Objective To develop a measurement method of dosimetric parameters for Hi-ART tomotherapy unit. Methods Percentage depth doses and beam profiles were measured using the dedicated mini water phantom, and compared to the results of 6 MV X-ray from Primus accelerator. Following the AAPM TG51 protocol, absolute dose calibration was carried out under SSD of 85 cm at depth of 1.5 cm for field of 5 cm ×40 cm. The output linearity and reproducibility were evaluated. The output variation with the gantry rotation was also investigated using 0.6 cm3 ion chamber in cylindrical perplex phantom and on-board MVCT detectors. Leaf fluence output factors were quantified for the leaf of interest and its adjacent leaves.Results The buildup depth was around 1.0 cm. The PDD values at 10 cm for Hi-ART and Primus were 59.7% and 64.7%, respectively. Varying with the field width, the lateral and longitudinal beam profiles were not so homogeneous as the Primus fields. The measured dose rate was 848.38 cGy/min. The fitted lint(sec) ,with a relative coefficient of 0. 999. The maximum deviation and standard deviation of output were 1.6% and less than 0.5% ; The maximum deviation and standard deviation of output changed by gantry angle were 1.1% and 0.5 % , respectively. Leaf fluence output factors did not increase significantly when leaves were opened beyond the two adjacent leaves. Conclusions Hi-ART Tomotherapy unit has a very high dose output and inhomogeneous beam profiles owing to its special design of the treatment head. This may be useful in dose calculation and treatment delivery.

Objective To explore the effect of melatonin(MT) on the behavior of rats treated with noise stress and the related bio-mechanism. Methods Fifty rats were randomly divided into a blank group,two experimental groups and two control groups. The blank group was untreated. The experimental and control groups were exposed to 120dB noise stress for 1 day or 3 days, 8 hours per day, and treated with 15 mg/kg melatonin by intraperitoneal injection,or the same volume of physiological saline 30 minutes before noise stress. After noise stress,the rats' behavior was measured by open field test, learning and memory ability of rats was investigated with the method of Morris water maze and then nitric oxide (NO), superoxide dismutase (SOD) and malondialdehyde (MDA) contents in cerebral cortex and hippocampus of the rats were measured by TBA and Griess method respectively. Results No matter noise stress time was 1 day or 3 days, the excitability and explorative behavior of the 2 experimental groups(total movement distance (TMD) (1322.50 ± 504.32) cm, (1819.55 ± 458.37) cm, faster movement time (FMT) (68.49 ± 23.90) s, (87.34 ± 16.01) s, distance to center (DTC) (63.56 ± 2. 75) cm, (60. 13 ±1.87)cm, inner toriod time(ITT) (7.87 ±2.06)s,(9.60 ±2.89)s) in the open field test decreased significantly compared with those of the control group (TMD (2042.03 ± 449. 19) cm, (2325.73 ± 384.90) cm,FMT (109.32 ±21.84)s,(124.65 ± 16.74)s, DTC (58.00± 1.53)cm,(55.05 ±5.13)cm, ITT (12.84 ±3.62) s, (14.92 ± 2.75) s, P ＜ 0. 05, P ＜ 0.01);the escape latency of the experimental groups (( 10. 69 ±3.37) s, (18.87 ± 4.74) s) in Morris water maze was significantly shorter than that of the control group (( 23.86± 7.66)s, (33.55 ± 7.20)s, P＜ 0.05, P＜0.01). The contents of NO or MDA in cerebral cortex and hippocampus of the experimental groups (NO in cerebral cortex (3.35 ± 0.40) μmol/gprot, (4.50 ± 0.41) μmol/gprot, NO in hippocampus (2.24 ±0.18) μmol/gprot,(3.15 ±0.21) μmol/gprot, MDA in cerebral cortex(1.34 ±0.44)nmol/mgprot, (2.39 ± 0. 18) nmol/mgprot, MDA in hippocampus (0. 13 ± 0. 07) nmol/mgprot, (0.53 ± 0. 10)nmol/mgprot) were lower than those of the control group (NO in cerebral cortex (3.35 ± 0. 40) μmol/mgprot,(5.03 ± 0.44)μmol/mgprot, NO in hippocampus (2.93 ± 0. 31) μmol/gprot, (3.38 ± 0.24) μmol/gprot, MDA in cerebral cortex (2.24 ± 0.26) nmol/mgprot, (4.21 ± 0.21) nmol/mgprot, MDA in hippocampus (0.47 ± 0.29)nmol/mgprot, (1.33 ± 0. 187) nmol/mgprot, P ＜ 0.05, P ＜ 0. 01) respectively and the contents of SOD in cerebral cortex and hippocampus of the experimental groups (in cerebral cortex (763.95 ± 214.36) U/mgprot, (491.33 ±35.85) U/mgprot, in hippocampus (817.02 ± 232.39) U/mgprot, (644.85 ± 28.02) U/mgprot) were higher than those of the control group(in cerebral cortex (556.50 ± 101.51) U/mgprot, (327.35 ± 30.54) U/mgprot, in hippocampus (279.74 ± 117.02) U/mgprot, (108.75 ± 15.52) U/mgprot, P ＜ 0.05, P＜ 0.01) respectively. Conclusion Melatonin is effective in improving the ability of learning and memory in the rats of noise stress,possibly by inhibiting the increase of NO and MDA and increasing the SOD activity in cerebral cortex and hippocampus of the rats.

To conduct environmental education intervention for medical students,a survey of environmental protection and sustainable development-related knowledge,attitudes,behavior were conducted through questionnaire among the medical students to explore the impact of envi-ronmental quality with creation of environmental education curriculum and the appropriate way for institutions of higher medical education.

With the development of modern medical technology,accurate resection of tumor and timely repair and repair of defective tissues and organs are important concerns in the field of tumor research.The precise excision of tumor,refers to the preoperative assessment of systemic and local detection based on detailed to personalized surgical planning,the use of precise operation in operation,ensure as much as possible while minimizing surgical trauma to patients after removal of the lesions,creating the optimal conditions of recovery for trauma patients.Repair and regeneration of defective tissues and organs refers to the deletion or damage of tissues and organs,and gradually resume its anatomical structure and function process under the action of a variety of cells,extracellular mechanisms and related regulatory factors.Then from the tumor resection,tumor resection and accurate regeneration after three point repair technology to change rapidly in the tissue of tumor plastic organ regeneration in tissue of origin.