Radiation Risk Reduction Research Articles

Multi-detector computed tomography in traumatic abdominal lesions: value and radiation control

Background, The contextA prospective study was conducted involving 81 patients (mean age, 20.79 years) with abdominal trauma who underwent ultrasonography and post-contrast CT on MDCT scanner. The total DLP for each patient was reviewed, and the effective dose was calculated. Purpose of the study to: explore the role of MDCT in assessing traumatic abdominal lesions, demonstrate radiation dose delivered by MDCT, and describe specific CT technical features to minimize radiation.ResultsThe spleen was the most commonly injured organ (49.4%) followed by liver (39.5%) and kidney (24.7%). Pancreatic injury occurred in seven patients, whereas only two patients had intestinal injuries. One patient had adrenal injury. Minimal, mild and moderate free intra-peritoneal fluid collection was detected in 21 (25.9%), 47 (58%) and 10 (12.3%) patients, respectively. Only three (3.7%) patients had no collection. One patient had active uncontrolled bleeding and died. Radiation dose was below the detrimental level (calculated effective dose), with optimal image quality.ConclusionsMDCT is sensitive to all types of traumatic abdominal lesions. Not only in determining the injury, but also in its grading. MDCT has affected the treatment directions, spotting a focus on conservative treatment by raising the diagnostic confidence. FAST cannot be the sole imaging modality. The individual radiation risk is small but real. Advancements in medical imaging reduce radiation risk.

Emerging Technologies in Spinal Surgery: Ultra-Low Radiation Imaging Platforms.

Spine surgery has seen tremendous growth in the past 2 decades. A variety of safety, practical, and market-driven needs have spurred the development of new imaging technologies as necessary tools for modern-day spine surgery. Although current imaging techniques have proven satisfactory for operative needs, it is well-known that these techniques have negative consequences for operators and patients in terms of radiation risk. Several mitigating techniques have arisen in recent years, ranging from lead protection to radiation-reducing protocols, although each technique has limits. A hitherto-problematic barrier has been the fact that efforts to diminish radiation emission come at the cost of reduced image quality. To describe new ultra-low radiation imaging modalities that have the potential to drastically reduce radiation risk and minimize unacceptable adverse effects. A literature review was performed of articles and studies that used either of 2 ultra-low radiation imaging modalities, the EOS system (EOS-Imaging S.A., Paris, France) and LessRay (NuVasive, San Diego, CA). Both ultra-low radiation imaging modalities reduce radiation exposure in the preoperative and perioperative settings. EOS provides 3-dimensional reconstructive capability, and LessRay offers intraoperative tools that facilitate spinal localization and proper visual alignment of the spine. These novel radiation-reducing technologies diminish patient and surgeon exposure, aid the surgeon in preoperative planning, and streamline intraoperative workflow.

Reducing Fluoroscopic and Cineangiographic Contribution to Radiation Exposure for Chronic Total Coronary Occlusion Interventions

BackgroundThe treatment of chronic total coronary occlusions (CTO) carries the highest radiation exposure among percutaneous coronary interventions (PCI). In order to minimize radiation damage, we need to understand and optimize the contribution of all components of radiation exposure. MethodsA total of 1000 CTO procedures performed between 2011 and 2020 were compared according to implemented radiation modifications. Group 1 used the original set-up of the X-ray equipment (Artis Zee, Siemens). In group 2 a modified protocol aimed at reducing the fluoroscopy exposure, in group 3 further modifications aimed at reducing cineangiographic exposure. ResultsDespite an increased lesion complexity, Air Kerma (AK) was reduced from 2619 mGy (1653–4574) in group 1 to 2178 mGy (1332–3500; p < 0.001) in group 2 by mainly reducing fluoroscopic contribution by 54.1%, the cineangiographic contribution was lowered by only 6.6%. In group 3 AK dropped drastically to 746 mGy (480–1225; p < 0.001) mainly by reducing the cineangiographic contribution by 53.4%, still there was a further reduction of fluoroscopy contribution of 8.2%. This also led to a reduction of the skin entry dose from 1038 mGy (690–1589) in group 2 to 359 mGy (204–591; p < 0.001) in group 3. This was achieved both in normal weight and obese patients, and both in antegrade and retrograde procedures. ConclusionsThe present study demonstrates that by modifying both the fluoroscopic and cineangiographic contribution to radiation exposure a drastic reduction of radiation risk can be achieved, even in obese patients. Currently accepted radiation thresholds may no longer be a limit for CTO PCI.

Weakly-supervised progressive denoising with unpaired CT images.

Although low-dose CT imaging has attracted a great interest due to its reduced radiation risk to the patients, it suffers from severe and complex noise. Recent fully-supervised methods have shown impressive performances on CT denoising task. However, they require a huge amount of paired normal-dose and low-dose CT images, which is generally unavailable in real clinical practice. To address this problem, we propose a weakly-supervised denoising framework that generates paired original and noisier CT images from unpaired CT images using a physics-based noise model. Our denoising framework also includes a progressive denoising module that bypasses the challenges of mapping from low-dose to normal-dose CT images directly via progressively compensating the small noise gap. To quantitatively evaluate diagnostic image quality, we present the noise power spectrum and signal detection accuracy, which are well correlated with the visual inspection. The experimental results demonstrate that our method achieves remarkable performances, even superior to fully-supervised CT denoising with respect to the signal detectability. Moreover, our framework increases the flexibility in data collection, allowing us to utilize any unpaired data at any dose levels.

Deep Learning Driven Noise Reduction for Reduced Flux Computed Tomography.

Deep neural networks have received considerable attention in clinical imaging, particularly with respect to the reduction of radiation risk. Lowering the radiation dose by reducing the photon flux inevitably results in the degradation of the scanned image quality. Thus, researchers have sought to exploit deep convolutional neural networks (DCNNs) to map low-quality, low-dose images to higher-dose, higher-quality images, thereby minimizing the associated radiation hazard. Conversely, computed tomography (CT) measurements of geomaterials are not limited by the radiation dose. In contrast to the human body, however, geomaterials may be comprised of high-density constituents causing increased attenuation of the X-rays. Consequently, higher-dose images are required to obtain an acceptable scan quality. The problem of prolonged acquisition times is particularly severe for micro-CT based scanning technologies. Depending on the sample size and exposure time settings, a single scan may require several hours to complete. This is of particular concern if phenomena with an exponential temperature dependency are to be elucidated. A process may happen too fast to be adequately captured by CT scanning. To address the aforementioned issues, we apply DCNNs to improve the quality of rock CT images and reduce exposure times by more than 60%, simultaneously. We highlight current results based on micro-CT derived datasets and apply transfer learning to improve DCNN results without increasing training time. The approach is applicable to any computed tomography technology. Furthermore, we contrast the performance of the DCNN trained by minimizing different loss functions such as mean squared error and structural similarity index.

A preliminary study on the radiation dose reduction during catheterization procedures using simple partial patient shielding.

Reduction in X-ray exposure during cardiac catheterization is important to reduce radiation risks to operators and personnel. Reducing scattered radiation from the patient can achieve this goal. The goal of this study was to evaluate the reduction in radiation using simple partial shielding of patients undergoing cardiac catheterization. By putting a lead-based apron on the lower extremities of patients undergoing cardiac catheterization, we analyzed the reduction in total radiation dose with and without this shielding. One hundred and twelve patients were divided into two groups. In one group, the protective lead-based apron was put on the lower extremities of patients. Another group did not have any shielding. Total duration of angiography was 332 minutes and 45 seconds in the first group and 269 minutes and 10 seconds in the second group. The total radiation exposure was 33 μGy in the first group vs 606 μGy in the second group. Despite higher exposure time, total radiation dose was 22 times lower in the simple shielded group. Our simple method without any additional cost can significantly reduce radiation exposure in the cardiac catheterization laboratory.

COPD Imaging on a 3rd Generation Dual-Source CT: Acquisition of Paired Inspiratory-Expiratory Chest Scans at an Overall Reduced Radiation Risk.

As stated by the Fleischner Society, an additional computed tomography (CT) scan in expiration is beneficial in patients with chronic obstructive pulmonary disease (COPD). It was thus the aim of this study to evaluate the radiation risk of a state-of-the-art paired inspiratory-expiratory chest scan compared to inspiration-only examinations. Radiation doses to 28 organs were determined for 824 COPD patients undergoing routine chest examinations at three different CT systems–a conventional multi-slice CT (MSCT), a 2nd generation (2nd-DSCT), and 3rd generation dual-source CT (3rd-DSCT). Patients examined at the 3rd-DSCT received a paired inspiratory-expiratory scan. Organ doses, effective doses, and lifetime attributable cancer risks (LAR) were calculated. All organ and effective doses were significantly lower for the paired inspiratory-expiratory protocol (effective doses: 4.3 ± 1.5 mSv (MSCT), 3.0 ± 1.2 mSv (2nd-DSCT), and 2.0 ± 0.8 mSv (3rd-DSCT)). Accordingly, LAR was lowest for the paired protocol with an estimate of 0.025 % and 0.013% for female and male patients (50 years) respectively. Image quality was not compromised. Paired inspiratory-expiratory scans can be acquired on 3rd-DSCT systems at substantially lower dose and risk levels when compared to inspiration-only scans at conventional CT systems, offering promising prospects for improved COPD diagnosis.

Analysis of direction of association between radiation risk perception and relocation using a random-intercept and cross lagged panel model: The Fukushima Health Management Survey.

In the aftermath of a nuclear disaster, a person's radiation risk perception can harm their sociopsychological health. Although there are reports of an association between radiation risk perception and relocation, the direction of this association has not been clarified yet. In this study, we used a random-intercept and cross lagged panel model (RI-CLPM) to investigate the association and its direction between radiation risk perception and the prefectural-level relocation (i.e., inside/outside of Fukushima Prefecture). We did this by using five waves of longitudinal surveys between 2011 fiscal year and 2015 fiscal year among the people affected by the Fukushima disaster in 2011. We included 90,567 participants aged ≥15 years during the time of the disaster who responded to the questionnaire at least once. RI-CLPM was applied to examine the reciprocal relationship between radiation risk perception and locations. We used two radiation risk perception indicators (i.e., genetic effect and delayed effect) and two handling methods on missing data (i.e., listwise deletion and full information maximum likelihood estimation) as sensitive analyses. The effects of radiation risk perception on relocation were found to be negligibly small. Living inside Fukushima Prefecture reduced radiation risk perception irrespective of the difference of indicators or methods, highlighting that radiation risk perception did not dominantly govern whether people were living inside Fukushima Prefecture, but that the locations also affected radiation risk perception. This was the first study to reveal the direction of the association between radiation risk perception and relocation in the aftermath of nuclear disasters.

Radiation risk for patients undergoing cardiac computed tomography examinations

The various technological advancements in computed tomography (CT) have resulted in remarkable growth in the use of CT imaging in clinical practice, not the least of which has been its establishment as the most valuable imaging examination for the assessment of cardiovascular system disorders. The objective of this study was to assess the effective radiation dose and radiation risk for patients during cardiac CT procedures, based on studies from four different hospitals equipped with 128 slice CT equipment. A total of eighty-three patients were investigated in this study with different clinical indications. Effective doses were also calculated using software based on Monte Carlo simulation. The mean patient age (years), weight (kg), and body mass index (BMI (kg/m2)) were 49 ± 11, 82 ± 12, and 31 ± 6, respectively. The results of the study revealed that the tube voltage (kVp) and tube current-exposure time product (mAs) ranged between 100 to 140 and 50 to 840 respectively. The overall average patient dose values for the volume CT dose index [(CTDIvol), in mGy)] and dose length product (DLP) (in mGy·cm) were 34.8 ± 15 (3.7–117.0) and 383.8 ± 354 (46.0–3277.0) respectively. The average effective dose (mSv) was 15.2 ± 8 (1.2–61.8). The radiation dose values showed wide variation between different hospitals and even within the same hospital. The results indicate the need to optimize radiation dose and to establish diagnostic reference levels (DRLs) for patients undergoing coronary computed tomography angiography (CCTA), also to harmonize the imaging protocols to ensure reduced radiation risk.

Implant Placement Under Dynamic Navigation Using Trace Registration: Case Presentations.

Trace registration is a new, alternative registration method for dynamic navigation implant surgery that eliminates the need for an artificial fiducial marker and stent to be present in the CBCT scan, substituting it with other high-contrast landmarks such as teeth, implants, or abutments. Clinical advantages include a streamlined, simplified workflow with fewer opportunities for error; elimination of presurgical steps associated with stent fabrication and imaging; and reduction in radiation risk. Sufficient high-contrast intraoral structures are a prerequisite for using this technique. This case series presents the trace registration protocol and workflow and reports on cases that demonstrate the application of this technology, including postoperative placement accuracy evaluation.

The HARMONIC project: study design for the assessment of radiation doses and associated cancer risks following cardiac fluoroscopy in childhood

The HARMONIC project (Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy in Paediatrics) is a European study aiming to improve our understanding of the long-term health risks from radiation exposures in childhood and early adulthood. Here, we present the study design for the cardiac fluoroscopy component of HARMONIC. A pooled cohort of approximately 100 000 patients who underwent cardiac fluoroscopy procedures in Belgium, France, Germany, Italy, Norway, Spain or the UK, while aged under 22 years, will be established from hospital records and/or insurance claims data. Doses to individual organs will be estimated from dose indicators recorded at the time of examination, using a lookup-table-based dosimetry system produced using Monte Carlo radiation transport simulations and anatomically realistic computational phantom models. Information on beam geometry and x-ray energy spectra will be obtained from a representative sample of radiation dose structured reports. Uncertainties in dose estimates will be modelled using 2D Monte Carlo methods. The cohort will be followed up using national registries and insurance records to determine vital status and cancer incidence. Information on organ transplantation (a major risk factor for cancer development in this patient group) and/or other conditions predisposing to cancer will be obtained from national or local registries and health insurance data, depending on country. The relationship between estimated radiation dose and cancer risk will be investigated using regression modelling. Results will improve information for patients and parents and aid clinicians in managing and implementing changes to reduce radiation risks without compromising medical benefits.

Radiation dose and its protection in the Moon from galactic cosmic rays and solar energetic particles: at the lunar surface and in a lava tube

The lunar surface is directly and continuously exposed to Galactic Cosmic ray (GCR) particles and Solar energetic particles (SEPs) due to the lack of atmosphere and lunar magnetic field. These charged particles interact with the lunar surface materials producing secondary radiations such as neutrons and gamma rays. In a departure from precise GCR and SEP data, we estimated the effective dose equivalent at the lunar surface and in a lunar lava tube in this paper by using PHITS, a Monte Carlo simulation tool. The effective dose equivalent due to GCR particles at the lunar surface reached 416.0 mSv yr−1 and that due to SEPs reached 2190 mSv/event. On the other hand, the vertical hole of the lava tube provides significant radiation protection. The exposure by GCR particles at the bottom of the vertical hole with a depth of 43 m was found to be below 30 mSv yr−1 while inside a horizontal lava tube, the value was less than 1 mSv yr−1 which is the reference value for human exposure on the Earth. We expect that the lunar holes will be useful components in the practical design of a lunar base to reduce radiation risk and to expand mission terms.

Electroanatomic guidance versus conventional fluoroscopy during transseptal puncture for atrial fibrillation ablation.

Technological advancement in the setting of atrial fibrillation (AF) ablation has decreased radiation exposure and complications associated with the procedure. Yet, transseptal puncture (TSP) remains a challenging step that necessitates accurate guidance. We describe our experience performing TSP under electroanatomic (EA) guidance. The analysis included 145 consecutive EA-guided ablation procedures performed between June 2018 and April 2019 and 145 consecutive standard ablations performed before June 2018. EA guidance utilized the CARTO 3 three-dimensional mapping system to reconstruct anatomic and electrical characteristics of the right atrium and fossa ovalis. Patients with a history of previous cardiac surgery were excluded. For EA-guided procedures, the mean patient age was 60 ± 10 years, 75.2% were male, and 69.0% had paroxysmal AF. Similarly, the mean age for conventional procedures was 60 ± 11 years, 71.0% were male, and 71.7% had paroxysmal AF. The fossa ovalis was detected as a region of low voltage, <0.75 mV. EA guidance yielded shorter fluoroscopy times (EA vs. conventional, 3.6 ± 2.5 vs. 13.5 ± 10.5 min; p < .001) and a lower dose area product than conventional guidance (13 ± 11 Gy* cm2 vs. 28 ± 27 Gy* cm2 ; p < .001).The total procedure duration was similar between groups (146 ± 48vs. 148 ± 54 min). There were no significant complications related to TSP. During AF ablation, TSP with EA guidance facilitated safe access to the left atrium while reducing radiation risk to both patients and operators.

Prioritizing Communication About Radiation Risk Reduction in the United States: Results from a Multi-criteria Decision Analysis.

The lack of radiation knowledge among the general public continues to be a challenge for building communities prepared for radiological emergencies. This study applied a multi-criteria decision analysis (MCDA) to the results of an expert survey to identify priority risk reduction messages and challenges to increasing community radiological emergency preparedness. Professionals with expertise in radiological emergency preparedness, state/local health and emergency management officials, and journalists/journalism academics were surveyed following a purposive sampling methodology. An MCDA was used to weight criteria of importance in a radiological emergency, and the weighted criteria were applied to topics such as sheltering-in-place, decontamination, and use of potassium iodide. Results were reviewed by respondent group and in aggregate. Sheltering-in-place and evacuation plans were identified as the most important risk reduction measures to communicate to the public. Possible communication challenges during a radiological emergency included access to accurate information; low levels of public trust; public knowledge about radiation; and communications infrastructure failures. Future assessments for community readiness for a radiological emergency should include questions about sheltering-in-place and evacuation plans to inform risk communication.

Low radiation tomographic reconstruction with and without template information

Low-dose tomography is highly preferred in medical procedures for its reduced radiation risk when compared to standard-dose Computed Tomography (CT). However, the lower the intensity of X-rays, the higher the acquisition noise and hence the reconstructions suffer from artefacts. A large body of work has focussed on improving the algorithms to minimize these artefacts. In this work, we propose two new techniques, rescaled non-linear least squares and Poisson-Gaussian convolution, that reconstruct the underlying image making use of an accurate or near-accurate statistical model of the noise in the projections. We also propose a reconstruction method when prior knowledge of the underlying object is available in the form of templates. This is applicable to longitudinal studies wherein the same object is scanned multiple times to observe the changes that evolve in it over time. Our results on 3D data show that prior information can be used to compensate for the low-dose artefacts, and we demonstrate that it is possible to simultaneously prevent the prior from adversely biasing the reconstructions of new changes in the test object, by means of careful selection of a weights map, subsequently followed by a method called “re-irradiation”. Additionally, we also present a technique for automated tuning of the regularization parameters for tomographic inversion.

Radiation risk reduction analysis considering related adverse events for establishment of people-centred stable iodine prophylaxis

Radiation risk reduction analysis considering related adverse events for establishment of people-centred stable iodine prophylaxis

Radiation risk reduction analysis considering related adverse events for establishment of people-centred stable iodine prophylaxis

Radiation risk reduction analysis considering related adverse events for establishment of people-centred stable iodine prophylaxis

Radiation Risk Awareness Among Health Care Professionals: An Online Survey

This study was conducted to evaluate awareness and knowledge regarding the risk of the ionizing radiation and exposure doses and the suitable techniques for radiation protection among health care professionals in Tabuk City, Saudi Arabia, and to identify areas that require further training and education. A total of 196 responses were collected from two hospitals using a structured seven-item questionnaire. Data were collected between January and May 2019 in Tabuk City, Saudi Arabia. Overall, the study shows a negative trend in knowledge related to radiation risk. Most participants (71.8%) believed correctly that x-ray radiation doses used for diagnostic imaging examinations might increase the risk of patients developing cancer in the future. In terms of awareness regarding the measures of patients’ radiation protection, 30.3% (n = 57) reported that increasing the distance from the source of radiation would be the best way to reduce radiation risk toward patients. Respondents had difficulties determining the exact amount of radiation dose equivalent to that of a chest x-ray in different diagnostic methods. Most respondents reported incorrectly that abdominal ultrasound (86.4%; n = 159) and brain MRI (88%; n = 162) use ionizing radiation. The knowledge of health care professionals regarding radiation risk needs improvement. A focus on educational interventions on radiation protection is required to develop a well-informed medical staff.

P5361Pregnancy in patients with cardiac arrhythmias

Abstract Introduction Negative trends in the state of somatic and reproductive health of the female population are observed in the last decades all over the world. On the background of declining birth rates, the problems of managing pregnancy in women with extragenital pathology become relevant. Aim To study the effects of cardiac arrhythmias and antiarrhythmic treatment on the course and outcomes of pregnancy. Material and methods A total of 55 case histories of pregnant women hospitalized in the Department of Interventional Arrhythmology. All patients signed informed consent to be enrolled in the study. The age of patients ranged from 17 to 41 years (mean age of 30.2±4.0 years). Patients were hospitalized on average at 28.0±6.4 weeks of gestation (from 12 to 37 weeks) and had some form of cardiac arrhythmia. Results Cardiac arrhythmias were idiopathic in 65% of cases; the rest of patients had verified cardiovascular diseases. Cardiac arrhythmias were registered in 41 (74%) of women prior to pregnancy and their arrhythmological history lasted for 7.9±1.1 years. Extrasystolic arrhythmia was the most common type of cardiac arrhythmias: ventricular premature beats occurred in 23 pregnant women (42%) including supraventricular premature beats in 8 patients (14%), supraventricular tachycardia in 12 patients (22%), and ventricular tachycardia (VT) in 5 women (9%). In three cases, VTs were hemodynamically significant. Radiofrequency ablation (RFA) of VT was performed in pregnant women at 26, 27, and 32 weeks of gestation. Five patients with gestational ages of 27–34 weeks received RFA for atrial tachycardia and atrioventricular (AV) reciprocal tachycardia to treat symptomatic intracardiac tachycardia (n=4) and continuous recurrent AV nodal tachycardia (n=1), paroxysms of which were accompanied by destabilization of hemodynamics. AV block was registered in 4 pregnant women (9%); sick sinus syndrome was diagnosed in 1 patient (2%). Implantation of pacemaker was required in 1 case for a second-degree AV block type II (Mobitz type II) at 24 weeks of pregnancy. RFA and pacemaker implantation were carried out with minimal or zero fluoroscopy and only after the 22nd week of pregnancy, that is, without or with reduced radiation risk to the fetus. 16 patients (29%) had cesarean section; the rest of patients had spontaneous vaginal delivery. The average Apgar scores were 8.64 immediately after birth and 9.35 five minutes after birth. Preterm births (n=2) were due to obstetric pathology and were not associated with cardiac arrhythmias. Cardiac arrhythmias were not observed in any patient in childbirth. Conclusions Cardiac arrhythmias, observed in patients, did not require termination of pregnancy. Catheter ablation for symptomatic, hemodynamically significant, and life-threatening cardiac arrhythmias made it possible to effectively guide pregnant women to delivery with a close follow-up.

Estimation of Radon Exhalation Rate, Radium Activity and Uranium Concentration in Biscuit Samples in Iraq

Introduction: Radioisotopes are naturally the main sources of human exposure to external and internal radiation. Biscuit is a type of food that is widely distributed in all markets, especially in the markets of Iraq. Therefore, the current study aimed to measure the radiation level of some nuclei in biscuit samples and determine the radiation risks that may be caused by this snack. Material and Methods: This study aimed to evaluate the concentration of alpha radiation activity in 22 different samples of biscuits collected from the markets in Iraq. The analysis of radium activity and radon exhalation rate was performed by employing alpha-sensitive CR-39 plastic track detectors. Results: The effective radium values ranged within 23.312-200.44 Bq/kg with a mean value of 58.927 Bq/kg. Radon emission values for the mass unit was within the range of 0.172-1.515 𝐵𝑞/kg.h, with a mean of 0.445 Bq /kg.h, while radon emission values for the surface unit were 3.988-34.3 𝐵𝑞 /𝑚2.h, with a mean of 10.081 Bq /m2.h. The uranium concentrations found in these samples were within the range of 0.02-0.172 ppm with a mean value of 0.05 ppm. Moreover, there was a direct relationship between radium activity and radon exhalation rate. Additionally, the findings showed that uranium correlated positively with radium activity. Conclusion: The results of the present study were within internationally permissible limits. Therefore there is no risk of consumption of biscuits on human health. However, we must use modern techniques and techniques to reduce radiation risk.