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OBJECTIVE: To understand the status of pre-procedural safety practices in radiological examinations at radiology residency training institutions in various Asian regions. METHODS: A questionnaire based on the Joint Commission International Accreditation Standards was electronically sent to 3 institutions each in 10 geographical regions across 9 Asian countries. Questions addressing 45 practices were divided into 3 categories. A five-tier scale with numerical scores was used to evaluate safety practices in each institution. Responses obtained from three institutions in the United States were used to validate the execution rate of each surveyed safety practice. RESULTS: The institutional response rate was 70.0% (7 Asian regions, 21 institutions). 44 practices (all those surveyed except for the application of wrist tags for identifying patients with fall risks) were validated using the US participants. Overall, the Asian participants reached a consensus on 89% of the safety practices. Comparatively, most Asian participants did not routinely perform three pre-procedural practices in the examination appropriateness topic. CONCLUSION: Based on the responses from 21 participating Asian institutions, most routinely perform standard practices during radiological examinations except when it comes to examination appropriateness. This study can provide direction for safety policymakers scrutinizing and improving regional standards of care. ADVANCES IN KNOWLEDGE: This is the first multicenter survey study to elucidate pre-procedural safety practices in radiological examinations in seven Asian regions.

Purpose: Monte Carlo (MC) simulation is an important technique that can help design advanced and challenging experimental setups. GATE (Geant4 application for tomographic emission) is a useful simulation toolkit for applications in nuclear medicine. Transarterial radioembolization is a treatment for liver cancer, where microspheres embedded with yttrium‐90 (90Y) are administered intra‐arterially to the tumor. Personalized dosimetry for this treatment may provide higher dosimetry accuracy compared to the conventional partition model (PM) calculation. However, incorporation of three‐dimensional tomographic input data into MC simulation is an intricate process. In this article, 3D Slicer, free and open‐source software, was utilized for the incorporation of patient tomographic images into GATE to demonstrate the feasibility of personalized dosimetry in hepatic radioembolization with 90Y. Methods: In this article, the steps involved in importing, segmenting, and registering tomographic images using 3D Slicer were thoroughly described, before importing them into GATE for MC simulation. The absorbed doses estimated using GATE were then compared with that of PM. SlicerRT, a 3D Slicer extension, was then used to visualize the isodose from the MC simulation. Results: A workflow diagram consisting of all the steps taken in the utilization of 3D Slicer for personalized dosimetry in 90Y radioembolization has been presented in this article. In comparison to the MC simulation, the absorbed doses to the tumor and normal liver were overestimated by PM by 105.55% and 20.23%, respectively, whereas for lungs, the absorbed dose estimated by PM was underestimated by 25.32%. These values were supported by the isodose distribution obtained via SlicerRT, suggesting the presence of beta particles outside the volumes of interest. These findings demonstrate the importance of personalized dosimetry for a more accurate absorbed dose estimation compared to PM. Conclusion: The methodology provided in this study can assist users (especially students or researchers who are new to MC simulation) in navigating intricate steps required in the importation of tomographic data for MC simulation. These steps can also be utilized for other radiation therapy related applications, not necessarily limited to internal dosimetry. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to measure the absorbed doses in selected organs for prospectively ECG-triggered coronary computed tomography angiography (CCTA) using five different generations CT scanners in a female adult anthropomorphic phantom and to estimate the effective dose (HE). Materials and Methods: Prospectively ECG-triggered CCTA was performed using five commercially available CT scanners: 64-detector-row single source CT (SSCT), 2 × 32-detector-row-dual source CT (DSCT), 2 × 64-detector-row DSCT and 320-detector-row SSCT scanners. Absorbed doses were measured in 34 organs using pre-calibrated optically stimulated luminescence dosimeters (OSLDs) placed inside a standard female adult anthropomorphic phantom. HE was calculated from the measured organ doses and compared to the HE derived from the air kerma-length product (PKL) using the conversion coefficient of 0.014 mSv∙mGy-1∙cm-1 for the chest region. Results: Both breasts and lungs received the highest radiation dose during CCTA examination. The highest HE was received from 2 × 32-detector-row DSCT scanner (6.06 ± 0.72 mSv), followed by 64-detector-row SSCT (5.60 ± 0.68 and 5.02 ± 0.73 mSv), 2 × 64-detector-row DSCT (1.88 ± 0.25 mSv) and 320-detector-row SSCT (1.34 ± 0.48 mSv) scanners. HE calculated from the measured organ doses were about 38 to 53% higher than the HE derived from the PKL-to-HE conversion factor. Conclusion: The radiation doses received from a prospectively ECG-triggered CCTA are relatively small and are depending on the scanner technology and imaging protocols. HE as low as 1.34 and 1.88 mSv can be achieved in prospectively ECG-triggered CCTA using 320-detector-row SSCT and 2 × 64-detector-row DSCT scanners. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the effectiveness of dose-saving protocols in dual-source computed tomography (CT) coronary angiography compared with invasive coronary angiography (ICA). On 50 patients who underwent coronary CT angiography was performed dual-source CT (DSCT) and compared with ICA procedures. Entrance skin dose (ESD), which was measured at the thyroid gland, and effective dose (E) were assessed for both imaging modalities. The mean ESD measured at the thyroid gland was the highest at 120 kVp, followed by the 100 kVp DSCT and the ICA protocols with 4.0±1.8, 2.7±1.0 and 1.1±1.2 mGy, respectively. The mean E was estimated to be 10.3±2.1, 6.2±2.3 and 5.3±3.4 mSv corresponding to the 120-kVp, 100-kVp DSCT and ICA protocols, respectively. The application of 100 kVp in DSCT coronary angiography is feasible only in patients with a low body mass index of <25 kg m−2, which leads to a significant dose reduction with the radiation dose being equivalent to that of ICA. [ABSTRACT FROM AUTHOR]

This study was conducted on a human anthropomorphic phantom to investigate the effective dose and entrance skin dose (ESD) in selected radiosensitive organs through invasive and computed tomography (CT) coronary angiography procedures using different dose-saving techniques. The effective dose was calculated as 2.49, 3.35 and 9.62 mSv, respectively, corresponding to three coronary CT angiography protocols, including prospective ECG gating and retrospective ECG gating with and without tube current modulation. In comparison, the effective dose was calculated as 7.26, 6.35, 5.58 and 4.71 mSv at four different magnifications acquired with invasive coronary angiography. The highest ESD was measured in the breast during the coronary CT angiography and in the thyroid gland during invasive coronary angiography. Although invasive coronary angiography produces lower radiation dose than coronary CT angiography, application of modified techniques in both CT and invasive coronary angiography is recommended in clinical practice for radiation dose reduction. [ABSTRACT FROM AUTHOR]

Summary The purpose of this paper is to perform a systematic review on radiation dose reduction in coronary computed tomography (CT) angiography that is done using different generations of multidetector CT (MDCT) scanners ranging from four-slice to 320-slice CTs, and have different dose-saving techniques. The method followed was to search for references on coronary CT angiography (CTA) that had been published in English between 1998 and February 2011. The effective radiation dose reported in each study based on different generations of MDCT scanners was analysed and compared between the types of scanners, gender, exposure factors and scanning protocols. Sixty-six studies were eligible for inclusion in this analysis. The mean effective dose (ED) for MDCT angiography with retrospective electrocardiogram (ECG) gating without use of any dose-saving protocol was 6.0 ± 2.8, 10.4 ± 4.90 and 11.8 ± 5.9 mSv for four-slice, 16-slice and 64-slice CTs, respectively. More dose-saving strategies were applied in recent CT generations including prospective ECG-gating protocols, application of lower tube voltage and tube current modulation to achieve a noteworthy dose reduction. Prospective ECG-gating protocol was increasingly used in 64, 125, 256 and 320 slices with corresponding ED of 4.1 ± 1.7, 3.6 ± 0.4, 3.0 ± 1.9 and 7.6 ± 1.6 mSv, respectively. Lower tube voltage and tube current modulation were widely applied in 64-slice CT and resulted in significant dose reduction ( P < 0.05). This analysis has shown that dose-saving strategies can substantially reduce the radiation dose in CT coronary angiography. The fact that more and more clinicians are opting for dose-saving strategies in CT coronary angiography indicates an increased awareness of risks associated with high radiation doses among them. [ABSTRACT FROM AUTHOR]

A computed tomography (CT) scanner is often used for visualization during the radiofrequency (RF) ablation (RFA) procedure. Temperatures at the ablation zone, power output, efficiency, and annotation are recorded once per second in the RF generator. Radiologists often review the RF and CT data post-operation for diagnostic and research purposes. However, they often rely on the CT data solely as it is difficult to relate the RF information to its CT counterpart. This paper describes the development of a graphical user interface application to co-register the CT images and the information from the RF generator temporally. Information from the RF generator, CT images during the RFA, and the pre-RFA CT images are displayed together. Users pinpoint a specific timestamp based on the RFA operation, and the corresponding CT images are retrieved and displayed. [ABSTRACT FROM AUTHOR]

This work aims to compare absorbed dose accuracy in tumour, normal liver, and lungs between the Partition Model (PM) and Monte Carlo (MC) simulation using MIRD phantom and patient tomography, considering patient-specific factors like pre-treatment parameters, source distribution, and tumour location. It outlines the procedure for acquiring patient images and treatment parameters from a medical institute and prepared by importing, segmenting, and registering tomographic images using the 3D Slicer software. Subsequently, the processed images are imported into GATE for MC simulation, with various source distributions applied for each patient. Absorbed dose estimates are also obtained using MC simulations with the MIRD phantom in Geant4, utilizing treatment parameters exclusively. These absorbed dose estimations are then compared with those obtained from patient measurements (PM). To visualize the isodose distributions resulting from the MC simulation, the SlicerRT extension of 3D Slicer is employed. The results revealed that, in most cases, higher absorbed doses when compared to PM calculations for MIRD phantom MC simulation. This discrepancy is attributed to the PM's assumption of localized energy deposition, neglecting crossfire effects. In MC simulation, when SPECT images were considered for source distribution, PM calculations yielded considerably higher absorbed doses for patients 1, 4, and 5, while patients 2 and 3 had lower values due to variations in source distribution intensity within the SPECT images. Employing region VOI for source distribution generally resulted in higher absorbed doses for the tumour in PM calculations, except for patient 3. Normalizing the prescribed tumour dose to 120 Gy highlighted differences in dose distribution, particularly for patients 2, 3, and 4. Isodose distribution analysis revealed variations in dose concentration between the simulations, with some regions experiencing higher doses in Geant4 simulations. This study emphasizes the significance of individualized dosimetry for 90Y radioembolization therapy through the utilization of MC simulation, the MIRD phantom, and patient tomography images. It presents a comparative analysis of this approach against PM calculations. • Monte Carlo toolkit: GATE for simulation study. • Comparison between Partition Model (PM) and Monte Carlo simulation in 90Y radioembolization. • Dosimetry evaluation in radioembolization treatment. [ABSTRACT FROM AUTHOR]

Abstract: Coronary CT angiography has been increasingly used in the diagnosis of coronary artery disease due to rapid technological developments, which are reflected in the improved spatial and temporal resolution of the images. High diagnostic accuracy has been achieved with 64- and more slice CT scanners and in selected patients, coronary CT angiography is regarded as a reliable alternative to invasive coronary angiography. Although the tremendous contributions of coronary CT angiography to cardiac imaging are acknowledged, appropriate use of cardiac CT as the first line technique by physicians has not been well established. Optimal selection of cardiac CT is essential to ensure acquisition of valuable diagnostic information and avoid unnecessary invasive procedures. This is of paramount importance since cardiac CT not only involves patient risk assessment, prediction of major cardiac events, but also impacts physician decision-making on patient management. Applications of CT in cardiac imaging include coronary artery calcium scoring for predicting the patient risk of developing major cardiac events, followed by coronary CT angiography which is commonly used to determine the diagnostic and prognostic accuracy in the coronary artery disease. This review presents an overview of the applications of CT in cardiac imaging in terms of coronary calcium scoring and coronary CT angiography. Judicious use of both cardiac CT tools will be discussed with regard to their value in different patient risk groups with the aim of identifying the appropriate criteria for choosing a cardiac CT modality. An effective diagnostic pathway is finally recommended to physicians for appropriate selection of cardiac CT in clinical practice. [Copyright &y& Elsevier]