To assure the clinical quality and requirement of CT shelter used in field environment, the factors related with the practical application were studied. The evaluation indicators of CT equipment were investigated. Based on the technical modification of vehicle shelter CT, the scanning conditions of shelter CT were analyzed. Moreover, the comparative study was done between shelter CT and common CT in hospitals. In result, in order to meet maneuverability application in the field, vehicle shelter CT was restrictive by the field conditions, traffic impacts and running requirement. The application of vehicle shelter CT was affected by the factors, such as mechanical stabilization, moving precision, power fluctuations and variations of temperature and humidity, etc. The results were helpful to improve the clinical quality of vehicle shelter CT and made a base for the quality control study in the future.
Humidity ; Temperature ; Tomography, X-Ray Computed ; instrumentation

Objective To analyze the impact of parotid's position and volume changing on radiation dose for head and neck cancer treated with TomoTherapy.Methods Totally 12 patients with head and neck cancer were treated with TomoTherapy.Before the treatment,the dose distribution was recalculated with MVCT images,which would obtain the parameters of position,volume and actual radiation dose for parotids.Results The volume of parotids in Plan2 was significantly lower than in Plan1,and the percentage reduction was 29.06％ and 31.78％ for left and right parotid,respectively (Z =6.77,3.06,P ＜ 0.05).Distance between the COM (center of mass) of parotids and the midline of body was significantly smaller in Plan2 than in Plan1,and the percentage reduction was 6.72％ and 6.19％ (t =5.14,5.80,P ＜ 0.05) at left and right side,respectively.Average dose and V26 for both parotids were higher than those in Plan1,increasing by an average of 37.74％,25.08％ (Z =-6.03,-5.31,P ＜ 0.05) for left parotid and 30.45％,19.33％ (Z =-5.43,-3.26,P ＜0.05) for right parotid,respectively.Conclusions The actual radiation dose to parotids was significantly increased during the radiation therapy for patients with head and neck cancer.There was a linear correlation between the decrease of distance between the COM of parotids and the midline of body and the percentage increase of parotids' radiation dose.No correlation between the reduction of parotids' volume and dose to parotids.In order to reduce the parotids' radiation dose,modification of treatment plan at the appropriate time is essential.

Objective:To investigate the clinical effect of minimally invasive plate osteosynthesis (MIPO) through anterolateral approach in treatment of middle-distal humeral shaft fracture.Methods:A retrospective case series study was conducted to analyze the clinical data of 21 patients with middle-distal humeral shaft fracture admitted to 7th Medical Center of Chinese PLA General Hospital from August 2015 to March 2018, including 12 males and 9 females, aged 18-68 years [(31.3±3.6)years]. All were closed fracture. According to AO classification, the fracture were classified as type A in 6 patients, type B in 10 and type C in 5. All patients were treated with anterolateral minimally invasive plate fixation. The operation time, intraoperative blood loss and hospital stay were recorded. The fracture healing was observed after operation. The visual analogue scale (VAS), University of California at Los Angeles (UCLA) shoulder rating scale, and Mayo elbow performance score (MEPS) were used to evaluate the effectiveness before operation and at 2 weeks, 3 months and 12 months after operation.Results:All patients were followed up for 12-26 months [(18.2±2.4)months]. The operation time was 50-82 minutes [(68.2±19.4)minutes], with intraoperative blood loss of 40-95 ml [(60.2±21.3)ml]. The hospital stay was 6-16 days [(6.8±1.2)days]. There was no iatrogenic vascular or nerve injury during operation. The patients with radial nerve injury before operation were all adventitia contusion. The nerve function returned to normal within 3 months after operation. All fractures were healed within 5-10 months [(5.3±1.2)months]. At 2 weeks, 3 months and 12 months after operation, the VAS [(3.6±0.8)points, (2.1±0.4)points, (1.8±0.3)points] was lower than that before operation [(8.3±1.6)points] ( P<0.05); UCLA shoulder rating scale [(31.2±1.5)points, (33.6±0.8)points, (34.6±0.5)points] was higher than that before operation [(28.4±2.3)points] ( P<0.05); and MEPS [(80.2±3.4)points, (93.4±2.2)points, (96.4±3.5)points] was higher than that before operation [(60.5±4.5)points] ( P<0.05). At the last follow-up, the UCLA shoulder rating scale and MEPS showed excellent results. Conclusion:For middle and lower humeral shaft fracture especially for the fracture line relatively distal to the shaft, MIPO technique through anterolateral approach can attain satisfactory results in terms of pain, range of motion of shoulder and elbow joint, and joint function.