[Model construction and software design of computed tomography radiation system based on visualization].

The Monte Carlo N-Particle (MCNP) is often used to calculate the radiation dose during computed tomography (CT) scans. However, the physical calculation process of the model is complicated, the input file structure of the program is complex, and the three-dimensional (3D) display of the geometric model is not supported, so that the researchers cannot establish an accurate CT radiation system model, which affects the accuracy of the dose calculation results. Aiming at these two problems, this study designed a software that visualized CT modeling and automatically generated input files. In terms of model calculation, the theoretical basis was based on the integration of CT modeling improvement schemes of major researchers. For 3D model visualization, LabVIEW was used as the new development platform, constructive solid geometry (CSG) was used as the algorithm principle, and the introduction of editing of MCNP input files was used to visualize CT geometry modeling. Compared with a CT model established by a recent study, the root mean square error between the results simulated by this visual CT modeling software and the actual measurement was smaller. In conclusion, the proposed CT visualization modeling software can not only help researchers to obtain an accurate CT radiation system model, but also provide a new research idea for the geometric modeling visualization method of MCNP.

[A comprehensive review on photon-counting computed tomography: Principles, technical hurdles and analysis of clinical applications].

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.

PHANTOM EXPERIMENTAL STUDY ON PATIENT DOSES OBTAINED FROM 320-MULTIDETECTOR-ROW COMPUTED TOMOGRAPHY IN WHOLE-BRAIN PERFUSION SCAN.

This study aimed to precisely evaluate organ dose and effective dose (E) obtained from a 320-multidetector-row computed tomography (CT) scanner in brain perfusion scans and to estimate the conversion factor (k) between E and dose length product (DLP). A total of 270 thermoluminescent dosemeters were implanted in a male anthropomorphic phantom to measure air kerma. The ratios of mass-energy absorption coefficients were used to convert air kerma into organ doses. The organ doses ranged from 0.01 to 150 mGy. Doses in brain, salivary glands and red bone marrow were relatively high, and dose in eye lens reached about 110 mGy. The resulting effective dose was 5.30 mSv. The resulting conversion factor k = (0.0022 ± 0.0002) mSv·(mGy·cm)-1 was not significantly different from that of 0.0021 mSv·(mGy·cm)-1 reported for head CT scan in ICRP Publication 102.

[Design and Implementation of Medical Equipment Rational Deployment Information System Based on ASP.NET].

Based on ASP.NET framework, The Intelligent Estimated System for Rational Deployment of Medical Equipment (MERDIS) is designed and developed with SQL Server 2012 database and C# language. The system is used to realize the rational deployment suggestions and evaluation of medical equipment in hospitals. The system input the data of hospital medical equipment and clinical pathway into the database, and then feedback the deployment information to users which are calculated by big data information, so as to achieve the purpose of giving rational deployment of hospital medical equipment.

[Risk Control of UPS Power Supply for Medical Equipment].

OBJECTIVE: Putting forward that the risk of using UPS for medical matching is easy to be ignored by managers. METHODS: The method of UPS inspection was designed and used in hospital. RESULTS: The qualified rate of UPS for equipment matching was 66.7% and the problems were corrected. Based on the Internet of Things technology, the UPS monitoring technology was prospected. CONCLUSIONS: It is effective to control the risk of UPS by recognizing the risk of using UPS and specifying the strategy.

STUDY ON A SPECIFIC TEST METHOD FOR DOSIMETRIC CHARACTERIZATION OF ULTRA-WIDE DETECTOR COMPUTED TOMOGRAPHY.

The purpose of this study was to establish a specific test method for dosimetric characterization of wide-beam computed tomography (CT). For a wide beam, the dose distribution curve and the area of the curve were obtained by using pencil-like ionization chamber, a long CT dose profiler probe, a head phantom and a body phantom. The absolute dose conversion coefficient was multiplied to obtain the total integration integral of the absolute dose distribution, and then the computed tomography dose index (CTDI) value under any wide beam condition was obtained by dividing the collimation width. It was calculated that the absolute dose conversion coefficient was 1.135 under the narrow beam of 8 mm. To a 160 mm-wide beam, the value of CTDI was 7.57 mGy/100mAs after normalized in the head 80 kV CT scanning, and it was 9.80 mGy/100mAs after normalized in the body 120 kV CT scanning. The specific test method solves the problem that the previous measurement method underestimates the CTDI value.

CONSTRUCTION AND APPLICATION OF BREP PHANTOM FOR CHINESE WOMEN OF CHILDBEARING AGE IN RADIATION PROTECTION.

The purpose of this study is to construct boundary representation (BREP) phantom for Chinese women of childbearing age, to estimate the external radiation dose and to analyze radiation protection scheme. The BREP phantom for Chinese women of childbearing age was constructed by image segmentation, 3D reconstruction, non-uniform rational B-spline surface construction and voxelization. The photon-irradiated organ absorbed dose-conversion coefficients (DCCK) of the three female specific organs and the photon effective dose-conversion coefficient (ECCK) were calculated by Monte-Carlo method. The results showed that age, body fat-tissue thickness, direction and area of irradiation, organ location and volume all affected the dose of women specific organs when receiving medical exposure. In the case of ensuring the quality of the diagnosis, radiation protection for female specific organs can be achieved by organ dose modulation techniques and reducing exposure area or volume.

[Research on Risk Control of Hysteroscopy and Laparoscopy Based on Cloud Computing].

This paper discusses the use of Medatc System for the inspection and failure statistics of hysteroscopy and laparoscopy equipment. We add up our hospital one year of hysteroscopy and laparoscopy repair failure about 200 cases, more than 20 cases of patrol inspection. The equipment is inspected by professional quality control tools. The purpose is to summarize experience, improve maintenance efficiency, reduce the risk of using instruments, and serve clinical departments well.

[Research on Quality Evaluation System of Ultrasound Diagnostic Equipment Maintenance].

In order to improve the quality of medical equipment after-sales service quality and improve the quality of medical equipment maintenance, this paper discusses the establishment of an evaluation index system to evaluate the quality of ultrasonic diagnostic equipment. From the three aspects of maintenance results, maintenance process and maintenance coverage, the quality of the post-maintenance quality of hospital ultrasound diagnostic equipment manufacturers is objectively evaluated.

A survey of pediatric CT doses in the Shanghai metropolitan area.

The purpose of this study was to evaluate computed tomography (CT) doses in child examinees at different ages throughout the Shanghai metropolitan area. The head and body CT dose indices (CTDIs) of 50 CT scanners were tested by phantom measurements using standard imaging protocols. The values of CTDIw, CTDIvol and dose length product (DLP) were calculated and saved in a table along with the parameters of routine head and chest scans for different age groups of children and adults. The effective doses were estimated from the K-factors by age and DLP. The CTDIvol, DLP and effective dose for multi-detector row CT (MDCT) in children during routine head scans were larger than those for single-detector row CT (SDCT) and dual-detector row CT (DDCT). The CTDIvol, DLP and effective dose for MDCT and DDCT in children during routine chest scans were lower than those for SDCT. Radiation risks are higher for children in CT examinations compared to adults.

[Application of Quality Control Circle Activity in CT Quality Control Management].

To explore the effect and experience of quality control circle(QCC) in quality control testing for CT scanners, the quality control circle group was set up to determine the theme of quality control circle, and the causes of the failure of the quality control testing for CT scanners were analyzed, then the corresponding corrective measures were formulated and carried out. After the activity of the quality control circle, the qualified rate of CT quality control testing in the second level 2nd Class of public hospitals and private hospitals in Shanghai increased from 40.6% to 86.1%. By conducting quality control circle activities, we found the problems existed in the quality control testing of CT scanners, and put forward many corresponding corrective measures and solutions which finally improved the qualified rate of CT quality control testing.

[Design and Application of High-risk Pregnancy Monitoring & Warning Internet Platform Based on Internet of Things].

Through illustrating the designing of high-risk pregnancy maternal-fetal monitoring system based on the internet of things, this paper introduced the specific application of using wearable medical devices to provide maternal-fetal mobile medical services. With the help of big data and cloud obstetrics platform, the monitoring and warning network was further improved, the level-to-level administration of high-risk pregnancy was realized, the level of perinatal health care was enhanced and the risk of critical emergency of pregnancy decreased.

[CT Quality Control Test from the Second Level 2nd Class Hospitals in Shanghai].

The purpose of this study is to assess the present situation about the overal performance quality of CT scanners from Second Level 2nd Class hospitals and private hospitals in Shanghai. The test and evaluation methods refer to Specification for Quality Assurance Test for Computed Tomography X-ray Scanners (GB 17589­2011). A total of 62 CT scanners from 59 hospitals were tested. The mean value of high-contrast resolution was 6.8 lp/cm, low contrast detectability was 2.4, CT number of water was 3.0 HU, noise was 0.43% and uniformity was 2.3 HU. In quality control tests, 20 of 62 CT scanners were qualified, and the percent of pass was only 32%. The equipment aging and lack of preventive maintenance were main reasons for performance degradation of CT scanners.

Organ and effective dose evaluation in coronary angiography by using a 320 MDCT based on in-phantom dose measurements with TLDs.

The purpose of this study is to estimate the organ and effective dose (E) from computed tomography coronary angiography (CTCA) on a 320-MDCT scanner. Radiation dose was estimated for the prospectively ECG-gated CTCA in a male phantom. A total of 451 chips of thermoluminescent dosimeter were implanted in the phantom for measuring the organ doses. The effective doses were calculated using measured organ doses and the tissue-weighting factors. The dose length product (DLP) values were recorded and used to develop the conversion coefficient k = 0.017 mSv•(mGy•cm)(-1) (E/DLP). In a 3-beat acquisition, the organ doses ranged from 0.24 to 71.55 mGy, and the doses in breast, bone surface, oesophagus, and lung were higher than 20 mGy. The effective doses in 2-beat and 3-beat acquisition were estimated to be 14.3 and 24.3 mSv. More beats of acquisition led to higher radiation dose. The reported k values for chest CT scan can be used to roughly estimate the E value from CTCA for 320 MDCT.

Evaluation on the environmental radioactivity in Shanghai city during the normal operational condition of Qinshan nuclear power station.

The objective of this work was to evaluate the impact of environmental radioactivity in Shanghai from the operation of Qinshan Nuclear Power Station (QNPS). The levels of terrestrial gamma radiation and radioactivities in the drinking water, main food and soils in the Jinshan area where is only 38 km far away from the QNPS were continuously measured in the past 19 y. Both the levels of terrestrial gamma radiation and the radioactivities in the samples were on the normal background levels. No significant changes were found before and after the running of QNPS. The annual public exposure to the terrestrial gamma radiation was estimated to be ∼0.1 mSv, and the annual exposure from intakes of (90)Sr and (137)Cs in food was ∼0.5 µSv. In the past 19 y, no significant impact on the environmental radioactivity in Shanghai was observed due to the operation of QNPS.