Refine your search:     
Report No.
 - 
Search Results: Records 1-5 displayed on this page of 5
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Spectrum of radiation-induced clustered non-DSB damage; A Monte Carlo track structure modelling and calculations

Watanabe, Ritsuko; Rahmanian, S.*; Nikjoo, H.*

Radiation Research, 183(5), p.525 - 540, 2015/05

 Times Cited Count:40 Percentile:6.53(Biology)

To calculate the spectrum of initial base damage induced by selected electrons and ions, Monte Carlo track structure method was used to simulate the radiation induced DNA damage in a cell mimetic condition based on a single track action. We present relative yield of strand breaks and base damage for selected monoenergetic electrons 100 eV - 100 keV, photons C$$_{K}$$, Al$$_{K}$$ and Ti$$_{K}$$; and some selected ions (3.2 MeV/u proton; 0.74 and 2.4 MeV/u $$^{4}$$He; 29 MeV/u $$^{14}$$N, and 950 MeV/u $$^{56}$$Fe). Data are presented for simple and complex types of DNA damage. The ratios of yields of base damage to SSBs were estimated to be about 2-4 independent on the LETs examined. The contribution of base damage to the complexity of damage site was shown to be significant. The data can be used for testing mechanistic models of DNA repair kinetics and in particular the base excision repair.

Journal Articles

Can Monte Carlo track structure codes reveal reaction mechanism in DNA damage and improve radiation therapy?

Nikjoo, H.*; Emifietzoglou, D.*; Watanabe, Ritsuko; Uehara, Shuzo*

Radiation Physics and Chemistry, 77(10-12), p.1270 - 1279, 2008/10

 Times Cited Count:47 Percentile:4.63(Chemistry, Physical)

Microdosimetry and track structure have been applied to scrutinize and understand aspects of radiation damage in biological molecules from a theoretical approach. To this end track structure has provided a basis for understanding the mechanism(s) that shape dose-effect relationships. There is a wealth of information and data accumulated from radiation biology that need to be placed in the framework of a general descriptive theory. While there are many classical radiobiology questions remain unanswered new ideas and challenging question are emerging. Among many, simulation of radiation track at molecular level is an emerging tool in radiobiology and theoretical radiotherapy. In this paper we present recent progress in development of low energy electron tracks in condensed media and high energy proton tracks and discuss progress in characterizing DNA damage in terms of types and complexity.

Journal Articles

Modelling the effect of incorporated halogenated pyrimidine on radiation-induced DNA strand breaks

Watanabe, Ritsuko; Nikjoo, H.*

International Journal of Radiation Biology, 78(11), p.953 - 966, 2002/11

 Times Cited Count:35 Percentile:9.96(Biology)

Incorporation of halogenated pyrimidines, iodo- and bromo-deoxyuridines (HP), into DNA is known to sensitize cells to radiation. The aim of this study is to estimate the enhancement of DNA strand break induced by low LET radiation in the presence of HP and examine source, complexity and clustering properties of damage that could provide correlation between DNA damage and lethality. Monte Carlo track structure methods were used to model the induction of strand breakage by X-ray photons. As a result, the increase of strand breaks due to Br/IdU incorporation could be explained by the mechanism of uracilyl radical production originated from e-aq and direct hits on bases. The significant contribution of electron migration along DNA within limited distance is shown. It is also shown that the incorporation of Br/IdU causes a spectral shift towards greater complexity of clustered DNA damage. Further, it has been supported that DSB is responsible for radiation-induced cell killing.

Oral presentation

Simulation of clustered DNA damage including base damage using Monte Carlo track structure methods

Watanabe, Ritsuko; Nikjoo, H.*

no journal, , 

no abstracts in English

Oral presentation

Development of track-structure simulation mode of ions in PHITS

Kai, Takeshi; Sato, Tatsuhiko; Liamsuwan, T.*; Nikjoo, H.*

no journal, , 

A general purpose particle transport simulation code, PHITS is expected to apply dose evaluation in macroscopic systems as well as radiation interaction investigation in nanoscale for study of interaction between radiations and materials. To clear the problem, we implemented track structure calculation codes into the PHITS. The codes make microscopic behavior as well as energy depositions (ionization and excitation) of the electrons, protons and carbon ions possible. The PHITS could evaluate radiation dose of cellar size. As this implementation, DNA damage predictions, which need radiation interaction in the molecular levels, will be expected using this track-structure simulation mode.

5 (Records 1-5 displayed on this page)
  • 1