Abstract
Abstract A major purpose of total body irradiation (TBI) for bone marrow transplantation in leukemia patients is to help eradicate all leukemia cells; the ideal regimen has not yet been determined. To answer basic questions regarding leukemic cell survival kinetics, a human acute lymphoblastic leukemia (ALL) cell line (Reh), with the common ALL antigen (CALLA-positive), has been used to assess in vitro the efficacy of one widely used hyperfractionated TBI (HTBI) regimen versus single dose TBI (SDTBI). The regimen studied in this model was 1.2–1.25 Gy/fraction, 3 fractions/day, 5 h apart each day, for 5 days (11–12 fractions) for a total dose of 13.2–15.0 Gy. It was found that: (i) cell survival was consistent with the linear-quadratic model for early responding tissues ( α β = 7.0 Gy ). (ii) The change in shape of the ‘effective’ cell survival curve for three fractions/day was consistent with the hypothesis that there was complete repair between fractions. (iii) Cell regrowth between fractions was minimal (≤ 5%). (iv) Division delay between fractions (2.9 h/Gy) could explain the small contribution to the survival curve of regrowth between fractions.(v) For a full HTBI course to 15 Gy, cell survival was predicted to be ~5 × 10 −5, compared with ~ 10−3 for a low dose rate (0.04–0.07 Gy/min) SDTBI to 10 Gy; the latter projected from the initial slope of the high dose rate, single dose survival curve.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
