https://doi.org/10.3857/roj.2018.00122Radiat Oncol J 2018;36(1):1-10We noticed that the original version of this paper contains typographical errors.In Table 1, the year of study by Park et al. [23], ‘2002’, must be changed into ‘2001’.On page 6, line 11, ‘2002’ must be changed into ‘2001’.