Objective To evaluate the penumbra of a new multileaf collimator equipped with Elekta Synergy accelerator. Methods The penumbra were derived from beam profiles measured in air and water using PinPoint ion chamber with PTW MP3 water phantom. Variations of penumbra with X-ray beam energy, depth in water, and leaf position were investigated. Results The penumbra in air for 6 MV X-ray was 2 mm less than that at depth of maximal dose in water. The penumbra of leaf side was 1 mm less than that of the leaf end. The penumbra had close relationship with beam energy, depth in water and leaf position. Penumbra was increased with beam quality and water depth. The leaf position had great influence on the penumbra. Conclusions The penumbra of the multileaf collimator is related to its original design and radiation delivery technique. Special considerations should be taken into during treatment planning.Regular measurement should be performed to guarantee the delivery quality.

BACKGROUND:At present,plant-derived absorbable hemostats are mainly imported,so it is necessary to develop domestic alternatives that are not inferior to similar imported products. OBJECTIVE:To investigate the hemostatic effect of oxidized regenerated cellulose hemostatic material on a model of minipig liver hemorrhage. METHODS:A total of 24 Bama minipigs were selected and randomly divided into three groups.In the sham operation group(n=6),only an open operation was performed,and the damaged side of the liver was removed and put back in situ.In the experimental group(n=12),the liver hemorrhage model was established,and the oxidized regenerated cellulose hemostatic material was applied to the wound.In the control group(n=6),commercially available absorbable hemostatic gauze was used on the wound after establishing liver hemorrhage models.Hemostatic time and blood loss were recorded.The venous blood of the minipig anterior cavity was collected at different time points before and after modeling,and the blood routine and liver and kidney functions were analyzed.Hematoxylin-eosin staining and Masson staining were performed at 2,6,and 14 weeks after modeling.The main organs were observed by histopathology at 14 weeks after modeling.A liver ultrasound examination was performed at different time points after modeling to observe the degradation and absorption of materials. RESULTS AND CONCLUSION:(1)There was no significant difference in intraoperative hemostatic time and blood loss between the experimental group and the control group(P>0.05).(2)The monitoring results of blood biochemical indexes demonstrated that the levels of aspartate transaminase and glutamic pyruvic transaminase in the three groups were higher 24 hours after modeling than before modeling,and the indexes basically recovered to the normal levels 72 hours after modeling.There were no significant differences in blood biochemical indexes such as liver and kidney functions,blood glucose and inflammatory factors among the three groups(P>0.05).(3)Hematoxylin-eosin staining and Masson staining of histopathology revealed that 2 weeks after surgery,granulation tissue formation and a large amount of collagen fiber deposition were observed on the liver wounds of the two groups,and there were obvious fibrous hyperplasia zones and inflammatory cell infiltration,and the wound healed well.14 weeks after modeling,the liver wounds of two groups of minipigs exhibited mild fibrous hyperplasia zone,collagen fiber deposition and a small amount of inflammatory cell infiltration,complete material degradation,and the healed wound.Hematoxylin-eosin staining showed no significant pathological changes in major organs.(4)Ultrasonic examination demonstrated that the materials of both groups were degraded gradually with the extension of implantation time,and most of them were degraded and absorbed by 56 days after molding.(5)The results confirm that the oxidized regenerated cellulose hemostatic material can effectively prevent liver wound hemorrhage in minipigs,and the hemostats are safe and reliable.

Objective:To analyze the 6-year operation faults of PHILIPS Brilliance big bore CT, identify the common problems, make corresponding maintenance plans, reduce the incidence of failures, and carry out simulation prediction of the occurrence rate of failures in the next few years.Methods:The failure data of Brilliance big bore CT from June 2012 to June 2018 were collected, and the curve estimation function in SPASS 19.0 software and the pareto diagram were used to analyze the relationship between the number of failures, time and failure types, and the prediction was made.Results:A total of 28 faults occurred during the 6-year opeation of Brilliance big bore CT. During the first half year, five times of faults occurred with the highest fault rate and then tended to stabilize. The linear function model was obtained using the curve estimation: y=-0.033 x+ 2.099( y for the number of fault, unit for times, x for the unit of time for half a year), the model of R2=0.003. In the next three years, approximately twice faults occurred within half year. The pareto chart showed that 16 faults occurred during data collection, including 3 faults in the treatment bed and 3 faults in the power supply system, respectively. The accumulative ratio of the above three faults was 71.4%, which were the main fault sources. Conclusion:The fault statistical analysis of Brilliance big bore CT is helpful for department maintenance personnel to better understand CT, develop effective maintenance programs, reduce the occurrence of faults, and predict the incidence of faults in the future.

OBJECTIVETo compare the efficacy and safety of 5 mg perindopril arginine salt and 4 mg perindopril tert-butylamine salt for patients with mild to moderate essential hypertension.

METHODSThe study was designed as multicenter, randomized, double-blind, active controlled trial with two parallel groups enrolling 524 participants with mild to moderate essential hypertension. After 2-week run-in period, 186 patients were enrolled and randomly treated with 5 mg perindopril arginine salt and 183 patients were enrolled and randomly treated with 4 mg perindopril tert-butylamine salt. The random sequence was generated by the I.R.I.S., and a balance was made in each center. After double-blind treatment for 8 weeks, the dose could be doubled for patients with uncontrolled BP ((SBP) ≥ 140 mmHg (1 mmHg = 0.133 kPa) or diastolic blood pressure (DBP) ≥ 90 mmHg) and patients were treated for another 4 weeks.

RESULTSThe sitting SBP was similarly decreased by (19.9 ± 17.2) mmHg in perindopril arginine group and (18.5 ± 14.7) mmHg (P = 0.000 5) in perindopril tert-butylamine group post 8 weeks treatment. Dose was doubled in 109 patients (59.9%) in perindopril arginine group and 116 patients (63.7%) in perindopril tert-butylamine group. At 12 weeks post therapy, the sitting SBP decreased by (19.8 ± 16.2) and (19.6 ± 16.3) mmHg respectively in the 2 groups. The decrease of sitting DBP was also similar in both groups (-12.0 ± 10.0) mmHg and (-11.0 ± 8.9) mmHg (P < 0.000 1), respectively. The control rate or response rate was also similar between the two groups (control rate over 8 weeks was 38.5% vs. 31.3%, 95% CI (-2.6-16.9), control rate over 12 weeks was 36.3% vs. 35.7%, 95% CI (-9.3-10.4), response rate over 8 weeks was 64.3% vs. 63.2%, 95% CI (-8.8-11.0), response rate over 12 weeks was 65.9% vs. 64.8%, 95% CI (-8.7-10.9)). Incidence of adverse events was low and similar in both therapy groups.

CONCLUSIONSThe results show that perindopril arginine salt 5 mg is as efficient as perindopril tert-butylamine 4 mg on lowering BP for patients with mild to moderate essential hypertension. Both drugs have good safety profile and are well tolerated by patients in this cohort.

Antihypertensive Agents ; Arginine ; Blood Pressure ; Butylamines ; Double-Blind Method ; Essential Hypertension ; Humans ; Hypertension ; Perindopril ; Sodium Chloride