The specific diagnostic tests used to determine the type and stage of lymphoma depend on the individual's unique situation. However, some commonly used tests include:

1. Biopsy: This is the primary diagnostic test for lymphoma. A small tissue sample is taken from a swollen lymph node or other affected area and is examined under a microscope to identify any cancer cells.

2. Blood tests: Blood tests may be used to measure the levels of certain proteins, such as lactate dehydrogenase (LDH), which can be elevated in some types of lymphoma.

3. Imaging tests: Imaging tests such as CT scans, PET scans, and MRI scans may be used to identify the size and location of tumors, as well as to detect any spread of cancer to other parts of the body.

4. Bone marrow biopsy: This involves the removal and examination of a small sample of bone marrow to determine if cancer has spread to this area.

5. Lumbar puncture: Also known as a spinal tap, this test involves the removal and examination of a small sample of cerebrospinal fluid to detect any signs of cancer spread to the brain or spinal cord.

The specific treatment options for lymphoma depend on the type, stage, extent of the disease, and the individual's overall health. However, some common treatment options include:

1. Chemotherapy: This is the most common treatment for lymphoma. It involves the use of drugs to kill cancer cells. Chemotherapy can be given alone or in combination with other treatments, such as radiation therapy or immunotherapy.

2. Radiation therapy: This involves the use of high-energy radiation to kill cancer cells. It can be used alone or in combination with other treatments. Radiation therapy may be given to the affected lymph nodes or other affected areas of the body.

3. Immunotherapy: This involves the use of drugs to boost the body's immune system to recognize and attack cancer cells. Common types of immunotherapy for lymphoma include monoclonal antibodies and CAR T-cell therapy.

4. Stem cell transplant: This involves the transplant of healthy stem cells into the body to replace damaged or cancerous cells. Stem cell transplant may be used in combination with chemotherapy or radiation therapy.

5. Surgery: This is rarely used as primary treatment for lymphoma. In some cases, surgery may be performed to remove large tumors or to take a biopsy of an affected area.

CAR T-cell therapy, also known as chimeric antigen receptor T-cell therapy, is a type of immunotherapy that has shown remarkable success in the treatment of certain types of lymphoma. Here's how it works:

1. Collection of T-cells: The process starts by collecting a sample of the patient's own T-cells, a type of immune cells, through a process called leukapheresis.

2. Genetic modification: In a laboratory setting, the collected T-cells are genetically modified to express a chimeric antigen receptor (CAR) on their surface. This CAR is designed to recognize a specific protein, called an antigen, that is commonly found on the surface of lymphoma cells.

3. Expansion and activation: The genetically modified T-cells are then multiplied in the laboratory to create a large population of CAR T-cells. These CAR T-cells are specifically engineered to target and attack cancer cells.

4. Infusion of CAR T-cells: Once a sufficient number of CAR T-cells have been produced, they are infused back into the patient's bloodstream. The CAR T-cells then travel throughout the body, seeking out and binding to the targeted antigen present on lymphoma cells.

5. Killing of cancer cells: When the CAR T-cells encounter lymphoma cells expressing the targeted antigen, they become activated and initiate a potent immune response. They release toxic substances that directly kill the cancer cells, effectively eliminating the tumor.

CAR T-cell therapy has shown remarkable efficacy in treating certain types of lymphoma, particularly diffuse large B-cell lymphoma (DLBCL) and acute lymphoblastic leukemia (ALL). It has demonstrated impressive response rates and even the potential for long-lasting remissions in some patients who have not responded to traditional treatments. It's important to note that CAR T-cell therapy is a highly specialized and complex treatment, typically reserved for patients who have not responded to other therapies or have relapsed. It requires a specialized healthcare team and careful monitoring for potential side effects, including cytokine release syndrome (CRS) and neurological toxicity.