Inclusion Criteria:  Patients aged 18 or older with bladder cancer or urothelial carcinoma who are able to provide informed consent Negative serum pregnancy test in female patients of childbearing potential at screening. Confirmation of negative pregnancy test result from urine within 24 hours prior to receiving investigational product. Consent to practise double-barrier contraception until a minimum of 42 days after 89Zr-TLX250 administration.  Exclusion Criteria:  Active malignancy other than urothelial carcinoma or bladder cancer Administration of a radioisotope within 10 physical half-lives prior to study enrolment. Administration of chemotherapy, radiotherapy, or immunotherapy within 4 weeks prior to planned administration of 89Zr-TLX250 or continuing adverse effects from such therapy Planned antineoplastic therapies for the period between administration of 89Zr-TLX250 and imaging Serious non-malignant disease that may interfere with the objectives of the study Renal insufficiency with glomerular filtration rate ≤45 mL/min/1.73m2 Pregnancy or lactation Exposure to murine or chimeric antibodies within the last 5 years Known hypersensitivity or human anti-chimeric antibodies against girentuximab Exposure to any experimental diagnostic or therapeutic drug 30 days prior to the date of planned administration of 89Zr-TLX250 Contraindications to FDG PET/CT