Average Dose-area Product Research Articles

Assessment of occupational dose during abdominal fluoroscopic-guided procedures in Thailand using nanoDot OSL dosimeters

Interventional radiology is one of the most widely used treatment options for abdominal abnormality. Due to new dose limitations, radiation is a hazard that needs to be considered when choosing the international treatment technique. The aim of this study was to measure the effective/equivalent doses and to investigate the associated factors correlating with the doses during Transarterial Chemoembolization (TACE) and Percutaneous Transhepatic Biliary Drainage (PTBD) for radiologists, technologists and nurses involved with the treatment. This prospective study reports occupational dose per procedure of 57 cases (TACE = 42, PTBD = 15) in a Thailand hospital spanning one year. All staff included in this study wore 30 nanoDot Optically Stimulated Luminescence Dosimeter for measuring doses at 7 bodily locations. The average dose area product and cumulative doses was 151.3 Gy·cm2, 1,185.1 mGy during TACE and 21.3 Gy·cm2, 212.2 mGy during PTBD. The radiation exposure of the radiologists was significantly higher than technologists and nurses (p-value < 0.05). The lead protection equipment was a dose-reducing factor which decreased the dose up to 93%. The present study also contributes to the establishment of an individual dose location report and identifies significant correlations between associated factors and dose values. The left hand (1.2 mSv) and the left eye (1.1 mSv) showed maximum doses during the PTBD procedure. The exceeded dose over the limitation was observed in the left eye. We concluded that the dose feedback was able to increase awareness of the occupation staff. So, dose monitoring, updating education and regular training could be applied simply and effectively to improve skills, while reducing the occupational dose.

Pulsed-field ablation of atrial fibrillation in elderly and frail patients: procedural efficacy and safety from a single-center experience

Abstract Introduction The demographic data shows a growing population, mostly elderly and with multiple comorbidities, therefore becoming increasingly frail. In this context Atrial fibrillation (AF) is the predominant sustained arrhythmia, and over the years trans-catheter isolation of pulmonary veins (PVI) has become a crucial approach in AF treatment. Among the technologies and energy resources employed through the years to perform atrial fibrillation transcatheter ablation, a novel technique has recently begun to gain ground, specifically pulsed-field ablation (PFA). PFA employs sequential brief and high amplitude electrical pulses to induce selective and irreversible electroporation of the myocardium, leading to cell death. The high selectivity of the lesion, ensured by the lower electroporation threshold of myocardial tissue compared to adjacent anatomic structures, allows for a decrease in potential complications associated with conventional thermal ablation. Purpose To assess the efficacy and safety in the use of pulsed field ablation in a selected population of elderly and frail patients undergoing atrial fibrillation ablation. Method We conducted a retrospective study focusing on elderly and frail patients admitted to our centre for paroxysmal or persistent AF ablation. The inclusion criteria were: age greater than 75 years and a Clinical Frailty Scale ≥ 5. The study population consisted of 26 patients [male gender 18, mean age 78 ± 3 years] including 8 who were affected by an oncological or haematological disease at the time of admission. The majority of patients were affected by paroxysmal AF while two of them presented persistent AF (9%). The primary ablation endpoint was the pulmonary vein isolation (PVI) that was achieved by delivering an energy of 2 kV over 8 applications, employing an alternating approach between the two configurations of the basket and flower catheter for each individual vein. Results The short-term success, represented by the complete and verified electrical isolation of the veins was achieved in all 26 patients without any periprocedural complications. First-pass pulmonary vein isolation (FPI) was universally achieved among the patient in study, with a mean skin-to-skin procedural time of 70 ± 30 minutes. From the procedural data perspective, ablation was achieved using an average fluoroscopy time of 22 ± 8.4 minutes and an average dose area product (DAP) of 1320 cGy×cm2. Conclusions In elderly and frail patients, we assessed the efficacy and safety of ablative procedures using the PFA technique. Successful electrical PVI was achieved without additional touch-ups, thanks to a high FPI rate. This results in lower procedural times and shorter intra-operative radiation exposure. These data confer an augmented value within the elderly-frail population, wherein shorter procedural times contribute to a better postoperative course, characterized by reduced bed rest and shorter intra-hospitalization periods.

Advanced pulsed field ablation: comprehensive analysis of safety and efficacy in a real-world cohort

Abstract Background Pulsed field ablation (PFA) represents a novel energy modality for catheter ablation of atrial fibrillation (AF). Initial preclinical and clinical studies indicate a higher safety profile with promising efficacy outcomes as well as shorter procedure times. Real world data are sparce and methods to improve clinical success rates are under development. Methods In this observational study 124 patients underwent pulmonary vein isolation with PFA (Farapulse, Boston) for paroxysmal and persistent AF. For anatomical visualization and optimal positioning of the PFA catheter a 3D mapping system was used (Ensite X, Abbott). Patients were followed over a 15-month period to evaluate both efficacy and safety of PFA in a real-world cohort using an advanced mapping technology. Results The patient cohort had a mean age of 67 ± 11 years, 38% females (n= 47), paroxysmal AF 53% (n = 66), persistent AF 47% (n = 58). Acute pulmonary vein isolation (PVI) rate was 100%. After a median FU of 6 months, 17 patients (14%) had a recurrence of AF. In our study population no esophageal complications, pulmonary vein stenosis, or persistent phrenic palsy occurred. Major complications were observed in 2.4% of the cases (3/124), involving two pericardial tamponades (1.6%) and one vascular complication with intervention (0.8%). There were no stroke events and no occurrences of death. Noteworthy was the absence of complications such as coronary arterial spasm or hemolysis-related acute renal failure. The average dose-area product and average procedure time were 9.54 ± 7.68 µGym² and 57.94 ± 18 minutes, respectively. Conclusion PVI with PFA in a real world cohort demonstrates a high safety profile. Furthermore, high clinical success rates can be achieved also in mixed paroxysmal/persistent AF populations. The use of 3D mapping systems might even improve clinical outcomes of PVI with PFA and will also help to guide more complex ablation strategies in the future. These findings pave the way for further exploration into the long-term benefits and broader applicability of PFA in AF ablation.

The Effect of the Use of Activation 3D Mapping on the Patient X-Ray Load During Radiofrequency Ablation of Typical Atrial Flutter

Supraventricular macro re-entry tachyarrhythmias occupy the leading places among all types of tachyarrhythmias. The most common in this category is typical atrial flutter (AFL). This heart rhythm disorder has a negative impact on the patients’ quality of life. Its complications can lead to disability and death due to possible thromboembolism. Therapeutic treatment is limited in effectiveness. The main method of intervention is catheter radiofrequency ablation (RFA). The standard approach of RFA of AFL is performed without the use of navigation systems under fluoroscopy guidance. However, this results in an increased radiation exposure to the patient and the medical personnel. Modern technologies in the field of invasive electrophysiology make it possible to create anatomical models of heart and reproduce the spread of electrical excitation. However, the routine use of additional navigation methods remains controversial.&#x0D; The aim. To compare the duration of RFA of typical AFL and radiation exposure with the use of anatomical and propagation mapping.&#x0D; Materials and methods. This study is based on the analysis of the treatment results obtained for 53 patients at the National Amosov Institute of Cardiovascular Surgery in the period from 2014 to 2023. Depending on imaging methods, the patients were divided into two groups. The first group included 27 patients with an anatomical mapping of the right atrium. The second group included 26 patients with propagation mapping.&#x0D; Results. In all the patients we have achieved a bidirectional conduction block through cavotricuspid isthmus. In the first group, the total duration of confirming the diagnosis and creating the anatomical model was 312 ± 26 seconds. The mean time to the moment of AFL termination and restoration of sinus rhythm was 230 ± 19 seconds. The average duration of the procedure was 41.5 ± 3.5 minutes, the average fluoroscopy time was 120 ± 10 seconds, the average dose area product (DAP) was 15 ± 1.3 Gy·cm2. In the second group, the average time for creating a 3D propagation model of right atrium and verifying the diagnosis was 748 ± 65 seconds. The average time from the first application to the termination of tachycardia was 227 ± 20 seconds. The average duration of the procedure was 55 ± 4.7 minutes, X-ray time was 93 ± 8 seconds, average DAP was 13 ± 1.1 Gy·cm2. The duration of the procedure in the second group was significantly longer (p = 0.03), however, the radiation exposure and DAP were not statistically different (p = 0.31) between the observation groups.&#x0D; Conclusions. The use of propagation mapping increases the time of the procedure by 24.5% and does not give a significant advantage in reducing the radiation exposure. The use of a navigation system during cavotricuspid isthmus RFA is recommended for concomitant radical treatment of complex supraventricular arrhythmias, such as atrial fibrillation.

Impact of Electronic Collimation on Reducing Unnecessary Patient Dose in Digital Radiography.

In radiology, optimizing radiation protection is crucial, and field collimation plays a critical role in minimizing patient dose. As technology has evolved, electronic collimation has become the preferred method due to its effectiveness in digital imaging systems, replacing traditional film-screen systems. The current study aimed to investigate the prevalence of cropping in digital radiography and its potential impact on patient radiation dose because of improper collimation practices. This retrospective analysis was conducted on digital X-ray machine images. Quality control tests were performed to ensure equipment accuracy, and image cropping was then measured by analyzing archived images. Finally, the cropped image fraction and associated unnecessary radiation doses were calculated. Quality control tests confirmed that all imaging equipment was functioned within acceptable alignment and angle tolerances. The analysis of 911 images revealed a high prevalence of cropping (82%), with significant variation across different projections. Lateral knee images exhibited the highest cropping rate (96.2%), while abdominal images had the lowest (36.1%). Electronic image cropping can lead radiologic technologists to inaccurately define the primary radiation field, affecting image quality and potentially increasing patient radiation exposure. Based on the obtained results, proper collimation can reduce the average Dose Area Product (DAP) by 29.01%. This approach not only enhances patient safety but also minimizes unnecessary radiation exposure and potentially reduces healthcare costs.

Application of virtual navigation in the treatment of macro-re-entrant atrial tachyarrhythmias

Macro-re-entrant atrial tachyarrhythmias occupy the leading positions in the structure of tachyarrhythmias, and one of the most common in this group is atrial flutter. These abnormal rhythms lead to a significant decrease in the quality of patients’ life, and sometimes, indirectly due to complications, can lead to disability and fatal consequences. Medical treatment for this group of arrhythmias has limited effectiveness, and the surgical method of treatment – catheter ablation – comes to the first place. Ablation of atrial flutter is traditionally performed under the guidance of fluoroscopy without the use of a navigation system, but this is associated with increased radiation exposure to patients and staff. Advances in modern arrhythmology make it possible to create anatomical models of heart chambers and activation models of the excitation spreading along anatomical models, reducing the radiation load, but requiring additional equipment and skills. Aim: to compare the procedure duration and radiation load during radiofrequency catheter ablation of the cavo-tricuspid isthmus using 3D navigation with traditional methods. Materials and methods. The work was based on the analysis of treatment results in 84 patients at National M. Amosov Institute of Cardiovascular Surgery affiliated to National Academy of Medical Sciences of Ukraine in the period from 2014 to 2021. Depending on the imaging method, patients were divided into 2 groups. Group I included 31 patients who underwent radiofrequency cavo-tricuspid isthmus (CTI) ablation according to the traditional method under fluoroscopic control without using a navigation system. Group II comprised 27 patients in whom an anatomical model of the right atrium was created. Results. Success criteria were achieved in all groups, bidirectional block line was created at the level of the CTI. In group I, the average time from the first application to the restoration of sinus rhythm was 325 ± 25 s with an average number of applications of 7.4 ± 0.6 (from 5 to 10). The average procedure time was 43.0 ± 3.3 min, with an average X-ray time of 572 ± 44 s and an average dose area product (DAP) was 62.0 ± 5.0 Gy.cm2. In group II, the total duration of the first stage of the intervention was 312 ± 26 s. The average time to stopping tachycardia and restoring sinus rhythm was 230 ± 19 s. The average time from sinus rhythm restoration to confirmation of bidirectional CTI block was 71 ± 6 s with an average number of applications of 3.2 ± 3.0 per the procedure. The average procedure time was 41.5 ± 3.5 min, the average X-ray time was 120 ± 10 s, the average DAP was 15.0 ± 1.3 Gy.cm2. Conclusions. The usage of the anatomical model of the right atrium reduces X-ray exposure by 75.8 %, in comparison to the traditional technique, during radiofrequency catheter ablation of the cavo-tricuspid isthmus with similar procedure time. The anatomical model can be recommended for ablation of the cavo-tricuspid isthmus.

Radiation-induced cataract-an occult risk for urologists

Radiation-induced cataracts represent arelevant risk to people occupationally exposed to radiation. The annual limit dose for the eye lens was reduced to 20 mSv per year by German legislation (radiation protect law StrlSchG 2017; 2013/59/Euratom) based on recommendation of International Commission on Radiation Protection (2011 ICRP) to avoid radiation-induced cataracts. Is there arisk of exceeding the annual limit dose for the eye lens in routine urological practice without special radiation protection for the head? As part of aprospective, monocentric dosimetry study, of 542 different urological, fluoroscopically guided interventions, the eye lens dose was determined using aforehead dosimeter (thermo-luminescence dosemeter TLD, Chipstrate) over aperiod of 5months. An average head dose of 0.05 mSv per intervention (max. 0.29 mSv) was found with an average dose area product of 485.33 Gy/cm2. Significant influencing factors for ahigher dose were ahigher patient body mass index (BMI), alonger operation time, and ahigher dose area product. The level of experience of the surgeon showed no significant influence. With 400 procedures per year or an average of 2procedures per working day, the critical annual limit value for the eye lenses or for the risk of radiation-induced cataract would be exceeded without special protective measures. Consistently effective radiation protection of the eye lens is essential for daily work in uroradiological interventions. This may require further technical developments.

Overview of cone beam CT patient radiation dose levels in a dental institution regarding patient age, clinical indications, and CBCT scanners

<h3>Objective</h3> To present an overview of typical cone beam CT patient radiation dose levels in a dental institution for different age groups, clinical indications, and CBCT scanners. <h3>Study Design</h3> The patient dose database for CBCT exams performed in 2019, using the 3D Accuitomo 170 (Morita, Kyoto, Japan) and NewTom VGi evo (QR, Verona, Italy) CBCT systems in a dental education institution was assessed and extracted through an automated dose quality management system DOSE (Qaelum NV, Leuven, Belgium). Data regarding age, gender, and clinical indications related to patients, and the type of CBCT scanner, FOV size (small, medium, and large), and dose-area product (DAP) value related to imaging were recorded for each CBCT imaging procedure. A descriptive data analysis was performed, and the average DAP, an average of effective dose, and frequency of examinations were calculated. <h3>Results</h3> A total of 5,166 CBCT examinations were screened. Surgical planning and follow-up were the most frequent clinical indication being the majority indication in medium (35.7%) and large (27.6%) FOVs. In general, DAP and effective dose increased with FOV size. The effective dose ranged from 42.9 to 188.1 µSv for Accuitomo 170 to 46.7 to 140.1 µSv for NewTom VGi evo. <h3>Conclusion</h3> DAP values and effective doses were heterogeneously distributed amongst age groups and mostly influenced by clinical indications of the related FOV size selection. While patient-specific imaging remains advocated, the fact that two-thirds of the indications are surgically oriented makes the medium and large field of views predominant. Developers of CBCT systems could be advised to move towards patient-specific collimation and dynamic field-of-view selection, preferably via an automated algorithm to facilitate clinical implementation of the optimal patient-specific and indication-oriented dose (ALADAIP). <b>Statement of Ethical Review</b> Ethical review was sought and study was exempted from ethical review

Evaluation of DAP Values Obtained from Chest X-rays in Children under 12 Years of Age Referred to Educational Hospitals of Birjand University of Medical Sciences in 2020

Purpose: Dose Area Product (DAP) is a quantity for radiation risk assessment in diagnostic X-ray tests. Children's tissues are up to 10 times more sensitive to radiation than adults, and life expectancy is higher in children than adults, as well as a higher risk of hematopoietic and mass malignancies in them. Therefore, this study aimed to measure DAP values for X-ray fields adjusted by Birjand radio-technologists in chest X-rays of children under 12 years of age.&#x0D; Materials and Methods: 233 children from Birjand University hospitals who performed chest X-rays were included in the study. To collect data related to DAP, the DAP meter model KermaX® plus SDP was used. It should be noted that no intervention was performed in the patient's imaging method and at the time of radiation and measurement of the DAP values, there was no need for the patient's presence. In the end, the measured DAP values were compared with DAP values of other studies. Data were analyzed using SPSS software version 22 at 5% error level using Analysis of Variance (Anova), t-test, and Pearson correlation tests.&#x0D; Results: Out of 233 patients who were included in the study, 134 males (57.5%) and 99 females (42.5%) participated in the study, it should be noted that there was no significant difference between the mean of DAP in male and female (p = 0.52). In our study, the average DAP was 5.78 ± 3.54 μGy.m2 and DAP values in the range of 0.55 μGy.m2 to 15.54 μGy.m2 that were higher than the average of other studies and there was a significant difference. There was a direct relationship between radiation field dimensions and DAP values so that as the dimensions of the radiation field increase, the DAP value increases. There was a significant difference between the mean DAP of the lowest and the highest age groups, lowest and the highest age groups, and lowest and the highest height groups of patients.&#x0D; Conclusion: In our study, it was observed that there is a significant relationship between patients' weight, age, and height, radiation field dimensions with DAP values. The amount of DAP in the present study was significantly higher than in other studies. The most important effective parameter in DAP is the radiation field size and if sufficient optimization is done in imaging parameters (kVp, mAS, field size), the DAP values will be greatly reduced.

The efficacy of TACE; how can automated feeder software help?

BackgroundThis is a prospective study of 44 patients having 57 hepatocellular carcinoma (HCC) lesions indicated for transarterial chemoembolization (TACE) and a control group of 41 patients having 55 HCC lesions. TACE in the study group was performed on an angiography machine with an installed automated feeder detection (AFD) software (EmboGuide; Philips Healthcare, Best, The Netherlands) and in the control group was performed on a similar angiography machine (ALLURA XPER FD 20, Philips, Holland), but lacking the AFD software. The aim is to evaluate the clinical utilization of cone-beam CT (CBCT) and (AFD) software in accurate detection of (HCC) arterial feeders, the effect of (AFD) software utilization on the outcome of (TACE) and its utilization effect on fluoroscopy time and radiation dose to the patient during the (TACE) procedure.ResultsThe highest percentage of agreement was between the number of arterial feeders detected by EmboGuide and the actual number of feeders detect during embolization reaching 91.2% with p value < 0.001. The residual non-intended non-embolized areas among the study group at 1-month follow-up were found in 2 out of 57 lesions compared to 9 out of 55 lesions in the control group. The average dose-area product (DAP) among the study group was less than that of the control group.ConclusionCBCT using AFD software provides more information about tumor feeders with consequent more efficient targeted embolization, higher success rate of TACE and less patient exposure to radiation.

Reference Person Dose-Area Product and Organ Dose-Area Product Estimates During Pelvis Radiography in Some Selected Centres in Lagos Conurbation, Nigeria

Background: In diagnostic radiology, focus on patient’s dose measurement has been on the estimation of entrance skin surface dose and its equivalent risk assessor (effective and organ doses). So, this study identified DAP’s as capable of performing same function as ESD in patient dose monitoring. Thus, reported estimates on dose area product (DAP) and the equivalent risk to organ’s exposed in adult patients during pelvis examination in Lagos State, Nigeria. Patients and Methods: Gender percentage ratio of 39.4 and 60.4 for male and female respectively, from six selected centres, exposed for both pelvis AP and LAT of the procedures were monitored using mathematical approach and dose Cal version 2.31 software, designed to monitor organ’s dose and DAP. Results: The average DAP and it equivalent organ dose area product (ODAP) values recorded from a population of 278 adult patients studied were found to be within expected limits for a reference adult person. Though, DAP for pelvis AP was found almost twice that recorded for the pelvis LAT. High and low organ DAP recorded for both gender from urinary bladder and lungs respectively for pelvis AP whilst these were pelvis bone and lungs for male and ovaries and lungs for female from pelvis LAT respectively. High values were equally recorded for the reproductive organs (Testicles and Ovaries) during pelvis AP. Conclusion: This study therefore suggest that better understanding of organ anatomical position in relation to specific examination will better promote as low as reasonable practicable.

Intervariability in radiographic parameters and general evaluation of a low-dose fluoroscopic technique in patients with idiopathic scoliosis.

BackgroundRadiographic images in adolescent idiopathic scoliosis (AIS) have a potential radiation-induced oncogenic effect; thus lowering radiation dose by using fluoroscopic imaging technique of low-dose fluoroscopic technique (LFT) which might be relevant for clinical evaluation.PurposeTo compare radiographs of LFT with gold standard radiographs for AIS ordinary radiographic technique (ORT).Material and MethodsImage quality was evaluated for LTF and ORT of a child phantom and two 3D-printed models (3DPSs) of AIS. We measured the primary physical characteristics of noise, contrast, spatial resolution, signal-to-noise ratio, and contrast-to-noise ratio. Three independent evaluators assessed the radiographs by observer-based methods of image criteria (ICS) and visual grading analysis(VGAS). Radiation doses were evaluated by the dose-area-product (DAP) of the 25 phantom radiographs. Reliability and agreement of Cobb’s angle (CA) and other radiographic parameters were evaluated on the 3DPSs and reliability on 342 LFT.ResultsThe average noise and contrast were approximately 15-fold higher for LFT. SNR and CNR were similar. Overall, ICS and VGAS were 3-fold higher for ORT than for LFT for L3 and similar for Th6. Reliability and agreement were good for the experimental LFT, and the interclass correlation coefficient for CA was 0.852 for the clinical LFT. The average DAP and effective dose for LFT were 8-fold lower than those for ORT.ConclusionIn conclusion, LFT is reliable for CA measurements and is thus useful for clinical outpatient follow-up evaluation. Even though the image quality is lower for LFT than ORT, the merits are the substantially reduced radiation and a lowered malignancy risk without compromising the measurement of Cobb’s angle, thus following the principles of ALARA.

The radiation doses and radiation protection on the endoscopic retrograde cholangiopancreatography procedures.

Although many interventions involving radiation exposure have been replaced to endoscopic procedure in the gastrointestinal and hepatobiliary fields, there remains no alternative for enteroscopy and endoscopic retrograde cholangiopancreatography (ERCP), which requires the use of radiation. In this review, we discuss the radiation doses and protective measures of endoscopic procedures, especially for ERCP. For the patient radiation dose, the average dose area product for diagnostic ERCP was 14-26 Gy.cm², while it increased to as high as 67-89 Gy.cm² for therapeutic ERCP. The corresponding entrance skin doses for diagnostic and therapeutic ERCP were 90 and 250 mGy, respectively. The mean effective doses were 3- 6 mSv for diagnostic ERCP and 12-20 mSv for therapeutic ERCP. For the occupational radiation dose, the typical doses were 94 μGy and 75 μGy for the eye and neck, respectively. However, with an over-couch-type X-ray unit, the eye and neck doses reached as high as 550 and 450 μGy, with maximal doses of up to 2.8 and 2.4 mGy/procedure, respectively.A protective lead shield was effective for an over couch X-ray tube unit. It lowered scattered radiation by up to 89.1% in a phantom study. In actual measurements, the radiation exposure of the endoscopist closest to the unit was reduced to approximately 12%. In conclusion, there is a clear need for raising awareness among medical personnel involved endoscopic procedures to minimise radiation risks to both the patients and staff.

An evaluation of the effect of tube potential on clinical image quality using direct digital detectors for pelvis and lumbar spine radiographs.

IntroductionHigh kVp techniques, 15% or 10‐kVp rules, are well‐known dose reduction methods. Traditionally, the use of high tube potential (i.e. increased kVp) is associated with decreased radiographic contrast and overall image quality. Recent studies suggest contrast and image quality are not heavily reliant on kVp with digital systems. This study aims to assess the effects of the high tube potential technique on clinical radiographic image quality when using digital systems, to validate high kVp as a dose saving technique.MethodsA selection of comparable pelvis and lumbar spine radiographs were collected from the hospital’s picture archiving and communication system (PACS), with technical factors recorded. All clinical radiographs were assessed by 5 senior radiographers using a 15‐point visual grading analysis (VGA) rubric.ResultsFor 40 AP pelvis radiographs and 40 lateral lumbar spine radiographs, reduction in the dose area product (DAP) with higher kVp is seen. Average pelvis DAP at 75 kVp = 14.06 mGy.cm2; 85 kVp = 7.47 mGy.cm2. Average lumbar spine DAP at 80 kVp = 15.76 mGy.cm2; 90 kVp = 14.83 mGy.cm2. Image quality and contrast scores showed no statistically significant difference between the high and low kVp groups (z = 0.06 and 0.12, respectively). Average pelvis VGA score at 75 kVp = 11.26; 85 kVp = 12.55. Average lumbar spine VGA score at 80 kVp = 9.23; 90 kVp = 10.64.ConclusionsThe high tube potential techniques allowed for reduced patient radiation doses whilst showing no degradation of diagnostic image quality in a clinical setting. This study successfully validates the high kVp technique as a useful tool for reducing patient radiation doses whilst maintaining high diagnostic image quality for digital pelvis and lumbar spine radiography.

892 A Retrospective Study of the Influencing Factors on Fluoroscopy Time (FT) and Patient Radiation Dose (DAP) During ERCP in a Setting of 12 Large Tertiary Academic Hospitals

INTRODUCTION: ERCP uses endoscopic and radiological guidance to accomplish diagnosis and therapy of biliary and pancreatic disorders. During ERCP, the patients are exposed to a higher amount of radiation dose compared to endoscopy staff and over the years both the number and the complexity of the procedure associated has increased significantly resulting in longer procedural and fluoroscopy times. This increasing exposure of patients to such medical radiation is concerning. The primary aim of this study was to get familiar and better understand the various factors influencing patient radiation dose to be able to optimize radiation exposure in fluoroscopy procedures, thereby, minimizing the risk of any radiation-induced injury. METHODS: Retrospective analysis of a prospectively collected database over a study period of 3.5 years (January 2015 to May 2018) was performed. Data related to patient demographics, ERCP indication and radiation exposure in ERCP procedures (n = 7400) in a setting of 12 large tertiary academic hospitals was reviewed and analyzed. Statistical significance, increased Fluoroscopy Time (FT) and Dose area product (DAP) were identified. All ERCPs were graded on their procedural complexity with scores from 1 to 4 signifying simple to the most complex ERCPs. RESULTS: Factors independently associated with an increased FT and DAP included age, level of complexity and the volume of the hospitals performing ERCPs (High volume hospital – more than 450 ERCPs a year). The average Fluoroscopy time (FT) and DAP for different ages (Patients under 35 years old, 35-65 years old and over 65 years old). The average FT was 45.8% higher in patients with higher complexity score and also had a higher DAP of about 13.5%. Also, ERCPs performed in a lower volume hospital had a higher FT (2.93 vs 2.78) and a higher dose area product (12.5 vs 10.1) compared to the higher volume hospitals. CONCLUSION: A number of factors were found to affect the FT and DAP in ERCP. The awareness about the risks of radiation exposure to patients, specific settings of the fluoroscopy machine used and various fluoroscopy modifications that can decrease radiation exposure will help to predict prolonged procedures thereby facilitating the use of appropriate precautions.

Radiation Dose in Prostatic Artery Embolization Using Cone-Beam CT and 3D Roadmap Software.

To evaluate the radiation dose in patients undergoing prostatic artery embolization (PAE) using cone-beam CT and 3-dimensional (3D) guidance software. In this single-center retrospective study, 100 patients with benign prostatic hyperplasia (mean prostate volume, 83.6 mL ± 44.2; 69.4 ± 9.6 years of age; body mass index, 26.5 ± 4.2) were treated using PAE between October 2016 and April 2018. Informed consent was obtained from all participants included in the study. All patients received at least 1 intraprocedural cone-beam CT per side for evaluation of the vessel anatomy and software rendering of 3D guidance for catheter guidance. Digital subtraction angiography (DSA) was performed in the distal branches only. The total dose area product (DAP), along with the DAP attributed to fluoroscopy, DSA, and cone-beam CT, were assessed. Bilateral embolization was achieved in 83 patients (83%). The average total DAP was 134.4 Gy ⋅ cm2 ± 69.5 (range, 44.7-410.9 Gy ⋅ cm2). Fluoroscopy, DSA, and cone-beam CT accounted for 35.5 Gy ⋅ cm2 ± 21.3 (range, 8.6-148.6 Gy ⋅ cm2) or 26.4% (percentage oftotal DAP), 58.2 Gy ⋅ cm2 ± 48.3 (range, 10.3-309.3 Gy ⋅ cm2) or 43.3%, and 40.7 Gy ⋅ cm2 ± 14.5 (range, 15.9-86.3 Gy ⋅ cm2) or 30.3%, respectively. Average procedure time was 89.4 ± 27.0 minutes, and the average fluoroscopy time was 30.9 ± 12.2 minutes. Intraprocedural cone-beam CT in combination with 3D guidance software allows for identification and catheterization of the prostatic artery in PAE. Furthermore, the results of this trial indicate that this study protocol may lead to a low overall radiation dose.

Reducing Radiation Dose for High-resolution Flat-panel CT Imaging of Superior Semicircular Canal Dehiscence

High-resolution flat panel computed tomography (FPCT) is useful for the evaluation of temporal bone pathologies. While radiation exposure remains a concern, efforts have been devoted to reduce dose, while maintaining image quality. We hypothesize that removing the antiscatter grid (ASG) results in decreased radiation exposure, while maintaining diagnostic image quality for the evaluation of superior semicircular canal dehiscence (SSCD). Ten patients with clinical suspicion for SSCD participated in this prospective study. Two sequential collimated 20-second FPCT acquisitions were performed (first: grid in; second: grid removed) in all patients. Secondary reconstructions were created by manually generating the volume of interest to include the middle ear using a voxel size of 0.1 mm and 512 × 512 matrix. Radiation dose parameters (air kerma (Ka,r) in mGy and dose area product (DAP) in μGym) were recorded. Three reviewers analyzed images for the ability to diagnose SSCD, to identify the stapes crurae, and to determine if an ASG was present. The average Ka,r and DAP for the grid-in acquisitions were 246.7 mGy (SD 47.9) and 2838.0 μGym (SD 862.8), versus 160.2 mGy (SD 33.2) and 2026.3 μGym (SD 644.8) for the grid-out acquisitions, respectively (p<0.001 for both Ka,r and DAP). Radiation exposure was reduced by approximately 30% solely by removing the ASG. All reviewers correctly identified all patients with SSCD (confirmed at surgery), with mean AUC of 0.99 (κ = 0.90). Removing the antiscatter grid during FPCT imaging of the temporal bones is a simple and effective way to reduce radiation exposure while maintaining diagnostic image quality for the evaluation of SSCD.

Radiation Reduction in Low Dose Pulsed Fluoroscopy versus Standard Dose Continuous Fluoroscopy during Fluoroscopically-Guided Lumbar Punctures: A Prospective Controlled Study.

Purpose:The purpose of this study was to evaluate radiation dose reduction in fluoroscopically guided lumbar punctures (FGLP) using “pulsed fluoroscopy in a low dose mode” compared with the commonly used “continuous fluoroscopy in a standard dose mode” while maintaining the technical success.Materials and Methods:Thirty-five consecutive patients who underwent FGLP divided randomly to seventeen patients in the control group with standard dose continuous FGLP and eighteen patients in the study group with low-dose low-frame-rate of 3 frames per second (fps) FGLP. Entrance surface dose measurements from a dosimeter device were recorded as well as the dose area product (DAP).Results:A total of 35 patients with average age of 52 years (range: 15–87 [±17 standard deviation [SD]]) were evaluated. Average entrance surface dose of the study group was significantly lower (3.81 mGy [range: 0.21–11.14, [±2.8 SD]]) compared with the control group (22.45 mGy [range: 1.23–73.44, [±19.41 [SD]]). The average DAP of the study group (10 mGy·cm2 [range: 1–41, [±9.8 SD]]) was also significantly lower than the control group (65 mGy·cm2 [range: 5–199, [±53 SD]]). Success rate was similar between the study and control groups.Conclusion:Low dose pulsed fluoroscopy of 3 fps significantly reduces radiation exposure by about 600% compared with standard dose continuous fluoroscopy in FGLP. Utilizing this radiation saving strategy will allow to dramatically reduce radiation exposure, without impacting the technical success rate.

Radioprotection Measures during the Learning Curve with Hybrid Operating Rooms

Endovascular procedures come with a potential risk of radiation hazards both to patients and to the vascular staff. Classically, most endovascular interventions took place in regular operating rooms (ORs) using a fluoroscopy C-arm unit controlled by a third party. Hybrid operating rooms (HORs) provide an optimal surgical suit with all the qualities of a fixed C-arm device, while allowing the device to be controlled by the surgical team. The latest studies suggest that an operator-controlled system may reduce the radiation dose. The purpose of the present study is to determine the amount of absorbed radiation using an HOR in comparison with a portable C-arm unit and to assess whether the radioprotection awareness of the surgical team influences the radiation exposure. The primary end point was the effective dose in milliSievert (mSv) for the surgical team and the average dose-area product (ADAP) in Gray-meters squared (Gym2) for patients. The values of absorbed radiation of the surgical team's dosimeters were collected from January 2015 to May 2016. The HOR was installed in June 2015, and a radioprotection seminar was given in October 2015. The HOR-issued radiation, measured by the maximum dose-area product, ADAP, average dose (AD) per procedure, maximum dose per procedure per month, maximum fluoroscopy time, average fluoroscopic time, peak skin dose, and average skin dose (ASD), was collected monthly from September 2015 to July 2016. The timeline was divided into 3 periods: 5months pre-HOR (Pre-HOR), 5months after the HOR installation (PreS-HOR), and 5months after a radioprotection seminar (PostS-HOR). The average number of procedures per month was 22.55 (±4.9), including endovascular aneurysm repair/thoracic endovascular aneurysm repair, carotid, visceral, and upper and lower limb endovascular revascularization. The average amount of absorbed radiation by the surgeons during PreS-HOR was 1.07±0.4mSv, which was higher than the other periods (Pre-HOR 0.06±0.03mSv, P=0.002; PostS-HOR 0.14±0.09mSv, P=0.000, respectively). The ADAP during PreS-HOR was 0.016±0.01 Gym2, which was lower than the PostS-HOR (0.001±0.002 Gym2) (P=0.034). The AD during PreS-HOR was 0.78±0.3Gy and 0.39±0.3Gy during PostS-HOR (P=0.098). The ASD during PreS-HOR was 0.40±0.2Gy and 0.20±0.1Gy during PostS-HOR (P=0.099). In our experience, the HOR increases the amount of absorbed radiation for both patients and surgeons. The radioprotection seminars are of utmost importance to provide a continued training and optimize the use of ionizing radiation while using an HOR. Despite the awareness of the surgical team in the radioprotection field, the amount of absorbed radiation using an HOR is higher than the one using a C-Arm unit.

Relationship between radiologist training level and radiation exposure for therapeutic hip injections

ObjectiveThe aim of this study was to determine the relationship between the level of training of the performing radiologist and patient radiation exposure, as measured by fluoroscopy time (FT) and dose area product (DAP), during fluoroscopic guided hip injections. Materials and methodsThis IRB-approved retrospective review of our institutional radiology report database identified all fluoroscopic guided hip injections performed between August 1st, 2012 and May 30th, 2015. Performing radiologists were divided into groups based on their level of training at the time of the procedure: first-year residents (R1), second-year residents (R2), third-year residents (R3), fourth-year residents (R4), staff fellowship trained musculoskeletal radiologists, and non-musculoskeletal radiologists. A mixed effects model was applied, using level of training as an independent predictor to model FT and DAP separately. ResultsThere were 20, 19, 18 and 20 residents in the R1, R2, R3 and R4 groups, respectively. There were 5 performers in the non-MSK radiologist group, and 7 in the MSK radiologist group. A total of 1362 hip injection procedures met the inclusion criteria and were included in the analysis. The overall average FT was 26s (±17SD) and overall average DAP was 20.4uGy*m2 (±22.3SD). The mixed effects model showed no statistically significant difference between the groups, for FT (p=0.31) and for DAP (p=0.82). ConclusionThere is no association between radiologist level of training and patient radiation exposure for fluoroscopic hip injections. Resident trainees maintain radiation exposure to patients at levels comparable to their more experienced colleagues.