clinical Consequences

Skarsgard, L. D.

doi:10.1080/028418699432581

Cited by 7 publications

(5 citation statements)

References 36 publications

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“…The phase of the normal cell cycle was synchronized and stopped at G 1 /G 0 in this experiment by keeping the cells at the 100% confluent condition to exclude the extra variation in response due to the cell-cycle dependence of the radiosensitivity [24, 25]. …”

Section: Methodsmentioning

confidence: 99%

Modeling the biological response of normal human cells, including repair processes, to fractionated carbon beam irradiation

Wada

Suzuki²,

Liu³

et al. 2013

Journal of Radiation Research

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To understand the biological response of normal cells to fractionated carbon beam irradiation, the effects of potentially lethal damage repair (PLDR) and sublethal damage repair (SLDR) were both taken into account in a linear-quadratic (LQ) model. The model was verified by the results of a fractionated cell survival experiment with normal human fibroblast cells. Cells were irradiated with 200-kV X-rays and monoenergetic carbon ion beams (290 MeV/u) at two irradiation depths, corresponding to linear energy transfers (LETs) of approximately 13 keV/μm and 75 keV/μm, respectively, at the Heavy Ion Medical Accelerator in Chiba of the National Institute of Radiological Sciences. When we only took into account the repair factor of PLDR, γ, which was derived from the delayed assay, the cell survival response to fractionated carbon ion irradiation was not fully explained in some cases. When both the effects of SLDR and PLDR were taken into account in the LQ model, the cell survival response was well reproduced. The model analysis suggested that PLDR occurs in any type of radiation. The γ factors ranged from 0.36–0.93. In addition, SLD was perfectly repaired during the fraction interval for the lower LET irradiations but remained at about 30% for the high-LET irradiation.

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Section: Methodsmentioning

confidence: 99%

Modeling the biological response of normal human cells, including repair processes, to fractionated carbon beam irradiation

Wada

Suzuki²,

Liu³

et al. 2013

Journal of Radiation Research

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“…Experiments with cultured mammalian cells [2] , [3] like that shown in Fig. 2 indicate the range of transition between line A and B survival is from about 3 to 5 Gy.…”

Section: Discussion: Malignant Tumorsmentioning

confidence: 77%

“…Chronic late developing injuries considered by Barendsen [6] include those for D ⊗ equal to the dose that produces 50 percent death of mice by 180 days from respiratory failure [3] , [23] , [24] ; D ⊗ equal to the dose causing 50 percent death by 180 days from kidney failure [25] ; D ⊗ equal to the dose that produces 30 percent contraction of mouse skin by 250 days [26] ; D ⊗ equal to the dose that produces paralysis of the hind legs of 50 percent of rats from radiation myelopathy of the spinal cord [27] , [28] , [29] ; and 50 percent death of rats by one year from brain irradiation [30] . Like that for the acute early injuries there is a suggestion of downward concavity of the iso effect relation.…”

Section: Discussion: Normal Tissuesmentioning

confidence: 99%

“…The survival of some cells deviates from the linear quadratic relation as dose decreases to less than about 0.5–1 Gy because of low dose hypersensitivity [3] , [5] . This effect is not included in the present discussion.…”

Section: Introductionmentioning

confidence: 98%

“…2 . It has been pointed out that curvature in the intermediate dose range and convergence to the lines A and B in the low and high dose limits can be attributed to a mixture of cells in the sensitive and resistant phases of the cell replication cycle that make up the asynchronous irradiated population [3] .

Fig.…”

Section: Introductionmentioning

confidence: 99%

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Effect of heterogeneous radio sensitivity on the survival, alpha beta ratio and biologic effective dose calculation of irradiated mammalian cell populations

Hawkins

2017

Clinical and Translational Radiation Oncology

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It is demonstrated that the surviving fraction of a population of cells with heterogeneous radio sensitivity, like that composing most malignant tumors, conforms to a different linear quadratic survival relation for dose less than about 3–5 Gy and dose greater than about 7–9 Gy. In the intermediate range of dose the survival relation for the population, as a whole, is not linear quadratic. Consequently, the value of the alpha beta ratio and the associated biologically effective dose calculation are different for the low and high dose range for most malignant tumors.Normal tissue cell populations responsible for organ function also have heterogeneous radio sensitivity, though to less degree than most malignant tumors. Consequently, the alpha beta ratio and associated biologically effective dose calculation related to the development of some acute early and chronic late developing radiation injuries are not the same in the low and high dose range.Variance of the distribution of α of a heterogeneous cell population lowers the effective value of the quadratic survival constant β of the population, as a whole, and increases the α/β ratio in the low dose range. Heterogeneous appearance of tumor cells (pleomorphism) and necrosis on biopsy or imaging studies reflect heterogeneity of the radio sensitivity of the cells. Greater heterogeneity implies a tendency to higher α/β ratio. This may furnish a clinically accessible way to estimate a value of the α/β ratio specific to an individual patient and tumor.

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Model of Tumor Growth and Response to Radiation

Liu

Brown

Schlesinger

2013

Modern Aspects of Electrochemistry

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Evidence for Two Forms of Substructure in the Cell Survival Curve: Mechanisms and Clinical Consequences

Cited by 7 publications

References 36 publications

Modeling the biological response of normal human cells, including repair processes, to fractionated carbon beam irradiation

Modeling the biological response of normal human cells, including repair processes, to fractionated carbon beam irradiation

Effect of heterogeneous radio sensitivity on the survival, alpha beta ratio and biologic effective dose calculation of irradiated mammalian cell populations

Model of Tumor Growth and Response to Radiation

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