Total-body irradiation as a conditioning regimen for hematopoietic cell transplantation: current status eight years after the last national survey

Abstract

Total-body irradiation varies according to the irradiation method, irradiation dose, dose fractionation, and dose rate at each facility. In 2015, a nationwide survey of total-body irradiation was conducted by the Japanese Radiation Oncology Study Group. A questionnaire survey was conducted with 82 body irradiation facilities that responded to a structural survey of the Japanese Society of Radiation Oncology. For myeloablative transplantation, the most common irradiation method was the long source-to-skin distance method at 64 facilities (82.9%) and the moving couch method at eight facilities (17.1%); none of the facilities responded that they used the sweeping beam method or helical tomotherapy. The most common fractionation dose was 12 Gy/six fractions/three days at 52 facilities (63.4%). Regarding shielding, the most common practice was shielding the lungs and lenses in 47 facilities (57.3%). For non-myeloablative transplantation, the most common dose fractions were 4 Gy/two fractions/1–2 days (57.7%) and 2 Gy/fraction/day (28.2%). Besides the lungs (43.6%) and eyes (50.0%), the ovaries (14.1%), thyroid gland (6.4%), and testicles (16.7%) were shielded.

Recently, several guidelines for total-body irradiation have been published overseas, and high-precision total-body irradiation treatments have been applied clinically. There are plans to create clinical guidelines in Japan, and total-body irradiation methods may become more standardized eventually; hence, further development is expected.