The applications of nuclear technology in industries, medicine, and other fields have increased the risk of radiation injury. Although some small-molecule drugs for radiation injury treatment have been applied clinically or are in preclinical research, their therapeutic efficacy is significantly limited by short circulation time and rapid metabolism. Nanomaterials have attracted growing attention with their outstanding bioactivity, chemical stability, tissue compatibility, and targeted delivery capabilities, therefore having the promise of offering the potential solutions to the limitations of current small-molecule drugs. However, their biosafety and clinical efficacy require further investigation. This review summarizes the design strategies and classifications of nanomaterials for radiation injury treatment, analyzes current research progress in their therapeutic applications, and introduces nanomaterial-based approaches for enhancing the elimination of internal radionuclide contamination. Finally, the challenges and future prospects of nanomaterials in radiation injury treatment are discussed. This review aims to provide researchers with a comprehensive understanding of recent advances in nanomaterial-based radiation injury therapeutics, thereby promoting further development in this field.
ObjectiveTo explore the new treatment strategies for radiation proctitis, which is the most common complication of pelvic tumor malignancies.MethodsFour cases of patients with severe radiation proctitis were treated with high-dosage vitamin C (VC, 12–24 g/d, iv) combined with cyclooxygenase-2 (cyclooxygenase-2, COX-2) inhibitors.ResultsFor these four cases, the diarrhea, hematochezia, tenesmus, pain, and other symptoms were significantly improved. The edema of the rectal wall is also significantly improved in the imaging review.ConclusionThe high-dosage VC combined with the treatment of severe radiation proctitis is safe and effective.
Machine learning methods based on radiomics can be used to establish a prediction model of gamma pass rate for specific dosimetric verification of pelvic intensity modulated radiotherapy. The classification performance of support vector machine model and gradient boosting decision trees model is better than that of random forest model and adaptive boosting model. The prediction model for a specific site is helpful to improve the performance of the model.
Drug-associated lung injury (DALI) is one of the important factors affecting the prognosis of patients with lymphoma, and early identification and timely intervention for DALI are essential. Currently, the commonly used imaging examinations, e. g. high-resolution computed tomography, and laboratory tests all have hysteresis, so that the lung injury may be irreversible. Nuclear medicine imaging provides functional and metabolic information for DALI before morphological changes, so that the opportunity for early clinical intervention can be obtained. This article reviews the application of nuclear medicine imaging in lymphoma DALI.
Objective:To evaluate the radiation shielding performance for a novel self-shielded ZAP-X radiotherapy system used for intra-cranial and neck treatments. The present evaluation was performed according to the relevant Chinese national standards and the clinical placement of the radiotherapy system in an unshielded treatment room.Methods:The radiation source of the ZAP-X was a 3 MV linear accelerator. A total of 33 detection sites were selected surrounding the self-shielded system at 1.3, 2.3 and 3.3 m away from the periphery of the equipment. The maximum ambient dose equivalent rate in each irradiation condition was measured accordingly. A commonly used clinical treatment plan was selected to simulate the treatment process. During the delivery of this treatment plan, the cumulative doses of these 33 sites were measured, separately. The applicable current radiation protection standard for radiotherapy in China was chosen to evaluate the radiation shielding performance of the system.Results:According to the measurement result of the ambient dose equivalent rates along the aforementioned perimeter lines, a suggestion was put forward to redefine the existing 1 m controlled area by determining the distance at which the instantaneous dose rate of 10 μSv/h will not be exceeded. This is to meet the requirements of the Chinese standard GBZ 121-2020.Conclusions:According to the existing Chinese national radiation protection standards, the self-shielded radiotherapy system in the unshielded treatment room has the clinical applicability in China. But for such a novel self-shielded system, the corresponding performance testing and radiation protection standards shall be formulated.
Objective:To assess the impact of the general education course entitled " The Basics of Radiation Protection" on enhancing undergraduates′ awareness of radiation safety, a questionnaire was utilized. Additionally, this study aims to propose novel strategies for improving health literacy among undergraduates, fostering the development of innovative, talented individuals with reasonable knowledge structures and strong practical abilities.Methods:From 2021 to 2022, 127 undergraduates from all colleges of Shandong University took the general course" The Basics of Radiation Protection". To compare the learning effects of the medical and non-medical students, invitations to participate in this study were extended to 101 (79.5%) students from School of Medicine and School of Electrical Engineering. A questionnaire survey was conducted to determine and compare the changes in the students’ basic cognition of radiation safety and protection before and after learning the course. The aim was to evaluate the teaching effectiveness and significance of the course.Results:From 2021 to 2022, 94 undergraduates from School of Medicine and School of Electrical Engineering accepted the invitation and voluntarily completed questionnaires twicely, accounting for 74.0% of the total number of selected students. The questionnaire survey showed that through course learning, the cognitive level of radiation protection among college students had significantly improved. The Likert quantification scores befroe taking the course were 3.59±1.35, 3.81±1.17, 3.45±1.16, 4.11±1.13, 3.62±1.05, 3.98±1.24 and after completing the course 4.94±0.32, 4.87±0.32, 4.96±0.21, 4.98±0.15, 4.81±0.39, 4.98±0.15, respectively, with the difference being statistically significant ( t=6.55, 5.50, 9.10, 5.36, 7.60, 5.34, P< 0.05). Further analysis revealed that different professional backgrounds affected students′ understanding of radiation safety and protection: before learning this course, medical students were superior to electrical engineering students in their knowledge of ionizing radiation ( t=5.69, 4.06, 6.46, 6.27, 7.78, P < 0.001). After taking the course, the cognitive level of students from both majors had considerably improved, but there was no significant difference ( P> 0.05). Feedback on the course learning showed that the awareness of " routine radiation protection" had significantly improved (96.8%), pseudoscience and pseudoinformation could be identified (93.6%), " nuclear power" -related fears had been dispelled (95.7%), and the concept of " cherishing life" had been effectively established (91.5%). Conclusions:The general education course " The Basics of Radiation Protection" has effectively improved the students′ awareness of radiation safety, strengthened their knowledge regarding radiation safety and protection, and provided a new avenue for cultivating innovative talents on a well-structured knowledge base. The course would be worth further promoting and applying in the education of undergraduates with different backgrounds and taking different majors.
Objective:To explore the effects of glycosylated nanoparticles on early radiation responses including the generation of reactive oxygen species (ROS), the polarization of pulmonary macrophages, and secretion of inflammatory cytokines in mice lung tissues.Methods:Twenty mice were randomly divided into control group, drug administration group, irradiation group and irradiation + drug administration group. The irradiation group and irradiation + drug administration group were subjected to whole lung irradiation with X-rays. The antioxidant ability of glycosylated nanoparticles was characterized using ROS indicator (CM-H 2DCFDA). The M2 polarization of pulmonary macrophages was detected by flow cytometry and PCR. The mRNA and protein expression levels of inflammatory cytokines were investigated by PCR and ELISA assay, respectively. Results:Compared with the irradiation group, the intensity of ROS fluorescence signals was significantly lower ( t=15.76, P < 0.05), the proportion of M2-type macrophages was significantly higher ( t=2.89, P < 0.05), the expression level of arginase 1 (ARG-1) gene was elevated, and the expression levels of tumour necrosis factor α (TNF-α), interleukin 1β (IL-1β) and interleukin 6 (IL-6) inflammatory factors were significantly reduced ( t=3.32, 2.90, 2.85, 4.55, 2.88, P < 0.05) in the lung tissues of irradiation + treatment group. Conclusions:Glycosylated nanoparticles can effectively scavenge ROS, trigger polarization of M2 macrophage, dampen inflammatory responses, and thus potentially alleviate radiation-induced lung injury.
Iodine-125 ( 125I) interstitial brachytherapy, a primary method for treating parotid gland cancer, allows for a high dose to the target area while protecting surrounding normal tissues. The efficacy of radioactive 125I seeds is closely related to the dose and accuracy. However, there is a lack of specifications for the application of radioactive 125I seeds in the treatment of parotid gland cancer presently, with relevant criteria differing greatly between medical centers. To further standardize the process of 125I interstitial brachytherapy for parotid gland cancer, this expert consensus was achieved through repeated discussions and modifications of many Chinese experts in the field of brachytherapy. This consensus, consisting of the normative recommendations on the indications, contraindications, treatment parameters, operation process, technical specifications, radiation protection, adverse reactions, and follow-up of the brachytherapy, can be used as a reference for clinical practice.
Objective:To evaluate the efficacy and safety of simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) for rectal cancer with lateral lymph node metastasis (LLNM).Methods:From January 2016 to December 2022, 103 rectal cancer patients with LLNM were enrolled. The patients were divided into SIB-IMRT group (52 cases) and conventional chemoradiotherapy (CRT) group (51 cases) using the random number table method. The dose was 50 Gy for the pelvis with 60 Gy of SIB-IMRT for the LLNM in the SIB-IMRT group. The dose was 50 Gy for the pelvis in the CRT group. The primary endpoint was the lateral recurrence rate. The efficacy and adverse reactions of the two groups were compared.Results:The adverse reactions and surgical complications after neoadjuvant radiotherapy were comparable between the two groups. The response rates of LLNM treatment were 76.9% and 56.9%, respectively, in the two groups ( χ2=4.69, P=0.03). The SIB-IMRT group and CRT group had a local recurrence rate of 7.7% and 25.5% ( χ2=5.92, P=0.015), respectively, and a lateral recurrence rate of 3.8% and 23.5% ( χ2=8.49, P=0.004), respectively. Univariate analysis showed that the SIB-IMRT, short axis of lateral lymph nodes <5 mm after radiotherapy, and negative result in the postoperative lymph node pathological examination were factors associated with lateral recurrence. Multivariable regression analysis demonstrated that the SIB-IMRT ( HR=6.42, 95% CI: 1.40-29.49) and short axis of lateral lymph nodes <5 mm after radiotherapy ( HR=0.17, 95% CI: 0.04-0.66) were independent factors associated with lateral recurrence. The two groups had a 3-year disease-free survival of 73.25% and 62.6% ( P>0.05), respectively, and a 3-year overall survival of 87% and 82.5% ( P>0.05), respectively. Conclusions:The SIB-IMRT is safe and effective for rectal cancer with LLNM. The short axis of lateral lymph nodes <5 mm after neoadjuvant radiotherapy and SIB-IMRT is an independent risk factor for lateral recurrence.
Renal cell carcinoma (RCC) is one of the most aggressive malignancies in the genitourinary system with a poor prognosis, especially in patients with RCC who have metastases. RCC is conventionally considered not sensitive to radiotherapy. Compared with conventional radiotherapy, stereotactic body radiotherapy (SBRT) has the characteristics of higher precision, higher irradiation dose, and less damage to the surrounding tissue. In recent years, SBRT has shown definite efficacy in the treatment of primary and advanced metastatic RCC. SBRT combined with targeted therapy and immunotherapy can improve the local tumor control rate and cause fewer adverse reactions in patients with primary and advanced metastatic RCC. This article reviews the literature on the strategy and progress of SBRT in combination with targeted therapy and immunotherapy.
Objective:To explore the affects of the filling degree of the abdominal and pelvic cavity to the position of the diaphragm.Methods:The computed tomography (CT) images of 25 patients from 137 CT scans stored in the Picture Archiving and Communication System of the First Affiliated Hospital of Soochow University from March 2018 to September 2020 were reviewed and analyzed retrospectively. Every patient was scanned 4-7 times. The outline of the abdominal and pelvic cavity from the diaphragmatic dome to the superior margin of pubic symphysis was drawn at every cross section, and then the filling volumes of the abdominal and pelvic cavities and the overall filling volume were calculated. For the same patient within 4-7 CT scans, per pair of different images was compared randomly and 379 comparison pairs were obtained. The volume change rate (△ VR) of the abdominal and pelvic cavity and the height difference (△ H) of the diaphragmatic dome were calculated. The images with "larger overall filling volume of the abdominal and pelvic cavity and higher diaphragmatic dome" were defined as consistent group, and those with "larger overall filling volume and lower diaphragmatic dome" were defined as inconsistent group. The percentage of images in the consistent group in all samples and the percentage of images showing deep inspiration in the inconsistent group in all samples were calculated. △ VR and △ H were compared between the consistent and inconsistent groups. △ VR of the abdomen and pelvic cavities in the consistent group was compared using the Mann-Whitney test. The correlations between △ VR of the abdomen and pelvic cavities and the elevation of the diaphragmatic dome in the consistent group were analyzed using Spearman correlation analysis. The average elevation of the diaphragmatic dome in all samples and the consistent group was simulated if the filling volume of the abdomen and pelvic cavity was increased by 500 ml. Results:The percentage of images in the consistent group in all samples was 67.28%. The percentage of images showing deep inspiration in the inconsistent group in all samples was 26.39%. There were significant differences in △ VR and △ H of the abdomen and pelvic cavity between the consistent and inconsistent groups ( Z=-4.95, -5.49, P<0.05). In the consistent group, there were significant differences in △ VR between the abdominal cavity and pelvic cavity ( Z=-7.53, P<0.05), and the elevation of the diaphragmatic dome was correlated with the △ VR of the abdominal cavity ( rs=0.43, P<0.05). The simulated calculation showed that an average increase of 500 ml in the filling volume of the abdominal and pelvic cavity result ed in an average elevation of 4.54 and 8.43 mm in the diaphragmatic dome in all samples and the consistent group, respectively. Conclusions:The filling degree of the abdominal and pelvic cavity may be one of the main factors affecting the position of the diaphragm and the precision of radiotherapy for relevant organs near the diaphragm, especially the filling degree of the abdominal cavity. It is recommended to repeat the filling degree of the abdominal and pelvic cavity by CT localization scanning as much as possible during radiotherapy.
Objective:To design a method to introduce random six-dimensional setup error (6D-SE) into the intensity-modulated radiotherapy (IMRT) planning for rectal cancer and evaluate its dosimetric effect.Methods:A total of 21 IMRT plans for patients with rectal cancer were randomly selected as reference plans [2 Gy per fraction for a total of 50 Gy; a 5 mm uniform margin around the clinical target volume (CTV) was taken as the planning target volume (PTV)]. For each fraction of the reference plan, a randomly generated 6D-SE was introduced by adjusting the geometrical parameters of the radiation field, and the dose was recalculated. The overall dose distribution with 6D-SE was obtained by adding up the dose of each fraction. A treatment simulation program that could complete the above workflow was developed using the Varian Eclipse scripting API (ESAPI). 6D-SEs that obey two preset distributions [distribution 1: translational error obey N(0, 4 2), and rotational error obey N(0, 2 2); distribution 2: translational error obey N(0, 2 2), and rotational error obey N(0, 1 2)] were introduced into the reference plans, and the dosimetric effects were assessed. Results:When the reference plans, error distribution 1, and error distribution 2 were applied, the Dmin values of the CTV were (49.4±0.41), (47.56±0.76), and (49.17±0.64) Gy, respectively; the D98% values of the CTV were (50.23±0.07), (49.98±0.10), and (50.27±0.09) Gy, respectively; the D98% values of the primary target area (the kernel part of the target area, excluding the margins) were (50.25±0.08), (50.42±0.13), and (50.33±0.10) Gy, respectively; the D98% values of the marginal area were (50.22±0.10), (49.88±0.11), and (50.26±0.10) Gy, respectively. In addition, compared with the result of the reference plans, the result of errors 1 and 2 showed no significant changes in the mean dose of the bladder and femoral heads ( P>0.05), despite slight decreases in the conformity index of the dose distribution with limited clinical significance. Conclusion:The proposed method and the treatment simulation program developed thereupon can introduce the 6D-SE obeying different distributions into the IMRT plans for rectal cancer on demand and provide overall dosimetric changes.
Hypothyroidism (HT) can arise as a complication of radiotherapy for breast cancer. Despite having a significant impact on patients′ quality of life, HT had always been overlooked by radiotherapists in the past. In recent years, many studies highlighting the protection of the thyroid in the process of radiotherapy for breast cancer have been conducted, achieving valuable conclusion. These studies can serve as a guide for radiotherapists to limit the dose to the thyroid during radiotherapy, thus reducing the incidence of HT.
Objective:To compare the radiation chemistry effects on water molecules after ultra-high dose rate (FLASH) and conventional irradiation.Methods:Both FLASH and conventional irradiation were applied to ultrapure water, with the hydroxyl radical yield in the homogeneous phase detected using electron paramagnetic resonance (EPR) and the hydrogen peroxide (H 2O 2) yield in the diffusion phase analyzed uuxing fluorescence probe. The liposome model was then established to investigate the radiation chemistry effect of FLASH and conventional irradiation in inducing lipid peroxidation. Results:Radiation chemistry reactions were observed in water molecules after irradiation. In the homogeneous phase, the yield of free radicals using FLASH irradiation is similar to those from conventional irradiation ( P>0.05). In the diffusion phase, the amount of H 2O 2 produced by FLASH irradiation was significantly lower than those from conventional irradiation ( t=0.49-12.81, P<0.05). The liposome model confirmed that conventional irradiation could significantly induce lipid peroxidation through the radiation chemistry effect in water molecules as compared with FLASH irradiation ( t=0.31-11.73, P<0.05). Conclusions:The radiation chemistry effect in water molecules after FLASH irradiation was significantly lower than that from conventional irradiation. This could be one of the mechanisms of FLASH effect.
Objective:To investigate the current status of radiodiagnostic and radiotheraputic resources and the frequency of medical radiation exposure in order to provide basic data for reasonably allocating medical resource and standardizing meical exposure.Methods:According to data available from the Jiangsu Radiation Health Information Management Platform in 2020 and the total number of permanent residents from Wuxi Statistical Yearbook 2019, a statistical analysis was carried out of the staff and equipment and the frequency of medical radiation exposure in Wuxi mecical institutions.Results:There were 923 items of radiodiagnostic and radiotheraputic equipment, 2 480 medical radiation workers in Wuxi city in 2020, which were estimated to be 140.03 items of equipment and 376.24 workers per 10 6 population. The frequency of X-ray diagnosis and treatment were 1 137.53 procedures per 10 3 population, including 646.17 per 10 3 population for conventional X-ray diagnosis, 394.11 per 10 3 population for CT scan, 5.34 per 10 3 population for interventional radiology, 0.79 per 10 3 population for radiotherapy and 7.12 per 10 3 population for nuclear medicine. Interventional radiology, radiotherapy and nuclear medicine was mainly concentrated in tertiary hospitals. Conclusions:The number of radiodiagnostic and radiotheraputic resources in Wuxi is above the national and provincial level, although in a unbalanced state. Conventional X-ray diagnosis frequency in Wuxi is higher than that of provincial level, resultsing in higher collective dose. Radiological diagnosis and treatment activities needs a approach to the process of justification.
Objective:To formulate clinical commissioning procedures, items, and testing method for Flexitron afterloader hardware and software and establish relevant quality control procedures in order to meet national standards and clinical requirements.Methods:Clinical commissioning included hardware, treatment planning system (TPS), and end-to-end (ETE) full-process testing. The radioactive source positioning accuracy was measured using a source position check ruler. The accuracy and linearity of dwell time were evaluated using three method: stopwatch timing, ion chamber measurement, and video analysis. The accuracy of source position simulator, connecting tubes, source position check ruler, and other measuring tools was tested using a high-precision ruler. Films were used for calibration of marker lines and applicators. The electrometer and well chamber were used to calibrate the radioactive source activity. The display and reconstruction accuracies of the TPS were evaluated using physical image data. ETE testing was conducted using a custom-made phantom for scanning, planning, and dose measurement.Results:The accuracy testing result of the commissioning items were within acceptable limits. The deviation in source activity measurements was 0.21%, and the ETE point dose measurement deviation was 2.32%, both of which met the clinical requirements. However, there was a 2 mm difference between the nominal and measured values of the magnetic resonance marker line in the accuracy testing items. Therefore, adjustments were required when using marker line for catheter reconstruction based on magnetic resonance images.Conclusions:By summarizing the clinical commissioning experience of the Flexitron afterloader, this study has developed quality control method and baseline levels of result of afterloader and TPS items, which provides a reference for the commissioning before clinical use.
Objective:To explore the influence of deep learning reconstruction algorithm combined with low-dose CT on image quality and bone mineral density measurement and the application value in opportunistic osteoporosis screening.Methods:A total of 119 patients (aged ≥40 years) who underwent a combined chest and upper abdominal low-dose scan were prospectively included. All the images were reconstructed using filtered back projection(FBP) alogrithm, hybrid model-based adaptive statistical iterative reconstruction (ASIR-V) 50% and three levels of deep learning reconstruction algorithm respectively. Bone mineral density (BMD) values for different reconstruction conditions were measured and compared using asynchronous quantitative CT software. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of descending aorta, liver and spleen were calculated, and the image noise was the standard deviation of anterior abdominal wall fat and the image quality was objectively evaluated by using the five-point subjective evaluation method. The objective and subjective image quality of different body parts with different reconstruction method was compared.Results:There was no statistical difference in BMD with different reconstruction method ( P > 0.05). Compared with ASIR-V 50%, the SNRs of high level deep learning image reconstruction (DLIR-H)in descending aorta, latissimus dorsi, liver and spleen were increased by 103.88%, 125.09% and 136.13% respectively, and the image noise was decreased by 55.98%. Both the CNR and subjective scores (except the ability to display lung lesions) of DLIR-H were better than those of DLIR-L and ASIR-V 50% ( χ2 =158.31-275.35, P<0.001). Conclusions:The deep learning algorithm does not affect the accuracy of bone mineral density measurement, and the image quality is better than that of ASIR-V 5%. Deep learning algorithm combined with low-dose CT can be used for opportunistic osteoporosis screening.
Objective:To analyze the effectiveness and safety of the second course radiotherapy for unresectable colorectal cancer liver metastases.Methods:We retrospectively collected the data of 28 patients with unresectable colorectal cancer liver metastases who received the second course radiotherapy at Peking University Cancer Hospital and Institute from 2017 to 2023, to analyze the feasibility of re-irradiation.Results:For the 28 patients, the median follow-up time after re-irradiation was 20.2 months. The median time interval between the first- and second-course radiotherapy was 11.1 months. The median biologically effective doses of the first- and second-course radiotherapy were 100 Gy and 96 Gy, respectively. Stereotactic body radiotherapy was administered to 25 patients (89.3%) during the first course and 24 patients (85.7%) during the second course of radiotherapy. The mean equivalent dose in 2 Gy fractions to the normal liver was 10.1 Gy in the first-course radiotherapy and 7.9 Gy in the second-course radiotherapy. The complete response rate, partial response rate, and objective response rate after re-irradiation were 54.5%, 18.2%, and 72.7%, respectively. After re-irradiation, the 2-year cumulative local failure rate was 17.0% when calculated based on patients and 15.1% when calculated based on lesions, the 1-year progression-free survival rate was 27.4%, and the 3-year overall survival rate was 46.7%. The second-course radiotherapy was well tolerated, with most patients (75.0%) experiencing grade 1-2 acute adverse reactions and only one case (3.6%) experiencing grade 3 acute adverse events.Conclusions:Second course radiotherapy is an effective and safe treatment approach for selected patients with unresectable colorectal cancer liver metastases.
2023年11月4日，《中华放射医学与防护杂志》第十一届编委会成立大会在合肥召开，全体委员齐聚一堂，共同回首，展望未来。按中华医学会规定，编委会每4年换届。第十届编委会于2018年在大理成立，由于疫情原因，推迟到今年换届。王玉华，全体编委的坚守与付出使杂志保持高质量发展。中华医学会杂志社社长魏均民、中华医学会期刊管理部王旌编审出席本次大会。杂志总编辑、副总编辑、编委、通讯编委共110余人参会。会议由编辑部郭鲜花主任主持。
Objective:To evaluate the feasibility of coronary artery calcium (CAC) detection, quantification and risk classification using ultra-low-dose chest CT (ULD-CT) combined with a calcium-aware algorithm.Methods:A total of 115 patients were prospectively enrolled from April to October 2022 at Zhejiang Provincial People′s Hospital, who underwent a standard calcium scoring CT (CACS-CT) scan followed by an additional ULD-CT scan. CACS-CT adopted a prospective ECG-triggered sequence scan with a tube voltage of 120 kVp, and the reconstruction algorithm with Qr36 (group CACS-CT Qr). ULD-CT adopted non-ECG-triggered high-pitch scan with a tube voltage of Sn 100 kVp, and the standard algorithm Qr36 (group ULD-CT Qr) and calcium-aware algorithm Sa36 (group ULD-CT Sa) were respectively used to reconstruct two groups of images. Taking the CAC detection of CACS-CT as a reference, the accuracy of ULD-CT for detecting CAC was calculated, and kappa was used to evaluate the agreement of CAC detection between scanning protocols. The agreement of CACS quantification between scanning protocols was assessed using intraclass correlation coefficients (ICC) and Bland-Altman plots, and the agreement of risk classification between scanning protocols was assessed using weighted kappa. Results:The CAC was found in 66.96% (77/115) of patients in CACS-CT Qr. Taking the CAC detection in CACS-CT Qr as a reference, the sensitivity of CAC detection in ULD-CT Qr and ULD-CT Sa was 96.1% and 97.4%, respectively, and the specificity was 94.73% (k= 0.902, 0.921). The CACS for ULD-CT Qr and ULD-CT Sa was lower than that for CACS-CT Qr (3.6, 6.2 vs. 8.5; P< 0.001), but strongly correlated with CACS for CACS-CT Qr ( r= 0.983, P< 0.001). The mean difference in CACS for ULD-CT Sa and CACS-CT Qr was smaller (12.33), and the agreement was better (ICC= 0.992). The agreement of risk classifications between ULD-CT Sa and CACS-CT Qr was relatively high (weighted k= 0.936), and the reclassification rate (6.08%) was relatively low. The effective radiation dose for ULD-CT was reduced by approximately 77.22% compared with that for CACS-CT. Conclusions:It is feasible to evaluate CACS using Non-ECG-triggered ULD-CT combined with a calcium-aware algorithm.
