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- Cancer patient experience in a nuclear medicine department: comparison between bone scintigraphy and 18F-FDG PET/CTPublication . Grilo, Ana Monteiro; Vieira, Lina Oliveira; Carolino, Elisabete; Costa, Melissa; Galaio, Salomé; Melo, Inês; Geão, Ana; Santos, Andrea; Colarinha, PaulaObjective: To assess the emotional impact on cancer patients undergoing Nuclear Medicine scans and identify how professionals can improve patient experience. Methods: 94 patients undergoing a Bone Scan (BS) or a Positron emission tomography/Computed Tomography (18F-FDG PET/CT) completed two Scan Experience Questionnaires and the State Anxiety Inventory (STAI-S) prior to the scan and after image acquisition. Results: Before the exam, the mean anxiety levels were higher for the BS patients compared to the 18F-FDG PET/CT group. For the post-scan STAI-S mean score, the opposite is true. Both groups experienced a reduction in levels of anxiety after the scan (BS - STAI score pre-scan = 51.75, and post-scan = 36.70; 18F-FDG PET/CT - STAI score pre-scan = 44.67, and post-scan = 38.82). The greatest anxiety factor for the BS group was the duration of the exam - 5.34 ± 2.08 (mean ± SD), while for the 18F-FDG PET/CT group it was the result - 5.40±1.80 (mean ± SD). Conclusion: Patients undergoing NM exams in an oncological context revealed significant anxiety levels prior to and after their scans. However, the BS and 18F-FDG PET/CT have different triggers. It is of extreme importance that healthcare professionals are aware of these peculiarities and adjust their procedures accordingly.
- Impact of the background Region of Interest in the relative renal functionPublication . Sousa, Eva; Raminhas Carapinha, Maria João; Vaz, Tânia; Lucena, Filipa; Vieira, Lina OliveiraRenal scintigraphy with 99mTc-dimercaptosuccinic acid (99mTc-DMSA) is performed with the aim of detect cortical abnormalities related to urinary tract infection and accurately quantify relative renal function (RRF). For this quantitative assessment Nuclear Medicine Technologist should draw regions of interest (ROI) around each kidney (KROI) and peri-renal background (BKG) ROI although controversy still exists about BKG-ROI. The aim of this work was to evaluate the effect of the normalization procedure, number and location of BKG-ROI on the RRF in 99mTc-DMSA scintigraphy.
- Evaluation of the attenuation correction on myocardial perfusion imaging: a phantom studyPublication . Machado, Marisa; Oliveira, Francisco P. M.; Vieira, Lina Oliveira; Costa, Durval C.Myocardial perfusion imaging (MPI) with single-photon emission computed tomography (SPECT) is important for risk stratification of coronary artery disease. MPI quantification obtained from available images may not be accurate due to several potential sources of error, being photon attenuation, especially in overweight patients, a significant problem. Attenuation maps derived from X-ray computed tomography (CT) may be used to correct for photon attenuation. The aim of this study was to evaluate the effects of non-attenuation correction (NAC) and attenuation correction (AC) in MPI SPECT imaging using anthropomorphic phantoms simulating patients with different attenuation profiles. Forty-nine SPECT and CT studies of Heart/Thorax phantoms with different attenuation layers were acquired. All SPECT imaging data were reconstructed with and without AC. Quantification of the myocardial signal (uptake) was performed in four regions of interest: septum, anterior wall, inferior wall, and apex. This was done both in NAC and AC SPECT images. A qualitative evaluation was performed by a nuclear medicine physician also in NAC and AC SPECT images. The results demonstrated, as expected, statistically lower counts when the thickness of the phantom attenuating material increased and attenuation correction was lacking. On the other hand, when attenuation correction was applied, there were no statistically significant count differences whatever the thickness of the phantom attenuating material. In the qualitative evaluation, the nuclear medicine physician observed small variations in the anterior wall uptake according to the various conditions under test. However, the changes were not statistically significant. In conclusion, there is no evidence that the effects of attenuation in overweight patients are not properly corrected when the MPI SPECT images are reconstructed with CT-based AC. In terms of qualitative visual assessment, there is no significant variation in the classification of myocardial walls uptake with and without AC when the evaluation is done by an experienced physician.
- Estratégias não-farmacológicas para redução da ansiedade em doentes submetidos a PET/CT: revisão sistematizada de literaturaPublication . Pedro, Beatriz; Henriques, Daniela; Grilo, Ana Monteiro; Vieira, Lina OliveiraIntrodução – A ansiedade, caracterizada por sentimentos de tensão e preocupação relativamente a situações que o indivíduo perceciona como potencialmente perigosas ou desconhecidas, é uma das reações emocionais experienciadas pelos doentes oncológicos aquando da realização do exame Positron Emission Tomography/Computed Tomography (PET/CT). Elevados níveis de ansiedade podem influenciar negativamente a experiência e a satisfação do paciente, bem como ter implicações a nível imagiológico. Deste modo, a avaliação da ansiedade nesses pacientes é de extrema importância, assim como a necessidade de adotar estratégias de intervenção eficazes na sua redução. Objetivos – Nesta revisão sistematizada pretende-se identificar e analisar a eficácia de técnicas não-farmacológicas que visam a redução da ansiedade em doentes submetidos a PET/CT, antes e durante o exame. Métodos – Recorreu-se a duas bases de dados (PubMed e Science Direct) e a outras fontes de pesquisa de onde resultaram 22 estudos. Foram incluídos todos os estudos que incluíssem estratégias para redução da ansiedade em exames PET/CT e que estivessem publicados nas línguas portuguesa e inglesa. Foram excluídos artigos de revisão sistemática, com população pediátrica e que não apresentassem o texto na íntegra. Resultados – Foram selecionados para análise oito estudos, num espaço temporal entre 2000 e 2020. Identificaram-se quatro estratégias que visam a redução da ansiedade nos doentes submetidos a PET/CT: música, meios audiovisuais, práticas de mindfulness e comunicação profissional de saúde-doente. Conclusão – São várias as técnicas que podem ser aplicadas de modo a minimizar o sentimento de ansiedade no doente e proporcionar uma melhor experiência no serviço. No entanto, ainda existe pouca evidência neste tema. Sendo assim, sugerem-se estudos adicionais que possam identificar mais técnicas e comprovar a sua eficácia.
- Evaluation of SPECT imaging: a multi-center and multi-vendor phantom studyPublication . Gonçalves, Maria Inês Rebelo; Parafita, Rui; Costa, Mauro; Geão, Ana; Pereira, Edgar; Vieira, Lina OliveiraBackground: Single-photon emission computed tomography (SPECT) is a nuclear medicine (NM) imaging method sensitive to the evaluation and quantification of physiological processes in patients. However, there are different factors that affect qualitatively and quantitatively the SPECT images and, consequently, the reliability of the data. There is a degree of variability underlying the intrinsic performance of systems from the same or different manufacturers. In addition, the different configurations of the gamma cameras (GC) and the acquisition and reconstruction protocols used may lead to heterogeneity of results. This study compared SPECT images acquired in three GC from three NM centers, using the Jaszczak and NEMA IEC Body phantoms, filled with a homogeneous solution of technetium-99m. Acquisitions were performed in each GC, following the protocols used in the clinical practice of the respective NM center, and the images were analyzed and compared in terms of spatial resolution, sensitivity, noise, contrast, and contrast recovery (CR). Subsequently, the processing and reconstruction parameters were harmonized to assess their impact on the standardization of results. Results: With the clinical protocols, the images acquired with the three GC showed small differences in spatial resolution, noise, and contrast, with the greatest difference being observed in the quantitative accuracy, since the CR has achieved variabilities of 0.17 and 0.28, for different activity concentrations. This intersystem variability was reduced to 0.09 and 0.08 after reconstruction algorithm standardization. However, this change increased the differences in the contrast percentage. Conclusion: GC from different manufacturers showed the greatest heterogeneity of results, however, by eliminating possible sources of variation it is possible to reduce the differences between systems. It was demonstrated the need to include different parameters for the evaluation and comparison of SPECT images so that procedures can be established between the different NM centers to ensure a trade-off between the various parameters assessed here, as the improvement of some usually leads to the deterioration of others.
- Analysis of the interference of endogenous circadian rhythms on 3'- deoxy- 3'- [18F]Fluorothymidine physiological uptake at the human bone marrowPublication . Varela, N. M.; Lucena, Filipa; Raminhas Carapinha, Maria João; Vieira, Lina OliveiraThe main purpose of the present study is to determine if the circadian rhythms present in the human bone marrow are likely to influence 3’- deoxy- 3’-[18F] Fluorothymidine (18F-FLT) uptake in the same organ. The 18F-FLT is a Thymidine analogous proliferation agent. The relatively high physiological uptake of this tracer in the bone marrow diminishes the Tumor/Background (T/B) ratio, decreasing the detection accuracy of PET/CT and possibly affecting SUV quantifications.
- Assessment of the potential of convolutional neuronal networks in the differential diagnosis of Parkinson’s disease based on brain imaging [123I]FP-CIT SPECTPublication . Valador, N.; Oliveira, F. P.; Ferreira, P. M.; Vieira, Lina Oliveira; Costa, D. C.Aim/Introduction: To evaluate the potential of convolutional neural networks (CNN) in the differential diagnosis of Parkinson’s disease (PD) based on [123I]FP-CIT single-photon emission computed tomography (SPECT) images, compared to other machine learning-based classifiers. Materials and Methods: This work included 806 [123I]FP-CIT SPECT brain images (208 health controls and 598 with PD). Data were obtained from the Parkinson’s Progression Markers Initiative (PPMI) database (www.ppmi-info.org/data). For each subject, only the first scan was considered (baseline or screening). The protocol of image acquisition and pre-processing is available at http://www.ppmi-info.org/study-design/research-documentsand-sops/. CNN was compared against k-nearest neighbor (kNN), logistic regression (LG), decision trees (DT), support vector machines (SVM), and artificial neural networks (ANN) classifiers. The CNN classifier was trained with 2-dimensional image patches (dimensions: 88 mm x 82 mm) containing the striatal region, extracted from the head superior-inferior maximum intensity projection. The remaining classifiers were trained with five features extracted from the 3-dimensional striatal region: caudate binding potential, putamen binding potential, putamen to caudate ratio, the volume of the striatal region with “normal uptake”, and the major axis of that region. The minimum values extracted from each cerebral hemisphere were used. The split ratio of the dataset was 75:25 (75% for training and 25% for testing). Each of the five features was also considered individually to assess its potential for classification in terms of performance (accuracy, sensitivity, and specificity). Results: In the test dataset, the accuracy, sensitivity, and specificity of the CNN were 96%, 98%, and 91%, respectively. This finding was very similar to what we obtained with the other classifiers (kNN: 95%, 99%, 85%; LG: 94%, 97%, 86%, DT: 94%, 97%, 84%, SVM: 94%, 98%, 88%, and ANN: 94%, 97%, 86%). The accuracy differences are not statistically significant (Cochran Q test, p = 0.592). Individually, the feature that best differentiates PD from normal scans was the putamen binding potential with 93% accuracy, 93% sensitivity, and 94% specificity in the test dataset, based on the optimal cutoff (1.716) that maximizes Younden’s coefficient in the training dataset. Conclusion: CNN classifier proved to be as robust and accurate as the other classifiers frequently used in the type of problems as in this work, with the great advantage of using images as direct input. All machine learning-based classifiers tested are robust and very accurate in the classification of brain [123I]FP-CIT SPECT scans. Standard visual clinical evaluation should be complemented with quantification classification used also as a training tool.
- Quantitative estimation of the renal tubular function with 99mTc- MAG3: comparative software approach using two methods in a pediatric populationPublication . Raminhas Carapinha, Maria João; Silva, R.; Silva, F.; Figueiredo, Sérgio; Vieira, Lina OliveiraIntroduction - The ability to quantify function by Effective Renal Plasma Flow (ERPF) using camera-based Technetium-99m mercaptoacetyltriglycine (99mTc-MAG3) clearance methods is an accurate and time-saving technique as compared with the standard laboratory tests. Often providing information not possible with the conventional radiological modalities, this quantitative assessment can be determined by a linear formula - Modified Gates Method (MGat) - or a quadratic approach - Modified Schlegel Method (MSch). The aim of this work was to evaluate the effect of the MGat and MSch methods on the absolute value of ERPF in 99mTc-MAG3 dynamic renography.
- Influence of adipose tissue in myocardial counts using attenuation correction in SPECT/CT imaging: study in phantomPublication . Galvão, Tiago; Roberto, João; Figueiredo, Sérgio; Carolino, Elisabete; Marques, Andreia; Pintão, Sophia; Vieira, Lina OliveiraMyocardial perfusion imaging (MIP) with single photon emission computed tomography is one of the most accurate procedures for the detection of coronary artery disease. Tissue attenuation artifacts are a significant limitation of MIP, especially in obese patients. CT-based attenuation correction (AC) is widely used to undermine these artifacts. The objective of this study was to evaluate the influence of an adipose tissue equivalent in the total myocardial counts after AC in SPECT/CT imaging. To accomplish this a Heart Thorax Phantom was filled with 99m TcO4-(simulating the uptake of 99m Tc-tetrofosmin in the cardiac walls and liver) for SPECT/CT imaging using an additional layer of 100% lipid fat and a torso phantom. The acquired data were reconstructed with Filtered Back Projection (FBP), iterative algorithms without AC (IRNC) and iterative algorithms with AC (IRAC) for posterior evaluation of total cardiac wall count (Anterior, Inferior, Lateral and Septal). There was a significant reduction in total mean counts of the lateral and septal walls, with the addition of a layer of fat and the torso phantom, when FBP and IRNC reconstructions were applied (p ≤ 0,05) which may have been caused by tissue attenuation artifacts. The addition of a layer of fat and of the torso phantom, directly increased the total mean counts of the septal, lateral and inferior walls, when IRAC reconstruction was used (p ≤ 0,05) suggesting a benefit in the use of AC in larger body habitus. In conclusion, the adipose tissue equivalent directly influenced the total myocardium counts when AC methods were applied, and further research is advised.
- 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.