Analysis of earthquakes predictability

Earthquake prediction is a complex task for scientists due to the rare occurrence of high-intensity earthquakes and their inaccessible depths. Despite this challenge, it is a priority to protect infrastructure, and populations living in areas of high seismic risk. Reliable forecasting requires comprehensive knowledge of seismic phenomena. In this thesis, the development, application, and comparison of both deterministic and probabilistic forecasting methods is shown. Regarding the deterministic approach, the implementation of an alarm-based method using the occurrence of strong (fore)shocks, widely felt by the population, as a precursor signal is described. This model is then applied for retrospective prediction of Italian earthquakes of magnitude M≥5.0,5.5,6.0, occurred in Italy from 1960 to 2020. Retrospective performance testing is carried out using tests and statistics specific to deterministic alarm-based models. Regarding probabilistic models, this thesis focuses mainly on the EEPAS and ETAS models. Although the EEPAS model has been previously applied and tested in some regions of the world, it has never been used for forecasting Italian earthquakes. In the thesis, the EEPAS model is used to retrospectively forecast Italian shallow earthquakes with a magnitude of M≥5.0 using new MATLAB software. The forecasting performance of the probabilistic models was compared to other models using CSEP binary tests. The EEPAS and ETAS models showed different characteristics for forecasting Italian earthquakes, with EEPAS performing better in the long-term and ETAS performing better in the short-term. The FORE model based on strong precursor quakes is compared to EEPAS and ETAS using an alarm-based deterministic approach. All models perform better than a random forecasting model, with ETAS and FORE models showing better performance. However, to fully evaluate forecasting performance, prospective tests should be conducted. The lack of objective tests for evaluating deterministic models and comparing them with probabilistic ones was a challenge faced during the study.

A prospective study on the early evaluation of response to androgen receptor-targeted agents with 11C-Choline, 68Ga-PSMA and 18F-FACBC PET in metastatic castration-resistant prostate cancer: a single center experience.

Background: The early identification of responsive and resistant patients to androgen-receptor targeting agents (ARTA) in metastatic castration resistant-prostate cancer (CRPC) is not completely possible with PSA assessment and conventional imaging. Considering its ability to determine metabolic activity of lesions, PET assessment might be a promising tool. Materials and methods: We performed a monocentric prospective study in patients with metastatic CRPC under treatment with ARTA to evaluate the role of different PET radiotracers: 49 patients were randomized to receive 11C-Choline, 18F-FACBC or 68Ga-PSMA PET, one scan before therapy onset and one two months later. The primary aim was to investigate the performance of three different novel PET radiotracers for the early evaluation of response to ARTA in metastatic CRPC patients; with regards to this aim, the outcome evaluated was biochemical response (PSA reduction ≥50%). The secondary aim was to investigate the prognostic role of several semiquantitative PET parameters and their variations with the different radiotracers in terms of biochemical PFS (bPFS) and overall survival (OS). The study was promoted by the Italian Department of Health (code RF-2016-02364809). Results: With regards to the primary endpoint, at univariate analysis a statistically significant correlation was found between MTV_VARIATION% (p=0.018) and TLA_VARIATION% (p=0.025) with 68Ga-PSMA PET and biochemical response. As for the secondary endpoints, significant correlations with bPFS were found for 68Ga-PSMA PET MTV_TOT_PET1 (p=0.001), TLA_TOT_PET1 (p=0.025), MTV_VARIATION% (p=0.031). For OS, statistically significant correlations were found for: MAJ_SUV_MAX_PET1 with 11C-Choline PET (p=0.007); MTV_TOT_PET1 (p=0.004), MAJ_SUV_MAX_PET1 (p=0.029), SUVMAX_VARIATION% (p=0.04), MTV_VARIATION% (p=0.015), TLA_VARIATION% (p=0.03) with 68Ga-PSMA PET,; MTV_TOT_PET1 (p=0.011), TLA_TOT_PET1 (p=0.009), MAJ_SUV_MAX_PET1 (p=0.027), MTV_VARIATION% (p=0.048) with 18F-FACBC. Conclusions: Our prospective study highlighted that several 68Ga-PSMA and 18F-FACBC semiquantitative PET parameters and their variations present a prognostic value in terms of OS and bPFS and a correlation with biochemical response, that could help to assess response to ARTA.