This is a Phase 1 study is to visualize biodistribution of a PET tracer called [18F]F-AraG (VisAcT) in cancer patients expected to undergo immunotherapy and/or radiation therapy.

This is an exploratory Phase 1, prospective study assessing the biodistribution and radiation dosimetry of the Positron Emission Tomography [18F]FAraG (VisAcT) in cancer patients selected for immunotherapy and/or radiation therapy. Each patient may have up to two [ 18F]FAraG PET imaging sessions, a baseline scan and a post start of immunotherapy scan. For each imaging session, patients will receive a single injection of [18F]FAraG and undergo a whole-body PET scans an hour after injection of the tracer. Following each imaging session, the patient will be called within 72 hours to note any side effects.

Optional - Blood samples may be collected at up to 9 time points post-injection to analyze whole-blood/plasma time activity of [18F]FAraG in addition an urine sample may be collected post scan.

Inclusion Criteria:

• Cancer patients with identified tumor mass
• Cancer patients expected to undergo immunotherapy and/or radiation therapy

Exclusion Criteria:

• Under the age of 18
• Pregnant women
• Women who are breastfeeding
• Individuals with known or suspected substance abuse
• Individuals unable or unwilling to comply with the study procedures