Efficacy of a Minicourse in Radiation-Reducing Techniques in Invasive Cardiology

Knowledge of radiation exposure associated with common trauma imaging modalities among orthopaedic surgeons, emergency medicine physicians, and general surgeons in the United States

BACKGROUND

Few contemporary studies have assessed physicians' knowledge of radiation exposure associated with common imaging studies, especially in trauma care. The purpose of this study was to assess the knowledge of physicians involved in caring for trauma patients regarding the effective radiation doses of musculoskeletal (MSK) imaging studies routinely utilized in the trauma setting.

METHODS

An electronic survey was distributed to United States orthopaedic surgery, general surgery, and emergency medicine (EM) residency programs. Participants were asked to estimate the radiation dose for common imaging modalities of the pelvis, lumbar spine, and lower extremity, in terms of chest X-ray (CXR) equivalents. Physician estimates were compared to the true effective radiation doses. Additionally, participants were asked to report the frequency of discussing radiation risk with patients.

RESULTS

A total of 218 physicians completed the survey; 102 (46.8%) were EM physicians, 88 (40.4%) were orthopaedic surgeons, and 28 (12.8%) were general surgeons. Physicians underestimated the effective radiation doses of nearly all imaging modalities, most notably for pelvic computed tomaography (CT) (median 50 CXR estimation vs. 162 CXR actual) and lumbar CT (median 50 CXR estimation vs. 638 CXR actual). There was no difference between physician specialties regarding estimation accuracy (P=0.133). Physicians who regularly discussed radiation risks with patients more accurately estimated radiation exposure (P=0.007).

CONCLUSION

The knowledge among orthopaedic and general surgeons and EM physicians regarding the radiation exposure associated with common MSK trauma imaging is lacking. Further investigation with larger scale studies is warranted, and additional education in this area may improve care.

Shading operators from the Gray: Are novel radiation barriers or changing physician behaviors the best next step?

Lead barriers to reduce operator radiation exposure in the catheterization laboratory are effective. This study of a novel vertical radiation shield suggests significant reduction in operator radiation exposure when used in addition to standard protection methods. Although additional barriers may help reduce radiation exposure, further education and training of operators in radiation safety may be as effective and perhaps more effective than additional barriers.

Team perception of the radiation safety climate in the hybrid angiography suite: A cross-sectional study

BACKGROUND

Good radiation safety practice in the angiosuite is essential to protect patients and healthcare workers. Most strategies aim to advance radiation safety through technological upgrades and educational initiatives. However, safety literature suggests that additional ways to improve radiation safety in the angiosuite do exist. The safety climate reflects the way team members perceive various key characteristics of their work environment and is closely related to relevant safety outcomes. A specific 'radiation safety climate' has not been described nor studied in the hybrid angiosuite. This study explores the radiation safety climate in the hybrid angiosuite and its relation to team members' radiation safety behavior, knowledge and motivation.

MATERIALS AND METHODS

Vascular surgeons, fellows/trainees and operating room nurses active in the angiosuite at five hospitals were invited to complete an online self-report questionnaire assessing the radiation safety climate (28 items); radiation safety behavior; radiation safety knowledge and radiation safety motivation. Relations between climate scores and behavior were investigated using Pearson correlations. Mediation was analyzed using the Baron and Kenny analysis. P-Values < 0.05 were considered statistically significant.

RESULTS

No major differences were identified in total radiation safety climate scores between centers or team member functions. Scale reliability for radiation safety climate was good to excellent (α > 0.663). Total radiation safety climate scores were positively related to the radiation safety behavior score (r = 0.403; p = 0.015). This relation was partially mediated by radiation safety knowledge (β = 0.1730; 95% CI: [0.0475; 0.3512]), while radiation safety motivation did not act as a mediator: (β = 0.010; 95% CI: [-0.0561; 0.0998]).

CONCLUSION

A well-developed radiation safety climate in the hybrid angiosuite fosters positive radiation safety behaviors, which may partially be explained through improved radiation safety knowledge transfer. Further research on (radiation) safety climate and its impact on radiation safety-related outcome measures for patients is recommended.

A propensity score matched valuation on feasibility of low frame rate fluoroscopy during primary percutaneous coronary intervention for patients with STEMI

The present study aimed to evaluate the feasibility of low frame rate fluoroscopy during primary percutaneous coronary intervention (PPCI) for patients with acute ST elevation myocardial infarction (STEMI). From January 2016 to December 2017, 165 consecutive patients with STEMI who underwent PPCI were retrospectively divided into two groups: the 7.5-frame group (fluoroscopy at 7.5 frames/s) and the 15-frame group (fluoroscopy at 15 frames/s), according to the frame rate of fluoroscopy used in their treatment. Reduction of radiation and safety of fluoroscopy at 7.5 frames/s were compared by a method of propensity score matching (PSM) with fluoroscopy at 15 frames/s. After PSM, there were 56 patients in each group. There were no differences in patients' baseline characteristics between two groups. The 7.5-frame protocol resulted in 48.9% reduction of DAP (9917 ± 5543 cGycm² vs. 14766 ± 7272 cGycm², P < 0.001) and 61.1% reduction of AK (1209 ± 562 mGy vs. 1948 ± 1105 mGy, P < 0.001) with comparable procedural time (38.1 ± 15.3 min vs. 38.8 ± 17.2 min, P = 0.830), fluoroscopy time (13.0 ± 7.2 min vs. 13.5 ± 8.1 min, P = 0.703) and contrast volume (122.3 ± 39.4 ml vs. 119.3 ± 49.4 ml, P = 0.725) to the 15-frame group. Meanwhile, this new protocol didn't increase the incidence of contrast-induced nephropathy (23.2% vs. 25.0%, OR = 0.907, 95% CI 0.381-2.157, P = 0.825) and peri-PPCI cumulative adverse events (30.4% vs. 28.6%, OR = 1.090, 95% CI 0.483-2.456, P = 0.836). In conclusion, low frame rate fluoroscopy at 7.5 frames/s is a safe and feasible strategy for reducing radiation during PPCI.

Educational Effects of Radiation Reduction During Fluoroscopic Examination of the Adult Gastrointestinal Tract

RATIONALE AND OBJECTIVES

This study aimed to evaluate the effects of educating radiology residents and radiographers about radiation exposure on reduction of dose area product (DAP) and fluoroscopy time in diagnostic fluoroscopy of the gastrointestinal (GI) tract in adult patients.

MATERIALS AND METHODS

In April 2015, we offered 1 hour of education to radiology residents and radiographers on how to reduce radiation doses during fluoroscopic examinations. Fluoroscopic examinations of the GI tracts of adult patients performed from June 2014 to February 2016 were evaluated. A total of 2326 fluoroscopic examinations (779 and 1547 examinations before and after education, respectively) were performed, including 10 kinds of examinations. Fluoroscopy time and DAP were collected. A radiologist evaluated the number of spot images, captured images, cine video, captured video, and the use of collimation or magnification. We used the Mann-Whitney U test to assess the difference in fluoroscopy-related factors before and after education.

RESULTS

Median DAP decreased significantly after education, from 21.1 to 18.2 Gy∙cm² (P < .001) in all examinations. After education DAP decreased significantly in defecography (P < .001) and fluoroscopy time decreased significantly in upper gastrointestinal series with water-soluble contrast (P < .001). Spot and cine images that increased the radiation dose were used less frequently after education than before in some kinds of examinations, especially in defecography (P < .001). More images were collimated after education in barium swallow than before (P < .001).

CONCLUSIONS

Educating radiologist residents and radiographers could reduce DAP in fluoroscopy examinations of the GI tract in adult patients.

Radiation dose reduction during neuroendovascular procedures

AIM

To describe the impact of steps towards reduction of procedural doses of radiation during neuroendovascular procedures.

METHODS

Phantom exposures under controlled circumstances were performed using a Rando-Alderson adult-sized head phantom. Customized imaging protocols were devised for pediatric and adult imaging and implemented in clinical use. Outcome data for estimated skin doses (ESD) and dose-area product (DAP) following pediatric and adult diagnostic and interventional procedures over 4.5 years were analyzed retrospectively.

RESULTS

Dose estimates were reduced by 50% or more after introduction of customized imaging protocols in association with modification of personnel behavior compared with doses recorded with previously used vendor-recommended protocols.

DISCUSSION

Substantial reductions in radiation use during neuroendovascular procedures can be achieved through a combination of equipment modification and operator behavior.

Radiation reduction during percutaneous coronary intervention: A new protocol with a low frame rate and selective fluoroscopic image storage

The percutaneous coronary intervention (PCI) procedure is associated with potentially high levels of radiation exposure and therefore increased risk of adverse radiation-induced outcomes, ranging from cataract to malignancy. Frame rate reduction and selective fluoroscopy storage may help reduce radiation exposure. In this study, we evaluated the efficacy of a radiation reduction protocol that uses a lower frame rate and selective storage of fluoroscopic images in terms of its effect on reducing the radiation dose during PCI.The new protocol incorporated a lower frame rate as compared with the conventional protocol, and used selective storage of fluoroscopic images. We reviewed the medical records of patients who underwent PCI under the conventional protocol from January 2013 to December 2013, and compared them with those who underwent PCI with the new protocol from January 2015 to December 2015. The primary endpoint was radiation dose reduction expressed as cumulative air kerma and dose-area product (DAP). The image quality was assessed by 3 independent well-trained cardiologists.One hundred fifty-five patients were enrolled in the conventional protocol group, and 152 were enrolled in the radiation reduction protocol group (total, n = 307). There was no statistical significance in terms of the baseline characteristics, including body mass index. Overall, the radiation reduction protocol group showed a significant reduction in both cumulative air kerma (1634.39 ± 717.95 vs 2074.75 ± 1003.72 mGy, P < .001) and DAP (12344.86 ± 5371.75 vs 15312.19 ± 7136.58 μGy m, P < .001). Image quality was acceptable in both groups.The radiation reduction protocol, which uses a lower frame rate and selective storage of fluoroscopic images, may be an alternative approach to reducing PCI radiation dose.

Minimizing Ionizing Radiation Exposure in Invasive Cardiology Safety Training for Medical Doctors

Advanced imaging systems, such as C-Arm machines, greatly improve physicians' diagnostic abilities and provide greater precision. Yet, these benefits come with a price of ionizing radiation exposure to medical teams and patients. Supplying proper training and skill improvement to operators on how to use this technology safely can help minimize risk of exposure. Previous studies on radiation knowledge among physicians and radiologists presented disturbing results of underestimated risk of exposure. The following research is based on an innovation in simulation-based training (SBT), a simulator using the Wizard of Oz (WOZ) concept that incorporates an online human trainer and was used for training emergency room (ER) physicians and ultrasound medical personnel. This research integrated WOZ technology with a radiation exposure formula for training to minimize unnecessary radiation exposure. The exposure formula presents real-time and overall exposure levels to operators based on their technique. The simulator also incorporates 3D animation graphics, enabling trainees to simulate the control of various factors. Image quality and the operator's radiation exposure levels are also animated, assisting trainees to focus on their exposure based on their device settings. Contrary to most previous studies, we measured radiation dose to the operator and quantified image quality accordingly. Validation was done on different C-Arm machines. Validation of learning outcomes was done using knowledge exams. Results from our knowledge exams presented significant improvement. The average result of knowledge exams given prior to training was 54%, whereas the average result after training was 94% (p < 0.001). Additionally, after a gap of 2–3 months, high retention was also found.

Radiation Doses to Patients in Interventional Coronary Procedures-Estimation of Updated National Reference Levels by Dose Audit

The objective of this study was to estimate the French national updated reference levels (RLs) for coronary angiography (CA) and percutaneous coronary intervention (PCI) by a dose audit from a large data set of unselected procedures and in standard-sized patients. Kerma-area product (PKA), air kerma at interventional point (Ka,r), fluoroscopy time (FT), and the number of registered frames (NFs) and runs (NRs) were collected from 51 229 CAs and 42 222 PCIs performed over a 12-month period at 61 French hospitals. RLs estimated by the 75th percentile in CAs and PCIs performed in unselected patients were 36 and 78 Gy.cm² for PKA, 498 and 1285 mGy for Ka,r, 6 and 15 min for FT, and 566 and 960 for NF, respectively. These values were consistent with the RLs calculated in standard-sized patients. The large difference in dose between sexes leads us to propose specific RLs in males and females. The results suggest a trend for a time-course reduction in RLs for interventional coronary procedures.

OPERATOR DEPENDENCY OF THE RADIATION EXPOSURE IN CARDIAC INTERVENTIONS: FEASIBILITY OF ULTRA LOW DOSE LEVELS

INTRODUCTION

Mean radiation exposure in invasive cardiology varies greatly between different centres and interventionists. The International Commission on Radiological Protection and the EURATOM Council stipulate that, despite reference values, 'All medical exposure for radiodiagnostic purposes shall be kept as low as reasonably achievable' (ALARA). The purpose of this study is to establish the effects of the routine application of ALARA principles and to determine operator and procedure impact on radiation exposure in interventional cardiology.

MATERIALS AND METHODS

A total of 240 consecutive cardiac interventional procedures were analysed. Five operators performed the procedures, two of whom were working in accordance with ALARA principles (Group 1 operators) with the remaining three working in a standard manner (Group 2 operators). Radiation exposure levels of these two groups were compared.

RESULTS

Total fluoroscopy time and the number of radiographic runs were similar between groups. However, dose area product and cumulative dose were significantly lower in Group 1 when compared with Group 2. Radiation levels of Group 1 were far below even the reference levels in the literature, thus representing an ultra-low-dose radiation exposure in interventional cardiology.

CONCLUSION

By use of simple radiation reducing techniques, ultra-low-dose radiation exposure is feasible in interventional cardiology. Achievability of such levels depends greatly on operator awareness, desire, knowledge and experience of radiation protection.

Radiation exposure, the forgotten enemy: Toward implementation of national safety program

Radiation safety is an important counterpart in all facilities utilizing ionizing radiations. The concept of radiation safety has always been a hot topic, especially with the late reports pointing to increased hazards with chronic radiation exposure. Adopting a nationwide radiation safety program is considered one of the most urging topics, and is a conjoint responsibility of multiple disciplines within the health facility.

Long-term strategies support autonomy in radiation safety in invasive cardiology

BACKGROUND AND PURPOSE

Despite comprehensive radiation safety programs, radiation exposure in invasive cardiology remains considerable. According to the 2013 German Registry, median in-hospital dose area products (DAP) amount to 19.8Gycm(2) for invasive coronary angiography (CA). We analyzed long-term radiation-reducing strategies for an experienced interventionalist from 1997 to 2012, for the target intervention of CA.

METHODS

Among representative cohorts, we evaluated iterative alterations in collimation, time on beam, pulse rates, detector entrance doses, and angulations on the basis of DAP, radiographic DAP(R) and fluoroscopic DAP(F), the respective times on beam, and the number of frames and runs.

RESULTS

Patients' median overall DAP decreased from 33.8Gycm(2) at baseline to 2.4 and 0.6Gycm(2) for CA in conventional (C) and electrocardiogram-gated (E) modes - one diastolic radiographic frame per heartbeat at 77% of the RR interval. Further median dose parameters for CA at baseline and finally in C/E mode were as follows: effective dose (6.76-0.48/0.13mSv), radiography time (43.8-12.9/21.7s), frames (548-105/25), frames/run (41.3-14.4/3.4), DAP(R)/frame (42.6-16.6/12.6mGycm(2)), DAP(R)/s (532-130/13.8mGycm(2)/s), fluoroscopy time (195-120/119s), DAP(F)/pulse (2.0-1.1/0.8mGycm(2)), and DAP(F)/s (48.9-4.4/3.1mGycm(2)/s).

CONCLUSIONS

Our data highlight the efficacy of various radiation-reducing strategies by autonomous control and iterative training in radiation safety toward submillisievert levels for CA, and define realizable benchmarks for comparison with the performance data of any individual.

The lateral plane delivers higher dose than the frontal plane in biplane cardiac catheterization systems

The objective of the study is to compare radiation dose between the frontal and lateral planes in a biplane cardiac catheterization laboratory. Tube angulation progressively increases patient and operator radiation dose in single-plane cardiac catheterization laboratories. This retrospective study captured biplane radiation dose in a pediatric cardiac catheterization laboratory between April 2010 and January 2014. Raw and time-indexed fluoroscopic, cineangiographic and total (fluoroscopic + cineangiographic) air kerma (AK, mGy) and kerma area product (PKA, µGym(2)/Kg) for each plane were compared. Data for 716 patients were analyzed: 408 (56.98 %) were male, the median age was 4.86 years, and the median weight was 17.35 kg. Although median beam-on time (minutes) was 4.2 times greater in the frontal plane, there was no difference in raw median total PKA between the two planes. However, when indexed to beam-on time, the lateral plane had a higher median-indexed fluoroscopic (0.75 vs. 1.70), cineangiographic (16.03 vs. 24.92), and total (1.43 vs. 5.15) PKA (p < 0.0001). The median time-indexed total PKA in the lateral plane is 3.6 times the frontal plane. This is the first report showing that the lateral plane delivers a higher dose than the frontal plane per unit time. Operators should consciously reduce the lateral plane beam-on time and incorporate this practice in radiation reduction protocols.

Multicenter long-term validation of a minicourse in radiation-reducing techniques in the catheterization laboratory

Patient radiation exposure in invasive cardiology is considerable. We aimed to investigate, in a multicenter field study, the long-term efficacy of an educational 90-minute workshop in cardiac invasive techniques with reduced irradiation. Before and at a median period of 2.5 months and 2.0 years after the minicourse (periods I, II, and III, respectively) at 5 German cardiac centers, 18 interventionalists documented various radiation parameters for 10 coronary angiographies. The median patient dose area product (DAP) for periods I, II, and III amounted to 26.6, 12.2, and 9.6 Gy × cm(2), respectively. The short-term and long-term effects were related to shorter median fluoroscopy times (180, 138, and 114 seconds), fewer radiographic frames (745, 553, and 417) because of fewer (11, 11, and 10) and shorter (64, 52, and 44 frames/run) runs, consistent collimation, and restriction to an adequate image quality; both radiographic DAP/frame (27.7, 17.3, and 18.4 mGy × cm(2)) and fluoroscopic DAP/second (26.6, 12.9, and 14.9 mGy × cm(2)) decreased significantly. Multivariate analysis over time indicated increasing efficacy of the minicourse itself (-55% and -64%) and minor influence of interventionist experience (-4% and -3% per 1,000 coronary angiographies, performed lifelong until the minicourse and until period III). In conclusion, autonomous self-surveillance of various dose parameters and feedback on individual radiation safety efforts supported the efficacy of a 90-minute course program toward long-lasting and ongoing patient dose reduction.

Radiation safety and vascular access: attitudes among cardiologists worldwide

OBJECTIVES

To determine opinions and perceptions of interventional cardiologists on the topic of radiation and vascular access choice.

BACKGROUND

Transradial approach for cardiac catheterization has been increasing in popularity worldwide. There is evidence that transradial access (TRA) may be associated with increasing radiation doses compared to transfemoral access (TFA).

METHODS

We distributed a questionnaire to collect opinions of interventional cardiologists around the world.

RESULTS

Interventional cardiologists (n=5332) were contacted by email to complete an on-line survey from September to October 2013. The response rate was 20% (n=1084). TRA was used in 54% of percutaneous coronary interventions (PCIs). Most TRAs (80%) were performed with right radial access (RRA). Interventionalists perceived that TRA was associated with higher radiation exposure compared to TFA and that RRA was associated with higher radiation exposure that left radial access (LRA). Older interventionalists were more likely to use radiation protection equipment and those who underwent radiation safety training gave more importance to ALARA (as low as reasonably achievable). Nearly half the respondents stated they would perform more TRA if the radiation exposure was similar to TFA. While interventionalists in the United States placed less importance to certain radiation protective equipment, European operators were more concerned with physician and patient radiation.

CONCLUSIONS

Interventionalists worldwide reported higher perceived radiation doses with TRA compared to TFA and RRA compared to LRA. Efforts should be directed toward encouraging consistent radiation safety training. Major investment and application of novel radiation protection tools and radiation dose reduction strategies should be pursued.

Reducing radiation exposure during invasive coronary angiography and percutaneous coronary interventions implementing a simple four-step protocol

BACKGROUND

With an increasing number of complex and repeated percutaneous coronary interventions (PCI), radiation-induced hazards for patients and operators remain an important issue in fluoroscopy-guided procedures. Our objective was to evaluate radiation exposure during coronary angiographic procedures and assess the efficacy of a four-step program to reduce radiation exposure during coronary angiography (CAG) and PCI.

METHODS AND RESULTS

A retrospective single-center analysis was performed in patients undergoing CAG or PCI in the first 6 months of 2012 vs. the first 6 months of 2014 (n = 3,107 procedures). During 2013, a four-step protocol was established in our hospital. It contained measures to reduce radiation exposure, including a frame rate reduction from 15 to 7.5 frames per second, the use of fluoroscopy storage, strict use of beam collimation, and repeat training on radiation safety. After adjustment for confounding variables, a dose-area product (DAP) reduction of 54.2% was observed subsequent to implementation of the four-step protocol. Independent predictors of DAP were age [odds ratio (OR) 1.01], body surface area (OR 5.47), prior coronary artery bypass grafting (OR 1.44), radial access (OR 1.16), PCI (OR 2.36), female gender (OR 0.91), and the implementation of the four-step program (OR 0.46).

CONCLUSION

A simple four-step protocol led to a significant reduction in radiation exposure in diagnostic and interventional coronary procedures without significant drawbacks in image quality. Hence, radiation safety programs are of paramount importance and should be established to improve patient and operator safety with regard to radiation-induced hazards.

ECG-gated coronary angiography enables submillisievert imaging in invasive cardiology

BACKGROUND

The median dose area products (DAP) and effective doses (ED) of patients arising from coronary angiography (CA) are considerable: According the 2013 National German Registry, they amount to 19.8 Gy × cm(2) and 4.0 mSv, respectively.

METHODS

We investigated the feasibility of prospective electrocardiogram (ECG)-gated coronary angiography (CA)-a novel technique in invasive cardiology-with respect to possible reduction in irradiation effects. Instead of universally fix-rated radiographic acquisition within 7.5-15 frames/s, one single frame/heartbeat was triggered toward the diastolic moment immediately before atrial contraction (77 % of ECG-RR interval) most likely to provide motion-free and hence optimized resolution of the coronary tree. For 200 patients (body mass index 27.8 kg/m(2), age 67.5 years, male 55 %, 68 bpm) undergoing ECG-gated CA, we measured various median (interquartile range) parameters for radiation exposure.

RESULTS

The total DAP was 0.64 (0.46-1.00), radiographic fraction was 0.30 (0.19-0.43), and fluoroscopic fraction was 0.35 (0.21-0.57) Gy × cm(2). Radiographic imaging occurred within 21.7 s (17.1-26.3), with 25 frames (20-30) over the course of 7 runs (6-8). Fluoroscopy time was 119 s (94-141). Radiographic DAP was 12.6 mGy × cm(2)/frame and 13.8 mGy × cm(2)/s. Fluoroscopic DAP was 0.8 mGy × cm(2)/pulse and 3.1 mGy × cm(2)/s. Patient reference point air kerma was 17.0 mGy (11.1-28.1) and contrast volume was 70 ml (60-85).

CONCLUSION

In conclusion, invasive ECG-gated coronary imaging is feasible in clinical routine and enables patient EDs of approx. 3 % of typical values in invasive cardiology: 0.13 mSv (0.09-0.20).