Study of the time and space distribution of β+ emitters from 80 MeV / u carbon ion beam irradiation on PMMA

Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms (Impact Factor: 1.12). 02/2012; 283. DOI: 10.1016/j.nimb.2012.04.021
Source: arXiv


Proton and carbon ion therapy is an emerging technique used for the treatment
of solid cancers. The monitoring of the dose delivered during such treatments
and the on-line knowledge of the Bragg peak position is still a matter of
research. A possible technique exploits the collinear $511\ \kilo\electronvolt$
photons produced by positrons annihilation from $\beta^+$ emitters created by
the beam. This paper reports rate measurements of the $511\ \kilo\electronvolt$
photons emitted after the interactions of a $80\ \mega\electronvolt / u$ fully
stripped carbon ion beam at the Laboratori Nazionali del Sud (LNS) of INFN,
with a Poly-methyl methacrylate target. The time evolution of the $\beta^+$
rate was parametrized and the dominance of $^{11}C$ emitters over the other
species ($^{13}N$, $^{15}O$, $^{14}O$) was observed, measuring the fraction of
carbon ions activating $\beta^+$ emitters $A_0=(10.3\pm0.7)\cdot10^{-3}$. The
average depth in the PMMA of the positron annihilation from $\beta^+$ emitters
was also measured, $D_{\beta^+}=5.3\pm1.1\ \milli\meter$, to be compared to the
expected Bragg peak depth $D_{Bragg}=11.0\pm 0.5\ \milli\meter$ obtained from

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    • "Swift heavy ions, among which accelerated carbon ions with energy of MeV, have been widely used as the irradiation source because of the relatively larger stopping range and chemicalactivation to transition metal [11] [12] [13] [14] [15]. Transition metal carbide was found to have great influence on mechanical properties of transition metal alloys [16] and it is also reported that the titanium carbide can be trapping sites for the He bubbles to release the He-swelling [17]. "
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    ABSTRACT: Newly developed Zr–45Ti–5Al–3V alloy were irradiated by 84 MeV carbon ions with doses of 4 * 1015 ions/cm2 and 12 * 1015 ions/cm2, respectively. XRD, SEM, TEM, SAD and tensile tests were performed to study the microstructural evolution and mechanical properties modification upon high energy carbon ion irradiation. XRD patterns show no phase change while the diffraction peak position and intensity vary with irradiation doses. Tensile tests verify monotonic change of alloy strengths and elongations upon irradiation. Microstructure observations of the irradiated samples reveal the irradiation-induced precipitation of (Zr,Ti)3C2, which was believed contributing to the alloy hardening. Superlattice was discovered by the SAD patterns of original and irradiated samples and the high energy C-ions implantation was demonstrated to promote the disorder–order transition by introducing lattice defects.
    Full-text · Article · Sep 2014 · Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms
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    • "The readout and performances of the DC and of the LYSO detector have been already reported elsewhere (Agodi et al 2012b) as well as the tracking algorithm and DC calibration. Details on the energy and time calibration of the LYSO crystals have also been reported elsewhere (Agodi et al 2012c). A 10 × 10 × 0.2 cm 3 plastic scintillator, marked as VETO in figure 1, is placed between the target and the DC to stop electrons with energy 0.55 MeV. "
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    ABSTRACT: The radiation used in hadrontherapy treatments interacts with the patient body producing secondary particles, either neutral or charged, that can be used for dose and Bragg peak monitoring and to provide a fast feedback on the treatment plans. Recent results obtained from the authors on simplified setups (mono-energetic primary beams interacting with homogeneous tissue-like target) have already indicated the correlation that exists between the flux of these secondaries coming from the target (e.g. protons and photons) and the position of the primary beam Bragg peak. In this paper, the measurements of charged particle fluxes produced by the interaction of a 220 MeV/u carbon ion beam at GSI, Darmstadt, with a polymethyl methacrylate target are reported. The emission region of protons (p), deuterons (d) and tritons (t) has been characterized using a drift chamber while the particle time-of-flight, used to compute the kinetic energy spectra, was measured with a LYSO scintillator. The energy released in the LYSO crystal was used for particle identification purposes. The measurements were repeated with the setup at 60° and 90° with respect to the primary beam direction. The accuracy on the fragments emission profile reconstruction and its relationship with the Bragg peak position have been studied. Based on the acquired experimental evidence, a method to monitor the dose profile and the position of the Bragg peak inside the target is proposed.
    Full-text · Article · Mar 2014 · Physics in Medicine and Biology
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    ABSTRACT: We have measured the properties of the secondary particles produced in the interaction of carbon ion beams with homogeneous targets, in order to reconstruct the profile of the dose delivered in an hadron therapy treatment. Our measurements have been done with a 80 MeV/u fully stripped carbon ion beam at the INFN Laboratori Nazionali del Sud (LNS), Catania, with a Poly-methyl methacrylate target (PMMA). Both the neutral and the charged component of the secondaries have been measured, the neutral component including prompt photons and ß+-annihilation photons (γ-PET).
    No preview · Conference Paper · Oct 2012
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