[en] The RadCam 2000 gamma imaging system's software supplied by the manufacture cannot be run when the PC disconnected to the system's hardware, also cannot be used to analysis the results acquired, therefore, we have developed easyRadCam using Matlab GUI with the ability of generating the 'hot point' three-dimensional distribution by importing the results acquired, giving the counts distribution versus channel number. After the system be calibrated, we can get the energy spectrum, even the type of nuclides exist. (authors)

[en] Objective: To investigate the value of computed tomography pulmonary angiography (CTPA) in evaluation of pulmonary embolism (PE) after coronary artery bypass graft (CABG), and to explore the correlation between the lower extremity deep vein thrombosis and PE. Methods: Thirty-seventh patients with coronary atherosclerotic heart disease underwent coronary artery bypass surgery during February 2014 to January 2016 were retrospectively recruited. Because of clinical suspicion of postoperative pulmonary embolism, they were examined with CTPA. Color doppler ultrasound was performed for lower extremity deep veins. Using axial scanning, combined with MIP, MPR and VR image post-processing method, the position, number and patterns of pulmonary embolism were recorded. Using two-dimensional and color doppler flow imaging, the location and the number of emboli of lower extremity deep vein were determined. Fisher exact probability of fourfold table data was performed to analyze the correlation between the occurrence of PE and lower extremity deep venous thrombosis. Results: Pulmonary embolism was detected in 15 patients (40.54%) on CTPA images, including unilateral 13 cases, bilateral 2 cases, single 7 cases, multiple 8 cases, massive 4 cases (1 cases dead). Nine cases were characterized as pulmonary artery complete filling defect and 6 cases displayed central filling defect. The incidences of lobar artery embolism, segmental artery embolism, main arterial embolism, and incidence of subsegmental embolism were 16%, 34.44%, 13.33%, and 4.44%, respectively. The color doppler ultrasound examination showed 12 cases of deep vein thrombosis, all equal to or below the popliteal vein level, unilateral 8 cases, bilateral 6 cases, single 6 cases, and multiple 8 cases. The incidence of lower extremity deep vein thrombosis in patients with PE after off-pump CABG was 80.0%. There was correlation between the occurrence of PE and lower extremity deep vein thrombosis formation (P < 0.05). Conclusion: CTPA can make definite diagnosis of pulmonary embolism, while color doppler ultrasound examination can clearly diagnose lower extremity deep vein thrombosis and can help in tracing the embolus source. Combination of the two methods is of important value to diagnose acute PE after off-pump CABG and trigger treatment. (authors)

[en] Silicon PIN diodes have been widely used as personal and areal dosimeters because of their small volume, simplicity and real-time operation. However, because silicon is neither a tissue-equivalent nor an air-equivalent material, an intrinsic disadvantage for silicon dosimeters is that a significant over-response occurs at low-energy region, especially below 200 keV. Using a energy compensation filter to flatten the energy response is one method overcoming this disadvantage. But for dose compensation method, the estimated dose depends only on the number of the detector pulses. So a weight function method was introduced to evaluate gamma dose, which depends on pulse number as well as its amplitude. (authors)

[en] Much interest in severe accident research has been attracted since Fukushima accident, which indicates that severe accident could possibly happen although the probability is extremely low. Although many researches have been conducted in severe accident progression simulation and emergency condition analysis, it is still necessary to do some research on emergency conditions of severe accident that have not been sufficiently analyzed. In this paper, a 50mm small break loss of coolant accident (SBLOCA) in cold leg along with station blackout (SBO) initiated severe accident was simulated using MELCOR code. The model which was built for this study consists of 46 control volumes (27 in primary loop, 17 in secondary loop, 1 in containment and 1 in environment) and 52 flow paths. Before the calculation, steady state was achieved in order to check the model. Main parameters of the model were compared with that of nuclear power plant (NPP). Relative error was acceptable, so the model could be used to simulate the accident. Based on the accident scenario, high pressure safety injection (HPSI) and low pressure safety injection (LPSI) were assumed to be lost because of loss of on-site and off-site power, as well as main feed water and auxiliary feed water of the steam generators. The accumulator is the only emergency cooling coolant source, since it is passive. The calculation ended with failure of lower head, and the response of the containment was not studied. Emergency condition progression of the accident was obtained, including start of uncover of the active core, start of zirconium-water reaction, failure of fuel clad and failure of the lower head. Thermal-hydraulics response of reactor was analyzed. In future work, research on emergency condition of other severe accidents could be conducted. (author)

[en] The temperature and radiation tolerance of detectors, used in reactor core, high energy experiment and outer space, is the focus of everyone's attention. SiC and GaN radiation detectors are presently developed for use in these conditions. Due to its wide bandgap, high displacement energy and electron mobility, SiC is currently the most promising alternative material to silicon for temperature and radiation hard detector devices, in future. (authors)

[en] The α value for radiation protection optimization is estimated with the combination of economic value of individual life and average loss of lifetime caused by radiation. Considering the current situation of china, four methods are used to estimate α base value: gross domestic product (GDP) method, governmental compensation regulations method, major accident compensation and willingness method. The α base value of China with a range of 50000-610000 RMB is recommended. (authors)

[en] Visual Reality (VR) technology is the computer-simulation of the real environment. A wide range of jobs can be done by use of VR system, such as training of workers, all kinds of virtual experimentals and operations, real-time calculation/display of data and so on. At present, VR has been used successfully in many aspects of radiation protection in some institutes abroad, such as training of workers, ALARA design and analysis, calculation and display of radiation field/dose distribution, etc. The VR has just been applied in the field of radiation protection in China. The experiencees learned shows that the VR technology application in radiation protection can both reduce operational cost and doses to worker effectively. (authors)

[en] An Operational Intervention Levels (OILs) is a type of action level that can be used immediately and directly (without further assessment) to determine the appropriate protective actions and other response actions on the basis of environmental measurements. This paper described the development of the concept of OILS and its evolvement as well as the default values of different versions and corresponding protective actions. Taking the Fukushima accident as an example, the differences of the earlier and late OILs versions in application of emergency actions were analyzed and compared. (authors)

[en] Method for prognosis of severe accident response progress initiated by large break loss of coolant (LBLOCA) was established, based on transient analysis for M310 reactor. The primary loop is rationally simplified based on characters of LBLOCA. The mass and energy conservation equations were solved approximately and the classical formula were used to prognose emergency condition progression. The active core area was divided into 4 radial rings and 10 axial levels, i.e. 40 cells. Experimental correlations were used to calculate heat transfer in the core and the cladding temperature was obtained. Then the core condition can be judged according to the cladding temperature. A code for prognosis of LBLOCA initiated emergency condition could be developed based on the method established in the paper. (authors)

[en] Objective: To evaluation the image quality and radiation dose of combining low kV, low concentration contrast agents and with iterative reconstruction in CT coronary angiography (CTCA). Methods: Ninety cases (52 males, 38 females; age 56.72 ± 14.51 years) were randomly equally divided into groups of A, B and C (30 cases in each group). The contrast agent concentrations of the three groups were: group A 270 mgI/mL, group B 350 mgI/mL, and group C 370 mgI/mL. Group A tube voltage 100 kV, group B and group C tube voltage 120 kV. Tube current were 200∼250 mAs. We used 4 points method to evaluate the quality of the images. The CT values at the entrances of left and right coronary arteries and the ascending aortic root were measured. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the images were calculated to evaluate the image quality objectively. At the same time, the CT dose index, dose length product (DLP) and contrast injection were recorded. The radiation dose and iodine dose were calculated respectively. The analysis of variance with Fisher's Least Significant Difference (LSD) post hoc was used to test the differences in age, DLP, effective dose, signal intensity, noise, CNR, and SNR among the three groups. Gender, subjective scores of image quality were checked by χ². Results: There was no significant difference in gender, age, height, body mass, body mass index among the 3 groups (P > 0.05). Total of 1210 (98.94%) coronary artery segments fulfilled diagnostic requirements in 3 groups. Among the 3 groups, the images quality of the coronary arteries showed no significant difference (χ² = 4.56, P = 0.325). There was no significant difference in CT value, SNR and CNR at entrances of left and right coronary arteries and ascending aorta roots among the 3 groups (P > 0.05). The total DLP, effective dose and iodine dose in group A were significantly lower than those in group B and C (P < 0.05), which decreased by 27.58%, 27.58% and 21.27% respectively compared with group B, and decreased by 28.21%, 28.21% and 24.83% respectively compared with group C. Conclusions: Low kV, low concentration contrast agent and iterative reconstruction in CTCA can obtain comparable image quality to conventional CTCA, while significantly reducing the radiation dose and the administration of iodine dose. (authors)