Organ Sparing Marrow-Targeted Irradiation (OSMI) as an Alternative to Traditional Total Body Irradiation (TBI) Methods: VMAT Treatment Planning and Clinical Implementation
Wednesday, November 8, 2017
1:00 - 20:00 pm ET
Following chemotherapy, Total Body Irradiation (TBI) can be employed as a myeloablative form of conditioning in preparation for Bone Marrow Transplant (BMT) for many leukemia patients. A commonly used treatment regimen is 12 Gray total—2 Gy per fraction for 6 fractions, treated BID separated by 8 hours—delivered AP/PA or laterals at extended distance. Often, lungs can be blocked to ≤ 10Gy to reduce the risk of pneumonitis. The common toxicity profile associated with traditional TBI consists of fatigue, nausea, emesis, parotid tenderness, pruritus, pneumonitis, and early cataracts—with potential pulmonary and GI toxicities limiting the use of this regimen for certain patient groups. As an alternative to traditional TBI, Volumetric Modulated Arc Therapy (VMAT) can be employed to treat the targeted marrow/extramedullary sites while reducing the dose to surrounding organs when compared to the dose levels associated with standard techniques. As a result, Organ Sparing Marrow-Targeted Irradiation (OSMI) can potentially be used to soften the traditional TBI toxicity profile. Given the ability to minimize dose to critical organs, OSMI also has to potential to supply a myeloablative conditioning regimen to a wider spectrum of pre-BMT leukemia patients. The purpose of this discussion is to introduce our VMAT OSMI treatment planning technique as it is utilized currently at the Ohio State University (OSU 13219), as well as to discuss potential considerations in terms of simulation, patient setup, and delivery.
Wesley Zoller, CMD is a medical dosimetrist at the Ohio State University for the past four years. He is a graduated from the Cleveland Clinic medical dosimetry program. He is very involved in many of the education programs at Ohio State and really enjoys the opportunity to present topics to this wonderful field.