A three-dimensional (3-D) imaging system based on Gray-code projection is described; it is thought to be used as an integration to the already developed profilometer based on the projection of multifrequency gratings. The Gray-code method allows us to evaluate the 3-D profile of objects that present even marked discontinuities of the surface, thus increasing the flexibility of the measuring system as to the topology of the objects that can be measured. The basic aspects of Gray-code projection for 3-D imaging and profiling are discussed, with particular emphasis devoted to the study of the resolution of the method and to the analysis of the systematic errors. The results of this study allow us to determine the optimal setting of the parameters of the measurement and to develop a suitable calibration procedure. The procedures for implementing the Gray-code method are presented, and some interesting experimental results are reported. Calibration of the system reveals an accuracy of 0.2 mm, corresponding to 0.1% of the field of view.
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In our laboratory, the performance of a 3D imaging system, based on structured light projection, has been improved by means of the development of three procedures, which are based on (i) the Gray Code projection Method (GCM), (ii) the Phase Shift Method (PSM), and (iii) the combination of GCM and PSM. In this paper, all the procedures are described and the results of the measurement performed on target objects are presented. The analysis of the systematic height error due to the crossed axes optical geometry of the system is performed, and the procedure for its compensation is presented
In the context of spreading interest in textbook outcome (TO) evaluation in different fields, we aimed to investigate an uncharted procedure, that is, laparoscopic microwave ablation (MWA) for hepatocellular carcinoma (HCC). Absence of post-MWA complications, a hospital stay of three days, no mortality nor readmission within 30 days, and complete response of the target lesion at post-MWA CT scan defined TO achievement. Patients treated between January 2014 and March 2021 were retrospectively reviewed, and of the 521 patients eligible for the study, 337 (64.7%) fulfilled all the quality indicators to achieve the TO. The absence of complications was the main limiting factor for accomplishing TO. At multivariable analysis, Child–Pugh B cirrhosis, age of more than 70 years old, three nodules, and MELD score ≥ 15 were associated with decreased probabilities of TO achievement. A score based on these factors was derived from multivariable analysis, and patients were divided into three risk groups for TO achievement. At survival analysis, overall survival (OS) was significantly (p = 0.001) higher in patients who achieved TO than those who did not. Moreover, OS evaluation in the three risk groups showed a trend coherent with TO achievement probability. The present study, having assessed the first TO for laparoscopic MWA for HCC, encourages further broader consensus on its definition and, on its basis, on the development of clinically relevant tools for managing treatment allocation.
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