Browsing by Author "Reiman, Robert E"
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Item Open Access A practical method of I-131 thyroid cancer therapy dose optimization using estimated effective renal clearance.(SAGE Open Med Case Rep, 2017) Howard, Brandon A; James, Olga G; Perkins, Jennifer M; Pagnanelli, Robert A; Borges-Neto, Salvador; Reiman, Robert EIn thyroid cancer patients with renal impairment or other complicating factors, it is important to maximize I-131 therapy efficacy while minimizing bone marrow and lung damage. We developed a web-based calculator based on a modified Benua and Leeper method to calculate the maximum I-131 dose to reduce the risk of these toxicities, based on the effective renal clearance of I-123 as measured from two whole-body I-123 scans, performed at 0 and 24 h post-administration.Item Open Access Synthesis and preliminary evaluation of 5-[18F] fluoroleucine.(Curr Radiopharm, 2016-12-30) Chin, Bennett B; McDougald, Darryl; Weitzel, Douglas H; Hawk, Thomas; Reiman, Robert E; Zalutsky, Michael R; Vaidyanathan, GanesanBACKGROUND: Amino acid transporters, such as LAT1, are overexpressed in aggressive prostate and breast carcinomas, directly influencing pathways of growth and proliferation. OBJECTIVE: The purpose of this study is to synthesize and characterize a novel 18F labeled leucine analog, 5-[18F]fluoroleucine, as a potential imaging agent for aggressive tumors which may not be amenable to imaging by FDG PET. METHODS: 5-fluoroleucine was synthesized and characterized, and its 18F-labeled analog was synthesized from a mesylate precursor. First, breast cancer cell line assays were performed to evaluate uptake of L-leucine and other essential amino acids. Both L-leucine and 5-[18F]fluoroleucine were tested for uptake and accumulation over time, and for uptake via LAT1. Biodistribution studies were performed to estimate radiation dosimetry for human studies. Small animal PET / CT studies of a breast cancer were performed to evaluate in vivo 5-[18F]fluoroleucine tumor uptake. RESULTS: Breast cancer cell lines showed increasing high net accumulation of L-leucine. Both L-leucine and 5-[18F]fluoroleucine showed increasing uptake over time in in vitro tumor cell assays, and uptake was also shown to occur via LAT1. The biodistribution study of 5-[18F]fluoroleucine showed rapid renal excretion, no significant in vivo metabolism, and acceptable dosimetry for use in humans. In vivo small animal PET / CT imaging of a breast cancer xenograft showed uptake of 5-[18F]fluoroleucine in the tumor, which progressively increased over time. CONCLUSION: 5-[18F]fluoroleucine is a leucine analog which may be useful in identifying tumors with high or upregulated expression of amino acid transporters, providing additional information that may not be provided by FDG PET.