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People recovered from COVID-19 may still present complications including respiratory and neurological sequelae. In other viral infections, cognitive impairment occurs due to brain damage or dysfunction caused by vascular lesions and inflammatory processes. Persistent cognitive impairment compromises daily activities and psychosocial adaptation. Some level of neurological and psychiatric consequences were expected and described in severe cases of COVID-19. However, it is debatable whether neuropsychiatric complications are related to COVID-19 or to unfoldings from a severe infection. Nevertheless, the majority of cases recorded worldwide were mild to moderate self-limited illness in non-hospitalized people. Thus, it is important to understand what are the implications of mild COVID-19, which is the largest and understudied pool of COVID-19 cases. We aimed to investigate adults at least four months after recovering from mild COVID-19, which were assessed by neuropsychological, ocular and neurological tests, immune markers assay, and by structural MRI and 18 FDG-PET neuroimaging to shed light on putative brain changes and clinical correlations. In approximately one-quarter of mild-COVID-19 individuals, we detected a specific visuoconstructive deficit, which was associated with changes in molecular and structural brain imaging, and correlated with upregulation of peripheral immune markers. Our findings provide evidence of neuroinflammatory burden causing cognitive deficit, in an already large and growing fraction of the world population. While living with a multitude of mild COVID-19 cases, action is required for a more comprehensive assessment and follow-up of the cognitive impairment, allowing to better understand symptom persistence and the necessity of rehabilitation of the affected individuals.

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3'-Deoxy-3-[F]fluorothymidine, or [F]FLT, is a positron emission tomography (PET) tracer used in clinical studies for noninvasive assessment of proliferation activity in several types of cancer. Although the use of this PET tracer is expanding, to date, few studies concerning its dosimetry have been published. In this work, new [F]FLT dosimetry estimates are determined for human and mice using Monte Carlo simulations. Modern voxelized male and female phantoms and [F]FLT biokinetic data, both published by the ICRP, were used for simulations of human cases. For most human organs/tissues the absorbed doses were higher than those reported in ICRP Publication 128. An effective dose of 1.70E-02 mSv/MBq to the whole body was determined, which is 13.5% higher than the ICRP reference value. These new human dosimetry estimates obtained using more realistic human phantoms represent an advance in the knowledge of [F]FLT dosimetry. In addition, mice biokinetic data were obtained experimentally. These data and a previously developed voxelized mouse phantom were used for simulations of animal cases. Concerning animal dosimetry, absorbed doses for organs/tissues ranged from 4.47 ± 0.75 to 155.74 ± 59.36 mGy/MBq. The obtained set of organ/tissue radiation doses for healthy Swiss mice is a useful tool for application in animal experiment design.

F]FLT production and the evaluation of its effect on radiochemical yield and product quality. The first eluent evaluated was water: ethanol (90:10, v/v), commercially available, and the second was NaCl 0.9% (saline): ethanol (92:8, v/v). The mean of the corrected radiochemical yields corresponded to 27% ± 7% for elution with water and ethanol and to 23% ± 3% for elution with saline and ethanol, which could indicate that the eluent solutions have similar elution strength. Besides, quality control results were in accordance with the requirements and demonstrated that there was no significant difference between both formulations. Considering that pharmaceutical preparations containing ethanol should be preferentially diluted with saline to avoid hemolysis, the eluent saline:ethanol (92:8, v/v)

Endometriosis is a debilitating disease that still needs surgery to be confirmed. Endometriosis is associated with increased plasma levels of phosphatidylcholines. F-fluorocholine ([F]FCH) is a radiopharmaceutical that is metabolized to phosphatidylcholine inside the cells and can be traced by positron emission tomography (PET). Here we evaluate [F]FCH as a potential tool for the noninvasive diagnosis of peritoneal endometriosis. Adult female Wistar rats had autologous uterine fragments dissected and grafted to the peritoneal wall to model peritoneal endometriosis. Ex vivo biodistribution assay and PET imaging studies were performed 30 minutes after [F]FCH administration. The [F]FCH uptake was 3-fold higher in endometriotic implant tissues than in muscle or peritoneum. Positron emission tomography imaging revealed the grafted uterine tissue in contrast to surrounding structures. Region-of-interest analysis of the reconstructed images showed higher accumulation of [F]FCH by endometriotic lesions, 0.34 (0.04)% of injected dose per gram of tissue (ID/g), in comparison with muscle tissue, 0.08 (0.01)% ID/g. However, sham implants with fat tissue were also detectable in PET imaging. These preliminary findings of [F]FCH uptake by ectopic uterine tissue implants and their localization by PET imaging encourage the future evaluation of this technique to detect small superficial endometriosis lesions in humans. Study protocols need to be further perfected and adapted for tests in women with endometriosis.

People recovered from COVID-19 may still present complications including respiratory and neurological sequelae. In other viral infections, cognitive impairment occurs due to brain damage or dysfunction caused by vascular lesions and inflammatory processes. Persistent cognitive impairment compromises daily activities and psychosocial adaptation. Some level of neurological and psychiatric consequences were expected and described in severe cases of COVID-19. However, it is debatable whether neuropsychiatric complications are related to COVID-19 or to unfoldings from a severe infection. Nevertheless, the majority of cases recorded worldwide were mild to moderate self-limited illness in non-hospitalized people. Thus, it is important to understand what are the implications of mild COVID-19, which is the largest and understudied pool of COVID-19 cases. We aimed to investigate adults at least four months after recovering from mild COVID-19, which were assessed by neuropsychological, ocular and neurological tests, immune markers assay, and by structural MRI and 18FDG-PET neuroimaging to shed light on putative brain changes and clinical correlations. In approximately one-quarter of mild-COVID-19 individuals, we detected a specific visuoconstructive deficit, which was associated with changes in molecular and structural brain imaging, and correlated with upregulation of peripheral immune markers. Our findings provide evidence of neuroinflammatory burden causing cognitive deficit, in an already large and growing fraction of the world population. While living with a multitude of mild COVID-19 cases, action is required for a more comprehensive assessment and follow-up of the cognitive impairment, allowing to better understand symptom persistence and the necessity of rehabilitation of the affected individuals.