Basic Original Report Functional liver image guided hepatic therapy (FLIGHT) with hepatobiliary iminodiacetic acid (HIDA) scans David E. Long MD a , Mark Tann MD b , Ke (Colin) Huang PhD a , Gregory Bartlett CMD, RTT a , James O. Galle MD a , Yukie Furukawa CMD, RTT c , Mary Maluccio MD, MPH d , John A. Cox MD c , Feng-Ming (Spring) Kong MD, PhD, FACR a , Susannah G. Ellsworth MD a, ⁎ a Indiana University, Department of Radiation Oncology, Indianapolis, Indiana b Indiana University, Department of Nuclear Medicine, Indianapolis, Indiana c Columbus Regional Health, Department of Radiation Oncology, Columbus, Indiana d Indiana University, Department of Surgery, Indianapolis, Indiana Received 30 January 2018; revised 5 April 2018; accepted 25 April 2018 Abstract Purpose: Hepatobiliary iminodiacetic acid (HIDA) scans provide global and regional assessments of liver function that can serve as a road map for functional avoidance in stereotactic body radiation therapy (SBRT) planning. Functional liver image guided hepatic therapy (FLIGHT), an innovative planning technique, is described and compared with standard planning using functional dose- volume histograms. Thresholds predicting for decompensation during follow up are evaluated. Methods and materials: We studied 17 patients who underwent HIDA scans before SBRT. All SBRT cases were replanned using FLIGHT. The following dosimetric endpoints were compared for FLIGHT versus standard SBRT planning: functional residual capacity b15 Gy (FRC 15 HIDA), mean liver dose (MLD), equivalent uniform dose (EUD), and functional EUD (FEUD). Receiver operating characteristics curves were used to evaluate whether baseline HIDA values, standard cirrhosis scoring, and/or dosimetric data predicted clinical decompensation. Results: Compared with standard planning, FLIGHT significantly improved FRC 15 HIDA (mean improvement: 5.3%) as well as MLD, EUD, and FEUD (P b .05). Considerable interindividual variations in the extent of benefit were noted. Decompensation during follow-up was associated with baseline global HIDA b2.915%/min/m 2 , FRC 15 HIDA b2.11%/min/m 2 , and MELD ≥11 (P b .05). Conclusions: FLIGHT with HIDA-based parameters may complement blood chemistry-based assessments of liver function and facilitate individualized, adaptive liver SBRT planning. © 2018 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved. Conflicts of interests: None. ⁎ Corresponding author. Indiana University School of Medicine, Radiation Oncology, 535 Barnhill Drive RT 101, Indianapolis, IN 46202. E-mail address: sgellswo@iu.edu (S.G. Ellsworth). www.practicalradonc.org https://doi.org/10.1016/j.prro.2018.04.014 1879-8500/© 2018 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved. Practical Radiation Oncology (2018) xx, xxx–xxx