Use Of Particle Beam Research Articles

Particle Therapy for Breast Cancer: Benefits and Challenges.

Hadron therapy with protons and carbon ions is widely attracting interest as a potential competitor of conventional photon radiotherapy. Exquisite dose distribution of charged particles allows for a higher local control of the tumor and lower probability of damage to nearby healthy tissues. Heavy ions have presumed biological advantages rising from their high-linear energy transfer (LET) characteristics, including greater cell-killing effectiveness and reduced heterogeneity dependence of radiation response. Although these advantages are clear and supported by data, only 18.0% of proton and carbon ion radiotherapy (CIRT) facilities in Europe are treating breast cancers. This review summarizes the physical and radiobiological properties of charged particles, clinical use of particle beam for breast cancer, and suggested approaches to overcome technical and financial challenges.

Advantages and Limitations in the Use of Combination Therapies with Charged Particle Radiation Therapy.

Studies are currently underway to help provide basic and clinical evidence for combination particle beam radiation therapy, on which there are few published reports. The purpose of this article is to summarize the current status in the use of particle beams combined with other modalities. Following from experiences in x-ray radiation therapy, combination therapy with proton beams (PBT) has been attempted, and several clinical studies have reported improved survival rates for patients with non-small cell lung cancer, pancreatic cancers, esophageal cancers, and glioblastomas. Recently, basic studies combining PBT with PARP inhibitors and histone deacetylase inhibitors have also reported promising results. In the area of carbon ion therapy (CIT), there are few clinical reports on combination therapy; however, the number of basic research reports exceeds that for PBT. So far, the combined use of cytotoxic drugs with CIT yields independent additive effects. In addition, it is notable that combination therapy with CIT is effective against radioresistant cancer stem-like cells. Recent evidence also suggests that local radiation therapy can induce an effective antitumor immune response. There has been an increased use of combination immune-modulating agents and cytokines with particle beams, especially CIT. The field of radiation therapy is evolving from a strong reliance on local-regional treatment to a growing reliance on systemic immunotherapy. The combined use of anticancer agents with particle radiation therapy has a considerable potential effect. Future research in molecular targeting therapy and immunotherapy may help identify the most efficacious approach for combination therapy with protons and carbon ions.

Robert R. Wilson (1914-2000): the first scientist to propose particle therapy-use of particle beam for cancer treatment.

Robert R. Wilson (1914-2000): the first scientist to propose particle therapy-use of particle beam for cancer treatment.

Backscattering and absorption coefficients for electrons: Solutions of invariant embedding transport equations using a method of convergence

The backscattering coefficient is a magnitude whose measurement is fundamental for the characterization of materials with techniques that make use of particle beams and particularly when performing microanalysis. In this work, we report the results of an analytic method to calculate the backscattering and absorption coefficients of electrons in similar conditions to those of electron probe microanalysis. Starting on a five level states ladder model in 3D, we deduced a set of integro-differential coupled equations of the coefficients with a method know as invariant embedding. By means of a procedure proposed by authors, called method of convergence, two types of approximate solutions for the set of equations, namely complete and simple solutions, can be obtained. Although the simple solutions were initially proposed as auxiliary forms to solve higher rank equations, they turned out to be also useful for the estimation of the aforementioned coefficients. In previous reports, we have presented results obtained with the complete solutions. In this paper, we present results obtained with the simple solutions of the coefficients, which exhibit a good degree of fit with the experimental data. Both the model and the calculation method presented here can be generalized to other techniques that make use of different sorts of particle beams.

Nuclear fusion in ordered crystal targets bombarded by monochromatic beams of light or middle-mass isotopes

In ordered crystal lattice there is very strong influence of crystal axes and planes electrical field on motion and interaction of fast charged particles with crystal atoms and nuclei. It is shown that in mono-crystal targets like LiD the rate of fusion process with the participation of both target nuclei (e.g. D) and beam of fast nuclei (e.g. T), directed at Lindhard angle, may be increased by 10–100 times compared to the alternative process of deceleration on atomic electrons. Such changes are based on the use of specific channeling physics regime of motion – “overbarrier motion”. At such regime the processes of spatial redistribution and dechanneling of accelerated ions take place. In this article the methods of optimization and practical realization of such a nuclear fusion are discussed in details.Another method for radical optimization of fusion processes with the use of monochromatic beams of middle mass isotopes is proposed. The features of optimized nuclear fusion model based on resonant tunneling effect were considered. This leads, in combination with the use of particle beams with optimum energy and energy spread, which correspond to total transparency “window” of reaction barrier, to the possibility of positive nuclear fusion energy release on one atomic monolayer! Such effect can be regarded as nuclear super absorption of accelerated beam. The possibility of nuclear reactions C12+O16 and C12+O18 at such motion regime with positive energy release is examined.

Plasma Liner with an Intermediate Heavy Shell and Thermal Pressure Drive

One of the challenging problems of magnetized target fusion (MTF) is developing ways to transport energy to the target situated at a distance far enough from the energy source so as to prevent damage to the permanent parts of the source. Several schemes were considered in the past, including the use of particle beams coupled with the inverse diode, mechanical projectiles in combination with magnetocompressional generators, and the plasma liner. In this paper, a possible modification of the original concept of the plasma liner (by Thio et al.) is described. The modification consists of creating a thin, higher-density shell made of a high-Z plasma and accelerating it onto an MTF target by the thermal pressure of hydrogen plasma with a temperature of ~10 eV. We discuss constraints on the parameters of this system and evaluate the convergence ratio that can be expected.

Plasma Processes and Polymers

Cover: To explore whether plasma is irritating to sensitive tissues such as wounds and eyes, the Hen's Egg Testchorioallantoic membrane (HET-CAM) is used to test different plasma sources and settings. Effects including the reversibility are compared and it is ascertained that the HET-CAM is useful for characterizing plasma properties and settings that are innocuous for living tissues. Further details can be found in the article by C. Bender,' R. Matthes, E. Kindel, A. Kramer, J. Lademann, K.-D. Weltmann, W. Eisenbeis, and N.-O. Hubner on page 318.

Solution conformation of model polypeptides with the use of particle beam LC/FT-IR spectrometry and electrospray mass spectrometry

Solution conformations of the polypeptides β endorphin ( β-END) and a cysteine peptide (CYSP) were investigated with the use of particle beam LC/FT-IR spectrometry. Gradient elution HPLC with mobile phases that contained acetonitrile with 0.1% TFA (v/v) and 0.1% aqueous TFA (v/v) were used. The conformations of both polypeptides were studied in 0.9% sodium chloride injection USP, 5% dextrose in water injection USP and sterile water for injection USP. Additional conformational studies over a pH range of 2–10, temperatures of 25, 50, 75 and 100°C and after storage for 24 h were investigated. The studies indicated that the two polypeptides did not behave similarly under identical conditions. It was observed that both β-END and CYSP had slightly different conformations in the various parenteral solutions. It was also shown that the conformation of CYSP changed with both pH and temperature while β-END was conformationally stable to both temperature and pH. The identity of the peptides and the conformationally sensitive charge-state intensities of the peptides were investigated with electrospray ionization mass spectrometry (ESI/MS). The combination of IR and MS data allowed an estimation of solution effects on the conformations of the model polypeptides.

Solution conformation of model peptides with the use of particle beam LC/FT-IR spectrometry and electrospray mass spectrometry

Solution conformations of the peptides angiotensin I (Ang I) and POMC-X (an octapeptide fragment of proopiomelanocortin) were investigated with the use of particle beam liquid chromatography/Fourier transform infrared (LC/FT-IR) spectrometry. Gradient elution high-performance liquid chromatography (HPLC) with mobile phases that contain acetonitrile, 2-propanol, 0.1% heptafluorobutyric acid (HFBA) and 0.1% trifluoroacetic acid (TFA) were used. The conformations of both peptides were studied in 0.9% sodium chloride injection USP, 5% dextrose in water injection USP and sterile water for injection USP. Additional conformational studies over a pH range of 2–10, to a temperature of 75°C and after a storage time of 24 h were investigated. The studies indicated that the two peptides do not behave similarly under identical conditions. It was observed that both Ang I and POMC-X had slightly different conformations in the various parenteral solutions. It was also shown that the conformation of Ang I changed with both pH and temperature while POMC-X was conformationally stable to both temperature and pH. The identity of the peptides and the conformationally sensitive charge-state intensities of the peptides were investigated with electrospray ionization mass spectrometry (ESI/MS). The combination of infrared and mass spectrometric data allowed a thorough estimation of solution effects on the conformations of the model peptides.

Use of Particle Beam Liquid Chromatography/Mass Spectrometry for the Characterization of Chromium Aminocarbene Complexes

Chromium carbenes are used in organic synthesis as reagents to obtain molecules of biological interest. In this work a particle beam (PB) coupled liquid chromatography/mass spectrometry (LC/MS) system was used for the characterization of a mixture of chromium aminocarbene complexes. Three of them are new compounds. The separation of the examined complexes was performed using normal-phase chromatography. The acquisition of electron ionization, positive-ion and negative-ion chemical ionization mass spectra of the eluates was accomplished. The capability of PB LC/MS technique in the on-line characterization of organometallic compounds is highlighted. In addition, the fragmentation patterns of all the compounds considered are discussed. © 1997 John Wiley & Sons, Ltd.

Use of Particle Beam Liquid Chromatography/Mass Spectrometry for the Characterization of Chromium Aminocarbene Complexes

Use of Particle Beam Liquid Chromatography/Mass Spectrometry for the Characterization of Chromium Aminocarbene Complexes

Pulsed particle beam treatment of implanted silicon

The formation of heavily doped silicon layers by P +, B +, In + ion implantation and their further treatment by powerful nanosecond (50 ns) ion pulses and microsecond (1.5 μs) electron pulses has been investigated. The concentration, mobility and depth distribution of the charge carriers have been measured. Transmission electron microscopy (TEM) is applied to investigate the layer structure. The use of particle beams allows control over large intervals of the depth distribution (∼ 2 μm) and formation of highly conducting layers (5 ω □ −1) with P and B concentrations exceeding the equilibrium solubility. The experimental results have been compared with those involving laser treatment and calculations of temperature fields.