Clinical experience of total body irradiation performed on Halcyon™ for a patient diagnosed with acute myeloid leukemia

Abstract

We aim to publish/document a clinically novel case of total body irradiation (TBI) performed on the Halcyon™. A 21-year-old gentleman diagnosed with high-risk tp53-positive acute myeloid leukemia planned for haploidentical bone marrow transplant post-chemotherapy following which he was declared minimal residual disease, negative was referred for TBI. The patient was placed in the supine position, arms by side with feet together. Immobilization was achieved using a full-body Vac-Lok. Two CT images of the cranial and caudal body parts were acquired. The PTV comprised the whole body minus 3 mm. The prescribed dose was 3 Gy in a single fraction. To achieve the desired dose distribution, we used 15 isocenters. Constraints were given to spare lungs and kidneys. The final plan was evaluated where 90% of the dose is received by 95% of volume, whereas lungs and kidneys received 80% of the prescribed dose, maximum dose of <130% of the prescribed dose is received by 2 cc of whole-body volume. The total time taken for delivering a single fraction is 1 h 15 min. This is the first known reported clinical treatment of TBI on Halcyon machine amidst available medical literature.