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Purpose: The first clinical biology-guided radiation therapy (BgRT) system—RefleXion TM X1—was installed and commissioned for clinical use at our institution. This study aimed at evaluating the treatment plan quality and delivery efficiency for IMRT/SBRT cases without PET guidance. Methods: A total of 42 patient plans across 6 cancer sites (conventionally fractionated lung, head, and neck, anus, prostate, brain, and lung SBRT) planned with the Eclipse TM treatment planning system (TPS) and treated with either a TrueBeam ® or Trilogy ® were selected for this retrospective study. For each Eclipse VMAT plan, 2 corresponding plans were generated on the X1 TPS with 10 mm jaws (X1-10mm) and 20 mm jaws (X1-20mm) using our institutional planning constraints. All clinically relevant metrics in this study, including PTV D95%, PTV D2%, Conformity Index (CI), R50, organs-at-risk (OAR) constraints, and beam-on time were analyzed and compared between 126 VMAT and RefleXion plans using paired t -tests. Results: All but 3 planning metrics were either equivalent or superior for the X1-10mm plans as compared to the Eclipse VMAT plans across all planning sites investigated. The Eclipse VMAT and X1-10mm plans generally achieved superior plan quality and sharper dose fall-off superior/inferior to targets as compared to the X1-20mm plans, however, the X1-20mm plans were still considered acceptable for treatment. On average, the required beam-on time increased by a factor of 1.6 across all sites for X1-10mm compared to X1-20mm plans. Conclusions: Clinically acceptable IMRT/SBRT treatment plans were generated with the X1 TPS for both the 10 mm and 20 mm jaw settings.

Can the media effectively hold politicians accountable for making false claims? Journalistic fact-checking assesses the accuracy of individual public statements by public officials, but less is known about whether this process effectively imposes reputational costs on misinformation-prone politicians who repeatedly make false claims. This study therefore explores the effects of exposure to summaries of fact-check ratings, a new format that presents a more comprehensive assessment of politician statement accuracy over time. Across three survey experiments, we compared the effects of negative individual statement ratings and summary fact-checking data on favorability and perceived statement accuracy of two prominent elected officials. As predicted, summary fact-checking had a greater effect on politician perceptions than individual fact-checking. Notably, we did not observe the expected pattern of motivated reasoning: co-partisans were not consistently more resistant than supporters of the opposition party. Our findings suggest that summary fact-checking is particularly effective at holding politicians accountable for misstatements.