Monitoring and Tracking the Evolution of a Viral Epidemic Through Nonlinear Kalman Filtering: Application to the COVID-19 Case.

This work presents a novel methodology for systematically processing the time series that report the number of positive, recovered and deceased cases from a viral epidemic, such as Covid-19. The main objective is to unveil the evolution of the number of real infected people, and consequently to predict the peak of the epidemic and subsequent evolution. For this purpose, an original nonlinear model relating the raw data with the time-varying geometric ratio of infected people is elaborated, and a Kalman Filter is used to estimate the involved state variables. A hypothetical simulated case is used to show the adequacy and limitations of the proposed method. Then, several countries, including China, South Korea, Italy, Spain, U.K. and the USA, are tested to illustrate its behavior when real-life data are processed. The results obtained clearly show the beneficial effect of the severe lockdowns imposed by many countries worldwide, but also that the softer social distancing measures adopted afterwards have been almost always insufficient to prevent the subsequent virus waves.

Impact of whole-body 18F-FDG PET on diagnostic and therapeutic management of Medical Oncology patients.

AIM: Most studies evaluating positron-emission tomography (PET) impact on decision making are based on questionnaires sent to referring physicians, with low response rates and potential bias. Studies directly evaluating influence of PET on routine management of Medical Oncology patients are scarce. PATIENTS AND METHODS: We retrospectively studied all patients evaluated by whole-body (18)F-FDG PET during 1 year in a Haematology/Oncology Department. We collected information regarding indication, PET results, modification of diagnostic and therapeutic management and adequacy of therapeutic changes. RESULTS: One hundred consecutive patients having PET were evaluated. Diagnostic strategy was modified in 63% of patients (30% avoiding biopsy). Therapeutic management was modified by PET in 34% of cases: changes were classified as adequate in 30% and as inadequate in 4% of patients. CONCLUSIONS: Our study shows a major impact of PET in the diagnostic and therapeutic management of cancer patients and supports its introduction as a routine diagnostic tool in Medical Oncology.