Boron and Gadolinium Neutron Capture Therapy

Abstract

Biochemistry Biochemistry Z 0250 Boron and Gadolinium Neutron Capture Therapy -[ principles, types of drugs , and clinical applications of the neutron capture therapy of tumor diseases, 159 refs.]. -(SALT, C.; LENNOX, A. J.; TAKAGAKI, M.; MAGUIRE, J. A.; HOSMANE*, N. S.; Russ.

Alanine blends for ESR measurements of thermal neutron fluence in a mixed radiation field

“…These results indicate that, even though the probability of neutron reactions in Gd is about 13 times higher than in 10 B, the sensitivity ratio is about three. According to literature (2) , after the Gd neutron capture reaction, the Auger electrons and the internal conversion electrons release their energy within a few micrometers. Therefore, these particles release their energy inside the dosemeter, whereas the X and gamma photons release most of their energy outside the dosemeter.…”

“…The addition of gadolinium therefore significantly enhances the sensitivity and reduces very much the LMF. Both these effects are due to the high neutron capture cross section and to the high LET particles, produced in the nuclear reactions induced by thermal neutrons, which release the energy in the proximity of the Gd nuclei (2) . As final remarks, the addition of gadolinium in alanine/ESR dosemeters described in this paper improves significantly the dosimetric properties of the alanine dosemeters because it increases the sensitivity to the neutron beam and it reduces the lowest detectable fluence.…”

“…The paths of these two high-LET particles are of the order of (4 -9 mm). Further, a gamma photon (2.31 MeV with probability of 94% and 2.79 MeV with probability 6%) is emitted (2) . The gadolinium is used because two of the seven stable gadolinium isotopes have high neutron capture cross section, 155 Gd (75 000 barn) and 157 Gd (250 000 barn).…”

“…In this reaction, complex inner shell transitions generate prompt g-emission displacing an inner-core electron, which involves the emission of an internalconversion electron emission, and finally the Auger electron emission, together with soft X-ray and photon emissions. In this case, the high LET particles are the Auger electron, which release their energy in several nanometers (2) . Thermal neutron fluences are currently measured with a technique using bare and cadmium-covered gold foils (4) .…”

Improvement of ESR dosimetry for thermal neutron beams through the addition of gadolinium

“…The nuclear reaction with neutrons induces complex inner shell transitions that involve the emission of prompt γ photons, of internal conversion electrons and of Auger electrons, together with soft x-ray and photon emissions. The Auger electrons are the high LET particles which release energy locally in tumor cells at a distance of a few nanometers from the reaction place (Salt et al 2004).…”