Browsing by Author "Oliveira, Luís"
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- Automatic versus semi-automatic method for the striatum specific uptake ratio quantification based on [I-123]FP-CIT SPECT imagesPublication . Elias, Maria; Jorge, Pedro; Figueiredo, Sérgio; Oliveira, Luís; Pereira, Edgar L.The aim of this work was to implement an automatic application (AA) for the quantification of the striatum transaxial slices based on [I-123]FP-CIT SPECT (Single Photon Emission Tomography) images. A sample of 68 subjects with and without pathology was collected from the nuclear medicine department of the Hospital Particular de Almada. In order to compare the striatum specific uptake ratios (SUR), a semi-automatic application (SAA) was also developed allowing manual adjustments by a specialist operator. The obtained results were compared with the DaTSCAN (R) V4 application, from General Electric Healthcare. The experimental results based on SUR demonstrate that the AA can successfully discriminate the healthy patients from the pathological subjects. Additionally, a strong correlation was verified between the AA and the semi-automatic methods (DaTSCAN (R) V4 and the SAA). These methods also evidence intra and inter-operator variability, suppressed by the AA. The proposed methodology for segmentation and quantification of the striatum transaxial images obtained by [I-123]FP-CIT SPECT demonstrated that the developed application can accurately complement the visual analysis, requiring future optimization.
- Automatic versus semi-automatic method for the striatum specific uptake ratio quantification based on [I-123]FP-CIT SPECT imagesPublication . Elias, Maria; Jorge, Pedro; Figueiredo, Sérgio; Oliveira, Luís; Pereira, Edgar L.The aim of this work was to implement an automatic application (AA) for the quantification of the striatum transaxial slices based on [I-123]FP-CIT SPECT (Single Photon Emission Tomography) images. A sample of 68 subjects with and without pathology was collected from the nuclear medicine department of the Hospital Particular de Almada. In order to compare the striatum specific uptake ratios (SUR), a semi-automatic application (SAA) was also developed allowing manual adjustments by a specialist operator. The obtained results were compared with the DaTSCAN (R) V4 application, from General Electric Healthcare. The experimental results based on SUR demonstrate that the AA can successfully discriminate the healthy patients from the pathological subjects. Additionally, a strong correlation was verified between the AA and the semi-automatic methods (DaTSCAN (R) V4 and the SAA). These methods also evidence intra and inter-operator variability, suppressed by the AA. The proposed methodology for segmentation and quantification of the striatum transaxial images obtained by [I-123]FP-CIT SPECT demonstrated that the developed application can accurately complement the visual analysis, requiring future optimization.
- True random number generator implemented in 130 nm CMOS nanotechnologyPublication . Monteiro, Pedro; Oliveira, Luís; Casaleiro, JoãoRandom generators systems have the capacity to generate cryptographic keys which, when mixed with the in formation, hide it in an efficient and timely manner. There are two categories of RNG, being truly random (TRNG) or pseudorandom (PRNG). To study the entropy source based on the noise of an oscillator, and to achieve that, an RNG circuit was designed to have a low power consumption, a high randomness and a low cost and area usage. The chosen architecture for this paper is a hybrid RNG, which uses oscillators and a chaotic circuit to generate the random bits. With the simulation of the circuit, it was found to be at the objectives mark, having a low power consumption of 1.19 mW, a high throughput of 25 Mbit/s and an energy per bit of 47.6 pJ/bit. However, due to limitations with the simulation, it wasn’t possible to run all the statistical tests, although all the ran tests were passed.