Inclusion Criteria:

• Patients aged 18 years or older.
• Before patient registration, written informed consent must be given according to ICH/GCP, and national/local regulations.
• Additional Part A: patients with pancreaticobiliary cancer (pancreatic, intra- or extrahepatic cholangiocarcinoma) and a tumor size of >20mm on CT.
• Additional Part B: patients with primary pancreatic (or pancreaticobiliary) cancer (depending on the results of part A) and a tumor size of >20mm on CT. No treatment may be given in between the two scans.
• Additional Part C: patients with pathologically proven pancreatic ductal adenocarcinoma, eligible for neoadjuvant therapy before surgical resection.

Exclusion Criteria:

• Women who are pregnant and/or lactating.
• Medical or psychiatric conditions that compromise the patient's ability to give informed consent. Presence of any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule.
• Impaired renal function (creatinine clearance <60 mL/min according to the Cockcroft-Gault equation.
• Leucocytes (WBC) ≤3.0 x 10^9/l
• Platelets ≤ 100 x 10^9 /l
• Hemoglobin ≤ 6 mmol/l
• Known hypersensitivity to drugs comparative to [68Ga]Ga-FAPI-46, or any of the excipients of [68Ga]Ga-FAPI-46.
• Inability to undergo PET/CT scanning (e.g. claustrophobia, weight limits or inability to tolerate lying for the duration of a PET/CT scan (~90 min)).

Additional Part A:

• Contra-indication for arterial cannula (e.g. inadequate circulation of extremity, positive Allen test, severe atherosclerosis, coagulant disorder (INR >1.4 or APTT >50)).

Additional Part C:

• Not eligible for surgery after neoadjuvant chemotherapy.
• If based on the first FAPI-46 PET/CT, there is a suspicion of metastatic disease the images will be discussed in the multidisciplinary meeting and one additional imaging modality (and a biopsy, if this would lead to a change of treatment strategy) can be used to confirm the suspicion. If metastatic disease is confirmed the patient will be excluded.