Objective:To create AAPM TG 119 test plans for intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) in order to evaluate the accuracy of the United Imaging Healthcare′s URT treatment planning system (URT-TPS). The plans were delivered to the phantom using the United Imaging Healthcare′s URT-Linac 506C.Methods:The overall accuracy of IMRT and VMAT planning, measurement, and analysis were evaluated for four test geometries provided by American Association of Physicists in Medicine (AAPM) Task Group Report 119(TG-119) on multi-target, prostate, head and neck and C-shape (easy). The dose distributions were measured in the coronal plane. The point measurements were measured by a Farmer type ion chamber and fluence measurements were completed with film and Delta4 phantom, respectively. Measured planar dose distributions were analyzed using gamma index with criteria 3%/3 mm.Results:For IMRT and VMAT plans, the planning results matched the TG-119 planning results. Measured point doses of IMRT and VMAT were within 2.62% and 3.90% of the planned doses, respectively. Measured film dosimetry gamma values of IMRT and VMAT were> 97.50% and> 93.27%, respectively.Conclusion:Based on these analyses which were performed in line with the TG119 recommendations, it is evident that the URT treatment planning system and URT-Linac 506C have commissioned IMRT and VMAT techniques with adequate accuracy.

目的 了解雷神山医院医疗污水处理设施运行情况,为新冠肺炎定点传染病医院污水处理系统建设及运行提供参考.方法 通过现场调查和采样检测方法,对雷神山医院2020年3月1日-3月20日期间污水排放指标和运行数据进行监测与分析.结果 经处理后的医疗污水,各项关键指标均符合传染病医院污水的排放标准.雷神山医院单位病床日均污水量为0.509 m3,单位病床日污水量变化系数为1.24,满足1500张床位的医疗污水日处理能力,应达到1039～1134 m3.结论 在病种单一的特种传染病医院,医疗污水产生量相对稳定,排放指标符合要求.

目的:通过比较胃癌调强放疗中共面锁野计划与非共面锁野计划的剂量学差异,为临床放疗方案的选择提供参考依据.方法:选取10例胃癌患者分别制定9野的共面锁野调强和9野非共面锁野调强的治疗计划,比较机器跳数、靶区和危及器官等参数的剂量学差异.结果:两种计划均满足临床需求.非共面计划相比锁野计划仅小肠的V20显著降低且差异具有统计学意义.对于右肾脏、肝脏、脊髓和小肠的Dmean,非共面计划略低于共面锁野计划,但参数差异均无统计学意义.结论:非共面技术相比与锁野技术在9野胃癌放疗中并未取得明显优势,从技术层面考虑,非共面技术需要转床可能会引入一些误差,所以笔者建议使用共面锁野技术.

Objective To evaluate the clinical application value of a novel immobilization system in total marrow irradiation ( TMI) with MVCT image. Methods From 2016 to 2017, a retrospective analysis of the setup errors of 22 patients receiving TMI in two groups ( twelve patients were immobilized with the novel immobilization system in group 1, ten patients were immobilized with the combinatorial immobilization devices in group 2) was performed in this study on Zhongnan Hospital of Wuhan University. Two-sample t-test was used to analyze the differences of setup errors and the consistency of setup between two groups. Results In group 1, the setup errors on left-right, superior-inferior, anterior-posterior and rotation directions were ( 1.06±0.79) , ( 1.34±0.66) , ( 2.45±1.48) mm and ( 0.63°±0.65°) for the head and neck position, ( 1.58±1.13) , ( 2.38±1.99) , ( 2.05± 1.68) mm and ( 0.31°± 0.32°) for the chest position, ( 1.67± 1.24) , ( 3.88±2.20) , ( 1.96± 1.32) mm and ( 0.48°± 0.53°) for the pelvis position, and ( 0.95± 0.73) , ( 1.99± 1.35) , ( 3.66±2.13) mm and ( 0.24°±0.31°) for the lower limb, respectively. In group 2, the setup errors were ( 2.59±2.58) , ( 3.28±1.85) , ( 3.71±2.43) mm and ( 1.15°±1.18°) for the head and neck position, ( 4.38±3.69) , ( 5.64±3.78) , ( 2.72± 1.91) mm and ( 1.55°± 0.86°) for the chest position, ( 4.14± 2.97) , ( 6.97±3.68) , ( 2.21±2.26) mm and ( 1.23°±0.74°) for the pelvis position, ( 2.28± 1.15) , ( 5.97± 3.00) , ( 3.44±1.93) mm and ( 1.09°±0.94°) for the lower limb, respectively. The setup errors significantly differed between two groups on the left-right, superior-inferior and rotation directions for all positions ( all P<0.05) . The setup consistency significantly differed between two groups on the left-right, superior-inferior and rotation directions for the chest and pelvis positions ( all P<0.05) . Conclusion The novel immobilization system can significantly improve the setup accuracy and setup consistency, and enhance the precision of treatment for patients.

Objective To evaluate the dosimetric differences of TomoDirect (TD), TomoHelical (TH) and fixed-field intensity-modulated radiotherapy (FF-IMRT) plans for nasopharyngeal carcinoma (NPC). Methods Ten patients with NPC were enrolled in this study, and based on their CT images, three plans were designed for each patient, namely TH, TD and FF-IMRT plans. The dose distribution in target areas, organs-at-risk and normal tissues were evaluated. Furthermore, the dosimetric differences were compared among three plans by single factor analysis of variance, and compared in pairs by LSD method. Results For dosimetric parameters in target areas, TD plans didn't showed any statistical differences with TH and FF-IMRT plans. TD and TH plans showed significant improvement over IMRT plans in terms of OAR protection. Compared with FF-IMRT plan, the maximum dose of spinal cord in the other two plans was reduced by about 4 Gy (P=0.000);the mean dose of parotid gland was decreased by about 20％(P=0.000) and the D33, D50 and D60 were significantly lower (P=0.000);the mean dose of oral cavity and larynx were reduced by about 7 Gy and 20 Gy, respectively (P=0.000, 0.000);and the maximum dose of temporomandibular joint was lower by 10 Gy (P=0.000). However, FF-IMRT plan was superior to TD and TH plans in the protection of optic nerve and chiasm. Besides, TD plans showed certain advantages in the irradiation dose of the normal tissues outside the target areas. Conclusion For patients with NPC, the differences in dosimetric parameters between TD and TH plans were trivial, and both TD and TH plans showed significant improvements over IMRT plans, completely meeting the clinical requirements. TD technology is feasible to treat patients with NPC.

Objective:To discuss the diagnosis and differential diagnosis value of MSCT on pleomorphic adenoma and ade-nolymphoma of parotid by investigating the imaging manifestations of CT. Methods:the CT characteristics of 25 cases of pleo-morphic adenoma and 18 cases of adenolymphomas in the parotid gland confirmed by histological pathology in our hospital were studied retrospectively. Results:25 cases of pleomorphic adenoma of parotid occurred in young patients,most lesions were located in the non-posteriorinferior quadrant of parotid gland,regular or irregular in shape with a clear boundary and heteroge neous or inhonmogeneous (cystosolid) density with large cysts. 18 cases of adenolymphoma occurred almost all in old men,lesions in unilateral sides or bilateral sides,most lesions were located in the posterior inferior quadrant,with a regular shape and clear boundary heterogeneous or inhonmogeneous (cystosolid) density with fracture cysts. Small vessels could be seen in or around the tumor. There were singificant differences (P<0.05),between pleomorphic adenoma and adenolymphoma of parotid in age,gender, number of morbidity,the incidence ratio quadrant,morphology,the ways of cyst and small vessels in or around the tumor. Con-clusion:There are some characteristics of CT in pleomorphic adenoma and adenolymphoma of parotid. Imaging characteristics combined with clinical materials can improve the diagnosis and differential diagnosis on pleomorphic adenoma and adenolym-phoma of parotid gland.

Objective To discuss the imaging manifestations of CT of in the parotid gland,in order to improve the understanding of the CT imaging features of parotid adenolymphomas before operation.Methods The CT characteristics of 18 cases of ademolymphomas in the parotid gland confirmed by histological pathology were studied retrospectively.Results There were totally 24 lesions in 18 cases,of which 14 cases with unilateral lesions and 4 cases with bilateral lesions.23 lesions were located in the superficial lobe of the parotid gland and one lesion involved the superfical and deep parotid lobe simultaneously.22 lesions were located in posterior and inferior quadrant of parotid and 2 were other sites.23 lesions were round or oval and 1 was lobulated in shape.The margins in 22 lesions were well-defined,2(8.3％) lesions were ill-defined with ipsilateral parotid gland were increased in density.The density of 17 lesions were homogeneous (solid) and 7 lesions were inhonmogeneous (cystosolid) on plain CT.2 lesions showed slightly enhanced,9 lesions showed moderate enhancement,13 lesions showed significant enhancement,and the cystic region within the lesions showed no enhancement.Small vessels could be seen in or around the tumor in 21 lesions and no enlarged cervical lymph node was noted.Conclusion There were some characteristics of CT in parotid adenolymphoma.Imaging characteristics combined with clinical materials can play a helpful role in the preoperative diagnosis of parotid adenolymphomas.