Direct effect in DNA radiolysis. Boron neutron capture enhancement of radiolysis in a medical fast-neutron beam.

SècheThis paper is devoted to the study of the molecular basis of the boron neutron capture enhancement of fast-neutron radiotherapy. Plasmid DNA was irradiated with a medical fast-neutron beam in the presence of either (10)B or (11)B. The number of induced SSBs and DSBs was much higher in samples containing (10)B compared to (11)B.

Beam collimation and bolusing material optimizations for 10boron neutron capture enhancement of fast neutron (BNCEFN): definition of the optimum irradiation technique.

Purpose: In boron-10 neutron capture enhancement of fast neutron irradiation (BNCEFN), the dose enhancement is correlated to the 10B concentration and thermal neutron flux. A new irradiation technique is presented to optimize the thermal neutron flux.

Methods And Materials: The coupled FLUKA and MCNP-4A Monte Carlo codes were used to simulate the neutron production and transport for the Nice and Orleans facilities.

Combined use of FLUKA and MCNP-4A for the Monte Carlo simulation of the dosimetry of 10B neutron capture enhancement of fast neutron irradiations.

Boron neutron capture enhancement (BNCE) of the fast neutron irradiations use thermal neutrons produced in depth of the tissues to generate neutron capture reactions on 10B within tumor cells. The dose enhancement is correlated to the 10B concentration and to thermal neutron flux measured in the depth of the tissues, and in this paper we demonstrate the feasibility of Monte Carlo simulation to study the dosimetry of BNCE. The charged particle FLUKA code has been used to calculate the primary neutron yield from the beryllium target, while MCNP-4A has been used for the transport of these neutrons in the geometry of the Biomedical Cyclotron of Nice.

Thiol WR-1065 and disulphide WR-33278, two metabolites of the drug ethyol (WR-2721), protect DNA against fast neutron-induced strand breakage.

The main metabolites of the cytoprotective drug Ethyol (Amifostine, WR-2721) are the thiol WR-1065 and the disulphide WR-33278 (formed by the oxidation of WR-1065). Both metabolites are well-known protectors against DNA damage induced by gamma-rays. Using supercoiled plasmid DNA and restriction fragments we show that they protect efficiently also in the case of fast neutrons.

[Computed tomography option on simulator: a 14-month use at the Orléans hospital radiotherapy department].

The purpose was to evaluate the use of the CT option for simulator during a 14-month period in the radiotherapy department. The CT option has been adapted on the Philips simulator SL23. The virtual tunnel diameter is 92 cm which allows slice acquisition regardless of the contention device used.