The purpose of this study is to see if positron emission tomography/ magnetic resonance imaging (PET/MRI) can be used to monitor the effectiveness of cancer treatment using an investigational radioactive drug called [Ga-68]PSMA.

Primary Objective

The primary objective of this pilot imaging study is to determine the feasibility of using positron emission tomography/ magnetic resonance (PET/MR) with [Ga-68] prostate-specific membrane antigen (PSMA) for staging and treatment monitoring of PSMA expressing tumors. [Ga-68]PSMA PET/MR findings will be compared with standard of care imaging, patient follow up, and histopathology if available. [Ga-68]PSMA PET/MR will not be used to change the patients' treatment plan. Investigators will assess PET/MR test-retest reproducibility and compare baseline [Ga-68]PSMA PET/MR with PET/MR after initiation (within 2-6 weeks) of therapy and evaluate if [Ga-68]PSMA is a suitable biomarker for treatment monitoring and assessment of early treatment response.

Secondary Objectives

• To compare early changes in PET biomarker ([Ga-68]PSMA) tumor uptake with treatment response assessed at completion of therapy (prediction of treatment response).
• To compare changes in MRI signal intensities (multi-parametric MRI) with treatment response assessed at completion of therapy.
• To compare results from multi-parametric MR imaging with [Ga-68]PSMA uptake.
• To assess combinations of quantitative PET and MRI metrics.

Study Design Patients, who enroll in this study, will undergo a baseline [Ga-68]PSMA PET/MR to assess the level of [Ga-68]PSMA tumor uptake. Patients with positive [Ga-68]PSMA tumor uptake (defined as [Ga-68]PSMA uptake twice the background activity) who are receiving systemic therapy will undergo a further [Ga-68]PSMA PET/MR 2-6 weeks after start of treatment. Patients with positive [Ga-68]PSMA tumor uptake will also be offered to participate in a test- retest study with a 2nd [Ga-68]PSMA PET/MR prior to treatment. Patients will therefore undergo a maximum of three [Ga-68]PSMA PET/MR imaging procedures. The first two test-retest Ga-PSMA-PET/MRI will be performed on separate days to allow for radioactive decay. There will be no other (e.g. clinically indicated) PET scan performed on the same day of [Ga-68]PSMA-PET/MRI.

Inclusion Criteria:

• Patients with PSMA-positive tumors including prostate cancer, breast cancer, lung cancer, and other tumor types know to express PSMA
• Patients able to tolerate PET/MRI scans
• Informed consent must be given and signed

Exclusion Criteria:

• Subjects who do not meet the above mentioned inclusion criteria
• Subjects who refuse to give and/or sign the informed consent
• Patients who have a history of serious adverse events related to a previous MRI or PET/CT
• Patients who are unable to undergo MRI scanning due to exclusion by institutional MRI restriction policies as mentioned in the standard institutional MRI informed consent form
• Patients who are currently pregnant or breast feeding. A pregnancy test within 72 hours of the first PET/MRI will be performed.
• Anti-cancer treatment (chemotherapy and/or radiation therapy) within the last 2 weeks.
• Renal insufficiency: elevated Creatinine and/or Glomerular Filtration Rate (GFR)<40ml/min/1.7sqm (exclusion criterion only for contrast enhanced MRI)
• Patients with a known allergy against any component of the contrast enhancing MR agent will not receive MR contrast agents. (exclusion criterion only for contrast enhanced MRI)

Patients diagnosed with tumors expressing PSMA including prostate cancer, breast cancer, lung cancer, renal cancer and other tumor types [Ga-68]PSMA PET/MRI known to express PSMA