An insight into tumoral hypoxia: the radiomarkers and clinical applications

Abrantes, Ana Margarida; Serra, M. Elisa Silva; Murtinho, Dina; Gonsalves, Antonio Rocha; Botelho, Maria Filomena

doi:10.4081/73

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“…In order to design a study or treatment using MI techniques, it is important to start by identifying the molecular process to be tracked. For example, there is an increased glucose consumption of most cancerous tumors [4]. Thus, radiotracers based on glucose are used for cancer diagnosis and therapy treatment assessment [5].…”

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confidence: 99%

Characterization of Dedicated PET Equipment with Non-Conventional Geometry

Ledo¹

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Since their introduction in the 1950-decade, tomographic images have become very valuable in the medical field helping both in diagnostics and in a variety of illnesses treatment. In the molecular imaging field, Positron Emission Tomography (PET) provides accurate information of the radio-tracers interactions with the patient tissue. Moreover, it is possible to combine this information with anatomical images provided by CT (Computed Tomography) or MR (Magnetic Resonance) scanners. With the aim to improve PET systems performance, such as the spatial resolution and the sensitivity, whole body (WB) PET scanners with large axial coverage are recently proposed. However, the system cost increases and, thus, makes difficult their installation in many hospitals or research centers. Organ-dedicated PET scanners, as an alternative to such large systems, use a lower number of detectors, so their price is considerably more economical. The goal of this kind of systems is to boost PET performance by placing the detectors as close as possible to the patient, optimizing the design for a specific organ instead of a large volume. Other advantage of these scanners is their portability. In this thesis we have worked in the design and validation of two organ-dedicated PET scanners with different geometries and technologies, as well as in a novel pre-clinical PET.The first scanner was the result from a national project called PROSPET. A PET system was designed and optimized to image the prostate area. Notice there is a high incidence rate of prostate cancer in the male population. 17% of male population will suffer prostate cancer. For this scanner, the detector modules were composed by a monolithic LYSO scintillation block coupled to a photosensor array based on silicon photomultipliers (SiPM). The first design configuration was made by two panels. However, patient results were not satisfactory due to the lack of angular information and the poor detector time resolution. Therefore, it was rebuilt in a ring configuration with a reduced diameter in comparison with WB-PET scanners. A high sensitivity and spatial resolution were found, as well as a good image quality using phantoms.The second PET scanner, called CardioPET, also arose from a national grant, and it was implemented to visualize the heart area when the patient is under stress condition. The two panels geometry was also implemented for this system, but using pixelated crystals, therefore improving the detector time resolution and allowing to use time of flight (TOF) reconstruction algorithms. Two panels were mounted and tested with both simulation and experimental data with good results. Furthermore, the patient motion was registered applying movement correction techniques with the help of an external optical camera device and ARUCO markers. These algorithms were tested showing a good performance. ivThe last device that we worked within this PhD thesis was designed to optimize the classical ring PET configuration as much as possible. To do so, the gaps between the detector mo...

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Section: Introductionmentioning

confidence: 99%

Characterization of Dedicated PET Equipment with Non-Conventional Geometry

Ledo¹

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“…Por outro lado, em células sob hipóxia após os compostos sofrerem redução, normalmente não há re-oxidação efetiva devido à baixa concentração de oxigênio. Assim, a redução prossegue até a geração de espécies citotóxicas ou liberação de compostos ativos(Figura 3)(ABRANTES et al, 2009; FAILES e HAMBLEY, 2006). via HIF-1 tem sido explorada para o desenvolvimento de novos compostos para o tratamento do câncer através de diferentes mecanismos: i) PT2385 inibe a dimerização HIF-1α, atualmente em fase clínica I da via da UPR impedindo que as células tumorais se adaptem neste processo de hipóxia (Figura 5)(WILSON e HAY, 2003).Outra via de crescente relevância corresponde a via mTOR, que atua como reguladora da energia celular e do status nutricional.…”

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Síntese de novas quinazolinas para tratamento de tumores sob hipóxia e nitroimidazol para diagnóstico por PET

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An insight into tumoral hypoxia: the radiomarkers and clinical applications

Cited by 2 publications

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Characterization of Dedicated PET Equipment with Non-Conventional Geometry

Characterization of Dedicated PET Equipment with Non-Conventional Geometry

Síntese de novas quinazolinas para tratamento de tumores sob hipóxia e nitroimidazol para diagnóstico por PET

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