New imaging technique could reveal how radiation wakes up the immune system

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

Inclusion Criteria: * Documented informed consent of the participant and/or legally authorized representative * Participant is willing and able to comply with all protocol required procedures * Age: \>= 18 years * Eastern Cooperative Oncology Group (ECOG) =\< 2 * Metastatic patients of any solid tumor malignancy amenable for SBRT as determined by the radiation oncologist * Lymphoma patients may be allowed as determined by the principal investigator (PI) * No change in systemic treatment regimen for past 2 months prior to start of SBRT * Patients able to comply with daily PET after SBRT * Patient meets all clinical safety lab values per institution's standard of care, or Investigator's discretion, for patients receiving cancer treatment * Women of childbearing potential (WOCBP): negative urine or serum pregnancy test * If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required * Agreement by females and males of childbearing potential to use effective double barrier contraceptive methods or abstain from heterosexual activity for the course of the study through at least 30 days after the last administration of the CD8 PET tracer * Childbearing potential defined as not being surgically sterilized (men and women) or have not been free from menses for \> 1 year (women only) Exclusion Criteria: * Patient who have splenic disorders or had splenectomy that per PI would interfere with CD8 imaging * Patients should not have any uncontrolled illness including ongoing or active infection * History of allergic reactions attributed to compounds of similar chemical or biologic composition to CD8 PET tracer * Serious nonmalignant disease or conditions that could compromise protocol objectives, in the opinion of the investigator * Females only: Pregnant or breastfeeding * Pregnant women are excluded from this study because CD8 PET tracer is an agent with the potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with CD8 PET tracer, breastfeeding should be discontinued if the mother is treated with CD8 PET tracer * Any other condition that would, in the Investigator's judgment, contraindicate the patient's participation in the clinical study due to safety concerns with clinical study procedures * Prospective participants who, in the opinion of the investigator, may not be able to comply with all study procedures (including compliance issues related to feasibility/logistics)