PSMA Expression and PSMA PET Imaging in Soft Tissue Sarcomas and Urothelial Cell Carcinomas

Inclusion Criteria:

* Age \>/= 18 years at the time of informed consent.
* Diagnosis of advanced (locally irresectable or metastasized) soft tissue sarcoma (cohort 1) or advanced (muscle invasive or metastasized) urothelial cell carcinoma (cohort 2).
* Voluntary agreement to provide written informed consent and the willingness and ability to comply with all aspects of the protocol.
* Recent (\< 8 weeks) standard imaging (with CT or \[18F\]-FDG PET/CT) with measurable disease (lesion diameter \> 1 cm).
* Biopsy available of primary tumour and/or metastasis
* WHO performance status of 0-2
* Either:

  * No previous systemic therapy for advanced soft tissue sarcoma or advanced urothelial cell carcinoma, or;
  * Previous systemic therapy for advanced soft tissue sarcoma or advanced urothelial cell carcinoma with progression of disease during systemic therapy or progression of disease after discontinuation of systemic therapy, or;
  * Previous systemic therapy for advanced soft tissue sarcoma or advanced urothelial cell carcinoma with partial response or stable disease, where the last dose of systemic therapy was given \> 8 weeks before.

Exclusion Criteria:

* Women who are pregnant and/or lactating.
* Medical or psychiatric conditions that compromise the patient's ability to give informed consent.
* Known hypersensitivity to drugs comparative to \[18F\]-JK-PSMA-7, any of their excipients or to any component of \[18F\]-JK-PSMA-7.
* Inability to undergo PET/CT scanning, e.g. claustrophobia, weight limits or inability to tolerate lying down for the duration of a PET/CT scan (\~30 minutes).