This phase II trial studies whether \[18F\]FTT can be used with positron emission tomography (PET)/computed tomography (CT) imaging to predict treatment response in patients scheduled to receive gemcitabine, cisplatin, and durvalumab (GCD) for newly diagnosed cholangiocarcinoma. PET/CT is an imaging technique that utilizes PET and CT in a single machine. PET is an established imaging technique that utilizes small amounts of radioactivity attached to very minimal amounts of tracer, in the case of this trial, \[18F\]FTT, to make detailed, computerized pictures of areas inside the body where the tracer is used. CT utilizes x-rays that traverse body from the outside. CT images provide an exact outline of organs and potential inflammatory tissue where it occurs in the patient's body. \[18F\]FTT targets and binds to poly (ADP-ribose) polymerase 1 (PARP1). Some cholangiocarcinoma tumor cells may express PARP1 which may make it easier to see them on PET/CT. Research has shown that tumor cells that express PARP1 may not respond well to GCD treatment. Researchers hope that by using \[18F\]FTT with PET/CT imaging they will be able to detect which patients have tumor cells that express PARP1, which may help predict treatment response in patients scheduled to receive GCD for newly diagnosed cholangiocarcinoma.