Radiobiology of ultrasoft X rays. III. Normal human fibroblasts and the significance of terminal track structure in cell inactivation

Michael Cornforth, M. E. Schillaci, D. T. Goodhead, S. G. Carpenter, M. E. Wilder, R. J. Sebring, M. R. Raju

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Ultrasoft characteristic X rays from carbon (0.28 keV) are severely attenuated as they pass through biological material, causing a nonuniform distribution of dose to cell nuclei. Complications of studying ultrasoft X rays can be minimized in this context by using cells with very thin cytoplasm and nuclei (e.g., less than the attenuation length of the X rays), and which exhibit a more nearly exponential dose response to cell killing, such as normal human fibroblasts compared with V79 cells. Using this cell system, we report the relative biological effectiveness (RBE) of A1-K and C-K X rays to be near unity. Previous studies of cell inactivation by characteristic carbon X rays gave RBEs of 3 to 4, supporting the idea that localized energy depositions from secondary electrons and primary track ends represent the principal mode of biological action for other low-LET radiations. In part, the reported high RBEs result from the use of mean dose to describe energy deposited within the cell nuclei by these poorly penetrating radiations. Implicit in the use of mean dose is that cellular damage varies linearly with dose within a critical target(s), an assumption that is of questionable validity for cells that exhibit pronounced curvi-linear dose responses. The simplest interpretation of the present findings is that most energy depositions caused by track-end effects are not necessarily more damaging than the sparsely ionizing component.

Original languageEnglish (US)
Pages (from-to)511-522
Number of pages12
JournalRadiation Research
Volume119
Issue number3
StatePublished - 1989
Externally publishedYes

Fingerprint

Radiobiology
radiobiology
cell structures
fibroblasts
deactivation
inactivation
X-radiation
Fibroblasts
X-Rays
dosage
cells
x rays
cell nucleus
Cell Nucleus
nuclei
dose response
energy
Carbon
Relative Biological Effectiveness
Radiation

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Biophysics
  • Radiology Nuclear Medicine and imaging
  • Radiation

Cite this

Cornforth, M., Schillaci, M. E., Goodhead, D. T., Carpenter, S. G., Wilder, M. E., Sebring, R. J., & Raju, M. R. (1989). Radiobiology of ultrasoft X rays. III. Normal human fibroblasts and the significance of terminal track structure in cell inactivation. Radiation Research, 119(3), 511-522.

Radiobiology of ultrasoft X rays. III. Normal human fibroblasts and the significance of terminal track structure in cell inactivation. / Cornforth, Michael; Schillaci, M. E.; Goodhead, D. T.; Carpenter, S. G.; Wilder, M. E.; Sebring, R. J.; Raju, M. R.

In: Radiation Research, Vol. 119, No. 3, 1989, p. 511-522.

Research output: Contribution to journalArticle

Cornforth, M, Schillaci, ME, Goodhead, DT, Carpenter, SG, Wilder, ME, Sebring, RJ & Raju, MR 1989, 'Radiobiology of ultrasoft X rays. III. Normal human fibroblasts and the significance of terminal track structure in cell inactivation', Radiation Research, vol. 119, no. 3, pp. 511-522.
Cornforth, Michael ; Schillaci, M. E. ; Goodhead, D. T. ; Carpenter, S. G. ; Wilder, M. E. ; Sebring, R. J. ; Raju, M. R. / Radiobiology of ultrasoft X rays. III. Normal human fibroblasts and the significance of terminal track structure in cell inactivation. In: Radiation Research. 1989 ; Vol. 119, No. 3. pp. 511-522.
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