Neutron and gamma-irradiation of bacteriophage M13 DNA: use of standard neutron irradiation facility (SNIF).
We describe here the use of the Van de Graaff accelerator as a source of high energy neutrons for biological irradiation. Single-stranded bacteriophage M13 DNA was chosen as the system to determine the relative biological effectiveness of monoenergetic neutrons. A Standard Neutron Irradiation Facility (SNIF) was established using a 3 MV Van de Graaff accelerator. The 2D (d,n)3He nuclear reaction was used to produce neutron fluxes of 3 x 10(8) cm 2 sec-1 yielding dose rates as high as 50 Gy h-1. A detailed description of the neutron source, neutron fluence measurement, dose calculation and calibration are included. Exposure of single-stranded bacteriophage M13 DNA to 90 Gy of neutrons reduced survival to 0.18% of the unirradiated value. 500 Gy of gamma-rays were required for the same level of killing, and RBE was estimated at 6 based on Do values. Determination of the extent of DNA damage after exposure to cleavage using gel electrophoresis, gave RBE values of 6-8 which was very similar to that observed for bacteriophage survival. The facility described here provides a reproducible source of high energy monoenergetic neutrons and dose levels suitable for experiments designed to measure DNA damage and effects on DNA synthesis.
Singh
S P
SP
Queensland Institute of Medical Research, Brisbane, Australia.
Cohen
D
D
Dytlewski
N
N
Houldsworth
J
J
Lavin
M F
MF
D003090:Coliphages / Q000528:radiation effects*; D004249:DNA Damage; D004267:DNA Viruses; D004277:DNA, Single-Stranded / Q000528:radiation effects*; D005214:Fast Neutrons; D005720:Gamma Rays; D012062:Relative Biological Effectiveness
D004277:DNA, Single-Stranded