Biomaterial Database

Can heavy charged particles really be regarded as high-LET radiations with respect to their radiobiological actions? I: LETs and fluences of heavy charged particles and associated delta-rays. 1999

S Iwanami, and N Oda

School of Allied Health Sciences, Kitasato University, Kanagawa, Japan. iwanami@medcc.kitasato-u.ac.jp

The structures of the energy transfer of heavy charged particles (HCP) to nm-size targets have been investigated, taking account of delta-ray generation by HCP as well as associated delta-rays. From the microdosimetric viewpoint, the radiobiological effects of HCP have to be analysed in terms of the microdosimetric quantities based on the local energy transfer (LET) to the target, that is the restricted linear energy transfer (Ldelta), and the fluences or the degradation spectra of charged particles including delta-rays. Ldelta of HCP and delta-rays, and the fluences of delta-rays have been calculated for various HCP (H-Ar) with energies 1, 10 and 100 MeV amu(-1). From the results obtained, it is concluded that heavy ions (HI) should be expressed as two-component radiations which are composed of high-Ldelta heavy ion tracks of low fluence and low-Ldelta delta-rays of high fluence; in other words, the currently used expression 'HI are high-LET radiations' is not valid.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009683	Nuclear Medicine	A specialty field of radiology concerned with diagnostic, therapeutic, and investigative use of radioactive compounds.	Atomic Medicine,Nuclear Radiology,Medicine, Atomic,Medicine, Nuclear,Radiology, Nuclear
D015233	Models, Statistical	Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.	Probabilistic Models,Statistical Models,Two-Parameter Models,Model, Statistical,Models, Binomial,Models, Polynomial,Statistical Model,Binomial Model,Binomial Models,Model, Binomial,Model, Polynomial,Model, Probabilistic,Model, Two-Parameter,Models, Probabilistic,Models, Two-Parameter,Polynomial Model,Polynomial Models,Probabilistic Model,Two Parameter Models,Two-Parameter Model
D018499	Linear Energy Transfer	Rate of energy dissipation along the path of charged particles. In radiobiology and health physics, exposure is measured in kiloelectron volts per micrometer of tissue (keV/micrometer T).	Energy Transfer, Linear,LET,Transfer, Linear Energy