PMID- 31682784
OWN - NLM
STAT- MEDLINE
DCOM- 20200423
LR  - 20200423
IS  - 1362-3095 (Electronic)
IS  - 0955-3002 (Linking)
VI  - 96
IP  - 2
DP  - 2020 Feb
TI  - Effects of indirect actions and oxygen on relative biological effectiveness: 
      estimate of DSB inductions and conversions induced by therapeutic proton beams.
PG  - 187-196
LID - 10.1080/09553002.2020.1688883 [doi]
AB  - Purpose: This study evaluated the DNA double strand breaks (DSBs) induced by 
      indirect actions and its misrepairs to estimate the relative biological 
      effectiveness (RBE) of proton beams.Materials and methods: From experimental 
      data, DSB induction was evaluated in cells irradiated by 62 MeV proton beams in 
      the presence of dimethylsulphoxide (DMSO) and under hypoxic conditions. The DNA 
      damage yields for calculating the RBE were estimated using Monte Carlo Damage 
      Simulation (MCDS) software. The repair outcomes (correct repairs, mutations and 
      DSB conversions) were estimated using Monte Carlo Excision Repair (MCER) 
      simulations.Results: The values for RBE of 62 MeV protons (LET = 1.051 keV/mum) 
      for DSB induction and enzymatic DSB under aerobic condition (21% O(2)) was 1.02 
      and 0.94, respectively, as comparing to (60)Co gamma-rays (LET = 2.4 keV/mum). DMSO 
      mitigated the inference of indirect action and reduced DSB induction to a greater 
      extent when damaged by protons rather than gamma-rays, resulting in a decreased RBE 
      of 0.86. DMSO also efficiently prevented enzymatic DSB yields triggered by proton 
      irradiation and reduced the RBE to 0.83. However, hypoxia (2% O(2)) produced a 
      similar level of DSB induction with respect to the protons and gamma-rays, with a 
      comparable RBE of 1.02.Conclusions: The RBE values of proton beams estimated from 
      DSB induction and enzymatic DSB decreased by 16% and 12%, respectively, in the 
      presence of DMSO. Our findings indicate that the overall effects of DSB induction 
      and enzymatic DSB could intensify the tumor killing, while alleviate normal 
      tissue damage when indirect actions are effectively interrupted.
FAU - Luo, Wei-Ren
AU  - Luo WR
AD  - Department of Radiology, Chung Shan Medical University Hospital, Taichung, 
      Taiwan.
FAU - Chen, Fang-Hsin
AU  - Chen FH
AUID- ORCID: 0000-0002-1671-4863
AD  - Department of Medical Imaging and Radiological Sciences, Chang Gung University, 
      Kweishan, Taiwan.
AD  - Radiation Biology Research Center, Institute for Radiological Research, Chang 
      Gung University/Chang Gung Memorial Hospital, Taoyuan, Taiwan.
AD  - Department of Radiation Oncology, Chang Gung Memorial Hospital-Linkou Branch, 
      Taoyuan, Taiwan.
FAU - Huang, Ren-Jing
AU  - Huang RJ
AD  - Department of Radiology, Chung Shan Medical University Hospital, Taichung, 
      Taiwan.
AD  - Department of Medical Imaging and Radiological Sciences, Chung Shan Medical 
      University, Taichung, Taiwan.
FAU - Chen, Yu-Pin
AU  - Chen YP
AD  - Department of Radiology, Taipei Manicipal Wan-Fang Hospital, Taipei Medical 
      University, Taipei, Taiwan.
FAU - Hsiao, Ya-Yun
AU  - Hsiao YY
AUID- ORCID: 0000-0001-7494-8767
AD  - Department of Radiology, Chung Shan Medical University Hospital, Taichung, 
      Taiwan.
AD  - Department of Medical Imaging and Radiological Sciences, Chung Shan Medical 
      University, Taichung, Taiwan.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20191113
PL  - England
TA  - Int J Radiat Biol
JT  - International journal of radiation biology
JID - 8809243
RN  - 0 (Cobalt Radioisotopes)
RN  - 0 (Protons)
RN  - 0 (Reactive Oxygen Species)
RN  - 9007-49-2 (DNA)
RN  - S88TT14065 (Oxygen)
RN  - YOW8V9698H (Dimethyl Sulfoxide)
SB  - IM
MH  - Cell Line, Tumor
MH  - Cell Survival/drug effects
MH  - Cobalt Radioisotopes
MH  - DNA/*radiation effects
MH  - *DNA Breaks, Double-Stranded
MH  - DNA Repair/radiation effects
MH  - Dimethyl Sulfoxide
MH  - Gamma Rays
MH  - Humans
MH  - Hypoxia
MH  - Monte Carlo Method
MH  - Mutation
MH  - Oxygen/*metabolism
MH  - Proton Therapy/*methods
MH  - Protons
MH  - Reactive Oxygen Species/metabolism
MH  - *Relative Biological Effectiveness
OTO - NOTNLM
OT  - Base excision repair
OT  - enzymatic DSB
OT  - indirect action
OT  - proton therapy
OT  - relative biological effectiveness
EDAT- 2019/11/05 06:00
MHDA- 2020/04/24 06:00
CRDT- 2019/11/05 06:00
PHST- 2019/11/05 06:00 [pubmed]
PHST- 2020/04/24 06:00 [medline]
PHST- 2019/11/05 06:00 [entrez]
AID - 10.1080/09553002.2020.1688883 [doi]
PST - ppublish
SO  - Int J Radiat Biol. 2020 Feb;96(2):187-196. doi: 10.1080/09553002.2020.1688883. 
      Epub 2019 Nov 13.