Total body irradiation (TBI) is a form of radiotherapy used primarily as part of the preparative regimen for haematopoietic stem cell (or bone marrow) transplantation. As the name implies, TBI involves irradiation of the entire body, though in modern practice the lungs are often partially shielded to lower the risk of radiation-induced lung injury. [1] [2] Total body irradiation in the setting of bone marrow transplantation serves to destroy or suppress the recipient's immune system, preventing immunologic rejection of transplanted donor bone marrow or blood stem cells. Additionally, high doses of total body irradiation can eradicate residual cancer cells in the transplant recipient, increasing the likelihood that the transplant will be successful.
Doses of total body irradiation used in bone marrow transplantation typically range from 10 to >12 Gy. For reference, an unfractionated (i.e. single exposure) dose of 4.5 Gy is fatal in 50% of exposed individuals without aggressive medical care. [3] The 10-12 Gy is typically delivered across multiple fractions to minimise toxicities to the patient. [4]
Early research in bone marrow transplantation by E. Donnall Thomas and colleagues demonstrated that this process of splitting TBI into multiple smaller doses resulted in lower toxicity and better outcomes than delivering a single, large dose. [5] [6] The time interval between fractions allows other normal tissues some time to repair some of the damage caused. However, the dosing is still high enough that the ultimate result is the destruction of both the patient's bone marrow (allowing donor marrow to engraft) and any residual cancer cells. Non-myeloablative bone marrow transplantation uses lower doses of total body irradiation, typically about 2 Gy, which do not destroy the host bone marrow but do suppress the host immune system sufficiently to promote donor engraftment.[ citation needed ]
In addition to its use in bone marrow transplantation, total body irradiation has been explored as a treatment modality for high-risk Ewing sarcoma. [7] However, subsequent findings suggest that TBI in this setting causes toxicity without improving disease control, [8] and TBI is not currently used in the treatment of Ewing sarcoma outside of clinical trials.
Total body irradiation results in infertility in most cases, with recovery of gonadal function occurring in 10−14% of females. The number of pregnancies observed after hematopoietic stem cell transplantation involving such a procedure is lower than 2%. [9] Fertility preservation measures mainly include cryopreservation of ovarian tissue, embryos or oocytes. Gonadal function has been reported to recover in less than 20% of males after TBI. [10]
Acute radiation syndrome (ARS), also known as radiation sickness or radiation poisoning, is a collection of health effects that are caused by being exposed to high amounts of ionizing radiation in a short period of time. Symptoms can start within an hour of exposure, and can last for several months. Early symptoms are usually nausea, vomiting and loss of appetite. In the following hours or weeks, initial symptoms may appear to improve, before the development of additional symptoms, after which either recovery or death follow.
A sarcoma is a malignant tumor, a type of cancer that arises from transformed cells of mesenchymal origin. Connective tissue is a broad term that includes bone, cartilage, fat, vascular, or hematopoietic tissues, and sarcomas can arise in any of these types of tissues. As a result, there are many subtypes of sarcoma, which are classified based on the specific tissue and type of cell from which the tumor originates. Sarcomas are primary connective tissue tumors, meaning that they arise in connective tissues. This is in contrast to secondary connective tissue tumors, which occur when a cancer from elsewhere in the body spreads to the connective tissue. The word sarcoma is derived from the Greek σάρκωμα sarkōma 'fleshy excrescence or substance', itself from σάρξsarx meaning 'flesh'.
Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood in order to replicate inside of a patient and to produce additional normal blood cells. It may be autologous, allogeneic or syngeneic.
Graft-versus-host disease (GvHD) is a syndrome, characterized by inflammation in different organs. GvHD is commonly associated with bone marrow transplants and stem cell transplants.
Hematopoietic stem cells (HSCs) are the stem cells that give rise to other blood cells. This process is called haematopoiesis. In vertebrates, the very first definitive HSCs arise from the ventral endothelial wall of the embryonic aorta within the (midgestational) aorta-gonad-mesonephros region, through a process known as endothelial-to-hematopoietic transition. In adults, haematopoiesis occurs in the red bone marrow, in the core of most bones. The red bone marrow is derived from the layer of the embryo called the mesoderm.
CD34 is a transmembrane phosphoglycoprotein protein encoded by the CD34 gene in humans, mice, rats and other species.
Cell therapy is a therapy in which viable cells are injected, grafted or implanted into a patient in order to effectuate a medicinal effect, for example, by transplanting T-cells capable of fighting cancer cells via cell-mediated immunity in the course of immunotherapy, or grafting stem cells to regenerate diseased tissues.
Platelet transfusion, also known as platelet concentrate, is used to prevent or treat bleeding in people with either a low platelet count or poor platelet function. Often this occurs in people receiving cancer chemotherapy. Preventive transfusion is often done in those with platelet levels of less than 10 x 109/L. In those who are bleeding transfusion is usually carried out at less than 50 x 109/L. Blood group matching (ABO, RhD) is typically recommended before platelets are given. Unmatched platelets, however, are often used due to the unavailability of matched platelets. They are given by injection into a vein.
Ewing sarcoma is a type of cancer that forms in bone or soft tissue. Symptoms may include swelling and pain at the site of the tumor, fever, and a bone fracture. The most common areas where it begins are the legs, pelvis, and chest wall. In about 25% of cases, the cancer has already spread to other parts of the body at the time of diagnosis. Complications may include a pleural effusion or paraplegia.
Aggressive NK-cell leukemia is a disease with an aggressive, systemic proliferation of natural killer cells and a rapidly declining clinical course.
The TomoTherapy platform is a helical radiation therapy delivery system that integrates a linear accelerator and CT technology. It delivers accurate high-quality helical fan-beam image-guided, intensity-modulated radiation therapy (IG-IMRT) from multiple 360-degree rotations around the patient as the treatment table moves. It enables accurate control of the radiation dose so it conforms precisely to the tumor and minimizes dose to healthy tissues. The TomoTherapy platform is designed to deliver image-guided 3D conformal radiation therapy (3DCRT), intensity-modulated radiation therapy (IMRT), stereotactic body radiation therapy (SBRT), and stereotactic radiosurgery (SRS).
Juvenile myelomonocytic leukemia (JMML) is a rare form of chronic leukemia that affects children, commonly those aged four and younger. The name JMML now encompasses all diagnoses formerly referred to as juvenile chronic myeloid leukemia (JCML), chronic myelomonocytic leukemia of infancy, and infantile monosomy 7 syndrome. The average age of patients at diagnosis is two (2) years old. The World Health Organization has included JMML as a subcategory of myelodysplastic and myeloproliferative disorders.
Peripheral blood stem cell transplantation (PBSCT), also called "Peripheral stem cell support", is a method of replacing blood-forming stem cells. Stem cells can be destroyed through cancer treatments such as chemotherapy or radiation, as well as any blood-related diseases, such as leukemia, lymphoma, neuroblastoma and multiple myeloma. PBSCT is now a much more common procedure than its bone marrow harvest equivalent due to the ease and less invasive nature of the procedure. Studies suggest that PBSCT has a better outcome in terms of the number of hematopoietic stem cell yield.
Subcutaneous T-cell lymphoma is a cutaneous condition that most commonly presents in young adults, and is characterized by subcutaneous nodules. Common symptoms include fever, fatigue, and pancytopenia.
Karen H. Antman is an American physician. She is the dean of Boston University School of Medicine and provost of the Boston University Medical Campus. Antman developed standards for the treatment of patients receiving chemotherapy including pharmacology, growth factors and mobilization of peripheral blood derived stem cells for blood and marrow transplant.
Mesenchymal stem cells (MSCs) also known as mesenchymal stromal cells or medicinal signaling cells are multipotent stromal cells that can differentiate into a variety of cell types, including osteoblasts, chondrocytes, myocytes and adipocytes.
The haematopoietic system is the system in the body involved in the creation of the cells of blood.
FLAG is a chemotherapy regimen used for relapsed and refractory acute myeloid leukemia (AML). The acronym incorporates the three primary ingredients of the regimen:
Andrew Louis Pecora is an American hematologist and oncologist involved in research on the use of stem cells and oncolytic viruses to treat diseases, including cancer. He is the CEO of Outcomes Matter Innovations. As of 2020, he is on the Board of Directors Celularity, Inc. (since 2017) and founder and Executive Chairman, COTA, Inc.. Previously, he was chief innovations officer, professor and vice president of cancer services at the John Theurer Cancer Center, part of the Hackensack University Medical Center. He is a professor of medicine and oncology at Georgetown University.
Shimon Slavin is an Israeli professor of medicine. Slavin pioneered the use of immunotherapy mediated by allogeneic donor lymphocytes and innovative methods for stem cell transplantation for the cure of hematological malignancies and solid tumors, and using hematopoietic stem cells for induction of transplantation tolerance to bone marrow and donor allografts.
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