18F-4FN represents a novel PET agent for imaging inflammation. Acute inflammatory signaling through the TLR axis recruits neutrophils and macrophages to inflammatory sites. Both cells activate the production of high energy reactive oxygen species/reactive nitrogen species (RONS), setting off a cascade that can be leveraged to detect the presence of these inflammatory cells by molecular imaging. 18F-4FN is efficiently oxidized by high energy RONS, leading to retention and accumulation in human neutrophil-like cells in vitro, and at the sites of acute inflammation in vivo. Like 18F-FDG, 18F-4FN clears rapidly through the kidney at 1 hr following i.v. injection

OBJECTIVES:

Primary Objective:

The primary objective of this first-in-human (FIH) study is to determine the safety, biodistribution, and dosimetry profile of a novel positron emission tomography (PET) imaging tracer, 4-[18F]fluoro-1-naphthol ([18F]4FN), which specifically targets reactive oxygen species (ROS). A currently proposed indication for this radiopharmaceutical (RP) is to non-invasively quantify inflammation by PET/CT imaging.

Exploratory Objectives:

One exploratory objective is to identify preliminary efficacy signals from PET/CT images indicating that the new radiopharmaceutical localized to known or clinically-suspected tissues or regions of inflammation mediated by innate immune-related adverse events (irAE). Another exploratory objective is to determine if a time point other than one-hour post injection will yield clinically meaningful improvements to imaging data.

Inclusion Criteria:

• Patient >/= 18 years of age.
• Patients with histologic diagnosis of solid or liquid tumor treated by ICI with evidence of or clinical suspicion of irAE or patients with suspected inflammation.
• Normal range standard renal and liver function tests for age:

eGFR >= 60 mL/min/1.73 m2

Adequate liver function:

Bilirubin ≤ the upper limit of normal (ULN) Alkaline phosphatase, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) ≤ the ULN

Exclusion Criteria:

• Pregnant or lactating women: pregnant women are excluded from this study because the effects of [18F]4FN in pregnancy are not known. Urine or serum pregnancy test (female \