Study On The Clinical Application Of Radiotherapy Of Cervical Cancer Patients After Adjustment Optimization

Background and objective:For early postoperative cervical cancer patients with high risk factors, postoperative pelvic intensity-modulated radiotherapy has been widely used.But there are still many irregular factors affecting radiation target accuracy, increase the target missing and normal tissue injury,do standardized treatment of IMRT is particularly important. This research through two aspects of the impact on the norms of the target area of sketch and different radiotherapy position, preferably postoperative cervical cancer IMRT target delineation method and radiotherapy position, and provide reference for future clinical radiotherapy.Methods:The first part:Target standardization sketch. From 2012 November to 2014 February in the Guangxi Zhuang Autonomous Region people’s Hospital of cervical cancer underwent total hysterectomy and pelvic lymph node dissection,20 cases of radiotherapy patients after postoperative (According to the American delineation of RTOG2008 target consensus guidelines, CTV outlined by visual observation of pelvic blood vessels 7mm), each patient positioning CT image re uploaded to the MIM software system, according to the American delineation of RTOG2008 target by consensus guidelines, outlining the new method of target area for each patient and organ to chart.The pelvic lymph node region of fixed point displacement was evident in every patient CT images, measure the fixed point displacement. Observe the specifications before and after the training target of delineation of pelvic lymph node CTV boundary displacement changes, clinical target volume (CTV) of total volume change. Comparison of two kinds of new and old method outlined in the plan target volume (PTV) and organ dosimetry change, including PTV D2, D50, D98, V110, V93 and V40 in the small intestine, rectum and bladder V30, V45, V30 of left femoral head, the right femoral head V30, pelvic bone marrow V20;Part two:radiotherapy position. From 2012 December to 2014 December in the Guangxi Zhuang Autonomous Region people’s Hospital of cervical cancer underwent total hysterectomy and pelvic lymph node dissection,20 cases of postoperative radiotherapy in patients with pseudo adjustment.For each patient underwent supine and prone position location of CT in the bladder filling status, comparing the different position of planning target volume (PTV) and organ dose variation, including PTV D2, D50, D98, V110, V93 and V40 in the small intestine, rectum and bladder V30, V45, V30 of left femoral head, the right femoral head V30, pelvic bone marrow V20, looking for the best position;The use of SPSS20.0 statistical software for statistical analysis of the results, statistical data with normal distribution data to mean ± standard deviation (x ± s) said, in line with the skewness distribution data in the median and four percentile interval (P50/P25-P75) said. On comparating the data about target volume delineation and body position of radiotherapy, when the distribution of data to conform to normal distribution using the paired T test, do not accord with normal distribution were compared by paired rank sum test, P<0.05 was statistically significant.Result:The first part:target standardization sketch. After the comparison of two kinds of target delineation methods in 20 cases of old and new,the total CTV before the standardization of sketch was 495.6±55.57ml, draw the outline of the total volume of CTV was 550.77±33.35ml, the difference was statistically significant (P=0.005< 0.05); Compared with the old hook descriptive, pelvic lymph node displacement CTV have different degrees of expansion range, common iliac lymph node expanding average displacement is 1.1 + 3.2mm, external iliac lymph nodes is 3.9±1.8mm, iliac lymph nodes is 1.5 ±1.4mm, obturator lymph nodes is 1.4 ± 0.8mm, sacral lymph nodes is 0.7±0.5 mm. PTV D2, D50, target D98, V93, V110 before and after the two kinds of new and old delineation methods results were 5370±195.42 cGy and 5336± 211.47cGy,5037±180.79 cGy and 4996±213.6 cGy,4692±225.76 cGy and 3390±1467.21 cGy,99.87% (99.75%-99.99%) and 93.61% (92.11%-98.84%), 3.16% (2.01%-7.08%) 与 3.74%(0.7%-5.35%). The target PTV D2, D50, D98, V93, V110, the differences were statistically significant (P<0.05).There was no significant difference in PTV V110 (P> 0.05); The oars Intestinal bag V40, the left femoral head V30, the right femoral head V30, bone marrow V30, rectum V30 and bladder V45 showed no significant difference (P>0.05).Part two:radiotherapy position. By comparing the 20 cases of patients with prone position and supine position of target and dosimetric changes threaten the target area.In the two position of target PTV D2,intestinal bag V40,left femoral head V30, bone marrow V20 were 5120 ±163.3cGy and 5337 ±261.66cGy,3.01% (0%-8.26%) and 18.65%(11.43%-27.33%),11.23% (10.62%-11.94%) and 14.75% (13.25%-15.37%),61.02%(54.38%-66.8%) and 65.97%(65.42%-70.46%).PTV D2 and V40 in the small intestine, left femoral head V30, bone marrow V20, the differences were statistically significant (P< 0.05), the target area PTV D50,D98, V93, V110, bladder V45and rectum V30and the right femoral head V30 showed no significant difference (P>0.05).Conclusion:1. cervical cancer postoperative IMRT standardized target delineation can more accurately outline the irradiation range of regional lymph nodes in the pelvic cavity, omission of target area is reduced, the dose distribution of target PTV radiotherapy more accord with the requirement, the dose limiting organs without significant differences; 2. postoperative cervical cancer IMRT prone position endanger organs such as bowel bag, bone marrow, left femoral head was significantly better than that in the supine position, and radiotherapy dose distribution of PTV, there was no significant difference.