Implementing VMAT for total body irradiation in a 3-year-old patient: Clinical workflow and positioning challenges

Total body irradiation (TBI) is a crucial part of conditioning therapy for hematopoietic stem-cell transplant (HSCT) procedures that occur due to acute lymphoid leukemia (ALL) in pediatric patients. Even though volumetric modulated arc therapy (VMAT) is superior to conventional techniques for TBI regarding dose conformity and sparing of organs at risk, it is a challenging task in young pediatric patients. This is a prospective observational case study on the clinical process and positioning difficulties that can arise during VMAT treatment of TBI of a 3-year-old girl presented with non-remission ALL and HSCT. A total 12 Gy was administered to the patient as a fractionation of six treatments over a period of three consecutive days through five anatomical segments. General anesthesia was required in treatment sessions for this patient. Results The overall treatment time for VMAT-TBI was significantly increased for each treatment session, taking as high as 3 h for each fraction (mean: 1.67 h), as opposed to about 40 min required for conventional TBI. The treatment session had an average of 10 interruptions. Conclusion VMAT TBI is quite viable in pediatric patients and can reach considerable dosimetric superiority over conventional TBI. However, longer treatment times, sensitivity to positioning errors, limitations imposed by patient anesthetics, and resource intensiveness can be considered considerable challenges associated with the delivery of VMAT TBI under the age of five years.