With the rapid development of intensity modulated radiation therapy (IMRT) technique,the accuracy of radiotherapy has improved,while the pretreatment dose verification has become more complex.Although the experimental measurements,a widely used way to perform dose verification,is accurate and effective,its time-consuming and labor-intensive is still a challenge for physicist.The independent dose verification method such as the depth dose-off axis ratios (OAR) empirical model,Clarkson integral model,convolution model and Monte Carlo model,could partially solve these problems effectively when the accuracy is ensured within a certain range.This approach could save physicists' time to conduct dose recalculation and plan check,and has become the hotspot in the world.This paper,therefore,mainly introduces the correction-based and the model-based independent dose verification methods,and briefly discusses the development of dose verification for IMRT plans.

OBJECTIVE To investigate the bacterial distribution and the extent of drug resistance in ICU patients,and offer the first-hand information to the clinical preventive and therapeutic countermeasures. METHODS The antimicrobial susceptibility tests to 28 commonly used antibiotics were performed using the ATB Expression of Bio-Merieux with K-B method.The ESBLs were detected by the disk diffusion tests and the confirmatory tests,and the MRSA,MRCNS,and VRE were also tested at the sametime. RESULTS Totally 264 strains were isolated from the 201 positive samples,among them 192 strains were Gram-negative bacteria,43 strains were Gram-positive ones,and 29 strains were fungi.The percentage of these three groups were 72.7%,16.3% and 11.0%,respectively.The main strains of the Gram-negative bacteria were PAE,ABA,KPN,ECO and SMA,and of the Gram-positive bacteria were EC,SAU and CNS.The major strain of fungi was C.albicans.The pathogens tested showed high drug resistance.The Gram-negative bacteria showed tendency of sensitivity to IPM,AZT,CAZ,FEP,SFC,AMK and CIP,and the Gram-positive bacteria to VAN,SXT,RIF and NIF.For KPN and ECO,the percentage of strains producing ESBLs were 64.7% and 64.3%.And the percentage of MRSA,MRCNS,VRE were 80%,66.7% and 22.2%,respectively. CONCLUSIONS It was showed that the major pathogens infected the ICU patients are Gram-negative bacteria,and the pathogens show the high drug resistance.Doctors should pay more attention to analyze the bacterial resistance profile in order to decrease the incidence of drug resistance and use the antibiotics properly.

In vivo dosimetry (IVD) is currently the most direct and effective means of quality assurance.The electronic portal imaging device (EPID) has been widely used for IVD verification owing to its favorable dosimetric properties.In recent years,an increasing number of EPID-based IVD studies have emerged around the world.The purpose of this paper is to give an overview of the present progress in EPID-based IVD studies,and to provide a reference for the subsequent application of EPID in IVD.

Objective To compare the effect of intravenous resuscitation with sodium pyruvate (Pyr) Ringer solution against lactated Ringer solution on hemodynamic and organ functions during shock stage in dogs with burn.Methods 28 Beagle dogs were subjected to 50％ total body surface area (TBSA) burn,and they were divided into three groups:burn injury without fluid resuscitation (N R,n =8),Ringer lactate solution(RL,n =10),and Pyr Ringer solution (RP,n =10).They were given intravenous fluid resuscitation according to Parkland formula 30 minutes after burn.The hemodynamics,organ functions and mortality were observed in conscious state before burn injury,and 2,6,8,12,24 hours after burn injury.Results Within 24 hours after burn,all the dogs in NR group died,and those in RL and RP groups were all alive.At 2 hours after burn,the mean arterial pressure (MAP),cardiac index (CI),dp/dt max of left ventricular contractility were significantly reduced in NR,RL and RP groups compared with those before injury [MAP(mmHg,1 mmHg =0.133 kPa):45.33 ± 7.78 vs.141.67 ± 5.98,91.33 ± 10.25 vs.142.33 ± 6.16,98.67 ± 9.54 vs.142.83 ±5.47; CI (mL·s-1·m-2):8.17 ±0.83 vs.48.34 ±3.33,16.84 ±2.17 vs.47.34 ± 1.67,19.00 ± 1.50 vs.47.34 ± 1.33; dp/dt max (mmHg/s):426.83 ± 51.91 vs.1 372.50 ± 39.61,594.00 ± 88.23 vs.1 363.83 ± 44.92,645.00 ±66.82 vs.1 395.83 ± 19.49,all P＜0.05],and the systemic vascular resistance (SVR) and alanine transaminase (ALT),creatinine (Cr),serum MB isoenzyme of creatine kinase (CK-MB),diamine oxidase (DAO) were significantly higher [SVR (kPa·s ·L-1):1 322.50 ±36.37 vs.281.45 ± 8.84,777.50 ±41.84 vs.289.72 ± 6.70,571.40 ±40.01 vs.286.27 ±8.66; ALT (U/L):89.50 ±4.11 vs.40.57 ±3.63,89.25 ±4.88 vs.37.92 ± 2.62,86.30 ±5.61 vs.38.47 ±3.50; Cr (μmol/L):75.62 ±4.61 vs.41.58 ±2.78,77.00 ±5.92 vs.46.55 ± 3.17,74.13 ±2.56 vs.45.65 ± 1.83; CK-MB (kU/L):13.122 ±0.282 vs.1.557 ±0.009,8.885 ±0.272 vs.1.497 ± 0.009,8.692 ± 0.180 vs.1.490 ± 0.005; DAO (kU/L):2.26 ± 0.14 vs.0.25 ± 0.02,1.50 ± 0.07 vs.0.25 ± 0.01,1.37 ± 0.07 vs.0.25 ± 0.02,all P＜0.05].All parameters in NR group kept on worsening till death,while hemodynamic and organ functions of two intravenous resuscitation groups were gradually improved,CI,SVR and DAO in RP group were significantly superior to those of RL group from 2 hours on after burn (all P＜0.05),and dp/dt max and CK-MB in RP group were significantly better than those of RL group from 6 hours on after burn [dp/dt max (mmHg/s):1 082.33 ± 63.59 vs.1 018.60 ± 47.36,CK-MB (U/L):7 898.70 ± 255.74 vs.8 438.70 ± 442.00,all P＜0.05],and MAP (mmHg) was significantly better than that of RL group at 6 hours (124.67 ± 9.39 vs.114.33 ± 9.16,P＜0.05),and Cr (tμmol/L) was significantly better than that of RL group from 24 hours on after burn (53.42 ± 4.99 vs.60.77 ± 3.11,P＜0.05).Conclusion The Pyr Ringer solution was superior to the Ringer lactate solution in improving hemodynamic and organ functions for intravenous resuscitation in dogs with 50％TBSA full thickness burn.

Objective To investigate the predictive value of dose?volume histograms ( DVHs ) of organs at risk ( OARs ) including the bladder, rectum, and small intestine in volumetric modulated arc therapy ( VMAT) plans for cervical cancer. Methods A total of 100 VMAT plans for cervical cancer were assigned into the learning group. The correlation of the anatomical information with the V30 , V40 , and V50 values of the bladder, rectum, and small intestine was evaluated in the group. The support vector regression ( SVR) algorithm was used to establish the correspondence between the anatomical information and the DVHs of OARs. The DVHs of OARs in the verification group containing 20 VMAT plans were predicted based on the anatomical information. Results The DVHs of the bladder, rectum, and small intestine were likely to be influenced mainly by the spatial relationship between these OARs and target volume. In the verification group, the prediction errors of V30,V40 and V50 by SVR algorithm were-2.4%±3. 5%,-2.5%±3. 8%, and-1.5%±4. 9% for the bladder, 0.5%±2. 6%,-1.5%±5. 1%, and-2.0%±7. 4% for the rectum, and-2.9%± 5. 3%, 2.7%±7. 7%, and 5.3%±11. 1% for the small intestine, respectively. Conclusions After learning the correlation between the anatomical information and the DVHs of OARs from prior VMAT plans for cervical cancer, SVR algorithm can precisely predict the DVHs of the bladder, rectum, and small intestine based on the anatomical information.

AIM: To investigate the effect of electro-acupuncture (EA) at Zusanli (ST36) on proinflammatory factors induced-multiple organ dysfunction in rats with sepsis. METHODS: Sixty four male Wastar rats were used to develop the sepsis model by cecal ligation and puncture (CLP). The animals were randomly divided into 4 groups (n=16 in each group): CLP+EA (CLP/EA), CLP+sham EA (CLP/SEA), vagotomy+ CLP+SEA (VA/CLP/SEA) and vagotomy+CLP+EA (VA/CLP/EA). Zusanli point (ST36) was electroacupunctured with constant voltage (2-100 Hz, 2 mA for 0.5 h) 20 min after CLP surgery. Bilateral cervical vagotomies were performed in rats in VA/CL/SEA and VA/CLP/EA groups. Twelve hours after CLP, animals were sacrificed and liver, kidney and jejunum were harvested for evaluating the contents of tumor necrosis factor-α (TNF-α), myeloperoxidase (MPO) and diamine oxidase (DAO). The rate of water content (WCR) of the organs was determined. At the same time, the plasma levels of alanine aminotransferase (ALT) and creatinine (Cr) in each group were also detected. RESULTS: The levels of ALT and Cr in plasma, as well as TNF-α, MPO and WCR in organ tissues were markedly lower, and the activity of DAO in jejunum tissue was obviously higher than that in CLP/SEA group at 12 h after CLP (all P<0.05). The levels of ALT, Cr, TNF-α, MPO and WCR in VA/CLP/SEA group and VA/CLP/EA group were significantly higher, the activity of DAO was obviously lower than that in CLP/SEA group (all P<0.05). No statistical difference in all above measurements between VA/CLP/EA group and VA/CLP/SEA) group was observed (all P>0.05). CONCLUSION: The results indicate that EA at Zusanli point obviously decreases the levels of TNF-α in liver, kidney and jejunum tissues after CLP, and alleviates the tissue edema and dysfunction of those organs. Vagotomy decreases or eliminates the effects of EA, suggesting that activation of cholinergic anti-inflammatory pathway is one of the main mechanisms to induce the effects of EA at ST36 on CLP sepsis.

Objective To find a method to improve the range accuracy of moving target such as peripheral lung tumors, since a single CT snapshot may not be accurate during the treatment process.Methods A simple harmonic motion phantom, embedded with a cube and a circular ball, was used to simulate the tumor motion. Individualized moving targets were scanned 24 times with different amplitudes and frequencies. Then the images were fused from every 1, 2 or 3 sets of CT scans. The GTV volume variation of circular target and the length variation of the cube target along the z axis were contoured and analyzed. Results As motion amplitude increased, the maximum of both circular target volume and cube target length was increased, while the minimum of the factors was decreased. Motion frequency affected the target volume less than amplitude. For a cube target with the length of 3.3 cm at stationary phase, when motion frequencies was 20 and motion amplitude was 2 cm, the maximal length was 2. 4 times of the minimal length (5. 1 cm vs. 2. 1 cm). When it came to the cube target groups fused from every 1,2 and 3 sets of CT scans, the average length and standard deviation were (3.77 ± 1.20) cm, (4.18 ±0. 91)cm and (4.52 ±0. 59) cm, respectively. With the increase of fused scan number, targets became bigger, the standard deviation decreased, and the change of center positions was decreased. Conclusions The motion amplitude, frequency and the number of CT scans are the main factors affecting target definition, though, the optimized scanning phase is not certained. When 4DCT and respiration gating technique are not available,the efficient and practical method to solve this problem is to scan the target three or more times and fuse them in planning system, which will generate a larger, more reproducible GTV volume for moving targets.

Independent check is one of the key measures of quality control (QC) in radiotherapy and is essential for the assurance of radiotherapy accuracy.In recent years,with the application of computer-aided system,the automaticity of independent check,as well as its accuracy and efficiency,increases.Meanwhile,QC has evolved from a device-centered to a process-centered program.Therefore,independent check has been increasingly systematic and specific.This review gives a brief summary of the implementation and development of independent check.

Stereotactic radiotherapy (SRT), also known as stereotactic ablative radiotherapy (SABR), includes stereotactic radiosurgery and stereotactic body radiotherapy (SBRT). This technique has the characteristics of large single fractional dose, few fractions, high equivalent biological doses, and rapid fall off-target doses. It can be implemented by relatively special equipment such as Gamma knife, Cyberknife, Tomotherapy and Vero 4D RT system, etc. In many cases, SBRT technique is employed based on linear accelerators. SRT differs from conventional radiotherapy in terms of the plan design and plan evaluation. Consequently, it is necessary to discuss the differences and provide guidance for clinical application and research.

Objective To investigate the difference of lung and target volume and dosimetry characteristics features of deep inhalation breathing holding-active breathing control (ABC) and the four dimensional CT (4D-CT) free breathing in stereotactic body radiation therapy (SBRT) technology for patients with lung cancer.Methods 10 patients with pulmonary malignant tumor who were proposed SBRT treatment were selected,and received CT under free breath (FB-CT),4D-CT scan under quiet respiration (4D-CT) and active breathing control CT scan (ABC-CT),respectively.With SBRT technology under the same condition designed four corresponding plans,FB-CT,ABC-CT,4D-CT and 4D-CT0 which was the end inspiratory phase of 4D-CT respectively.The lung volume(V),PTV,V5,V20,mean lung dose(MLD) and normal tissue complication probability(NTCP) of four treatment programs were counted and compared.Results Compared with FB-CT,V,PTV,V5,V20,MLD and NTCP of ABC-CT were 51.48％,-65.34％,-42.64％,-56.62％,-40.22％ and-98.53％ (t=-7.14 to6.16,P＜0.05);PTV,V5,V20,MLD and NTCP of 4D-CT were-40.14％,-16.90％,-37.16％,-17.85％ and-90.96％ (t =0.54 to 3.22,P＜0.05);PTV,V5,V20,MLD and NTCP of 4D-CT0 were-68.98％,-30.21％,-48.49％,-37.45％ and-95.82％ (t=1.32 to 5.46,P＜0.05),respectively.Compared with FB-CT,the lung volume of 4D-CT and 4D-CT0 had no statistical difference (P ＞ 0.05).Conclusions ABC-CT methods have ideal clinical characteristics,with larger double lung volume,smaller artifacts of image,and higher target matching precision.ABC-CT methods reduce the dose of normal lung tissues significantly.