Browsing by Author "Rodrigues, I."
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- Impact of music intervention on psychological and physiological parameters of patients undergoing myocardial perfusion scintigraphyPublication . Vieira, Lina Oliveira; Rotaru, A.; Rodrigues, I.; Martins, A.; Carvalho, C.; Alvernaz, A.; Oliveira, L.; Grilo, Ana; Raminhas Carapinha, Maria JoãoAim/Introduction: Myocardial Perfusion Scintigraphy (MPS), a well-established imaging procedure for diagnosing ischemic heart disease, has multiple phases that can induce patients’ anxiety, discomfort, and dissatisfaction. Several non-pharmacological strategies have been used to alleviate anxiety and improve patient comfort and satisfaction, such as music intervention. This study aimed to evaluate the efficacy of musical intervention in the outcomes of patients undergoing MPS. Materials and Methods: A randomized clinical trial was conducted on patients undergoing an MPS one-day protocol stress-rest, in a Nuclear Medicine Department between January 15, and March 18, 2024. Patients were divided into a control group (CG) and an experimental group (EG). In the EG, a musical intervention was performed during the rest image acquisition, allowing patients to choose from a selection of musical tracks curated by a music lecturer. Anxiety levels were assessed at four different moments in both groups: before and after the stress image acquisition (T1 and T2), and before and after the rest image acquisition (T3 and T4), using physiological parameters at all times and psychological parameters for CG at T1 and T4 and for EG at T1, T3 and T4. Image quality analysis was performed using measures of contrast, noise, number, and amplitude of patients' movements. All studies were reviewed by two researchers and evaluated by three nuclear medicine technologists. Results: The sample comprised 30 participants with an average age of 71±11.02yrs [45-87yrs] with 15 participants enrolled in each group. Patients in EG reduced their anxiety scores from 36±9.44 at T1 to 33±7.07 at T3 and 28±9.11 at T4, while patients in CG reduced their anxiety scores from 39±10.62 at T1 to 33±9.66 at T4. Regarding patient motion, there was a reduction from the CG to EG in movements between 1-2 pixels (CG = 21, EG= 19) and movements higher than 2 pixels (CG =19, EG=6). In some myocardial walls on the three tomographic slices, the correlation between psychological parameters and image noise was lower in T4 for the EG. No significant results were found in image contrast. Conclusion: For the EG, the image noise was ~3% lower than in CG. Anxiety decreased throughout the MPS procedure with lower values at T4 for the EG. Additionally, the musical intervention seems to be effective as the EG showed lower values of patient movement.
- Transmission of signals using white LEDs for VLC applicationsPublication . Louro, Paula; Silva, V.; Rodrigues, I.; Vieira, Manuel; Vieira, ManuelaIn this paper an integrated wavelength optical filter and photodetector for Visible Light Communication (VLC) is used. The proposed application uses indoor warm light lamps lighting using ultra-bright white LEDs pulsed at frequencies higher than the ones perceived by the human eye. The system was analyzed using two different types the white LEDs, namely, phosphor and trichromatic based LEDs. The signals were transmitted into free space and the generated photocurrent was measured by the pin-pin photodetector based on a-SiC:H/a-Si:H. This device operates in the visible spectrum, allowing thus the detection of the pulsed white light emitted by the LEDs. However, as it also works as a visible optical filter with controlled wavelength sensitivity through the use of adequate optical biasing light, it is able to detect different wavelengths. This feature allows the detection of the individual components of the tri-chromatic white LED, which enlarges the amount of information transmitted by this type of white LED, when compared to the phosphor based LED. A capacitive optoelectronic model supports the experimental results and the physical operation of the device. A numerical simulation is presented.
- VIS/NIR wavelength selector based on a multilayer pi'n/pin a-SiC:H optical filterPublication . Vieira, Manuela; Vieira, Manuel; Silva, V.; Louro, Paula; Rodrigues, I.; Fantoni, AlessandroIn this paper, we present a tandem visible/nearinfrared (VIS/NIR) wavelength selector based on a multilayer a-SiC:H optical filter that requires appropriate near-ultraviolet steady states optical switches to select the desired wavelengths in the VIS/NIR ranges. Spectral response measurements are presented and show the feasibility of tailoring the wavelength and bandwidth of a polychromatic mixture of different wavelengths. The selector filter is realized by using a two terminal double pi'n/pin a-SiC:H photodetector. Five visible/infrared communication channels are transmitted together, each one with a specific bit sequence. The combined optical signal is analysed by reading out the photocurrent, under near-UV steady state background. Results show that the background side and intensity works as a selector in the infrared/visible regions, shifting the sensor sensitivity. This nonlinearity allows the identification and decoding of the different input channels in the visible/infrared ranges. This concept is extended to implement a 1 by 5 wavelength division multiplexer with channel separation in the VIS/NIR range and a transmission capability of 30 Kbps. The relationship between the optical inputs and the output signal is established and an algorithm to decode the Multiplexed (MUX) signal presented. An optoeletronic model gives insight on the system physics.