| Objective:To determine target movement for gastric cancer radiotherapy after operation and compare the dose distribution with three—dimension conformal radiation therapy(3D-CRT) and intensity modulated radiation therapy(IMRT), to provide reference for clinical application.Methods:1、Select 15 patients with gastric cancer underwent D2 radical gastrectomy in the First Affiliated Hospital of Nanchang University, to position it by CT scan,keep the patients on an empty stomach for 3 hours,then drink 400 ml water 5 minutes before radiotherapy position, ensure full stomach filling,position by CT simulation scan In the Pinnacle planning system,draw the outline of the target area and the surrounding normal tissue,the physical teacher makes the plan,clinicians makes the confirmation.2、5 minutes before plan verification,the patients drink 400 ml water+10ml diatr-izoate on an empty stomach,observe gastric target mobility in thesimulation of machi ne,use the same method in radiotherapy and after radiotherapy to re observe the mobility for the gastric target area3、select the 5 cases of postoperative gastric cancer patients as above mentioned,designed for three-dimensional conformal radiotherapy(3DCRT) and intensity-modul ated radiotherapy(IMRT) plans to compare two groups, prescription dose of 95% PT V 45 Gy, 99% PTV 42.75 Gy with a prescription dose, dose curve and dose volume hi stogram(DVH) to evaluate the treatment plan, evaluation parameters including V95%, conformal index(conformal index, CI), evenness index(homogeneity index, HI),irradiation dose and the spinal cord, liver and kidney.Results:1 、 in the direction of the head and the foot,the mobility idex for the gastric cancer is maximum and is 11.76±0.46 mm.in the direction of the right and the left, itis minimum and is 5.24±0.20 mm.in the direction of the back and the belly, it is7.71±0.28 mm.there is no statistics meaning for the difference about the mobility idex for the gastric cancer in different time when it is in plan verification,in and after radiotherapy.2.Comparison of three-dimensional conformal radiotherapy and intensity- modul ated radiotherapy group 2, V95% had no significant difference(P>0.05), CI and HI for IMRT is better than that of 3DCRT(P < 0.05). As for liver,D1/3 and Dmean for IMRT liver is lower than 3DCRT(P < 0.05), the difference is significant to the statistical meaning. As for kidney,D1/3 for IMRT and 3DCRT meet the requirem-ents of the dosim-etry on kidney.Compare 2 groups,the difference of D1/3 makes no sense to the statistical meaning.3DCRT D1/2 for the right kidney is lower than IMRT,comparing 3DCRT and IMRT can reduce the right kidney D1/2(P<0.05), as for D1/2 for the left kidney, IMRT and 3DCRT make no sense to the statistical meaning. As for Dmax in the spinal cord:3DCRT is lower than IMRT.Conclusion:1、fter the operation for the gastric cancer in the direction of the head and the foot,the mobility idex is maximum and is 11.76±0.46 mm. in the direction of the right and the left, it is minimum and is 5.24±0.20 mm. in the direction of the back and the belly, it is 7.71±0.28 mm.2 、 In postoperative radiotherapy for gastric cancer, IMRT in the target area conformal, uniformity is better than 3DCRT. The irradiation dose on the liver IMRT was lower than that of 3DCRT. In the lower 2 plans were of no statistical significance of renal dose, 3DCRT spinal Dmax is better than IMRT, but IMRT Dmax is in the normal range of doses of spinal cord. |
PDF Full Text Request