Autologous Stem Cell Transplantation is a medical procedure where a patient's own stem cells are collected, stored, and later infused back into their body. This process is often used to treat certain types of cancer, such as multiple myeloma and lymphoma, as it helps restore the bone marrow after high-dose chemotherapy or radiation therapy. The procedure begins with the collection of stem cells from the patient's blood or bone marrow. After treatment, these cells are reintroduced to help regenerate healthy blood cells and restore the immune system. This approach reduces the risk of rejection since the cells are from the same individual.