A nanodosimetry-based linear-quadratic model of cell survival for mixed-LET radiations

Abstract

A new nanodosimetry-based linear-quadratic (LQ) model of cell survival for mixed-LET radiations has been developed. The new model employs three physical quantities and three biological quantities. The three physical quantities are related to energy depositions at two nanometre scales, 5 nm and 25 nm. The three biological quantities are related to the lesion production and interaction probabilities and the lesion repair rate. The coefficients alpha and beta of the LQ formula (alpha D + beta D(2)) are explicitly expressed in terms of the three physical quantities and the three biological quantities. The new model is shown to be consistent with the previously published cell survival curves of V-79 cells. The advantage of this new model is that it can be conveniently adopted to estimate the iso-effect for radiotherapies that involve ionizing radiation of mixed LET. An example is given to estimate the cell survival fractions for a high-dose-rate mixed neutron and gamma-ray field from a (252)Cf source.

Cellular apoptosis by nanosecond, high-intensity electric pulses: Model evaluation of the pulsing threshold and extrinsic pathway

“…Cell killing is also important for bacterial decontamination and microbial inactivation [21][22][23][24]. Though cell survival and dose-related killing have been studied in the context of radiation [25,26], electric pulsed survival studies and data are relatively scant. Reported data reveals a threshold effect in cell killing by electric fields, with survival being the eventual outcome if either the field intensities or number of pulses (or both) are not sufficiently high [27,28].…”

Mixed Beam Murine Harderian Gland Tumorigenesis: Predicted Dose-Effect Relationships if neither Synergism nor Antagonism Occurs

“…Simple effect additivity S(d), given by Eq. (4), is the most obvious default hypothesis, but is often not the best (20,34,36,55,56). In this work, we compared S(d) with incremental effect additivity I(d) as applied to mixed-beam experiments on murine HG tumorigenesis.…”

Biological optimization of tumor radiosurgery

“…Though LQ parameters depend on the cell line, cell-cycle stage, and modalities of radiation delivery, 15,16 it is accepted that various tumors have a ratio ␣ / ␤ of 10 Gy ͑1 Gy=1 Gray= 1 J / Kg͒ or even higher. 17 We assumed ␣ p = 0.1 Gy −1 and ␤ p = 0.01 Gy −2 .…”