This month marks the 10-year anniversary of the first successful total marrow irradiation (TMI) using the TomoTherapy System, first performed at City of Hope in Duarte, California. Since then, numerous centers around the world have adopted the approach, once considered to be impossible because of limitations inherent to conventional radiation therapy systems.
TMI is an advanced form of total body irradiation, which has traditionally been an important part of bone marrow transplants (BMT). People with certain types of cancers or other diseases including leukemias, lymphomas and multiple myeloma may undergo a BMT as part of their treatment. Before the transplant, chemotherapy and/or radiation may be given to neutralize any cancer in the marrow.
Traditional approaches to total body irradiation resulted in the same dose of radiation delivered to the entire body, not just the bone marrow, causing damage to healthy organs and side effects ranging from nausea and diarrhea to cataracts and secondary malignancies. In contrast, total marrow irradiation delivers small radiation "beamlets" from 360 degrees around the patient, allowing for greater control of the prescription dose so it conforms precisely to the target. This enables physicians to irradiate the bone marrow with larger doses of radiation while sparing nearby normal, healthy organs and limiting radiation side effects. Also, the system's CT scanner-based design allows efficient delivery of radiation to very large areas without field matching. These attributes are unique to the TomoTherapy System and facilitate its use for TMI as an alternative to total body irradiation.
The TomoTherapy System is the only radiation system specifically designed for image-guided intensity-modulated radiation therapy (IMRT). More than 950 scientific articles have been published on TomoTherapy technology, with many addressing the clinical value and patient benefit of this treatment modality across a broad the range of indications to:
Deliver highly accurate, individualized dose distributions to any tumor, at its true location, during each treatment; and
Treat all standard radiation therapy indications including breast, prostate, lung and head and neck cancers, in addition to complex treatments such as total marrow irradiation.