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- 99mTc-Technetium Shortage: old problems asking for new solutionsPublication . Metello, Luis F.Technetium 99-metastable (99mTc) is the most important radionuclide, responsible for more than 80% of applications in nuclear medicine, with more than 40 million procedures being performed each year, worldwide, in all major clinical fields. It decays with a half-life of 6.01 hours by isomeric tran sition to 99gTc, thereby emitting 140 keV gamma photons. This energy almost ideally meets the maximum sensitivity of single photon emission computed tomography (SPECT) cam era systems. In addition, the rich complex chemistry of Techne tium allows the incorporation of the radioisotope into a wide variety of ligands stabilizing the radionuclide at different oxida tion states. Thus, since the early 60s, hundreds of radiopharma ceuticals labeled with 99mTc have been developed, and some have gained significant market success. However, the main reason for the special role of Technetium in SPECT is probably the cost effectiveness and the on-demand worldwide availability of the isotope through the 99Mo/99mTc generator systems.
- Cyclotron Production of Unconventional Radionuclides for PET Imaging: the Example of Titanium-45 and Its ApplicationsPublication . Costa, Pedro; Metello, Luís; Alves, Francisco; Naia, M. DuartePositron emitting radionuclides are used to label different compounds, allowing the study of the major biological systems using PET (positron emission tomography) imaging. Although there are several radionuclides suited for PET imaging, routine clinical applications are still based on a restrict group constituted by 18F, 11C, and, more recently, 68Ga. However, with the enlarged availability of low-energy cyclotrons and technical improvements in radionuclide production, the use of unconventional radionuclides is progressively more common. Several examples of unconventional radionuclides for PET imaging are being suggested, and 45Ti could be suggested as a model, due to its interesting properties such as its abundant positron emission (85%), reduced positron energy (β+ endpoint energy = 1040 keV), physical half-life of 3.09 h, and interesting chemical properties. This review aims to introduce the role of cyclotrons in the production of unconventional radionuclides for PET imaging while using 45Ti as an example to explore the potential biomedical applications of those radionuclides in PET imaging
- Modification of [18F]-FDG PET/CT imaging protocols in obese oncology patients: A nationwide surveyPublication . Oliveira, R.; Figueiredo, L.; Costa, P.The use of medical imaging for diagnosis, staging and follow-up in Oncology context is incredibly important, being the use of [18F]-FDG PET/CT particularly advantageous in specific contexts like the case of obese patients. However, imaging the latter can be challenging sometimes, since their own body size may affect overall image quality and adds technical difficulties for the operator(s) performing the examination. This research project was developed with the aim of analysing the current personal practices of Portuguese Nuclear Medicine Technologists (NMTs) in the adaptation of 18F-FDG PET/CT oncological protocols for obese patients and comparing the results with parameters referenced in literature. A non-experimental research study was conducted using a survey delivered online to NMTs through social media platforms (Facebook® and LinkedIn®) and by sending the link directly to contacts within the research team professional and personal networks. Answers from a total of 26 participants were obtained, with 88.5% of participants admitting modifying technical protocols in examinations for obese patients. Changes in PET protocols included an increase in the administered activity (60.9%), an increase in scan time per individual bed position (69.6%) and the use of Time-of-Flight (TOF) technology whenever available. Protocol changes in CT included increasing the mA (82.6%), raising the KVp (47.8%), the application of iterative reconstruction (69.6%) and the use of automatic exposure control (AEC) (52.2%). The remaining parameters (pitch, algorithm, slice thickness, display FOV, gantry rotation time and energy acceptance window) were claimed not to be modified by around 90% of professionals. Portuguese NMTs tend to change the [18F]-FDG PET/CT protocols for obese patients. However, while some of the parameters appear to be contradictory or redundant, others require further optimisation, especially in the CT component.
- Optimization of OSEM parameters in myocardial perfusion imaging reconstruction as a function of body mass index: a clinical approachPublication . Barros, Pietro Paolo de; Metello, Luis F.; Camozzato, Tatiane Sabriela Cagol; Vieira, DomingosObjective The present study is aimed at contributing to identify the most appropriate OSEM parameters to generate myocardial perfusion imaging reconstructions with the best diagnostic quality, correlating them with patients’ body mass index. Materials and Methods The present study included 28 adult patients submitted to myocardial perfusion imaging in a public hospital. The OSEM method was utilized in the images reconstruction with six different combinations of iterations and subsets numbers. The images were analyzed by nuclear cardiology specialists taking their diagnostic value into consideration and indicating the most appropriate images in terms of diagnostic quality. Results An overall scoring analysis demonstrated that the combination of four iterations and four subsets has generated the most appropriate images in terms of diagnostic quality for all the classes of body mass index; however, the role played by the combination of six iterations and four subsets is highlighted in relation to the higher body mass index classes. Conclusion The use of optimized parameters seems to play a relevant role in the generation of images with better diagnostic quality, ensuring the diagnosis and consequential appropriate and effective treatment for the patient.
- PET imaging using titanium-45: Could it be useful?Publication . Costa, Pedro; Metello, Luís; Alves, F.; Naia, M. DuarteIn the last decade a wider application of positron emission tomography (PET) as one of the most powerful medical imaging technologies was observed. This was largely due to the increased availability of equipment dedicated to production of radioisotopes, mainly due to the installation of low energy cyclotrons in hospitals, research institutes and pharmaceutical industries specialized in radiopharmaceutical production.
- Preclinical Imaging: an Essential Ally in Modern BiosciencesPublication . Cunha, Lídia; Horvath, Ildiko; Ferreira, Sara; Lemos, Joana; Costa, Pedro; Vieira, Domingos; Veres, Dániel S.; Szigeti, Krisztián; Summavielle, Teresa; Máthé, Domokos; Metello, Luís F.Translational research is changing the practice of modern medicine and the way in which health problems are approached and solved. The use of small-animal models in basic and preclinical sciences is a major keystone for these kinds of research and development strategies, representing a bridge between discoveries at the molecular level and clinical implementation in diagnostics and/or therapeutics. The development of high-resolution in vivo imaging technologies provides a unique opportunity for studying disease in real time, in a quantitative way, at the molecular level, along with the ability to repeatedly and non-invasively monitor disease progression or response to treatment. The greatest advantages of preclinical imaging techniques include the reduction of biological variability and the opportunity to acquire, in continuity, an impressive amount of unique information (without interfering with the biological process under study) in distinct forms, repeated or modulated as needed, along with the substantial reduction in the number of animals required for a particular study, fully complying with 3R (Replacement, Reduction and Refinement) policies. The most suitable modalities for small-animal in vivo imaging applications are based on nuclear medicine techniques (essentially, positron emission tomography [PET] and single photon emission computed tomography [SPECT]), optical imaging (OI), computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy imaging (MRSI), and ultrasound. Each modality has intrinsic advantages and limitations. More recently, aiming to overcome the inherent limitations of each imaging modality, multimodality devices designed to provide complementary information upon the pathophysiological process under study have gained popularity. The combination of high-resolution modalities, like micro-CT or micro-MRI, with highly sensitive techniques providing functional information, such as micro-PET or micro-SPECT, will continue to broaden the horizons of research in such key areas as infection, oncology, cardiology, and neurology, contributing not only to the understanding of the underlying mechanisms of disease, but also providing efficient and unique tools for evaluating new chemical entities and candidate drugs. The added value of small-animal imaging techniques has driven their increasing use by pharmaceutical companies, contract research organizations, and research institutions.
- A scoping review of person-centred care strategies used in diagnostic Nuclear MedicinePublication . Champendal, M.; Grima, K. Borg; Costa, Pedro; Andersson, C.; Baun, C.; Gorga, R.G.; Murphy, S.; Kedves, A.; Santos, A.; Geao, A.Person-centred care (PCC) emphasises the need for the health care professional to prioritise individual patient needs, thereby fostering a collaborative and emphatic environment that empowers patients to actively participate in their own care. This article will explore the purpose of PCC in Nuclear Medicine (NM), while discussing strategies that may be used to implement PCC during diagnostic NM examinations performed on adult patients. The scoping review was conducted in accordance with the Joanna Briggs Institute methodology. The search was performed on PubMed, Embase and Cinhal in June 2023 and included studies in English, Spanish, Portuguese and Italian. The research equation combined keywords and Medical Subject Heading terms (MeSH) related to person-centred care (PCC), for all types of nuclear medicine diagnostic examinations performed. Three independent review authors screened all abstracts and titles, and all eligible full-text publications were included in this scoping review. Fifty-three articles, published between 1993 and 2022, met the inclusion criteria for this scoping review. Seven articles were published in 2015 while 56.6 % of all included studies were performed in Europe. Most studies (n = 39/53) focused on the patients only, with the identified patient benefits being: improve patient experience (67.9 %), increase patient comfort (13.2 %), increase patient knowledge (5.7 %), reduction of patient anxiety (9.4 %) and reduction of waiting/scan time (3.8 %). The scoping review identified a lack of research investigating the use of person-centred care strategies in NM. Future research will focus on using an international survey to explore this topic in nuclear medicine departments overseas.
- Single Low-Dose Ionizing Radiation Induces Genotoxicity in Adult Zebrafish and its Non-Irradiated ProgenyPublication . Lemos, Joana; Neuparth, T.; Trigo, M.; Costa, Pedro; Vieira, Domingos; Cunha, L.; Ponte, F.; Costa, P. S.; Metello, Luís; Carvalho, A. P.This study investigated to what extent a single exposure to low doses of ionizing radiation can induce genotoxic damage in irradiated adult zebrafish (Danio rerio) and its non-irradiated F1 progeny. Four groups of adult zebrafish were irradiated with a single dose of X-rays at 0 (control), 100, 500 and 1000 mGy, respectively, and couples of each group were allowed to reproduce following irradiation. Blood of parental fish and whole-body offspring were analysed by the comet assay for detection of DNA damage. The level of DNA damage in irradiated parental fish increased in a radiation dose-dependent manner at day 1 post-irradiation, but returned to the control level thereafter. The level of DNA damage in the progeny was directly correlated with the parental irradiation dose. Results highlight the genotoxic risk of a single exposure to low-dose ionizing radiation in irradiated individuals and also in its non-irradiated progeny.
- Survey on the knowledge of Portuguese society about Nuclear Medicine: A snapshot of the reality in the beginning of the decadePublication . Monteiro, Rafaela ; Costa, PedroNuclear Medicine has grown exponentially over the years, since it is useful in the early diagnosis and treatment of several pathologies. However, this field appears to be not widely recognized at the public level. An exploratory/descriptive cross-sectional study using a national survey assessed the Portuguese population's knowledge of Nuclear Medicine. A total of 211 questionnaires were collected and analyzed. The study population is made up of Portuguese adult citizens. The study revealed a lack of knowledge about Nuclear Medicine. Some respondents were aware of this field, however a significant number have low or no knowledge at all. Most individuals are not aware about the Nuclear Medicine Departments in their home districts. This project found limited knowledge within the Portuguese population about ionizing radiation in medical procedures, and mainly in Nuclear Medicine. Data highlighted the need to implement awareness campaigns to disseminate knowledge on this field. Health professionals should be aware about the lack of knowledge on this field by patients and public.
- The role of molecular imaging in modern drug developmentPublication . Cunha, Lídia; Szigeti, Krisztián; Mathé, Domokos; Metello, Luís F.Drug development represents a highly complex, inefficient and costly process. Over the past decade, the widespread use of nuclear imaging, owing to its functional and molecular nature, has proven to be a determinant in improving the efficiency in selecting the candidate drugs that should either be abandoned or moved forward into clinical trials. This helps not only with the development of safer and effective drugs but also with the shortening of time-to-market. The modern concept and future trends concerning molecular imaging will assumedly be hybrid or multimodality imaging, including combinations between high sensitivity and functional (molecular) modalities with high spatial resolution and morphological techniques.