Room: AAPM ePoster Library
Purpose: have previously shown a significant difference in body weight and survival time between mice treated with conventional (CRT) and pulsed low-dose-rate (PLDR) radiotherapy using 8 Gy TBI. This study compares the effects on survival of mice of 3 higher, fractionated total doses of CRT and PLDR: 12, 14, and 16 Gy.
Methods: male nude A549 tumor-bearing mice were randomized into 7 groups: untreated, 12, 14 and 16 Gy CRT, 12, 14 and 16 Gy PLDR radiotherapy. TBI 2 Gy daily consecutive fractions were delivered using TBI continuously at a dose rate of 300 MU/min (CRT groups), or with 10 x 0.2 Gy pulses separated by 3 min intervals (PLDR groups). Animals were monitored daily for 30 days for appearance, behavior, weight loss and survival.
Results: of the mice treated with CRT succumbed to radiation, except for one receiving 12 Gy that survived for one month. Mice treated with 14 and 16 Gy of CRT died within 17 days from the start of treatment, surviving on average for 14.4 and 16.1 days, respectively. Mice treated with 12 Gy CRT died within 25 days, surviving on average for 14.9 days. Similarly, in the PLDR groups, all of the mice died, except for one receiving 12 Gy that survived for one month. Mice irradiated with PLDR 14 and 16 Gy died within 19 days from the start of treatment, surviving for 15.3 and 17 days, respectively. Mice treated with 12 Gy of PLDR died within 28 days, surviving for 13 days.
Conclusion: was no difference in animal survival time between CRT and PLDR in this mouse model, likely due to excessive dosing. Since PLDR could lead to less toxicity in normal tissues than CRT, it is expected to be a viable treatment option for recurrent cancers.
Not Applicable / None Entered.