• Disease characteristics, as defined by:

∙ Histologically-confirmed relapsed/refractory non-Hodgkin lymphoma with at least one prior line of therapy.

‣ Planned treatment with a commercially available CD19 targeting CAR-T cell product .

• Willing to undergo post-treatment tumor biopsies and has safely accessible soft tissue lesion.

• Age \>= 18 years.

• Ability to understand and the willingness to sign a written informed consent document.

• Eastern Cooperative Oncology Group (ECOG) performance status \<2 (Karnofsky \>60%).

• Demonstrates adequate organ function as defined below:

∙ Absolute neutrophil count \>=1,500/microliter (mcL)

‣ Platelets ≥100,000/mcL

‣ Total bilirubin within normal institutional limits, unless elevated due to Gilbert's syndrome and direct bilirubin is within normal limits.

‣ Aspartate aminotransferase (AST)/serum glutamic-oxaloacetic transaminase (SGOT) \<=3 X institutional upper limit of normal.

‣ Alanine aminotransferase (ALT)/serum glutamic-pyruvic transaminase (SGPT) \<=3 X institutional upper limit of normal

‣ Creatinine \<= 1.5 x within institutional upper limit of normal OR creatinine clearance Glomerular filtration rate (GFR) \>= 40 mL/min/1.73 m\^2, calculated using the Cockcroft-Gault equation, unless data exists supporting safe use at lower kidney function values, no lower than 30 mL/min/1.73 m\^2.

• Human immunodeficiency virus (HIV)-infected individuals on effective antiretroviral therapy with undetectable viral load within 6 months are eligible for this trial.

• For participants with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated.

• Individuals with a history of hepatitis C virus (HCV) infection must have been treated and cured. Individuals with HCV infection who are currently on treatment are eligible if an undetectable HCV viral load is demonstrated.

⁃ Individuals with treated brain metastases are eligible if follow-up brain imaging after central nervous system (CNS)-directed therapy shows no evidence of progression.

⁃ Individuals with new or progressive brain metastases (active brain metastases) or leptomeningeal disease are eligible if the treating physician determines that immediate CNS specific treatment is not required and is unlikely to be required during the first cycle of therapy.

⁃ Individuals with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial. The effects of 64Cu-GRIP B on the developing human fetus are unknown. For this reason, participants of childbearing potential must agree to use adequate contraception: all participants should use barrier protection for the duration of study participation and for one month after last administration of study intervention. Should a participant become pregnant or suspect they are pregnant while they or their partner are participating in this study, they should inform their treating physician immediately. Male participants treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of study participation, and one month after last administration of study treatment.