Radiation Carcinogenesis and DNA Alterations pp 593-609 | Cite as

# The Physics of Absorbed Dose and Linear Energy Transfer

## Abstract

The objectives of dosimetry and dose specification concern the description of the temporal and spatial distribution of the energy deposition at a macroscopic and microscopic level.

The incident radiation field is defined when the type of particles and their initial energy spectrum are specified. Knowledge of interaction coefficients is required to convert the particle fluence to energy imparted to biological tissue. The absorbed dose is defined as the differential quotient of mean energy imparted and mass. It is pointed out that the energy deposition is a stochastic process, and this becomes important if small doses and small volumes of tissue are considered.

The quality of the radiation can be related to the linear energy transfer spectra or the lineal energy spectra. Lineal energy spectra for different types of radiation are described and the expectation values: frequency mean lineal energy and dose mean lineal energy for neutrons of different energies are compared.

To explain the differences in biological effectiveness of different types of radiation, the energy deposition processes have to be correlated with the sizes of the biological structures involved. Some of the biophysical approaches to understand the biological effects of ionizing radiation are summarized.

## Keywords

Energy Deposition Neutron Energy Linear Energy Transfer Relative Biological Effectiveness Lineal Energy## Preview

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## References

- 1.ICRU Report 33, “Radiation Quantities and Units,” International Commission on Radiation Units and Measurements, ICRU, Washington, D.C. (1980).Google Scholar
- 2.J. Zoetelief, R. W. Davies, G. Scarpa, G. H. Hofmeester, A. Dixon-Brown, A. J. van der Kogel, and J. J. Broerse, Protocol for X-ray dosimetry and exposure arrangements employed in studies of late somatic effects in mammals, Int. J. Radiat. Biol. 47:81–102 (1985).CrossRefGoogle Scholar
- 3.ICRU Report 30, “Quantitative Concepts and Dosimetry in Radiobiology,” International Commission on Radiation Units and Measurements, ICRU, Washington, D.C. (1979).Google Scholar
- 4.H. O. Wijckoff, Corrected f factors for photons from 10 keV to 2 MeV, Medical Physics 10:715–716 (1983).CrossRefGoogle Scholar
- 5.H. H. Rossi, Microscopic energy distribution in irradiated matter, in: “Radiation Dosimetry,” F. H. Attix and W. C. Roesch, eds., Academic Press, New York (1968), pp. 43–92.Google Scholar
- 6.ICRU Report 36, “Microdosimetry,” International Commission on Radiation Units and Measurement, ICRU, Washington, D.C. (1983).Google Scholar
- 7.D. T. Goodhead, Deductions’ from cellular studies of inactivation, mutagenesis and transformation, in: “Radiation Carcinogenesis: Epidemiology ad Biological Significance,” J. D. Boice, Jr. and J. F. Fraumeni, Jr., eds., Raven Press, New York (1984), pp. 369–385.Google Scholar
- 8.G. W. Barendsen, Impairment of the proliferative capacity of human cells in culture by α-particles with differing linear-energy transfer, Int. J. Radiat. Biol. 8:453–466 (1964).CrossRefGoogle Scholar
- 9.G. W. Barendsen, Responses of cultured cells, tumours and normal tissues to radiations of different linear energy transfer, in: “Current Topics in Radiation Research, Vol. 4,” M. Ebert and A. Howard, eds., North-Holland Publishing Company (1968).Google Scholar
- 10.E. L. Powers, Some physiochemical bases of radiation sensitivity in cells, in: “Cellular Radiation Biology, Proceedings Eighteenth Annual Symposium on Fundamental Cancer Research,” The Williams and Wilkins Company, Baltimore (1965), pp. 286–304.Google Scholar
- 11.A. M. Kellerer and H. H. Rossi, The theory of dual radiation action, in: “Current Topics in Radiation Research Quarterly ” Vol. 8, North-Holland Publishing Company (1972), pp. 85-158.Google Scholar
- 12.A. M. Kellerer, An algorithm for LET-analysis, Phys. Med. Biol. 17:232–240 (1972).PubMedCrossRefGoogle Scholar
- 13.J. J. Broerse, G. W. Barendsen, and G. R. van Kersen, Survival of cultured human cells after irradiation with fast neutrons of different energies in hypoxic and oxygenated conditions, Int. J. Radiat. Biol. 13:559–572 (1968).CrossRefGoogle Scholar
- 14.J. Booz, U. Oldenburg, and M. Coppola, Das Problem der Gewebeaquivalenz für schnelle Neutronen in der Mikrodosimetrie, in: Proceedings of the First Symposium on Neutron Dosimetry in Biology and Medicine, “ EUR 4896, G. Burger, H. Schraube and H. G. Ebert, eds., Commission of the European Communities, Luxembourg (1972), pp. 117–136.Google Scholar
- 15.J. J. Coyne and R. S. Caswell, Microdosimetric energy deposition spectra and their averages for bin-averaged and energy-distributed neutron spectra, in: “Proceedings of the Seventh Symposium on Microdosimetry, EUR 7147,” J. Booz, H. G. Ebert, and H. D. Hartfield, eds., Harwood Academic Publishers, London (1980), pp. 689–696.Google Scholar
- 16.J. Booz, Neutron dosimetry, radiation quality and biological dosimetry, in: “High LET Radiations in Clinical Radiotherapy,” G. W. Barendsen, J. J. Broerse, and K. Breur, eds., Pergamon Press, New York (1979), pp. 147–150.Google Scholar
- 17.G. W. Barendsen, Linear and quadratic terms in dose-effect relationships for cellular responses and implications for normal tissue tolerance at small doses per fraction and low dose rates, in: “Proceedings of the Eighth Symposium on Microdosimetry,” EUR 8395, J. Booz and H. G. Ebert, eds., Commission of the European Communities, Luxembourg (1983), pp. 811–821.Google Scholar
- 18.D. T. Goodhead, D. E. Charlton, W. E. Wilson, and H. G. Paretzke, Current biophysical approaches to the understanding of biological effects of radiation in terms of local energy deposition, in: “Proceedings of the Fifth Symposium on Neutron Dosimetry,” EUR 9762 Commission of the European Communities Luxembourg (1985), pp. 57.68.Google Scholar