Objective:To assess the clinical application of bedside X-ray photography assistor (Patent No. 202 023 219 898.1) in neonatal bedside photography.Methods:From April 2021 to February 2022, a total of 180 pediatric patients were selected who underwent bedside chest X-ray photography in neonatal intensive care unit (NICU) of Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology. These patients were divided into contrpol group, consisting of 48 males and 42 females aged at (3.3 ± 2.0) d (0-10 d), and experimental group, including 50 males and 40 females aged (3.1±2.2) d (0-12 d). For chest photography, routine workflow was followed in the control group while in experimental group bedside photography protection and body position fixing device was used. The examination time, reshoot rate and image quality were compared between the two groups.Results:The diagnostic physician score and patient comfort score in the experimental group were higher than those in the control group, with statistically significant differences ( t = 3.98, 3.82, P < 0.001). The success rate in the experimental group was higher than that in the control group, with statistically significant difference ( χ2= 7.84, P < 0.05). The average time of examination in the experimental group was not significantly different from in the control group ( P>0.05 ). Conclusions:The application of bedside X-ray photography assistor in neonatal bedside photography can significantly improve the success rate and image quality and reduce the radiation dose to pediatric patients without significantly increased examination time, which is worthy of clinical application and promotion.

Objective:To analyze the clinical reliability of neonatal bedside photography protection and body position fixing device during neonatal bedside X-ray photography.Methods:A mobile X-ray diagnostic machine was used to project the phantom of children. The samples were divided into group A with conventional bedside photography mode, and group B using neonatal bedside X-ray photography protection device. X-ray diagnostic level dosimeters were placed at the projection and radiation sensitive sites, respectively. The three parts of the chest, pelvis and skull were used as the projection center, and the radiation dose to the projection site and the radiation sensitive site were collected and recorded, and the statistical analysis was carried out.Results:When the chest was taken as the center of the projection, the radiation doses to the lens of the eye, thyroid and gonad in the body model group B of children were 94.4%, 96.9% and 96.7% lower than those in the non-injected part of group A, respectively ( t=-152.55, -445.16, -129.07, P<0.05). When the pelvis was taken as the projection center, the radiation doses to the lens, thyroid and thymus in the body model group B were 85.5%, 87.1% and 94.9% lower than those in the non-projection part of group A, respectively ( t=-50.68, -194.18, -535.94, P<0.05). When the head was taken as the projection center, the radiation doses to thyroid, thymus and gonad in the body model group B were 99.3 %, 97.4 % and 94.3 % lower than those in the non-projection position of group A, respectively ( t=-1 859.97, -542.08, -66.26, P< 0.05). Conclusions:The use of neonatal bedside photography protection and position fixing device during neonatal bedside X-ray photography can significantly reduce the radiation dose to children in non-projected areas under the premise of ensuring image quality. At the same time, it can fix and protect the children, improve the success rate of examination, being worthy of clinical promotion.

Objective:To compare the image quality of turbo gradient and spin echo-BLADE diffusion weighted imaging (TGSE-BLADE-DWI) with that of readout segmentation of long variable echo-trains (RESOLVE) at the sellar region.Methods:From September 15 th, 2019 to February 15 th, 2020, 38 patients with suspected sellar abnormalities were enrolled prospectively to perform RESOLVE and TGSE-BLADE-DWI at a 3.0 T MR scanner in Department of Radiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology. Totally, 32 patients were identified with sellar lesions. The DWI images were evaluated subjectively and objectively. Two experienced radiologists scored images of the two DWI methods for anatomical structures (including the internal carotid arteries, optic chiasm, pituitary stalk and pituitary gland), lesion conspicuity, susceptibility artifacts, geometric distortions and overall image quality using a five-point scale respectively. Objective parameters on the images of the two DWI methods were analyzed, including lesion size, signal to noise ratio (SNR) and apparent diffusion coefficient (ADC). The consistency of subjective scores of two radiologists was tested by Kappa test. Paired t-test, Wilcoxon signed rank test, Kappa statistics were used for statistical evaluation. Results:TGSE-BLADE-DWI performed significantly better than RESOLVE in depicting the sellar anatomical structures, lesion conspicuity, geometric distortion and overall image quality (all P<0.05). There were no significant differences in SNR, maximum longitudinal diameter of lesions and ADC of lesions between the two DWI methods(all P>0.05). The maximum transverse diameter measured by TGSE-BLADE-DWI was significantly smaller than that of RESOLVE ( Z=3.31, P=0.001). Conclusions:Compared with RESOLVE, TGSE-BLADE-DWI is superior in depicting the anatomical structures, decreasing susceptibility artifacts and geometric distortions at the sellar region and effectively improves the image quality of DWI, which has great value in clinical applications.

Objective:To explore the value of monoenergetic imaging on dual-layer spectral detector CT combined with individual injection protocol of contrast medium in brain CT angiography (CTA).Methods:Seventy-six patients who underwent brain CTA on the Philips IQon dual-layer spectral detector CT and individual injection protocol of contrast medium in Union Hospital of Tongji Medical College, Huazhong University of Science and Technology from August to November 2020 were retrospectively analyzed. Objective and subjective evaluation of image quality was performed in conventional energetic images (conventional group) which derived from 120 kVp hybrid iterative reconstruction algorithm and 50 keV virtual monoenergetic images (test group) which derived from spectral reconstruction algorithm. The objective evaluation content included CT values, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of internal carotid artery and middle cerebral artery, CT values and standard deviation (SD) of brain parenchyma. The subjective evaluation was completed by two senior radiologists according to the 5-point scale, and the inter-agreement between two radiologists was evaluated by Kappa test. Paired t test or Wilcoxon rank test was used for analysis between two groups. Results:The SNR and CNR of both internal carotid artery and middle cerebral artery, as well as CT values of internal carotid artery, middle cerebral artery and brain parenchyma, were significantly higher in test group than that in conventional group (all P<0.001). The subjective scores of two radiologists for test group were both 5 (5, 5) points, and the subjective scores for conventional group were both 4 (4, 4) points. The subjective scores of the radiologists were in good agreement, and the Kappa values were 0.74 and 0.84 respectively. The subjective scores of test group were significantly higher than that of conventional group ( Z=-11.15, P<0.001). Conclusion:Monoenergetic imaging on dual-layer spectral detector CT combined with individual injection protocol of contrast medium can improve SNR, CNR and the image quality of brain CTA.

Objective:To investigate the value of the size-specific dose estimate (SSDE) on dose estimations of children's head CT scans.Methods:A retrospective study was conducted on plain head CT scans of 252 patients with the 64-row detector CT device of Discovery 750HD in the Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from January to September in 2019. The volume CT dose index (CTDI vol)values were recorded. The head circumference (HC), area, and CT value were measured using a self-developed computer program, and the water equivalent diameter (WED), size-specific conversion factors ( f293 and f220), and absorbed dose (SSDE 293 and SSDE 220) were calculated according to the AAPM reports 293 and 220.The patients were divided into three groups by the quartering meth odaccording to their HC(<47.8 cm, 47.8-52.7 cm, >52.7 cm)and four groups based on their ages(0-2, 3-6, 7-10 and 11-14 years old). The difference between parameters ( f220 and f293, SSDE 220 and SSDE 293、SSDE 293 and CTDI vol) were compared for different groups, and the correlation of HC with f293 and SSDE 293 was analyzed. Results:There was an overestimation of f220 by 11.11% ( t=252.61, P<0.05) compared with f293. SSDE 220 was overestimated by 10.31% ( t=228.21, P<0.05) compared with SSDE 293, and SSDE 293 was underestimated by 9.60% ( t=-31.34, P<0.05)compared with CTDI vol. For the three HC groups, SSDE 220 was overestimated by 8.54%, 10.37%, and 11.57% ( t=73.73, 438.58, 275.52, P<0.05)compared with SSDE 293, and SSDE 293 was underestimated by 1.30%, 9.79%, and 14.61% ( t=-1.91, -60.95, -47.64, P<0.05)compared with CTDI vol. For the four age groups SSDE 220 was overestimated by 8.45%, 10.00%, 10.57%, and 11.36% ( t=63.58, 232.29, 247.84, 302.95, P< 0.05)compared with SSDE 293, and SSDE 293 was underestimated by 1.49%, 8.27%, 10.63%, and 13.78% ( t=-1.83, -28.27, -37.30, -49.80, P< 0.05)compared with CTDI vol. Furthermore, HC was highly correlated with f293 and SSDE 293 ( r2=0.88 and 0.76, respectively, P< 0.05). Conclusions:The radiation dose in children′s head CT scanning can be more accurately estimated according to the AAPM Report 293, while it can be overestimated by CTDI vol. Meanwhile, the CT radiation dose can be patently overestimated with the AAPM Report 220 compared with Report 293.HC is closely correlated with f293 and SSDE 293 and it can be used to estimatee more accurately for SSDE and the radiation dose received by children during head CT scanning.

Objective:To study the feasibility that using size-specific dose estimation (SSDE) to estimate organ dose and effective dose in coronary CT angiography (CTA).Methods:Totally 421 consecutive patients with coronary artery CTA were included and retrospectively analized. All patients were scanned using the 3rd generation dual-source Force CT with prospectively ECG gated axis scan mode. The size specific dose estimation(SSDE) for each patient was conducted by calculate water equivalent diameters with Radimetrics. The organ doses of heart, lung, liver and breast, were estimated with Monte Carlo method. Patient-specific effective dose was calculated as a weighted sum of simulated organ doses with the coefficients from ICRP 103. Linear correlation analysis was used to validate the relationship between SSDE and organ doses as well as effective dose, and to derive coefficients for patient specific dose estimation. The mean error rate was used to evaluate estimation accuracy.Results:The CTDI vol, SSDE and effective dose were (16.8±8.7)mGy, (20.8±8.8)mGy and (4.4±2.9)mSv, respectively. The linear fitting formula for estimating organ dose based on SSDE were: Y=1.2 X-6.4 ( R2=0.91, P<0.05, mean error 0.1%) for heart, Y=1.4 X-7.4 ( R2=0.91, P<0.05, mean error 7.9%) for breast, Y=0.89 X-4.6 ( R2=0.86, P<0.05, mean error 8.3%) for lung, and Y=0.36 X-1.8 ( R2=0.64, P<0.05, mean error -17.9%) for liver. The linear fitting formula for estimating the individual effective dose based on SSDE were: Y=0.21 X-1.2 ( R2=0.92, P<0.05, mean error 0.2%) for men, Y=0.39 X-2.2 ( R2=0.93, P<0.05, mean error 1.7%) for women. Conclusions:In coronary artery CTA, the absorbed dose of the organs and patient specific effective dose could be estimated with SSDE and the corresponding conversion coefficients, which will help to achieve personalized assessment and precise management of patient radiation dose and risk in clinical practice.

Objective:To survey and supervise the risk of infection control and radiation safety in the radiological diagnostic workplace for COVID-19, and provide data support for the safety protection of radiographers and related staff.Methods:4 emergency hospitals for COVID-19 including 2 makeshift hospitals, module hospital and brick pattern hospital in Hubei province were performed for testing and evaluation of imaging performance and radiological protection for the 8 new installed CT scanners and places according to the national standards of WS 519-2019 and GBZ 130-2013. The infection control safety factors such as the layout of the equipment room were monitored and investigated. Two COVID-19 designated hospitals including general hospital and infectious disease specialized hospital were selected to carry out field investigation and sampling of environmental biological samples for 4 CT rooms. Then the samples were detected for the nucleic acid of novel coronavirus. The results of radiodiagnostic workplace overall arrangement, infection prevention and the nucleic acid testing were analyzed, and the biological safety reliability and risk point were evaluated.Results:The indicators of imaging performance and radiation protection for 8 CT scanners in emergency hospitals could meet the requirements of national standards.Each of 2 makeshift hospitals had 3 CT rooms with the area of 38.8 m 2 and 4 mm Pb equivalent thickness of protective shielding. The CT rooms in module hospital and brick pattern hospital were 20.0 m 2, and 35.8 m 2 in areas, with 4 mm Pb equivalent and 3 mm Pb equivalent thickness of protection shielding, respectively. The 8 radiological diagnostic workplaces of the emergency hospitals were designed and constructed based on " three zones with two passage ways" . The result of the nucleic acid test indicated that the positive samples were found at the multiple sites such as scanning bed, internal of gantry and ground touched by patients in CT scanning room. The areas such as console panel and ground were risked of pollution by the virus infected hands and feet of radiographers. In addition, the similar positive samples were found in the areas in scanning room with no touch of patients, such as observation window and air outlet. Conclusions:8 CT scanners and rooms in 4 emergency hospitals basically meet the requirements of imaging performance and radiation protection. The disinfection of COVID-19 radiodiagnostic workplace should be standardized.

Objective:To investigate the clinical value of third-generation dual-source CT with high pitch, 70 kV combined with 16 ml contrast agent in low radiation dose imaging of pulmonary embolism (PE).Methods:Eighty-three patients with suspected PE underwent CT pulmonary angiography were randomly divided into two groups: group A with 36 cases, 100 kV, 1.0 pitch, and 60 ml contrast agent; group B with 47 cases, 70 kV, 2.2 pitch, and 16 ml contrast agent. The volume CT dose index and dose length product of the two groups were recorded to calculate the effective dose E, and the CT values of enhanced pulmonary arteries, background noise, and muscles values were recorded to calculate signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). The overall image quality and the beam-hardening artifact of superior vena cava were subjectively evaluated on a 3-point scale. Results:There were no significant differences in gender, age, height, weight, BMI, proportion of PE, and CT values of enhanced pulmonary arteries at all levels ( P>0.05). The value E of group B was (0.76±0.13) mSv, significantly lower than that in group A [(1.91±0.54) mSv, Z=-5.23, P<0.001]. Although background noise of group B was significantly higher than that of group A ( Z=-4.99, P <0.001), SNR and CNR values of group B were significantly lower than those of group A ( Z=-4.56, -4.48, P<0.001), there was no statistically significant difference in the overall image quality scores between the two groups ( P>0.05). The beam-hardening artifact caused by superior vena cava in group B was significantly lower than that in group A ( Z=-5.15, P <0.001). Conclusions:The third generation dual-source CT with high pitch, 70 kV combined with 16 ml contrast agent can significantly reduce the interference of contrast agent beam-hardening artifact on the right and right superior pulmonary arteries to ensure the diagnostic image quality of PE, and effectively reduce radiation dose by 60% and total volume of contrast agent by 73%.

Objective:To investigate the application value of third-generation dual-source CT(3-G DSCT) low-dose scan mode combined with iterative reconstruction technology in the screening of COVID-19 and to evaluate the radiation dose.Methods:One hundred and twenty patients suspected of COVID-19 from December 2019 to February 2020 were retrospectively analysed and randomly divided into two groups (test group and conventional group, 60 patients in each). The parameters for test group included 3-G DSCT, Turbo Flash scan mode, CARE kV, with reference 90 kV, pitch 2.0, and ADMIRE algorithm, while those parameters for conventional group included the 128-slice CT, conventional spiral scan mode, 120 kV, pitch 1.2, and FBP algorithm. The CT values of aorta, spinal posterior muscle, and subcutaneous fat, the aortic noise, signal-to-noise ratio (SNR), and contrast noise ratio (CNR) were compared to evaluate the image quality between two groups. Two experienced doctors scored the image quality using a double-blind method, and compared the CT dose index volume (CTDI vol), dose-length product (DLP), and effective dose ( E) of the two groups. Results:The CT value of the aorta and spinal posterior muscle and the aortic SNR in the test group were (45.38±4.77), (53.41±8.44) HU, and 2.82±0.59, and significantly higher than those in the conventional group [(39.68±6.26), (42.66±6.32) HU, 2.58±0.61, t=5.608, 7.897, 2.162, P<0.05]. The aortic noise, CNR and subjective scores between the two groups had no significant difference( P>0.05). The CTDI vol, DLP, and E in the test group were (3.09±1.02) mGy, (107.57±32.81) mGy·cm, (1.51±0.46) mSv, significantly lower than those in the conventional group [(7.00±1.80) mGy, (261.65±73.93) mGy·cm, (3.66±1.03) mSv; t=-14.680, -14.756, -14.756, P<0.05]. Conclusions:In the screening of COVID-19, using low-dose scanning mode of 3-G DSCT combined with iterative reconstruction technology would provide diagnostic quality images and meanwhile effectively reduce the radiation dose and improve the SNR of the image.

Objective:To explore a low dose CT scanning method on novel coronavirus (COVID-19) pneumonia based on infection prevention and control.Methods:A total of 140 patients with confirmed novel coronavirus pneumonia in Xiehe hospital from January 20, 2020 to February 28, 2020 were undertaken CT scan and divided into low dose group and conventional dose group. The patients in low dose group(120 kV, 31 mAs) consisted of mild type(51), severe type(15) and critically ill type(4); and those in conventional dose group(120 kv, adaptive milliampere second) consisted of mild type(48), severe type(17) and critically ill type(5). The effective radiation dose, SNR and CNR of CT scan were compared between two groups. A senior and a middle radiologist made the image subjective quality scores, respectively.Results:The effective dose in low dose group was lower than that of conventional dose group( t=-48.343, P<0.05). There was no significant difference in SNR and CNR between two groups( P>0.05). For severe and critically ill patients, the score in low dose group was significantly lower than that in conventional dose group( t=-2.781, P<0.05). There was no significant difference in scores between two groups for mild patients( P>0.05). Conclusions:Low-dose CT scanning could meet the image quality needs for patients with COVID-19 and meanwhile significantly reduce the radiation dose.