Various Regimens of Total Body Irradiation for Hematopoietic Stem Cell Transplant.

OBJECTIVES: We aimed to evaluate the safety of total body irradiation before bone marrow transplant. MATERIALS AND METHODS: We analyzed 110 patients (65 male, 45 female) who underwent total body irradiation for hematopoietic stem cell transplant between May 1998 and March 2013. Median age at total body irradiation was 17 years (range, 1-62 y). Median observation time was 777 days (range, 31-5494 d). Initial diagnoses were acute lymphoblastic leukemia (24 patients), acute myeloid leukemia (26 patients), chronic myeloid leukemia (7 patients), myelodysplastic syndrome (8 patients), malignant lymphoma (13 patients), mucopolysaccharidosis (12 patients), neuroblastoma (10 patients), and other diseases (10 patients). The total fractionated dose used for total body irradiation was 12 Gy in 69 patients and 6.0-10.8 Gy in 29 patients. Single-dose total body irradiation was administered to 12 patients. Most patients (63 of 110) received chemotherapy consisting of cyclophosphamide alone. RESULTS: Ocular complications were observed in 29.5% of the patients. Hypothyroidism, interstitial pneumonia, obliterative bronchiolitis, and veno-occlusive disease developed in 8.2%, 1.8%, 0.9%, and 2.7% of patients. Growth abnormality was observed in 10 (20%) of the 50 pediatric patients. The use of a lower dose (< 12 Gy vs 12 Gy) of fractionated total body irradiation did not decrease the incidence of adverse events; however, nonmyeloablative conditioning with low-dose singlefraction total body irradiation reduced the incidence of adverse events. Three patients who underwent total body irradiation as reirradiation therapy achieved long-term survival without adverse events. CONCLUSIONS: Fractionated total body irradiation given at a lower dose (<12 Gy vs 12 Gy) did not decrease the incidence of adverse events.

[Influence of deficit in top-of-the-head CT images on STI dose calculation].

In 54 cases of stereotactic irradiation (STI) seen at our hospital from April 2000 to March 2001, we examined the deficit in top-of-the-head computed tomography (CT) images and the influence that this deficit had on calculation of the STI dose. Results showed a slice deficit of more than 5 mm in 16 of the 54 cases and a maximum deficit of 25 mm. In most cases, the Gill-Thomas-Cosman (GTC) frame was used. The error in total dose monitor unit (DMU) calculation can be ignored if the top-of-the-head CT image deficit is less than 10 mm. If the deficit is more than 20 mm, it is possible that the total DMU calculation error will exceed 2 . In cases in which the deficit was greater than 30 mm, the average calculation error was 2.00 , and, in one case, the error was more than 7 . The GTC frame tends to produce CT image deficits in top-of-the-head images, whereas such images do not suffer this loss when a Brown-Roberts-Wells (BRW) head ring is used. When the CT image deficit is large, it is necessary to reduce the ratio of the arc that passes the area of the CT image deficit and to decrease the dose weight of the arc.