  The purpose of this study is to evaluate the clinical usefulness of modulated
arc (mARC) treatment techniques. The mARC treatment plans of the non-small cell
lung cancer (NSCLC) patients were performed in order to verify the clinical
usefulness of mARC. A pre study was conducted to find the most competent plan
condition of mARC treatment and the usefulness of mARC treatment plan was
evaluated by comparing it with the other Arc treatment plans such as
Tomotherapy and RapidArc. In the case of mARC, the optimal condition for the
mARC plan was determined by comparing the dosimetric performance of the mARC
plans with the use of various parameters. The various parameters includes the
photon energies (6 MV, 10 MV), optimization point angle (6{\deg}-10{\deg}
intervals), and total segment number (36-59 segment). The best dosimetric
performance of mARC was observed at 10 MV photon energy and the point angle 6
degree, and 59 segments. The each treatment plans of three different techniques
were compared with the following parameters: conformity index (CI), homogeneity
index (HI), target coverage, dose in the OARs, monitor units (MU), beam on time
and the normal tissue complication probability (NTCP). As a result, all three
different treatment techniques show the similar target coverage. The mARC
results the lowest V20 and MU per fraction compared with both RapidArc and
Tomotherapy plan. The mARC plan reduces the beam on time as well. Therefore,
the results of this study provided a satisfactory result which mARC technique
is considered as a useful clinical technique for radiation treatment.
