Search results for "ESR"

Characterization of the ESR response of alanine dosimeters to low-energy (1-40 keV) X-rays

2016

The aminoacid L-a-alanine has attracted considerable interest for use in radiation ESR dosimetry and has been formally accepted as a secondary standard for high-dose (kGy) and transfer dosimetry . The accuracy of the method is quite high, largely due to the low dependence of the alanine response on various irradiation parameters (photon energies above 100 keV, dose rate, temperature, etc.). Furthermore, this system presents alinear response to dose, fairly high sensitivity, tissue equivalence, absence of fading, small dimensions, ruggedn ess, and non-destructive readout. In this work, we examined the energy dependence of alanine ESR dosimeters in the low energy X-photon energy range between…

Phenol compounds as new materials for electron spin resonance dosimetry in radiotherapy

2016

Introduction: Among the various dosimetric techniques used for characterizing the radiation beams used in radiation therapy, the electron spin resonance (ESR) arouses increasing interest for applications in various therapy procedures. Free radicals are known to be produced when a compound is irradiated with ionizing radiations. The concentration of radiationinduced free radicals is proportional to the absorbed dose and this allows for dosimetric measurements through ESR technique which enables to quantitatively determine the radical concentration. In this work we report the ESR investigation of phenol pellets and thin films exposed to various types of radiation beams (clinical photon and el…

EPR ANALYSIS OF ALANINE WITH GADOLINIUM FOR DOSIMETRY AT TRIGA MARK II REACTOR OF MAINZ

2015

Negli ultimi anni il crescente interesse verso la radioterapia a cattura neutronica (internazionalmente nota come Neutron Capture Therapy - NCT) per il trattamento di neoplasie ha stimolato diverse attività di ricerca finalizzate alla caratterizzazione del fascio utilizzato e all'ottimizzazione delle procedure radioterapiche. La corretta riuscita del trattamento NCT e il monitoraggio della dose impartita non possono prescindere dalla valutazione delle varie componenti del fascio impiegato (neutronica e fotonica). Infatti, durante le procedure di moderazione dei neutroni, si verifica la produzione di fotoni e la stima dei rischi a cui sono soggetti i tessuti sani sottoposti al campo misto ne…

Electron structure, ultra-dense hydrogen and low energy nuclear reactions

2019

In this paper, a simple Zitterbewegung electron model, proposed in a previous work, is presented from a different perspective based on the principle of mass- frequency equivalence. A geometric- electromagnetic interpretation of mass, relativistic mass, De Broglie wavelength, Proca, Klein- Gordon, Dirac and Aharonov- Bohm equations in agreement with the model is proposed. A non-relativistic, Zitterbewegung interpretation of the 3.7 keV deep hydrogen level found by J. Naudts is presented. According to this perspective, ultra-dense hydrogen can be conceived as a coherent chain of bosonic electrons with protons or deuterons located in the center of their Zitterbewegung orbits. This approach sug…

Misa mayor socialista

1999

La gobernación del mundo

1999

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2004

El Desorden mundial

1997

ALANINE/EPR DOSIMETRY APPLIED TO THE VALIDATION OF A TOTAL BODY IRRADIATION (TBI) PROTOCOL AND TREATMENT PLANNING DOSE CALCULATION USING A HUMANOID P…

2015

L’irraggiamento a corpo intero (Total Body Irradiation - TBI) è una tecnica di radioterapia oncologica di largo impiego nella clinica ematoncologica nell’ambito del trattamento di pazienti avviati al trapianto di midollo osseo o al trapianto di cellule staminali periferiche. La TBI da una parte permette di sopprimere il sistema immunitario del ricevente per prevenire il rigetto del midollo del donatore ed eliminare le cellule neoplastiche residue dai trattamenti chemioterapici. In genere, la modalità di somministrazione della TBI prevede irraggiamenti in 3 giorni consecutivi con un bi-frazionamento giornaliero (2 Gy, 2 volte al giorno con intervallo minimo di 6 ore tra le sedute, per 3 gior…

EPR DOSIMETRY WITH ALANINE FOR TOTAL BODY IRRADIATION USING AN ANTHROPOMORPHIC PHANTOM

2016

The Total Body Irradiation (TBI) is a radiation therapy technique widely used in clinical hemato-oncological treatment of patients that underwent bone marrow transplantation or peripheral stem cell transplantation. Typically, the administration of TBI treatment provides irradiations in 3 consecu-tive days with a double daily fractionation, although other dose fractionation modes have been widely adopted in the clinic procedures. Although this tech-nique allows to irradiate the whole body from head to toes, it has some limitations such as the lack of homogeneity of the dose distribution (which can show varia-tions of 20% in the different areas), irradiation of critical organs such as lungs, …