The source maintains its speed even for the short interdwell distances. Dose variations due to the transit dose component are much lower than the prescribed treatment doses for brachytherapy, although transit dose component should be evaluated individually for clinical cases.

Agradeço primeiramenteà agência de fomento FAPESP pelo apoio financeiro concedido para o desenvolvimento deste projeto. Agradeço ao apoio e incentivo da minha família não só nesta etapa que se encerra, mas desde o começo da minha vida acadêmica. Agradeço aos amigos e colegas de trabalho no Departamento de Engenharia Nuclear do Instituto de Pesquisas Energéticas e Nucleares. Dividimos momentos de descontração e colaboração mútua que foram e são importantes para minha formação. Agradeço ao Dr. Hamilto Akihissa Yamamoto da Faculdade de Medicina da UNESP, câmpus de Botucatu, pela colaboração essencial ao desenvolvimento da pesquisa apresentada. Agradeço aos meus orientadores Adimir dos Santos e Hélio Yoriyaz. Vocês colaboraram ativamente com o meu progresso e merecem minha sincera gratidão e compromisso profissional. Agradeço especialmenteà Gisela de Assis Martini que, por meio de seu companheirismo e carinho, esteve presente ao meu lado em momentos cruciais. And finally, I am thankful for the advising from Anuj Kapadia who was my mentor during my one year internship abroad. Several things were accomplished trough a lot of work, research and simulations. I am also thankful for the friendship and collaboration from Greeshma Agasthya, Manu Lakshmanan, and Gretchen Raterman. Agradeçoà Deus... iv "Tenha em mente que tudo que você aprende na escolaé trabalho de muitas gerações. Receba essa herança, honre-a, acrescente a ela e, um dia, fielmente, deposite-a nas mãos de seus filhos."

This work describes a simulation study investigating the application of neutron stimulated emission computed tomography (NSECT) for noninvasive 3D imaging of renal cancer in vivo. Using MCNP5 simulations, we describe a method of diagnosing renal cancer in the body by mapping the 3D distribution of elements present in tumors using the NSECT technique. A human phantom containing the kidneys and other major organs was modeled in MCNP5. The element composition of each organ was based on values reported in literature. The two kidneys were modeled to contain elements reported in renal cell carcinoma (RCC) and healthy kidney tissue. Simulated NSECT scans were executed to determine the 3D element distribution of the phantom body. Elements specific to RCC and healthy kidney tissue were then analyzed to identify the locations of the diseased and healthy kidneys and generate tomographic images of the tumor. The extent of the RCC lesion inside the kidney was determined using 3D volume rendering. A similar procedure was used to generate images of each individual organ in the body. Six isotopes were studied in this work - (32)S, (12)C, (23)Na, (14)N, (31)P and (39)K. The results demonstrated that through a single NSECT scan performed in vivo, it is possible to identify the location of the kidneys and other organs within the body, determine the extent of the tumor within the organ, and to quantify the differences between cancer and healthy tissue-related isotopes with p ≤ 0.05. All of the images demonstrated appropriate concentration changes between the organs, with some discrepancy observed in (31)P, (39)K and (23)Na. The discrepancies were likely due to the low concentration of the elements in the tissue that were below the current detection sensitivity of the NSECT technique.

ABSTRACT.A radiotherapy planning is considered optimal when all the parameters involved, physical or biological, have been investigated and appropriate for each patient. In this type of planning, the major concern is with the tumor irradiation with the minimum possible damage to healthy tissues of the irradiated region, especially the organs at risk. The optimal planning for radiotherapy can be aided by Linear Programming and there is a wide literature addressing this subject. However, most published mathematical formulations do not contemplate a scenario in terms of practical applications, because they do not incorporate the heterogeneous composition of the irradiated tissue. This paper presents a methodology for heterogeneity correction in the composition of different types of irradiated tissues based on proportions among their different linear attenuation coefficient.

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AN ALTERNATIVE ROUTE TO OBTAIN METAL-ORGANIC FRAMEWORKS VIA SOLVOTHERMAL SYNTHESIS USING Eu2O3 AND 2,6-NAPHTHALENODICARBOXYLIC ACID. An alternative route to synthesis of metal-organic frameworks containing Eu(III) ion was proposed via solvothermal process in aqueous medium. The compounds of the minimal formulae [Ln2(NDC)3(H2O)4] were synthesized starting from the mixture of the 2,6-naphthalenedicarboxylic acid with europium(III) oxide. So far, this type of metalorganic framework based on the lanthanide ion synthetic route has not been investigated before as the main metal sources are nitrate and chloride salts. The structural characterizations were performed by FTIR spectroscopy, thermal analysis TG-DSC, and X-ray diffraction. The results of IR and TG were consistent with the structural determination results and complemented by X-ray diffraction patterns. SEM images also corroborate the morphologies found in recent research on this material. The materials obtained shown highintensity luminescence, for the Eu-NDC compound, which corroborates with an energy transfer efficient of the ligand to Eu(III) ion.