FDG PET-CT image acquisition in the abdominal and thoracic region is influenced by organ motion. Respiratory movement blurs the metabolic signal of the esophageal tumor and lymph nodes. The investigators hypothesize that the metabolic signal obtained with motion compensation results in higher SUV-max values and clearer demarcation of the esophageal tumor and lymph nodes.

Patients will receive a normal 3D FDG PET-CT scan. By participating in this trial, one extra 4D CT scan will be made. For both the PET and the 4D CT acquisition, the patient gets an abdominal belt around the waist to register breathing motion. No extra FDG PET scan is required for this study. The 4D CT scan is the only intervention which increases the radiation dose exposure compared to the standard PET-CT scan. However, in comparison to the expected radiation dose delivered, if a patient will be treated with curative chemoradiotherapy, this increase in radiation dose is negligible and secondary risks due to this intervention are therefore not increased. For patients who are not eligible for curative treatment the extra dose is also not relevant, given the life expectancy of this group.

Inclusion Criteria:

• Patients with pathology proven esophageal cancer or tumor highly suspicious for esophageal cancer
• > 18 years
• Written informed consent

Exclusion Criteria:

• <18 years
• Possibility of pregnancy