Quantitative determination of cyanide residues in polysaccharide-protein conjugate vaccines based on flow injection analysis(FIA) with amperometric detector / 中国生物制品学杂志

@#Objective To develop and verify a method for determination of cyanide residues in polysaccharide-protein conjugate vaccines based on flow injection analysis(FIA)with amperometric detector.Methods After removing macromolecular substances in the samples by ultrafiltration,the cyanide residues were determined by a 3700 automatic chemical analyzer with the injection time of 35 s,injection volume of 200 μL,pump speed of 40%,sample cycle time of 140 s,ultraviolet wavelength of 312 nm and an Ampere detector.The developed method was verified for the specificity,matrix effect,linear range,limit of detection(LOD),limit of quantitation(LOQ),accuracy,presicion and stability.The cyanide residues in the polysaccharide derivative bulk(13 batches)and conjugate bulk(21 batches)of Haemophilus influenzae type b conjugate vaccine and group A and C meningococcal conjugate vaccine produced by 5 manufacturers were determined by the developed method.Results Blank samples showed no interference to detection;The recoveries of the matrix effector solution of Haemophilus influenzae type b conjugate vaccine polysaccharide derivative and conjugate bulk,group A and C meningococcal conjugate vaccine polysaccharide derivative and conjugate bulk were 97.4%,102.4%,96.8% and 99.8% respectively,with all CV values less than 15%;In the range of 0.312 5 ～ 80 ng/mL,cyanogroup concentration showed a good linear relationship with peak height with a regression equation of y = 133.13 x + 57.556,R2= 0.999 1;The LOD was 0.2 ng/mL,and the LOQ was 0.6 ng/mL.The average recoveries of the control solution were 108.9%,106.5%,103.5% respectively with RSD value of 6.4% in the groups added with 5,10 and 20 ng/mL of cyanogroup and the CV values of precision verification were all less than 15%;The average concentrations of the control solution injected 20 times continuously were 76,38,18and 5 ng/mL with all CV values less than 15%,when cyanogroup concentration was 80,40,20 and 5 ng/mL,respectively.Cyanide residues were detected in 13 batches of derivative bulk samples,while not in 2 batches of 21 batches of polysaccharide conjugate bulk samples,and were detected in the others.Conclusion The developed method had good accuracy,precision and stability,which might be applied to the quantitative determination of cyanide residues in polysaccharideprotein conjugate vaccines.

Value of dual-layer spectral detector CT in evaluating the intramedullary invasion of limb osteosarcoma / 中华放射学杂志

Objective:To explore the optimal keV value of the virtual monoenergetic image (VMI) for displaying the osteosarcoma by using the dual-layer spectral detector CT and to evaluate its application value in determining the extent of intramedullary invasion of osteosarcoma.Methods:From August 2021 to August 2022, 57 patients with conventional osteosarcoma of long bone confirmed by biopsy in Beijing Jishuitan Hospital, Capital Medical University were retrospectively analyzed. All patients completed dual-layer spectral CT enhanced examination before limb salvage surgery, and tumor segment resection specimens were obtained after surgery. Conventional 120 kVp image and VMI of 40, 50, 60, 70 and 80 keV were obtained by spectral CT examination, and the CT values of tumors, image noise were measured and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the corresponding images were calculated. The objective evaluation among the six groups of images were assessed with the Friedman test, and then determined the optimal keV value. The maximum distance between the intramedullary boundary of osteosarcoma and the adjacent articular surfaces was measured on the best keV VMI and the tumor segment resection specimens. The Wilcoxon signed rank test was used to find the differences and the Spearman correlation analysis was used to evaluate the correlation between the distance measured from the best keV VMI and the specimens.Results:There were significant differences in CT value, image noise, SNR and CNR between 40-80 keV VMI and 120 kVp conventional CT images ( P<0.05). The CT value, SNR and CNR of 40 and 50 keV VMI were better than 120 kVp ( P<0.001). The 50 keV VMI was chosen as the best keV VMI to measure the intramedullary extent of osteosarcoma. The distance measured from 50 keV VMI was 103.9 (80.4, 131.4) mm, while the distance measured from specimens was 113.5 (94.0, 142.0) mm, and the difference was statistically significant ( Z=-5.76, P<0.001). The 50 keV VMI measurements in 51 patients were smaller than the gross specimens, which underestimated the tumor intramedullary extent, with the difference was 11.1 (6.6, 13.8) mm. The Spearman correlation analysis demonstrated a high positive correlation of distance measured on gross specimens with the 50 keV VMI ( r s=0.960, P<0.001). Conclusions:Dual-layer spectral detector CT with 50 keV VMI is the best image to show the limb osteosarcoma. Compared with gross specimens, the distance measured from CT underestimated the intramedullary invasion range of limb osteosarcoma about 10 mm, but the two show a good correlation.

The effect of CT detector width and signal acquisition positions on image quality / 中华放射学杂志

Objective:To evaluate the influence of different detector widths and signal acquisition positions of wide-detector CT in different scanning modes on CT number and noise, and to provide a basis for reasonable selection of scanning modes and related parameters in clinical practice.Methods:The body dose phantom was scanned by GE Revolution CT. The scan was performed with detector widths of 40, 80 and 160 mm in sequential scanning mode and with detector width/pitch combinations of 40 mm/0.516, 40 mm/0.984, 80 mm/0.508 and 80 mm/0.992 in spiral scanning mode. The phantom was placed at the central and peripheral of the selected detector widths, and the adjacent positions between two axial scans. The images of the phantom were evaluated subjectively and the CT numbers and SDs were measured. The differences between the measured values at different imaging parameters were compared. The multi-group Friedman test was used to compare CT numbers and SD under different scanning parameters in sequential scanning mode, and the Wilcoxon test was used to compare CT numbers and SD in spiral scanning mode.Results:There was no statistically significant difference in the geometric shapes of the phantom images obtained at any combination of parameters. In sequential scanning mode, the differences at different detector widths were statistically significant (χ 2=14.00, P=0.001) with CT numbers at 40 mm and 160 mm greater than CT numbers at 80 mm ( P<0.05). The differences at different signal acquisition positions were statistically significant (χ 2=12.04, P=0.002) with CT numbers at peripheral and adjacent greater than CT numbers at central ( P<0.05). In spiral scanning mode CT numbers at detector width at 80 mm were greater than CT numbers at 40 mm ( Z=-2.10, P=0.036). For SD, the differences at different detector widths were statistically significant in sequential scanning modes (χ 2=8.17, P=0.017) with SD at 160 mm greater than SD at 80 mm ( P<0.05). The differences at different signal acquisition positions were statistically significant (χ 2=13.50, P=0.001) with SD at peripheral greater than SD at central ( P<0.05). In spiral scanning mode SDs at pitches 0.984 and 0.992 were greater than SDs at 0.516 and 0.508 ( Z=-2.66, P=0.008). There were no significant differences among other groups. Conclusion:The selection of scanning mode, detector width and signal acquisition position of wide-detector CT will affect the image CT numbers and SDs.

Diagnosis of pulmonary artery sarcoma and differential diagnosis of pulmonary embolism with double-detector spectral CT: a case report / 中国医师杂志

Objective:The differential diagnosis of pulmonary artery sarcoma (PAS) and pulmonary embolism (PE) by double-detector spectral computerized tomography (CT) provides a new way to improve the detection rate of PAS and reduce the misdiagnosis rate.Methods:In the way of retrospective study, the Philips Nebula Workstation (ISP) was used to reconstruct electron density map, iodine density map and spectral curve in the spectral CT plain scan and enhancement of the PAS patient. In the plain scan image, the low density areas of the ascending aorta and the right pulmonary trunk were selected to measure their electronic density values. In the chest enhancement image, the iodine density of PAS area and PE area were measured respectively, and the spectral curves of PSA area and PE area were compared.Results:The electron density of the ascending aorta and the right pulmonary trunk in the low density area of the PAS patient during the plain scan of spectral CT were 104.4% EDW (relative to the percentage of the electron density of water) and 102.2% EDW, respectively, which were lower than those in the normal ascending aorta area. The fusion image of mixed energy and electron density clearly reflected the scope of the lesion. The iodine density in PAS area was 1.89 mg/ml, and the iodine density in PE area was 0.03 mg/ml during the enhancement phase. The iodine uptake in PAS area was significantly higher than that in PE area. The slope of PAS region was 2.08, and the slope of PE region was -1.86. The slopes of the two spectral curves were inconsistent.Conclusions:The electronic density, iodine density and spectral curve measured by double-detector spectral CT may provide powerful imaging basis for the diagnosis of PAS and the differentiation of PAS from PE, which is helpful for the early diagnosis of the lesions, and also provide basis for the biopsy location of the mixed lesions of PAS and PE.

A method of automatic determination of salt iodine by iodine element detector / 中华地方病学杂志

Objective:To establish a method for automatic determination of iodine level in salt by arsenic-cerium catalytic spectrophotometry using an iodine element detector (hereinafter referred to as this method), and to provide reference for in-depth study of salt iodine detection technology.Methods:This method was used to determine the iodine level in salt, and the linear range, detection limit, precision, and accuracy (determination of salt iodine standard substance GBW10006y and GBW10007y, and addition recovery experiment) of this method were determined. The iodine level of 35 salt samples was determined by this method and redox titration method recommended by the national standard, and the results were compared.Results:This method had a good linear relationship within the range of 50 - 600 μg/L standard curve, the absolute value of the correlation coefficients was > 0.999 0, and the detection limit was 5.0 mg/kg. The relative standard deviation of iodine concentration in salt samples with low, medium and high iodine concentrations were all < 6.0%. The determination results of salt iodine standard substance GBW10006y and GBW10007y were within the given value ranges; three iodine concentrations (6.0, 10.0 and 30.0 mg/kg) were added to the salt samples, with an average recovery rate of 96.7% to 105.0%, and a total average recovery rate of 100.9%. The method comparison experiment showed that there was no statistically significant difference between the salt iodine determination results of this method and the redox titration method ( t = - 1.54, P = 0.132). Conclusion:This method has the advantages of high accuracy, good precision and wide linear range in determining salt iodine, and is suitable for the detection of large quantities of samples in salt iodine monitoring.

Determination of eight active components in Buyang Huanwu Decoction by HPLC-DAD-ELSD / 国际中医中药杂志

Objective:To establish an HPLC-DAD-ELSD method for the simultaneous determination of eight main active components in Buyang Huanwu Decoction, including hydroxysafflor yellow A, paeoniflorin, calycosin glycoside, ferulic acid, ononin, calycosin, fermononetin and astragaloside.Methods:Agilent Eclipse XDB-C18 column (250 mm×4.6 mm, 5 μm) was used with acetonitrile-0.1% formic acid as the mobile phase. The flow rate was 1.0 ml/min; the column temperature was 30 ℃; the detection wavelengths were 230 nm (paeoniflorin), 254 nm (calycosin glycoside, ononin, calycosin, fermononetin), 322 nm (ferulic acid) and 403 nm (hydroxysafflor yellow A); the drift tube temperature of the evaporative light scattering detector was 60 ℃; the carrier gas flow rate was 1.6 L/min.Results:Under these conditions, the separation of hydroxysafflor yellow A, paeoniflorin, calycosin glycoside, ferulic acid, ononin, calycosin, fermononetin and astragaloside was good, and the linear relationship was in line with the requirements ( r=0.994 0-0.999 9). The average recovery was 97.8% - 101.4% ( RSD was 1.28% - 3.70%). Conclusion:The method is simple, stable and reproducible, and can be used for the quality control of Buyang Huanwu Decoction.

Development of a portable radiation detector for nuclide identification based on CdZnTe / 中国辐射卫生

Objective To develop a portable nuclear radiation detector with low-energy γ-nuclide recognition capability for rapid measurement of the dose levels in low-energy radiation fields and identification of nuclides. Methods A digital multi-channel circuit was developed for a detector based on the room temperature semiconductor cadmium zinc telluride, nuclide recognition was achieved using an intelligent nuclide recognition algorithm, and the energy response function G(E) was used to calculate the real-time ambient dose equivalent rate H*(10). Results The portable spectrometer had a minimum detectable energy of 20 keV, and the typical energy resolution for low-energy X-rays was > 4.10% at 59.5 keV and 20℃, enabling accurate identification of 241Am nuclide. Conclusion The device has a good measurement performance for low-energy γ/X rays, effectively addressing the limitations of existing devices for monitoring low-energy radiation fields, and provide reliable technical methods for monitoring and emergency response in spent fuel reprocessing plants or nuclear material production plants.

Analysis of the influence of probe position on quality control test results of dental panoramic radiography equipment / 中国辐射卫生

Objective To quantitatively study the influence of changes in probe position on the quality control test results of dental panoramic radiography and to provide a reference for analyzing the sources of deviations in quality control test results. Methods Eight different models of dental panoramic X-ray machines were selected for this study. The film analysis method was used to determine the position of the central axis of the main beam on the image detector. The position of the probe was accurately controlled through an auxiliary moving device. The tube voltage, radiation output, and half-value layer of the useful beam were measured for positions at the center of the beam; 1 cm upward, downward, left, and right from the center of the beam; and 2 cm upward, downward, left, and right from the center of the beam. Results The tube voltage, radiation output, and half-value layer had a maximum value at the center of the beam, with a decrease in the value as the position deviated from the center. There were significant differences in the probe position sensitivity between different models of dental panoramic radiography equipment. A 2 cm deviation in the probe position resulted in an impact on the measured tube voltage of less than 5.3 kV (5.8%) for less sensitive equipment. A 2 mm deviation in the probe position resulted in an impact on the measured tube voltage of less than 5.4 kV (6.0%) for sensitive equipment. Conclusion The probe position can lead to deviation in the quality control test results of dental panoramic photography. Therefore, determining the position of the central axis of the main beam on the image detector for accurate positioning of the probe is crucial for quality control testing.

Optimal Parameters for Virtual Mono-Energetic Imaging of Liver Solid Lesions / 中国医学科学院学报

Objective To explore the optimal parameters for virtual mono-energetic imaging of liver solid lesions. Methods A retrospective analysis was performed on 60 patients undergoing contrast-enhanced spectral CT of the abdomen.The iodine concentration values of hepatic arterial phase images and the CT values of different mono-energetic images were measured.The correlation coefficient and coefficient of variation were calculated. Results The average correlation coefficients between iodine concentrations and CT values of hepatic solid lesion images at 40,45,50,55,60,65,and 70 keV were 0.996,0.995,0.993,0.989,0.978,0.970,and 0.961,respectively.The correlation coefficients at 40(P=0.007),45(P=0.022),50 keV (P=0.035)were higher than that at 55 keV,and the correlation coefficients at 40 keV(P=0.134) and 45 keV(P=0.368) had no significant differences from that at 50 keV.The coefficients of variation of the CT values at 40,45,and 50 keV were 0.146,0.154,and 0.163,respectively. Conclusion The energy of 40 keV is optimal for virtual mono-energetic imaging of liver solid lesions in the late arterial phase,which is helpful for the diagnosis of liver diseases.

Quality evaluation methods of Poria based on yield and content of alkali extracted polysaccharide / 中国中药杂志

To improve the quality control methods of Poria and develop and utilize its resources fully, alkaline extraction was used in this study to determine the yield and content of alkali-soluble polysaccharides of Poria. The alkali-soluble extracts of Poria were obtained according to the optimum extraction conditions on the basis of single-factor test, and 30 batches of samples were determined. The structure and chemical composition of the alkali-soluble extracts was characterized by high-performance gel permeation chromatography(HPGPC), Fourier transform infrared spectrometry(FT-IR), nuclear magnetic resonance(NMR) spectroscopy and high-performance liquid chromatography(HPLC) with 1-phenyl-3-methyl-5-pyrazolone(PMP-HPLC). The results showed that the content of the alkali-soluble extracts was in the range of 46.98%-73.86%. The main component was β-(1→3)-glucan, and its molecular mass was about 1.093×10~5. Further, the content of alkali-soluble polysaccharides of Poria was measured by UV-Vis spectrophotometry and HPLC coupled with the evaporative light scattering detector(HPLC-ELSD), and 30 batches of samples were measured. The results indicated that the content of alkali-soluble polysaccharides determined by UV-Vis spectrophotometry was in the range of 73.70%-92.57%, and the content of samples from Hubei province was slightly higher than that from Yunnan province, Anhui province and Hunan province. The content of alkali-soluble polysaccharides determined by HPLC-ELSD was in the range of 51.42%-76.69%, and the samples from Hunan province had slightly higher content than that from the other three provinces. The content determined by UV-Vis spectrophotometry was higher than that by HPLC-ELSD. However, the content determined by HPLC-ELSD was close to that of alkali-soluble extract, which could accurately characterize the content of alkali-soluble polysaccharides in Poria, and the method was simple and repeatable. Therefore, it is recommended that the quantitative analysis method for alkali-soluble extract and alkali-soluble polysaccharides by HPLC-ELSD be used in the quality standards of Poria in Chinese Pharmacopeia.

A comprehensive review on photon-counting computed tomography: Principles, technical hurdles and analysis of clinical applications / 生物医学工程学杂志

In recent years, photon-counting computed tomography (PCD-CT) based on photon-counting detectors (PCDs) has become increasingly utilized in clinical practice. Compared with conventional CT, PCD-CT has the potential to achieve micron-level spatial resolution, lower radiation dose, negligible electronic noise, multi-energy imaging, and material identification, etc. This advancement facilitates the promotion of ultra-low dose scans in clinical scenarios, potentially detecting minimal and hidden lesions, thus significantly improving image quality. However, the current state of the art is limited and issues such as charge sharing, pulse pileup, K-escape and count rate drift remain unresolved. These issues could lead to a decrease in image resolution and energy resolution, while an increasing in image noise and ring artifact and so on. This article systematically reviewed the physical principles of PCD-CT, and outlined the structural differences between PCDs and energy integration detectors (EIDs), and the current challenges in the development of PCD-CT. In addition, the advantages and disadvantages of three detector materials were analysed. Then, the clinical benefits of PCD-CT were presented through the clinical application of PCD-CT in the three diseases with the highest mortality rate in China (cardiovascular disease, tumour and respiratory disease). The overall aim of the article is to comprehensively assist medical professionals in understanding the technological innovations and current technical limitations of PCD-CT, while highlighting the urgent problems that PCD-CT needs to address in the coming years.

Simultaneous determination of five components in Anemarrhenae Rhizoma by HPLC-ELSD / 药学实践杂志

Objective To establish a method for the simultaneous determination of new mangiferin, mangiferin, artemisinin BⅡ, icariin and artemisinin A in Anemarrhenae Rhizoma by high performance liquid chromatography-evaporation light scattering detector (HPLC-ELSD). Methods The column was Agilent Poroshell 120 EC-C18. The mobile phase used acetonitrile-0.2% acetic acid water system with gradient elution. Column temperature was 30 ℃. Flow rate was 0.7 ml/min. Evaporative light scattering detector used nitrogen as atomizing gas. The atomizing gas temperature was 40 ℃ and the drift tube temperature was 90 ℃. The nitrogen volume flow rate was 2.00 L/min and the sample volume was 20 μl. Results The five components were able to achieve baseline separation. Neomangiferin, Mangiferin, Anemaponin BⅡ, Baohuoside I , Anemarrhena saponin AⅢwere determined as 24.1-386 μg/ml (r=0.999 3), 23.2-371 μg/ml (r=0.998 6), 54.2-867.2 μg/ml(r=0.995 6), 5.3-84.8 μg/ml (r=0.996 8), 10-160 μg/ml (r=0.998 9) respectively, which showed a good linear relationship within the concentration range. The average recovery rate of the five components was between 101.8% and 105.0%, and the repeatability RSD was less than 2.4%. The content of the above five components in Zhimu medicinal materials were 1.62%, 0.82%, 7.36%, 0.07%, 0.34%, respectively. Conclusion The method is simple, accurate, and highly sensitive, which could be used as the quantitative determination of multiple index components of Anemarrhenae Rhizoma.

A detection method for relative response of a detector matrix / 中华放射医学与防护杂志

Objective:To test the relative response of a detector matrix used for measuring of the dose distribution in radiotherapy in order to ensure the accuracy and reliability of dose distribution measurement result.Methods:The two adjacent detectors can be irradiated at the same radiation dose by translating the detector matrix. The relative response of each detector to the reference detector can be obtained by combining the recursive algorithm. At the same time, the measurement data at different test steps are corrected to the reference step by setting the reference step, which correct the influence on the relative response result caused by the variation of the radiation condition and the detector response.Results:Based on the actual test of a 32 × 32 detector matrix, the relative response of each detector of the detected detector matrix to the reference detector varied from 0.896 to 1.077, with the expanded uncertainty of the relative response result being 0.8% ( k=2). Conclusions:On the premise of no known distribution of a radiation field, the relative response relationship of each detector of a detector matrix can be obtained by this method accurately and expediently, which provides a basic method for the performance evaluation of the detector matrix. The same idea can also be used to determine the relative response relationship of other detector matrices for different measurement purposes.

The experimental study of the effect of detector combination on image resolution in wide-detector CT / 中华放射医学与防护杂志

Objective:To investigate the effect of different scanning modes, detector width and location in detector on high and low contrast resolution of wide-detector CT image.Methods:The Catphan600 phantom with high and low contrast resolution modules was scanned with GE Revolution CT at the same CTDI vol. The scans were performed with the detector widths of 40, 80 and 160 mm for sequential scanning mode and with the detector width/pitch combinations of 40 mm/0.516, 40 mm/0.984, 80 mm/0.508 and 80 mm/0.992 for spiral scanning mode. The resolution modules were placed at the adjacent region between two sequential scans, central and foot side edge in the longitudinal scanning range seperately. The subjective evaluation of the high and low contrast resolution was performed by two radiologists. Results:The high contrast resolution was 8 LP/cm at adjacent region between two sequential scans with the detector width of 80 mm or 160 mm in sequential scanning mode, and at the pitch of 0.5 in spiral scanning mode, while it was 7 LP/cm for the rest of detector combinations. The distinguishable diameter was 3 mm at 1% low contrast resolution at foot side edge with the detector widths of 80 mm or 160 mm in the sequential scanning mode, and it was 2 mm for all the other conditions. The distinguishable diameter was 2 mm at 1% low contrast resolution with the detector width of 40 mm and pitch 0.516 in the spiral scanning mode and it was worse with the wider detector and larger pitch.Conclusions:For the wide-detector CT, scanning mode, detector width, location in detector and pitches will affect the high and low contrast resolution to some degree. Appropriate selection should be done according to actual needs in clinical practice.

Clinical value of CT-based three-section formula in identification of Siewert types of adeno-carcinoma of esophagogastric junction / 中华消化外科杂志

Objective:To investigate the clinical value of computer tomography (CT)-based three-section formula in identification of Siewert types of adenocarcinoma of esophagogastric junction (AEG).Methods:The retrospective and descriptive study was conducted. The clinicopatho-logical data of 62 AEG patients who were admitted to two medical centers, including 33 patients from Peking University Cancer Hospital and 29 patients from the First Affiliated Hospital of Amy Medical University, between January 2019 and January 2021 were collected. There were 53 males and 9 females, aged (66±9)years. All patients underwent CT examination to obtain the coronal and axial images and determine the upper and lower edges of the tumor and the esophagogastric junction, which were imported into the formula for Siewert classification. Observation indicators: (1) results of CT examination and pathological examination; (2) consistence of judgements for CT examination between doctors; (3) consistence of judgements between CT examination and patholo-gical examination. Results of pathological examination came from intraoperative surgical observa-tion and postoperative histopathological examination. Measurement data with normal distribution were represented as Mean± SD, and count data were described as absolute numbers or percentages. The consistency coefficient Kappa ( κ) was used to evaluate the consistency of diagnosis between resear-chers. The κ≥0.75 was regarded as excellent consistency, 0.40< κ<0.75 as good consistency, κ ≤0.40 as poor consistency. Wilcoxon rank sum test was used to evaluate the statistical difference between results of the CT-based three-section formula method and the pathological examination. Taking the results of histopathological examination as standard, the sensitivity, specifi-city, accuracy and 95% confidence interval of the CT-based three-section formula method were calculated. Results:(1) Results of CT examination and pathological examination: all the 62 patients underwent CT examination successfully to obtain the coronal and axial images and determine the upper and lower edges of the tumor and the esophagogastric junction, which were used for Siewert classifica-tion. There were 3 cases with AEG of Siewert type Ⅰ, 47 cases with AEG of Siewert type Ⅱ and 12 cases with AEG of Siewert type Ⅲ according to doctor's judgement from the Peking University Cancer Hospital, and there were 3 cases with AEG of Siewert type Ⅰ, 49 cases with AEG of Siewert type Ⅱ and 10 cases with AEG of Siewert type Ⅲ according to doctor's judgement from the First Affiliated Hospital of Amy Medical University, respectively. After arbitration, there were 2 cases with AEG of Siewert type Ⅰ, 48 cases with AEG of Siewert type Ⅱ and 12 cases with AEG of Siewert type Ⅲ determined by the CT based three-section formula. There were 7 cases of stage T1, 10 cases of stage T2, 24 cases of stage T3, 14 of stage T4a and 7 cases of stage T4b of pathological T staging. There were 2 cases with AEG of Siewert type Ⅰ, 48 cases with AEG of Siewert type Ⅱ and 12 cases with AEG of Siewert type Ⅲ determined by pathological examination. (2) Consistence of judgements for CT examination between doctors: the consistency of Siewert classification determined by CT-based three-section formula between 2 doctors was good ( κ=0.74, P<0.001). (3) Consistence of judgements between pathological examination and CT examination: with Siewert classification determined by pathological examination as reference, the accuracy of Siewert classification determined by CT based three-section formula was 90.3%( κ=0.73, P<0.001). The sensitivity and specificity of CT-based three-section formula were 66.7%(95% confidence interval as 20.8%-93.9%) and 100.0%(95% confidence interval as 93.9%-100.0%) for AEG of Siewert type Ⅰ, 97.7%(95% confidence interval as 88.2%-99.6%) and 72.2%(95% confidence interval as 49.1%-87.5%) for AEG of Siewert type Ⅱ, 73.3%(95% confidence interval as 48.0%-89.1%) and 97.9%(95% confidence interval as 88.9%-99.9%) for AEG of Siewert type Ⅲ, respectively. Conclusion:The CT-based three-section formula can be used for identification of Siewert types of AEG, with a high accuracy.

Investigation of radiation protection status in non-medical radiation institutions in Fujian Province, China / 中国辐射卫生

@#<b>Objective</b> To investigate the number and categorical distribution of non-medical radiation institutions in Fujian Province, China, and to explore the current situation of radiation occupational hazards prevention and control and the occupational health management of radiation workers in employing units. <b>Methods</b> The industrial enterprises engaged in the application of nuclear technology in our province were investigated, and different types of employing units were selected to monitor the radioactivity level in the workplace. <b>Results</b> A total of 377 non-medical radiation institutions were reported in the province, with a total of 5221 radiation workers (except luggage detector units); 1246 radiation workers held radiation worker certificates, accounting for 23.87%; 5103 radiation workers carried out personal dose monitoring, accounting for 97.74%; 5061 radiation workers participated in radiation protection knowledge training, accounting for 96.94%; a total of 4895 (93.76%)radiation workers received physical examination. <b>Conclusion</b> Health supervision authorities in Fujian Province should strengthen the supervision of non-medical radiation institutions, further improve the level of occupational health management, and protect the health rights and interests of radiation workers to the maximum extent.

Design Concept of CT Plate Detector and CT Machine / 中国医疗器械杂志

Because the mobility ratio of thin film transistors is too low, it is recognized that flat detector can not be used in CT machine.The current research direction is to find the detector material with higher mobility ratio, but with little success. This study puts forward a new scheme to solve the core problem that limits the application of CT, which is the mobility of thin film transistors:by moving various TFT functions in the thin film transistor to the peripheral circuit, the restriction of the mobility of thin film transistor on the CT machine is completely overcome, and the reading speed of the flat panel detector becomes very fast, which can perfectly meet the requirements of the scanning speed of the CT machine.This will provide new research ideas for the application of flat panel detector in CT machine.

Characterization of Geiger-Müller radiation detectors response at the University of Costa Rica's Cyclotron Facilities / Caracterización de la respuesta de detectores de radiación Geiger-Müller en el Ciclotrón de la Universidad de Costa Rica

To ensure a reliable verification of a radiation detector, the right parameters for this response verification must be determined and a specific characterization on the detectors of interest must be performed. These were the main pillars of this study, where four Geiger-Müller at the University of Costa Rica's Cyclotron Facilities' main laboratories were studied and characterized using a 137Cs source. First, a verification of the inverse-square law was performed to corroborate the correct measurement by the detectors as the distance from a 137Cs source to the detectors was varied using a new design for a positioner support to ensure repeatability. This verification yielded a potential fit curve with and equation D=670635 x-1.961 (error percentage of 1.95%) and an R2 value of 0.9836. Then, using combinations of copper plates of widths 1.0 mm and 2.0 mm as attenuators between the source and the detectors, the mass attenuation coefficient for copper was obtained only as a reference value for future calibrations of the detectors. The result for this value was 0.040 cm2 /g. The results obtained in this study and the method developed to achieve these results will serve as a base for calibrations of the detectors at these facilities, which will ensure the safety of the patients and personnel in this building.

Para asegurar respuesta correcta de un detector de radiación, se deben determinar los parámetros correctos para esta verificación y debe realizarse una caracterización específica de los detectores de interés. Estos fueron los pilares principales de este estudio, donde se estudiaron y caracterizaron 4 detectores Geiger-Müller en los laboratorios principales del Ciclotrón de la Universidad de Costa Rica utilizando una fuente radiactiva de 137Cs. Primero, se realizó una verificación de la ley del inverso-cuadrado para corroborar la medición correcta de los detectores según se varía la distancia entre la fuente de 137Cs al detector utilizando un diseño nuevo de un soporte posicionador para la fuente que asegura la repetibilidad entre experimentos. Esta verificación resultó en una curva de ajuste potencial de ecuación D=670635x-1,961 (porcentaje de error de 1,95%) y un valor de R2 de 0,9836. Luego, utilizando combinaciones de placas de cobre de espesores 1,0 mm y 2,0 mm como atenuadores entre la fuente y los detectores, se obtuvo el coeficiente de atenuación másico para el cobre como un valor de referencia para futuras calibraciones de los detectores. Este resultado fue de 0,040 cm2/g. Los resultados obtenidos en esta investigación y el método desarrollado para lograr estos resultados servirán como una base para una futura confirmación metrológica calibraciones de los detectores en estos laboratorios, lo cual colaborará con la seguridad y protección radiológica de pacientes y trabajadores en este edificio.

The effect of environmental radiation of radiotherapy workplace on stereotactic radiation therapy plan dose verification using an Exradin W1 scintillator detector / 中华放射医学与防护杂志

Objective:To study the influence of environmental radiation of radiotherapy workplace on the stereotactic radiation therapy(SRT) plan absolute dose verification with plastic scintillator detector Exradin W1.Methods:The computed tomography (CT) image of the stereotactic dose verification phantom (SDVP) was scanned and imported into the treatment planning system. Three schemes, including 3 cm × 3 cm to 20 cm × 20 cm square gradient field irradiation, virtual planning target volume(PTV) non-coplanar arcs irradiation and 10 cases of volumetric modulated arc radiotherapy SRT (VMAT SRT) clinical plan verification, were measured with or without a home-made shield over the photodiode. Measurements were recorded to analyze the impact of environmental radiation on dose measurement under different conditions.Results:The noise effect of the photodiode increased with the the lager open field size, and decreased with the reduced distance between the photodiode and isocenter. The contribution of photodiode noise effect increase with the lager non-coplanar arc field size, with the largest up to 4.16%. As for the clinical SRT plan verification measurement, the relative difference between the SRT plan measurements and treatment planning system(TPS) before and after shielding were (1.39±1.05)% and (0.59±1.03)%, respectively ( t=-5.343, P < 0.05). and for W1 vs. A16 microchamber was (1.22±1.56)% and (0.42±1.42)%, respectively ( t=-5.414, P < 0.05). Conclusions:The measurements of Exradin W1 are in good agreement with the TPS result and the ionization chamber measurements, but its accuracy is easily affected by the environmental radiation of radiotherapy workplace. To measure non-coplanar radiation, the photodiode should be placed as far away as possible from the isocenter and be properly shielded, which can effectively improve the accuracy and stability of the measurement and provide a strong guarantee for clinical precision radiotherapy.

Application value of wide detector CT target scanning technique in the preoperative evaluation of pancreatic cancer / 中华胰腺病杂志

Objective:To explore the application value of wide detector multi-slice spiral CT target scanning technique in the preoperative evaluation of pancreatic cancer.Methods:The clinical data of 22 patients with pancreatic cancer who underwent pancreatic arterial contrast enhanced CT scanning and were diagnosed by pathology in the First Affiliated Hospital of Naval Medical University from September 2019 to October 2019 were analyzed retrospectively. The CT phantom experiment was carried out on the international standard phantom CATPHON500. By changing the scanning radiation dose, scanning mode and scanning field of view, the spatial resolution and density resolution of the image were compared and analyzed. The target scan technical parameters obtained from the experiment were applied to the late arterial phase of MDCT enhanced scan in 22 patients with pancreatic cancer. Executive current, volume scanning mode and small scanning field were used for scanning. The attenuation value (CT value) and noise value (SD value) of pancreatic cancer tissue and normal pancreatic tissue were measured at different phases, the attenuation difference and contrast signal-to-noise ratio (CNR) of the two tissues were calculated, the contrast difference between the two tissues was evaluated, and the CT values of celiac trunk, renal artery and vein, superior mesenteric artery and vein, splenic vein and portal vein were measured, and the display of tumor tissue and peripancreatic important vessels was evaluated.Results:In the phantom experiment, under the condition of the same radiation dose, the image quality of the volume scan mode was better than that of the spiral scan mode (1%@4 mm versus 1%@9 mm at 5 mGy and 1%@2 mm versus 1%@6 mm at 25 mGy). In comparison between pancreatic tumor and pancreatic tissue, the enhancement process of pancreatic tumor tissue was increased at first and then decreased, while that of pancreatic tumor tissue was slightly enhanced. The attenuation difference between pancreatic tissue and tumor tissue and CNR also increased at first and then decreased, reaching the maximum at the late arterial stage [(91.96±29.29)HU, 8.60±5.71]. The differences between each phase were statistically significant ( F values were 47.20 and 19.80 respectively, all P values <0.05). The evaluation of vascular variation and invasion showed that a better arterial phase image could be obtained on the late arterial target scan images, while taking into account the display of splenic vein, mesenteric vein and portal vein. Conclusions:The wide detector MDCT target scanning technique can improve the spatial resolution and density resolution of the image, greatly improve the contrast between tumor tissue and peripancreatic tissue and blood vessels, and provide more accurate tumor staging and resectability evaluation information for preoperative evaluation of pancreatic cancer.