Quantitative ultrasound (QUS) has emerged as a viable tool in diagnosing and staging the onset and progression of various diseases. Within the field of QUS, shear wave elastography (SWE) has emerged as the clinical standard for quantifying and correlating the stiffness of tissue to its underlying pathology. Despite its widespread use, SWE suffers from drawbacks that limit its widespread clinical use; among these are low-frame rates, long settling times, and high sensitivity to operating conditions. Longitudinal speed of sound (SOS) has emerged as a viable alternative to SWE. We propose a framework to obtain 2D sound speed maps using a commercial ultrasound probe. Cisplatinum A commercial ultrasound probe is localized in space and used to scan a domain of interest from multiple vantage points; the use of a reflector at the far end of the domain allows us to measure the round trip travel times to and from it. The known locations of the probe and the measured travel times are used to estimate the depth and inclination of the reflector as well as the unknown sound speed map. The use of multiple looks increases the effective aperture of the ultrasound probe and allows for a higher fidelity reconstruction of sound speed maps. We validate the framework using simulated and experimental data and propose a rigorous framework to quantify the uncertainty of the estimated sound speed maps. By implementing dynamic circulating tumor DNA (ctDNA) analysis, we explored the impact of TP53 mutations on tumor evolution and resistance mechanisms to ensartinib in patients with ALK-positive NSCLC. In a multicenter phase 2 trial, patients with ALK-positive NSCLC who progressed on crizotinib were treated with ensartinib. Blood samples for ctDNA analysis were collected at baseline, cycle 3 day 1, and progression disease (PD) and analyzed with a 212-gene panel. A total of 440 samples were collected from 168 patients. Baseline TP53 mutations (20.2%) significantly correlated with inferior progression-free survival (4.2 mo versus 11.7 mo, p < 0.0001). Patients with TP53 mutations had higher mutation load than those without TP53 mutations at baseline (13.79 ± 3.72 versus 4.67 ± 0.39, p < 0.001). Although there was no significant difference in mutation load between these groups at cycle 3 day 1 (5.89 ± 2.25 versus 3.72 ± 0.62, p= 0.425), patients with mutated TP53 developed more mutations at PD (7.07 ± resistance mechanisms to ensartinib. The adverse prognostic impact of poor pathologic nodal staging has stimulated efforts to heighten awareness of the problem through guidelines, without guidance on processes to overcome it. We compared heightened awareness (HA) of nodal staging quality versus a lymph node collection kit. We categorized curative-intent lung cancer resections from 2009 to 2020 in a population-based, nonrandomized stepped-wedge implementation study of both interventions, into preintervention baseline, HA, and kit subcohorts. We used differences in proportion and hazard ratios across the subcohorts to estimate the effect of the interventions on poor quality (nonexamination of nodes [pNX] or nonexamination of mediastinal lymph nodes) and attainment of quality recommendations of the National Comprehensive Cancer Network, the Commission on Cancer, and the proposed complete resection definition of the International Association for the Study of Lung Cancer across the three cohorts. Of 3734 resections, 39% were preintervention, 40nical trial comparing both interventions. RET gene fusions are established oncogenic drivers in 1% of NSCLC. Accurate detection of advanced patients with RET fusions is essential to ensure optimal therapy choice. We investigated the performance of fluorescence in situ hybridization (FISH) as a diagnostic test for detecting functional RET fusions. Between January 2016 and November 2019, a total of 4873 patients with NSCLC were routinely screened for RET fusions using either FISH (n= 2858) or targeted RNA next-generation sequencing (NGS) (n= 2015). If sufficient material was available, positive cases were analyzed by both methods (n= 39) and multiple FISH assays (n= 17). In an independent cohort of 520 patients with NSCLC, whole-genome sequencing data were investigated for disruptive structural variations and functional fusions in the RET and compared with ALK and ROS1 loci. FISH analysis revealed RET rearrangement in 48 of 2858 cases; of 30 rearranged cases double tested with NGS, only nine had a functional RET fusion. RNA NGS yielded RET fusions in 14 of 2015 cases; all nine cases double tested by FISH had RET locus rearrangement. Of these 18 verified RET fusion cases, 16 had a split signal and two a complex rearrangement by FISH. By whole-genome sequencing, the prevalence of functional fusions compared with all disruptive events was lower in the RET (4 of 9, 44%) than the ALK (27 of 34, 79%) and ROS1 (9 of 12, 75%) loci. FISH is a sensitive but unspecific technique for RET screening, always requiring a confirmation using an orthogonal technique, owing to frequently occurring RET rearrangements not resulting in functional fusions in NSCLC.FISH is a sensitive but unspecific technique for RET screening, always requiring a confirmation using an orthogonal technique, owing to frequently occurring RET rearrangements not resulting in functional fusions in NSCLC. Patients with NSCLC may be treated with curative intent, yet they remain at high risk of both disease recurrence and second primary lung cancer (SPLC) and increased risk of early death. Guidelines provide recommendations for follow-up, but there is little consensus, and review of available evidence is necessary. The use of a systematic follow-up strategy for the detection of disease recurrence or SPLC after curative-intent treatment of NSCLC may increase the proportion of patients available for retreatment and increase the survival of patients with surveillance detection. We performed a systematic review and meta-analysis of prospective studies on follow-up of NSCLC after curative-intent treatment to answer the following three questions What is the effect of follow-up on detection of recurrence or SPLC? What is the effect of surveillance detection on curative-intent retreatment? What is the survival impact? Recurrence or SPLC was observed in 17.8% to 71% of patients. Scheduled imaging-detected recurrence in 60% to 100% of cases, yet neither computed tomography-based (OR= 2.