Abstract：Objective To explore the influence of the optimization tool normal tissue objective (NTO) on Eclipse on the dosimetry
of intensity modulated radiotherapy (IMRT) for cervical cancer, and to provide a reference for the design of cervical cancer IMRT.
Methods A retrospective study was conducted on 20 patients with cervical cancer after surgery, and 7 groups of reverse IMRT plans
were developed for each patient. First, automatic NTO was used as the control group, and the other 6 plans were changed to manual
NTO under the same optimized conditions, and the dose drop value K was 0.01, 0.1, 0.3, 0.5, 1, and 5 in order. The prescribed dose
of the target area was 4600 cGy/25F. The D2, D98, Dmean, conformity index (CI), homogeneity index (HI) and normal tissue (Body-
PTV) of each planned target area, and organ at risk (OAR) dosimetry of bladder, rectum, femoral head, small intestine, and pelvis
were analyzed. Results Compared with the control group, the CI was better when K=0.3 and above, and the HI was worse when
K=0.5 and above (P<0.05). Compared with the control group, the bladder D40 was smaller in the K=1 and 5 plan groups (P<0.05);
the rectum D40 results were not statistically different (P>0.05); the left femoral head D25 was higher in the K=1 and 5 plan groups
(P<0.05); the right femoral head D25 was larger in the K=5 plan group (P<0.05); the small intestine Dmax was larger in the K=1 and
5 plan groups (P<0.05); the pelvis was smaller in the K=0.01 plan group. When the K value of normal tissue was small, the volume
of the low dose was smaller and the volume of the high dose was larger; when the value of K was larger, the volume of the low dose
was larger, and the volume of the high dose was smaller. The number of monitor unit in the control group was smaller than that of
the other 6 groups (P<0.05). Conclusion In the design of cervical cancer IMRT plan, manual NTO has no absolute advantage over
automatic NTO in terms of target volume, OAR and normal tissues. However, automatic NTO has a smaller number of machine hops,
which can reduce the burden on the machine. Automatic NTO is recommended for clinical use in cervical cancer IMRT.
刘可，吴哲，明智，王东. Eclipse计划系统NTO优化对宫颈癌调强放疗计划的影响[J]. 中国医疗设备, 2022, 37(6): 39-43.
LIU Ke, WU Zhe, MING Zhi, WANG Dong. Influence of NTO Optimization on Eclipse Treatment Planning System for Cervical Cancer
Intense-Modulated Radiotherapy. China Medical Devices, 2022, 37(6): 39-43.
