Objective       To compare the dosimetric difference between volumetric modulated arc therapy (VMAT) with double arcs and seven-field fixed-gantry dynamic intensity modulated radiotherapy (dIMRT) in the treatment of cervical cancer for the best plan of radiotherapy.       Methods      Based on the Varian r

adiation treatment planning system （Eclipse 8.6）

2 arcs of VMAT plans and 7 fields of dIMRT plans were generated in 10 patients with cervical cancer

respectively. Dose volume histograms were used to compare the target volume

normal tissue and organs at risks in the radiation field. Machine number (MU)

irradiation time and optimization time were evaluated to assess plan quality.       Results      Compared to dIMRT

conformity index (CI) of VMAT was closer to 1 (

P

0.05)

and D

100%

were significantly greater and D

min

were closer to the prescription dose (

P

0.05)

but there was no significant difference in evenness index（HI）. D

mean

of caput femoris were significantly lower in VMAT than in dIMRT（

P

0.05）

while D

5%

was similar in the 2 planning. There was no difference in the protection of small intestine

bladder

rectum and cauda equine between VMAT and dIMRT

but the both of them reached the clinical requirement. The MU of VMAT was a quarter of that of dIMRT

and the treatment time was only a third of that of dIMRT.        Conclusion      Compared to the dIMRT

VAMT shows a better effect in target dose distribution

reduces the irradiation doses on organs at risk

and decreases the volume of high-dose area (20 to 30 Gy) in normal tissues

with the advantages of less MU and shorter overall treatment time. It is a better option for the development direction of cervical cancer radiotherapy.