New PET scan agent aims to map hidden prostate cancer spread

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Sub-cohort A1: Patients must have baseline evaluations performed within 12 weeks prior to the start of systemic therapy. 2. Sub-cohort A2: Patients must meet all the following requirements: * Have had a baseline pre-treatment 68Ga-PSMA-11 PET scan and PSA measurement performed within 12 weeks prior to the start of current systemic therapy. * Able to have an on-treatment 68Ga-PSMA-11 PET and a PSA measurement within 16 weeks (+/- 8 weeks) after the start of current systemic therapy. Note: The screening period for sub-cohort A2 is within 24 weeks after the patient started their current systemic therapy. 3. Patients must have progressive castration resistant prostate cancer, according to PCWG3 criteria. 4. Patients must have planned initiation of systemic treatment (sub-cohort A1), or ongoing systemic treatment (sub-cohort A2) for castration resistant prostate cancer within 12 weeks of baseline Ga-PSMA PET. 5. Patients must have at least one metastatic lesion with PSMA uptake at or above the blood pool on their baseline PSMA PET scan. 6. The patient must be able and willing to comply with study procedures and provide signed and dated informed consent. 7. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. 8. Patient must be Aged 18 years or older at the time of study entry. 9. Patients who undergo optional metastatic tumor biopsy following completion of baseline Ga-PSMA PET must additionally meet all of the following criteria: * Presence of one or more metastases by standard radiographic scans that is safely accessible to tumor biopsy in the judgment of treating clinician and/or Interventional Radiology. * No history of radiation therapy to the target metastatic lesion selected for tumor biopsy. * No contra-indication to biopsy including uncontrolled bleeding diathesis. * Platelets \> 75,000/ul and prothrombin time (PT) or institution normalized ratio (INR) and a partial thromboplastin time (PTT) \< 1.5 times the institutional upper limit of normal (ULN) within 14 days prior to biopsy. Exclusion Criteria: 1. Patients who because of age, general medical or psychiatric condition, or physiologic status cannot give valid informed consent. 2. Patients with any condition that, in the opinion of the Principal Investigator, would impair the patient's ability to comply with study procedures. 3. Patients with any contra-indication to magnetic resonance imaging (MRI) (e.g. pacemaker placement, severe claustrophobia) Note: The exclusion criteria above (3) is only applicable for patients scheduled for a Positron Emission Tomography (PET) MRI (PET/MRI).