The radiobiology of 24 keV neutrons. Measurement of the relative biological effect free-in-air, survival and cytogenetic analysis of the biological effect at various depths in a polyethylene phantom and modification of the depth-dose profile by boron 10 for V79 Chinese hamster and HeLa cells.
HeLa human carcinoma cells and V79 Chinese hamster fibroblasts have been irradiated in vitro with a beam of neutrons with a nearly pure 24 keV spectrum. The relative biological effectiveness (RBE) of the filtered neutron beam relative to 60Co gamma radiation was determined by irradiation of cell cultures "free-in-air". The values obtained for the RBE at 37% survival were 5.8 +/- 0.8, at a dose of 0.69 +/- 0.06 Gy for the HeLa cells and 3.14 +/- 1.1 at a dose of 1.09 +/- 0.091 Gy for the V79 cells. Cytogenetic analysis of the damage in irradiated V79 cells gave an RBE of 6.7 +/- 1.4. Irradiation in a polyethylene phantom markedly attenuated the beam's biological effect. For both cell lines 2 cm of polyethylene virtually eliminated cell killing. Addition of boron 10 to the medium led to increased cell killing and a value of 4 was obtained for the RBE of the 10B(n, alpha)7Li reaction in HeLa cells.
Morgan
G R
GR
Environmental and Medical Sciences Division, Harwell Laboratory, Oxfordshire.
Mill
A J
AJ
Roberts
C J
CJ
Newman
S
S
Holt
P D
PD
D000818:Animals; D001895:Boron; D002460:Cell Line; D002869:Chromosome Aberrations; D006224:Cricetinae; D003412:Cricetulus; D005347:Fibroblasts / Q000528:radiation effects; D006367:HeLa Cells; D006801:Humans; D007554:Isotopes; D009502:Neutrons; D011878:Radiotherapy; D012062:Relative Biological Effectiveness
D007554:Isotopes; D001895:Boron