Boron neutron capture therapy for cancer or short

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Unformatted text preview: on of tumors. Usually, reactions for PET are carried out by using up to 20 MeV protons or similar energy deuterons from cyclotrons with the concomitant problems of large size and cost and extensive radiation shielding. Production of short-lived isotopes via laser-driven proton beams may be feasible in the near future with the possibility of employing moderate energy, ultrashort, high-repetition tabletop lasers. Extrapolations based on present results point to the possibility of reaching the gigaBecquerel (GBq) activities required for PET if laser systems capable of delivering 1 J, 30 fs pulses focused at 1020 W cmÀ2 with kHz repetition will become available (Fritzler et al., 2003; Lefebvre et al., 2006) and economically competitive with existing technologies. E. Nuclear and particle physics FIG. 36 (color online). Top: Overview of an experimental setup for integrated dosimetry and cell irradiation system by laser-accelerated protons. Bottom: Fluorescence microscopy view of SKX tumor cell nuclei irradiated with such system, showing that the number of DNA double-strand breaks (bright spots, yellow-pink in the color version) increases with the delivered dose. From Kraft et al., 2010. Rev. Mod. Phys., Vol. 85, No. 2, April–June 2013 The interaction of laser-driven high-energy ions with secondary targets can initiate nuclear reactions of various types, which as mentioned (see Sec. II.E) can be used as a tool to diagnose the beam properties. This also presents the opportunity of carrying out nuclear physics experiments in laser laboratories rather than in accelerator or reactor facilities, and to apply the products of the reaction processes in several areas. Reactions initiated by laser-accelerated high-Z ions have been studied in a number of experiments. McKenna et al. (2003a, 2003b, 2004) showed that reactions between fast heavy ions from a laser-produced plasma and stationary atoms in an adjacent ‘‘activation’’ sample create compound nuclei in excited states, which deexcite through the evaporation of protons, neutrons, and particles. A similar experiment 786 Andrea Macchi, Marco Borghesi, and Matteo Passoni: Ion acceleration by superintense laser-plasma . . . with protons driving nuclear reactions and excitations in a Cu target was reported by Hannachi et al. (2007). Nuclear reactions of interest for spallation physics have also been investigated by employing multi-MeV proton beams (McKenna et al., 2005). The broad energy distribution of the beams is in this case advantageous for the determination of residual nuclide generation arising from specific spallation processes such as evaporation. In addition, MeV proton interaction with low-Z materials can produce short-lived isotopes29 of medical interest, e.g., for PET diagnostic (see Sec. V.D). Recently, a scheme of a ‘‘fission-fusion’’ process driven by RPA (see Sec. IV.A) was also proposed to produce neutronrich nuclei in the range of the r process (Habs et al., 2011); such studies, of...
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This document was uploaded on 09/28/2013.

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