Analysis of radiation exposure in trauma patients at a level I trauma center

BackgroundTrauma patients are exposed to potentially high levels of low-dose radiation during radiologic studies.ObjectivesTo assess the cumulative effective dose (CED) of radiation exposure (RE) in 177 successive patients admitted to a trauma service from January 1 through February 28, 2006.ResultsPatients received a total of 1505 radiographs and 400 computed tomography (CT) scans in the study period. The CED was 14.56 mSv (0.97 mSv radiographs, 13.59 mSv CT scans) per patient total length of stay (LOS). CED averaged 8.66 mSv in the first hour and 11.76 mSv in the first 24 h after arrival. The most commonly performed CT scan was brain (n = 147), followed by abdomen and pelvis (n = 80), and cervical spine (n = 69). CT scans of the brain and cervical spine were the most commonly performed combined imaging tests (35%). Twelve percent of patients received no radiographs, and 15% received no CT scans. Six or more CT scans were done in 6% of patients. RE increased with longer LOS (> 6 days vs. 3–5 days vs. 1 day, p < 0.05). “Pan-scans” (a combination of CTs of the brain, cervical spine, chest, abdomen, and pelvis) were done in 13% (n = 23) of patients. There was a higher total RE from CT scans (25.09 mSv ± 19.48 mSv vs. 4.93 mSv ± 14.20 mSv) in patients with injury severity score (ISS) > 9 vs. ≤ 9 ( p < 0.0001). First hour and first 24-h RE rates from radiographs were lower in patients younger than 15 years vs. 15–45 years and older-than-45-year age cohorts (p < 0.05).ConclusionsIn this study, CED was 14.56 mSv per patient. CT scans accounted for 21% of radiologic studies and 93% of CED. There was a higher CED rate in patients with ISS > 9 and longer LOS.     

Effects of radiation exposure on human body

There are two types of radiation health effect; acute disorder and late on-set disorder. Acute disorder is a deterministic effect that the symptoms appear by exposure above a threshold. Tissues and cells that compose the human body have different radiation sensitivity respectively, and the symptoms appear in order, from highly radiosensitive tissues. The clinical symptoms of acute disorder begin with a decrease in lymphocytes, and then the symptoms appear such as alopecia, skin erythema, hematopoietic damage, gastrointestinal damage, central nervous system damage with increasing radiation dose. Regarding the late on-set disorder, a predominant health effect is the cancer among the symptoms of such as cancer, non-cancer disease and genetic effect. Cancer and genetic effect are recognized as stochastic effects without the threshold. When radiation dose is equal to or more than 100 mSv, it is observed that the cancer risk by radiation exposure increases linearly with an increase in dose. On the other hand, the risk of developing cancer through low-dose radiation exposure, less 100 mSv, has not yet been clarified scientifically. Although uncertainty still remains regarding low level risk estimation, ICRP propound LNT model and conduct radiation protection in accordance with LNT model in the low-dose and low-dose rate radiation from a position of radiation protection. Meanwhile, the mechanism of radiation damage has been gradually clarified. The initial event of radiation-induced diseases is thought to be the damage to genome such as radiation-induced DNA double-strand breaks. Recently, it is clarified that our cells could recognize genome damage and induce the diverse cell response to maintain genome integrity. This phenomenon is called DNA damage response which induces the cell cycle arrest, DNA repair, apoptosis, cell senescence and so on. These responses act in the direction to maintain genome integrity against genome damage, however, the death of large number of cells results in acute disorder, and then DNA mis-repair and mutation is speculated to cause cancer. The extent to which this kind of cellular response could reduce the low-dose radiation risk is a major challenge for future research.     

Radiation exposure from imaging tests: is there an increased cancer risk?

The increasing exposure to low-dose radiation from diagnostic testing has prompted renewed interest in evaluating its carcinogenic risk, but quantifying health risk from low-dose radiation exposure remains controversial. The current approach is to adopt the linear non-threshold model, which is commonly applied to high-dose exposure, and apply it to assess risk from low-dose exposure. However, existing data are conflicting and limited to epidemiological studies and/or in vitro analyses. In this article, we will discuss the potential cancer risk from low- and high-dose radiation, their effects on DNA repair response pathways, and the best course of action for patients and providers to minimize risk.     

Coronary calcium scans and radiation exposure in the multi-ethnic study of atherosclerosis

With the increasing use of coronary artery calcium (CAC) scoring to risk stratify asymptomatic patients for future cardiovascular events, there have been concerns raised regarding the theoretical risk of radiation exposure to this potentially large patient population. Newer CT protocols have sought to reduce radiation exposure without compromising image quality, but the reported radiation exposures in the literature remains widely variable (0.7–10.5 mSv). In this study, we report the radiation exposure of calcium scoring from our MESA cohort across several modern CT scanners with the aim of clarifying the radiation exposure of this imaging modality. To evaluate the mean effective doses of radiation, using dose length product, utilized for coronary artery calcium scoring in the MESA cohort, in an effort to understand estimated population quantity effective dose using individual measurements of scanner radiation output using current CT scanners. We reviewed effective dose in milliSieverts (mSv) for 3442 participants from the MESA cohort undergoing coronary artery calcium scoring, divided over six sites with four different modern CT scanners (Siemens64, Siemens Somatom Definition, GE64, and Toshiba 320). For effective dose calculation (milliSieverts, mSv), we multiplied the dose length product by conversion factor k (0.014). The mean effective dose amongst all participants was 1.05 mSv, a median dose of 0.95 mSV. The mean effective dose ranged from 0.74 to 1.26 across the six centers involved with the MESA cohort. The Siemens Somatom Definition scanner had effective dose of 0.53 (n = 123), Siemens 64 with 0.97 (n = 1684), GE 64 with 1.16 (n = 1219), and Toshiba 320 with 1.26 mSv (n = 416). Subgroup analysis by BMI, age, and gender showed no variability between scanners, gender, ages 45–74 years old, or BMI less than 30 kg/m². Subjects over age 75 yo had a mean effective dose of 1.29 ± 0.31 mSv, while the <75 yo subgroup was 0.78 ± 0.09 mSv (p < 0.05). Effective doses in subjects with BMI > 40 kg/m² was significantly greater than other subgroups, with mean dose of 1.47 ± 0.51 mSv (p < 0.01). Using contemporary CT scanners and protocols, the effective dose for coronary artery calcium is approximately 1 mSv, an estimate which is consistently lower than previously reported for CAC scanning, regardless of age, gender, and body mass index.     

Design,Development, and Content Creation for an Open Education Physics Website for MRT Education

BackgroundAs health care technologies continue to advance rapidly, resulting in improved standards of practice, it is essential for health care professionals to continually expand on their current skills and knowledge. We describe here an initiative to use open education resources to provide ongoing education in radiation medical sciences and imaging.AimsThe aim of this study to design an interactive, engaging, multilevel radiation medical physics resource, which is fully open to the public, and functional on all types of computing devices. Our primary target audiences are students and workers in medical radiation technology and other health care professionals as part of their continuing professional development.Design and DevelopmentThe three tasks of design, development, and content creation were most efficiently performed in parallel wherever possible. A modern responsive web design was adopted to target all desktop and mobile devices. Only open-source tools and libraries were used in developing the OpenPhys website.Overall Website Design and NavigationThe homepage is a modern tile-based design containing one coloured tile for each lesson. Clicking anywhere on a coloured lesson tile will open up a two-dimensional interactive concept map linking to content pages. Currently, 10 lessons are available online ranging from the electronic structure of the atom to MRI basics: “NMR” and “Inside a Pixel”. Lesson pages include text, images, graphics, equations, quizzes, and interactive animations.User FeedbackAn online questionnaire was emailed to current radiation therapy students at the University of Alberta and alumni regarding the functionality and navigation of the website.Discussion/ConclusionTo our knowledge, OpenPhys is the first open education resource specializing in radiation physics and medical imaging. We believe OpenPhys will fill existing gaps in the realm of physics education delivery and could be a component of a blended learning initiative. Future steps will include a formal evaluation of the website and content.     

Effective Dose and Effective Risk from Post–Single Photon Emission Computed Tomography Imaging of the Lumbar Spine

PurposePlanar bone scans play an important role in the staging and monitoring of malignancy and metastases. Metastases in the lumbar spine are associated with significant morbidity; therefore, accurate diagnosis is essential. Supplementary imaging after planar bone scans is often required to characterize lesions; however, this is associated with additional radiation dose. This article provides information on the comparative effective dose and effective risk from supplementary lumbar spine radiographs, low-dose computed tomography (LDCT), and diagnostic CT (DCT).MethodOrgan dose was measured in a phantom using thermoluminescent dosimeters. Effective dose and effective risk were calculated for radiographs, LDCT, and DCT imaging of the lumbar spine.ResultsRadiation dose was 0.56 mSv for the anteroposterior and lateral lumbar spine radiographs, 0.80 mSv for LDCT, and 3.78 mSv for DCT. Additional imaging resulted in an increase in effective dose of 12.28%, 17.54%, and 82.89% for radiographs, LDCT, and DCT, respectively. Risk of cancer induction decreased as age increased. The difference in risk between the modalities also decreased. Males had a statistically significant higher risk than female patients (P = .023), attributed to the sensitive organs being closer to the exposed area.ConclusionsEffective dose for LDCT is comparable with radiographs of the lumbar spine. With the known benefits of image fusion, it is recommended that LDCT replace radiograph imaging for characterization of lumbar spine lesions identified on planar bone scans. DCT is associated with significantly higher effective dose than LDCT. Effective risk is also higher, and the difference is more marked in younger female patients.     

Estimation of additional dosimetry from low-dose CT scan to 99mTc-HMDP SPECT/CT

IntroductionCurrently, the addition of computed tomography (CT) to a gamma-camera has revolutionized nuclear medicine. Indeed the CT, because of its good spatial resolution, of the attenuation correction of the single photon emission computed tomography (SPECT) images and of a better anatomical localization of lesions, improves the sensitivity, specificity and accuracy of the examination. Despite the fact that the hybrid camera uses a low-dose non-diagnostic scanner, increases the overall delivered dose of radiation.MethodsThe aim of this study was to evaluate the contribution of CT to the total effective dose of ^99mTc-HMDP (hydroxymethylenediphosphonate labelled with technetium 99 metastable) SPECT/CT for an adult oncologic population. This prospective study included 103 patients (75 women and 28 men) aged 28 to 79 years.ResultsThe mean effective doses of SPECT, CT and SPECT/CT were respectively 3.8 mSv, 3.3 mSv and 7.1 mSv, respectively. The average contribution of CT scans to the total effective dose for SPECT/CT examination was 45 ± 9.7%, and ranged from 10 to 67.4%. The lowest value was for the thorax area.ConclusionThis radiation dose is not negligible. But, taking into account the benefit of hybrid imaging, this additional radiation remains justifiable. Nevertheless, the "As Low as Reasonably Achievable (ALARA)'' principle must be respected to ensure that the patient is not subjected to unnecessarily high levels of radiation.     

Patterns and trends of population radiation exposure and projected the risk of exposure-induced death from gamma camera examinations in Yazd Province

IntroductionThe use of nuclear medicine examinations as imaging modalities has recently increased. This study aimed to assess the radiation dose delivered to patients from common diagnostic nuclear medicine examinations and estimate the risk of exposure-induced death (REID). In addition, the frequency of nuclear medicine procedures were evaluated from 2015-2018.Materials and MethodsThe data were collected from adult patients who had undergone cardiac, skeletal, renal, lacrimal, and thyroid imaging. For each patient, the effective dose was calculated using dose conversion factors, and REID was estimated using PCXMC. The frequency of examinations between 2015 and 2018 was obtained from the hospital information system (HIS).ResultsThe highest estimated effective dose was attributed to the scans of myocardial stress (8.09 ± 1.28 mSv), myocardial rest (5.59 ± 1.27 mSv), and thyroid imaging (3.93 ± 0.55 mSv). In addition, cardiac stress examination had the highest REID values for solid cancers (212.5 ± 67.5) and bone scans had the highest REID values for leukemia (11.5 ± 2.5). A large increase in the number of myocardial perfusion scans was a significant contributor to an increase in collective effective dose from 23.37 man-Sv in 2015 to 49.47 man-Sv in 2018, a compound annual growth rate (CAGR) of 26%.ConclusionAlthough the annual frequency and per capita effective dose of nuclear medicine procedures in Yazd Province increased continuously, they were comparably lower than those reported for other countries. Despite this, the cancer risks of nuclear medicine scans at the individual level are negligible (around 0.01% excess fatal cancer risk), yet the increasing tendency for these examinations could be of concern.     

Association between a low dose of proton pump inhibitors and kidney function decline in elderly hypertensive patients: a retrospective observational study

ObjectivesProton pump inhibitors (PPIs) are widely used for acid suppression therapy. Recently, PPI use was reported to be associated with chronic kidney disease (CKD); however, whether a low dose of PPIs is associated with CKD remains unknown.MethodsThis retrospective observational study included hypertensive patients who visited Kenwakai Hospital between 2017 and 2019. Renal parameters, such as the estimated glomerular filtration rate (eGFR) and serum creatinine (Scr), were extracted from medical records and compared between three years before treatment and the baseline. PPI use was assessed as cumulative exposure for three years.ResultsThe study population included 152 patients (57.9% men; mean age, 74.5 years). Of those, 35.5% were PPI users (low dose, 17.1%; high dose, 18.4%). A significant decrease in eGFR and an increase in Scr were observed between three years before treatment and the baseline in the high-dose PPI group but not the non-use or low-dose PPI groups.ConclusionsOur results suggest that a low dose of PPIs may be safe in clinical settings, but further prospective studies are needed to clarify our findings.     

CT colonography versus double-contrast barium enema for screening of colorectal cancer: comparison of radiation burden

Our aim is to compare the radiation dose associated with a low-dose CT colonography (CTC) protocol for colorectal cancer screening with that delivered by double-contrast barium enema (DCBE). CTC of twenty asymptomatic individuals (M:F = 10:10) participating to a colorectal cancer screening program and DCBE of fifteen patients (M:F = 6:9) were evaluated. For CTC, absorbed dose was determined by calculating the dose-length product for each CTC examination from measurements on a CT dose phantom equipped with a CT ion chamber. For DCBE, the free-in-air Kerma at the patient’s X-ray entry surface and the Kerma-area product during fluoroscopy and fluorography were measured with a Barracuda system, with fluoroscopy times being recorded blinded to the performing operator. Effective dose at CTC was 2.17 ± 0.12 mSv, with good and excellent image quality in 14/20 (70%) and 6/20 cases (30%), respectively. With DCBE, effective patient dose was 4.12 ± 0.17 mSv, 1.9 times greater than CTC (P < 0.0001). Our results show that effective dose from screening CTC is substantially lower than that from DCBE, suggesting that CTC is the radiological imaging technique of the large bowel with the lowest risk of stochastic radiation effects.     

The need to increase patient awareness of radiation exposure in imaging modalities: A study on the awareness and attitude of patients

BackgroundA decline in requests for unnecessary imaging can be achieved through increased patient awareness about imaging modalities and can thus reduce radiation exposure. This study aimed to evaluate patient awareness and attitude about radiation exposure in various imaging modalities.MethodsThis cross-sectional study was performed on 900 patients and used a 12-item questionnaire, of which 824 were fulfilled and analyzed. Statistical analysis was done using SPSS software version 18.ResultsThe age of respondents ranged from 18-82; most participants were male (71.5%). The highest patient-estimated radiation exposures were for radiology, CT scans, and mammography. More than 20% of individuals believed that ionizing radiation (IR) is used in MRI, and 60% stated that IR is not used in mammography. Results show a significant statistical difference between attitude and behavior of respondents on the question about knowing who to address questions to in regard to amount of radiation, but they asked the person who is more accessible such as a radiology technologist instead of a medical physicist (P < 0.05). In addition, there was significant statistical difference between question 3 (X-ray is used in which method of radiation?) and question 4 (scoring of radiation exposure in each of the imaging modalities; Score one means no radiation, score has more than one meaning of rays), which indicates accuracy of responses of referees (P <0.05). 73.4% of individuals agree about the importance of reduction of radiation during imaging, and most of the individuals (87%) tended to be aware of radiation exposure in each of imaging modalities.ConclusionGiven the low patient awareness about imaging modalities and radiation dose, it is recommended to prepare brochures and guidance about radiation exposure and absorbed doses in each modality, to be provided and displayed in imaging clinics.     

Monte Carlo evaluation of effective dose and risk of exposure induced cancer death (REID) for common examinations in stereo radiography (EOS) imaging: Considering age and gender

IntroductionThe aim of this study is to evaluate the effective dose and cancer risk of examinations in EOS imaging system in different age and gender groups.Materials and methodsIn total, 555 patients who had undergone common EOS imaging examinations were entered into the study. Exposure parameters and patients’ characteristics for lower limb, full spine and full body imaging techniques, at different gender and age groups, were evaluated. Finally, effective dose and risk of exposure induced cancer death (REID) was calculated with the Monte Carlo based PCXMC software.ResultsThe difference between average effective doses of male and female was not significant (p ≥ 0.05), however, the corresponding REID showed statistically significant difference (p ≤ 0.001). The average effective dose of patients (without considering technique, age and gender) was obtained as 0.13 mSv. The corresponding average REID was 8.84 per million. The maximum average effective dose value was obtained for patients over 10 years of age with the full body technique (0.17 ± 0.05 mSv). The maximum average REID value was obtained for full body technique and for patient with 0–10 years old (15.20 ± 10.00 per million).ConclusionIn common EOS imaging examinations, the effective dose and REID values of patients in both genders in all age groups are less than the corresponding values in other imaging modalities (according to previous studies). However, according to stochastic effects of ionizing radiation and based on the As Low As Reasonably Achievable (ALARA) principle, more considerations are necessary, especially in the full body technique and for female examinations.     

Low radiation dose imaging of myocardial perfusion and coronary angiography with a hybrid PET/CT scanner

Objectives: To test the image quality and feasibility of a sequential low radiation dose protocol for hybrid cardiac PET/CT angiography (CTA). Background: Multidetector computed tomography (MDCT) is a non‐invasive method for coronary angiography. The negative predictive value of MDCT is high but perfusion imaging has a role in detecting functional significance of coronary lesions. This has encouraged combining these techniques. However, radiation dose is of concern. We report our first experiences with a low dose sequential CTA mode applicable to hybrid imaging. Methods: In the first phase, 10 consecutive cardiac MDCT angiographies were performed with spiral acquisition and compared in terms of image quality and dose with the following 10 patients performed with a new sequential mode. In the second phase, feasibility and radiation dose of a combined ¹⁵O‐water rest‐stress PET perfusion/sequential CTA protocol were assessed in another group of 61 consecutive patients. Results: Mean effective radiation dose was 60% lower in the sequential group than in the spiral group (19·3 versus 7·6 mSv, P<0·001). In the second phase, the new sequential hybrid protocol proved possible in 87% of the patients given the preconditions determined by the manufacturer. Mean effective dose of the CT acquisition was 7·6 mSv and total dose from the PET/CTA hybrid study 9·5 mSv. Conclusion: Low dose PET/CT allows cardiac hybrid studies with <10 mSv. The protocol can be applied to almost nine out of 10 patients with CT image quality comparable to spiral acquisition.     

新一代基于模型的迭代重建中肺特异性设置在亚mSv胸部CT检查中的应用

目的 比较自适应统计迭代重建（ASIR）、常规基于模型的迭代重建（MBIRc）、新一代基于模型的迭代重建（MBIRn）中肺特异性设置（MBIR_RP20和MBIR_NR40）重建算法对亚mSv胸部CT图像质量的影响。方法 收集接受两次胸部CT平扫的受检者30例。初检采用常规剂量（噪声指数=14） ASIR重建。复查采用低辐射剂量方案（噪声指数=28）,分别采用标准算法和肺算法ASIR、MBIRc、MBIR_RP20和MBIR_NR40重建,重建层厚0.625 mm。在标准算法ASIR、MBIRc和MBIR_NR40重建图像上测量胸廓入口层面、气管隆突下层面和肝门层面背部肌肉、皮下脂肪相同部位ROI的CT值与噪声（SD）,并计算SNR,采用单因素方差分析比较各重建算法SD和SNR。于肺窗ASIR、MBIRc、MBIR_RP20和纵隔窗标准算法ASIR、MBIRc、MBIR_NR40进行噪声和细节结构清晰度5分法主观评分,并采用Wilcoxon符号等级检验进行统计学分析。结果 初检有效剂量为（3.01±1.89） mSv,复查有效剂量为（0.88±0.83） mSv,下降约70.76%。MBIR_NR40图像噪声明显低于常规剂量ASIR、低剂量ASIR和MBIRc（P均< 0.05）。MBIR_NR40图像SNR绝对值明显大于常规剂量ASIR、低剂量ASIR和MBIRc（P均< 0.05）。MBIR_NR40的主观图像噪声评分低于常规剂量ASIR和MBIRc（P均< 0.05）;MBIRn可更清晰地显示肺、纵隔及上腹部细节结构,评分高于MBIRc和ASIR（P < 0.05）。结论 在胸部CT平扫时,与ASIR、MBIRc相比,MBIRn肺特异性设置中MBIR_NR40可显著降低图像噪声并提高SNR,可减少辐射剂量约70％,在低剂量条件下,MBIR_RP20可更好地显示肺内、MBIR_NR40可更好地显示纵隔、上腹部细节结构。     

Estimation of Radiation Exposure to Workers During [18F] FDG PET/CT Procedures at Molecular Imaging Center,Oman

Positron-emission tomography (PET) is the imaging modality of choice in oncology. In addition, there are several indications for using PET in cardiology and neurology. The main radiotracer used is the radiolabeled glucose analog [¹⁸F] fluorodeoxyglucose ([¹⁸F] FDG). The high-energy annihilation radiation from positron emission may lead to significant radiation exposure to medical imaging professionals such as technologists and staff nurses, patients, and direct acquaintances of the patient. In this cross-sectional observational study, the effective dose to workers in the Molecular Imaging Center from patients injected with [¹⁸F] FDG is assessed. Dose rates were estimated by a calibrated, portable gamma-ray survey meter at 0.3, 0.5, 1.0, and 2.0 m from 70 patients who underwent whole body [¹⁸F] FDG PET/CT procedure immediately and 2 hours post-injection. Electronic personal dosimeters were used to determine the radiation doses per PET/CT imaging for the five staff who directly involved in handling of the injected patients. The staff includes two technologists, two staff nurses, and one medical physicist. The mean dose rates from patients after injection and standard deviation (μSv/h) for the four distances were 98.1 ± 20.0, 55.3 ± 20.0, 28.2 ± 10.0, and 10.8 ± 5.0, respectively. After 2 hours, the measurements significantly dropped to 45.7 ± 10.0, 23.6 ± 10.0, 9.9 ± 4.0, and 3.7 ± 1.0 μSv/h. The average effective dose values for a technologist from injected patients throughout the procedure of PET/CT study was 4.17 μSv per study or 5 mSv/y. This is less than the annual limit recommended by the International Commission on Radiological Protection of 20 mSv/y received in the medical imaging profession.     

How do radiographic techniques affect image quality and patient doses in CT?

The radiation dose received by patients who undergo CT examinations has become a subject of considerable interest. Adult effective doses for head CT examinations are of the order of 1 to 2 mSv, and for single body examinations, patient doses are typically between 4 and 6 mSv. These doses are high in comparison to most other types of radiological examinations that use ionizing radiation. Patient CT doses may also be compared with natural background (3 mSv/year), dose limits to members of the public (1 mSv/year), and the highest level of occupational exposure, which is about 5 mSv/year. The advent of multi-slice technology will serve to increase CT utilization, as well as individual doses for any given examination. Radiologists are responsible for medical radiation doses to their patients, and it is imperative that they understand the relationship between radiation dose and image quality. In this review, we address the impact that variations in radiographic techniques (ie, selected values of X-ray kVp and mAs) have on patient doses as well as the quality of the resultant CT images.     

胸部低剂量CT辅助诊断新型冠状病毒肺炎

目的 探讨胸部低剂量CT（LDCT）辅助诊断新型冠状病毒肺炎（COVID-19）的临床应用价值。方法 收集50例咽拭子新型冠状病毒（2019-nCoV）核酸检测阳性的COVID-19患者。首次胸部CT采用常规剂量扫描（常规剂量组），随访胸部CT采用LDCT扫描方案（LD组），对2组图像质量进行评价。采用Kappa检验分析2名医师评价2组图像质量结果的一致性，比较2组图像质量及2种CT扫描方案X线有效辐射剂量（ED）。结果 2名医师图像质量评分一致性较高（Kappa=0.65，P<0.05）LD组与常规剂量组之间图像质量差异无统计学意义（Z=-0.93，P=0.35）。LD组ED[（2.43±0.66）mSv]较常规剂量组[（4.02±1.03）mSv]减少约39.55%（t=0.85，P<0.01）。结论 胸部LDCT可用于临床筛查和辅助诊断COVID-19，图像质量可满足临床诊断要求，且能降低辐射剂量，具有重要临床应用价值。     

数字减影血管造影手术室护理人员辐射恐惧心理现况分析

目的了解数字减影血管造影(DSA)手术室护理人员辐射恐惧心理现状及对辐射防护知识的认知度。方法选取115名DSA手术室护理人员进行问卷调查,调查内容包括辐射恐惧心理状况和辐射防护知识。比较不同特征人员辐射恐惧感差异。结果回收有效问卷115份。愿意从事DSA辐射环境工作的人数占80.87%(93/115),护理人员在从事DSA工作前对辐射防护知识了解占80.87%(93/115),具有个人辐射防护习惯的护士占91.30%(105/115),对职业辐射照射有恐惧感的护士占59.13%(68/115),担心DSA辐射环境对胎儿和本人健康影响的人数分别占90.43%(104/115)和86.96%(100/115),知道3种辐射防护方法、电离辐射的生物效应、个人年剂量限值和人体对辐射高度敏感组织4项放射卫生知识的人数分别占86.09%(99/115)、67.83%(78/115)、67.83%(78/115)和81.74%(94/115)。担心DSA手术室职业辐射对本人健康影响的护理人员辐射恐惧发生率更高,差异有统计学意义(x2=19.647,P<0.05)。结论DSA手术室护理人员职业辐射恐惧心理较普遍,对辐射防护知识认识和掌握并不全面应,应建立一个完善、持续的DSA手术室护士辐射安全教案。     

History of health management for radiation accident and disaster

According to the chronological evidences of radiation accident and disaster in the world, we can easily learn the valuable lessons on radiation health effects and also a necessity of well preparatory and organized system and network of emergency radiation medicine. Especially countermeasures on emergency radiation medicine have been categorized simply into two groups: acute and chronic effects, and high-dose and low-dose consequences. Based on the identification of potential impacts on radiation health and environmental effects, referring the past accidents and disasters, comprehensive risk analysis including risk estimation, risk management and risk communication is really required for maintaining healthy lives and safeguards in the unavoidable nuclear age of the 21st century.     

前置自适应统计迭代重建技术对体模肺纯磨玻璃结节图像质量及辐射剂量的影响

目的 分析高分辨率Revolution CT不同权重前置自适应统计迭代重建技术（Pre-ASiR-V）对仿真胸部体模中肺纯磨玻璃结节（pGGN）图像质量及辐射剂量的影响,以寻找最佳Pre-ASiR-V权重。方法 采用Revolution CT对含有4个pGGN的仿真胸部体模进行扫描,Pre-ASiR-V权重分别设置为0、20%、40%、60%、80%和100%,记录并比较不同Pre-ASiR-V权重图像的平均噪声、有效辐射剂量（ED）和pGGN图像质量的主观评分。结果 Pre-ASiR-V权重为0、20%、40%、60%、80%和100%的图像平均噪声分别为（17.93±2.20） HU、（17.30±3.68） HU、（18.20±3.44） HU、（18.80±0.20） HU、（19.87±2.56） HU和（15.90±4.56） HU,差异无统计学意义（F=0.568,P=0.723）;ED分别为7.40 mSv、5.16 mSv、3.36 mSv、1.97 mSv、0.97 mSv和0.33 mSv,与Pre-ASiR-V为0的图像比较,随着Pre-ASiR-V升高,ED分别降低30.27%、54.59%、73.38%、86.89%、95.54%。2名医师对pGGN图像的主观评分一致性较好（Kappa=0.778,P=0.003）,评分均 ≥ 3分。Pre-ASiR-V权重为80%及100%时,图像的主观评分略低。结论 Pre-ASiR-V权重对仿真胸部体模高分辨率图像的噪声影响较小,但可显著降低辐射剂量;Pre-ASiR-V权重60%为最佳选择。