The subject of this thesis is the development of new gamma ray imagers for nuclear medicine, in particular for scintimammography. The need for new compact detectors with high spatial resolution led to the design of the wavelength-shifting fibre (WSF) gamma camera, where the position of interaction of gamma rays inside an inorganic scintillator is read out by WSFs. The feasibility of the concept of a WSF gamma camera was assessed by simple analytical calculations and Monte Carlo simulations, based on the known characteristics of the individual components: the wavelength-shifting fibres, the scintillation crystal and the photodetectors. Studies were carried out of the light trapped inside WSFs coupled to CsI(Na) scintillation crystals irradiated by 122 keV gamma rays. The results confirm the feasibility of a WSF gamma camera despite the low light levels trapped in the fibres. Experimental tests of several position sensitive photomultiplier tubes (PSPMT) of the Hamamatsu R5900 series were performed to assess their suitability for the readout of scintillation crystals and of optical fibres in photon counting mode. The latter application is important for the readout of the WSFs signals in a WSF gamma camera. A WSF gamma camera prototype was built and tested. The R5900-M16 PSPMT was used to read out the signals from WSFs. The results confirm earlier predictions about its performance. In particular, the spatial resolution achieved is comparable to that of modern Anger cameras. It is expected that the inherently flexible design of the camera should allow better positioning around the object than conventional Anger cameras, which is important to optimise the spatial resolution of the system. Monte Carlo simulations show that the use of photodetectors with higher quantum efficiency than PSPMTs would significantly improve the intrinsic spatial resolution. A discussion on the most promising candidates for this application is presented.

Submitted by LUCIANA GURGEL DA TRINDADE MEIRA HENRIQUES (gustavoluciana@globo.com) on 2016-11-18T17:11:15Z No. of bitstreams: 1 LUCIANA GURGEL TRINDADE HENRIQUES.pdf: 1198247 bytes, checksum: 3ce5ab865cdb5ea1c6e1973bf14b8d1a (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-11-23T19:59:02Z (GMT) No. of bitstreams: 1 henriques_lgtm_dr_bot.pdf: 1198247 bytes, checksum: 3ce5ab865cdb5ea1c6e1973bf14b8d1a (MD5) / Made available in DSpace on 2016-11-23T19:59:02Z (GMT). No. of bitstreams: 1 henriques_lgtm_dr_bot.pdf: 1198247 bytes, checksum: 3ce5ab865cdb5ea1c6e1973bf14b8d1a (MD5) Previous issue date: 2016-09-21 / Introdução: o carcinoma de mama é uma das principais causas de morte no mundo e seu diagnóstico e tratamento precoces tem importante impacto na evolução clínica. A classificação imunoistoquímica (IHQ) determina o prognóstico do carcinoma e qual a melhor forma terapêutica a ser instituída. Autores sugerem que a cintilografia mamária poderia auxiliar a IHQ nessas definições de prognóstico. Casuística e Métodos: este estudo incluiu pacientes portadoras de carcinoma invasivo da mama que tiveram seu diagnóstico no período de 2011 a 2013 no Hospital das Clínicas da Faculdade de Medicina de Botucatu. Em todos os casos foram feitos exames imunoistoquímicos, determinando o índice proliferativo (IP) e a classificação. Associação entre ambos e os achados da cintilografia mamária foram analisadas. Resultados: dos 310 pacientes com carcinoma invasivo de mama diagnosticados no período, 243 tiveram sua classificação e IP definidos pela IHQ. Cintilografia normal está associada a baixo IP e a classificações responsivas à hormonioterapia. As pacientes com cintilografia alterada tiveram mais chance de ter IP maior ou igual a 14%, com alta acurácia, alto valor preditivo positivo e alta sensibilidade, e estão significativamente associadas a formas irresponsivas ao tratamento hormonal. Alterações mais intensas associam-se com formas de pior prognóstico. Conclusão: cintilografia mamária alterada em pacientes com diagnóstico histológico de carcinoma invasivo de mama indicam um pior prognóstico, bem como a normalidade indica a existência de classificação tumoral com melhor resposta à quimioterapia hormonal. Esses achados não permitem que a cintilografia de mama substitua a realização do painel prognóstico imunoistoquímico no tratamento dessa doença, mas sim possa orientar o prognóstico e responsividade a droga. Palavras chaves: carcinoma invasivo de mama; imuno-histoquímica; cintilografia mamária; radioisotopo; medicina nuclear. / Introduction: Breast carcinoma is one of the leading causes of deaths in the world and its early diagnosis and treatment have an important impact in the clinic evolution. The Immunohistochemical (IHC) profile determines the prognosis of the carcinoma and which is the best therapy to be established. Authors suggest that scintimammography could help immunohistochemistry (IHC) in these prognosis definitions. Methods: This study included patients with invasive breast carcinoma who were diagnosed in the period of 2011- 2013 at the Hospital das Clinicas of the Medical School of Botucatu. In all of the cases, IHC exams were performed, determining the proliferative index (PI) and the classification. The association between both results and the scintimammography (SMG) findings were analyzed. Results: of the 310 patients with invasive breast carcinoma diagnosed in the period, 243 had their classification and PI defined by the IHC. Normal SMG is associated to low PI and to hormonal therapy responsive classifications. The patients with altered SMG have had more chances of having a PI greater or equal to 14%, with high accuracy, high positive predictive valor and high sensibility, and are significantly associated to hormonal therapy irresponsive forms. More intense alterations are associated with forms of poor prognosis. Conclusion: altered SMG in patients with histological diagnosis of invasive breast carcinoma indicate a worse prognosis, as well as normaly indicates the existence of tumor classification with better response to hormonal chemotherapy. These findings do not allow the replacement of the immunohistochemistry prognosis profile for the scintimammography in the treatment of this disease, but can guide the prognosis and responsiveness to drug. Key Words: invasive breast carcinoma; immunohistochemistry; scintimammography; radioisotope; nuclear medicine.