Cell survival measurements in an argon, aluminium and sulphur filtered neutron beam: a comparison with 24 keV neutrons and relevance to boron neutron capture therapy

Abstract

Boron neutron capture therapy (BNCT) has been advanced as a suitable alternative therapy for the treatment of glioma. BNCT involves the selective uptake of a tumour with a boron-bearing substance and subsequent irradiation with a beam of neutrons. Previous attempts with BNCT have utilized thermal neutrons, but this involves resection of the scalp prior to treatment and is only possible with superficial tumours. An alternative is to use a beam of intermediate-energy neutrons which will produce a peak in the thermal neutron fluence at depth in tissue and so enable deep-seated tumours to be treated. A neutron beam with a mean energy of approximately 9 keV, obtained by filtering neutrons from a reactor with aluminium, argon and sulphur, has been used to explore the radiobiological advantage over thermal and 24 keV neutrons for BNCT. Irradiation of V79 and HeLa cells at various positions in a polythene phantom suggest that the beam is less cytotoxic for a given neutron fluence than the 24 keV neutron beam previously considered as an alternative to thermal neutrons for BNCT. However, optimization of boron distribution via the development of new compounds still appears to be necessary for BNCT to become a safe alternative option for the treatment of glioma.

Responses of Total and Quiescent Cell Populations in Solid Tumors to Boron and Gadolinium Neutron Capture Reaction Using Neutrons with Two Different Energy Spectra

“…This might have been partially because the low Cd ratio neutrons applied here included a higher proportion of fast neutrons (Table I), which include a larger proportion of 24 keV neutrons that are considered to induce chromosome abberations at high efficiency. 15,16) The values of RBE for total cells themselves were similar to those in other reports. 17,18) However, to our knowledge, this is the first report concerning RBE for Q cells in vivo related to neutron Cd ratio in neutron irradiation.…”

“…(Received July 17, 1997 / Revised September 10, 1997 / 2nd Revised October 9, 1997 / Accepted October 16, 1997) …”

Impact of the p53 Status of the Tumor Cells on the Effect of Reactor Neutron Beam Irradiation, with Emphasis on the Response of Intratumor Quiescent Cells

“…This might be partially because the low Cd ratio neutrons employed here included a higher percentage of fast neutrons, which include a higher proportion of 24 keV neutrons which induce chromosome aberrations at high efficiency. 22,30,31) In addition, this might be partially because the ratio of high LET neutron components to total radiation components is higher in low Cd ratio neutron beams than in high Cd ratio neutron beams (Table I). The values of RBE for total cells themselves were similar to those in other reports.…”