Reducing Radiation Dose in Coronary Angiography and Angioplasty Using Image Noise Reduction Technology

Current status of diagnostic reference levels in interventional cardiology

Interventional cardiology provides indisputable benefits for patients but uses a substantial amount of ionising radiation. The diagnostic reference level (DRL) is the tool recommended by the International Commission on Radiological Protection to optimise imaging procedures. In this work, a review of studies dealing with radiation dose or recommending DRL values for interventional cardiology since 2010 is presented, providing quantitative and qualitative results. There are many published papers on coronary angiography (CA) and percutaneous coronary intervention. The DRL values compiled for different continental regions are different: the DRL for CA is about 35 Gy cm²for Europe and 83 Gy cm²for North America. These differences emphasise the need to establish national DRLs considering different social and/or economic factors and the harmonisation of the survey methodology. Surveys with a large amount of data collected with the help of dose management systems provide more reliable information with less chance of statistical bias than those with a small amount of data. The complexity of procedures and improvements in technology are important factors that affect the radiation dose delivered to patients. There is a need for additional data on structural and electrophysiological procedures. The analysis of paediatric procedures is especially difficult because some studies present results split into age bands and others into weight bands. Diagnostic procedures are better described, but there is a great variety of therapeutic procedures with different DRL values (up to a factor of nine) and these require a dedicated review.

Trends and predictors of radiation exposure in percutaneous coronary intervention: the PROTECTION VIII study

BACKGROUND

Percutaneous coronary intervention (PCI) is indispensable in cardiology; however, exposure to potentially harmful ionising radiation remains a concern.

AIMS

This study was designed to assess the PCI-related radiation dose over the last decade and to identify predictors of increased dose exposure.

METHODS

The PROcedural radiaTion dose Exposure in percutaneous Coronary intervenTION (PROTECTION VIII) study included all PCIs reported to a German quality assurance programme between 2008 and 2018. Dose area product (DAP) and radiation time were analysed. Effective dose (ED) was estimated (ED=DAP*k; conversion coefficient k=0.0022 mSv/cGy*cm²). Multivariate linear regression analysis was used to identify predictors associated with a clinically relevant increase of radiation dose (ED ≥1 mSv).

RESULTS

We enrolled 3,704,986 patients undergoing PCI (median age 70 years, 30% female). Indications were chronic coronary syndrome (37.5%), unstable angina pectoris and non-ST-segment elevation myocardial infarction (non-STEMI; 33.2%) and STEMI (18.5%). Median DAP was 4,203 (interquartile range [IQR] 2,313-7,300) cGy*cm, ED was 9.2 mSv and median radiation time was 9.2 (IQR 5.8-15.0) min. Within the 10-year period, radiation exposure was reduced by 36% (p<0.001) and resulted in a median DAP of 3,070 cGy*cm (ED 6.8 mSv) in 2018. A significant 5.3-fold variability of median DAP was observed between catheterisation laboratories (p<0.001). We identified patient-related (gender, coronary artery bypass graft surgery, heart failure) and procedure-related (coronary occlusion PCI, ostial lesion PCI, left main PCI, multivessel PCI) predictors of increased radiation dose (all p<0.001).

CONCLUSIONS

This radiation dose survey demonstrates a considerable reduction of PCI radiation exposure during the last decade. However, large variability between catheterisation laboratories underlines the need for further radiation dose reduction.

Impact of dose reducing software on patient and staff temple dose during fluoroscopically guided pacemaker insertion, closure devices implantation and coronary angiography procedures

The aim of this study is to investigate the effectiveness of dose reducing software (ClarityIQ) on patient and staff dose during fluoroscopically guided cardiac procedures. Dose measurements were collected in a room without dose reducing software (n = 157) and compared with similar procedures performed in two rooms with the software (n = 1141). Procedures included diagnostic coronary angiography, percutaneous coronary intervention, deployment of cardiac closure devices (for occlusion of atrial septal defect, patent foramen ovale, and atrial appendage) and insertion of permanent pacemakers. The dose reducing software was found to be effective in reducing patient and staff dose by approximately 50%. This study has added to the limited literature reporting on the capability of dose reducing software to decrease radiation exposure during the implantation of cardiac closure devices, as well as demonstrating a reduction in dose to the cardiologist and nursing staff. Administrators should ensure timely upgrades to angiographic equipment to safeguard patients and staff against the potentially adverse effects of radiation exposure. Regardless of the use of dose reducing software, the mean occupational dose during closure devices was in descending order scout > scrub > cardiologist. Scrub nurse dose was found to be higher than the cardiologist during closure devices (0.98/0.26 μSv) and diagnostic coronary angiograms (1.51/0.82 μSv). Nursing staff should be aware that their levels of radiation dose during some cardiac procedures may come close to or even exceed that of the cardiologist.

Radiation dose reduction during adrenal vein sampling using a new angiographic imaging technology

To compare the patient radiation doses during angiographic selective adrenal vein sampling (AVS) before and after an imaging technology upgrade. In this retrospective single-center-study, cumulative air kerma (AK), cumulative dose area product (DAP), fluoroscopy time and contrast agent dosage were recorded from 70 patients during AVS. 35 procedures were performed before and 35 after an imaging processing technology upgrade. Mean values were calculated and compared using an unpaired student’s t-test. DSA image quality was assessed independently by two blinded readers using a four-point Likert scale (1 = poor; 4 = excellent) and compared using Wilcoxon signed-rank test. After the technology upgrade we observed a significant reduction of 35% in AK (1.7 ± 0.7 vs. 1.1 ± 0.7 Gy, p = 0.01) and a significant reduction of 28% in DAP (235.1 ± 113 vs. 170.1 ± 94 Gy*cm², p = 0.01) in comparison to procedures before the upgrade. There were no significant differences between the number of exposure frames (143 ± 86 vs. 132 ± 61 frames, p = 0.53), fluoroscopy time (42 ± 23 vs. 36 ± 18 min, p = 0.22), or the amount of contrast medium used (179.5 ± 84 vs. 198.1 ± 109 ml, p = 0.41). There was also no significant difference regarding image quality (3 (2–4) vs. 3 (2–4), p = 0.67). The angiographic imaging technology upgrade significantly decreases the radiation dose during adrenal vein sampling without increasing time of fluoroscopy or contrast volume and without compromising image quality.

Predictors of radiation dose for uterine artery embolisation are angiography system-dependent

This study sought to achieve radiation dose reductions for patients receiving uterine artery embolisation (UAE) by evaluating radiation dose measurements for the preceding generation (Allura) and upgraded (Azurion) angiography system. Previous UAE regression models in the literature could not be applied to this centre's practice due to being based on different angiography systems and radiation dose predictor variables. The aims of this study were to establish whether radiation dose is reduced with the upgraded angiography system and to develop a regression model to determine predictors of radiation dose specific to the upgraded angiography system. A comparison between Group I (Allura,n= 95) and Group II (Azurion,n= 95) demonstrated a significant reduction in kerma-area product (KAP) and Ka, r (reference air kerma) by 63% (143.2 Gy cm²vs 52.9 Gy cm²;P< 0.001,d= 0.8) and 67% (0.6 Gy vs 0.2 Gy;P< 0.001,d= 0.8), respectively. The multivariable linear regression (MLR) model identified the UAE radiation dose predictors for KAP on the upgraded angiography system as total fluoroscopy dose, Ka, r, and total uterus volume. The predictive accuracy of the MLR model was assessed using a Bland-Altman plot. The mean difference was 0.39 Gy cm²and the limits of agreement were +28.49 and -27.71 Gy cm², and thus illustrated no proportional bias. The resultant MLR model was considered system-dependent and validated the upgraded angiography system and its advance capabilities to significantly reduce radiation dose. Interventional radiologist and interventional radiographer familiarisation of the system's features and the implementation of the newly established MLR model would further facilitate dose optimisation for all centres performing UAE procedures using the upgraded angiography system.

High filtration in interventional practices reduces patient radiation doses but not always scatter radiation doses

OBJECTIVES

In fluoroscopy-guided interventional practices, new dose reduction systems have proved to be efficient in the reduction of patient doses. However, it is not clear whether this reduction in patient dose is proportionally transferred to operators' doses. This work investigates the secondary radiation fields produced by two kinds of interventional cardiology units from the same manufacturer with and without dose reduction systems.Methods:Data collected from a large sample of clinical procedures over a 2-year period (more than 5000 procedures and 340,000 radiation events) and the DICOM radiation dose structured reports were analysed.

RESULTS

The average cumulative H_p(10) per procedure measured at the C-arm was similar for the standard and the dose reduction systems (452 vs 476 μSv respectively). The events analysis showed that the ratio H_p(10)/KAP at the C-arm was (mean ± SD) 5 ± 2, 10 ± 4, 14 ± 4 and 14 ± 6 μSv·Gy^-1·cm^-2 for the beams with no added filtration, 0.1, 0.4 and 0.9 mm Cu respectively and suggested that the main cause for the increment of the ratio H_p(10)/KAP vs the "standard system" is the use of higher beam filtration in the "dose reduction" system.

CONCLUSION

Dose reduction systems are beneficial to reduce KAP in patients and their use should be encouraged, but they may not be equally effective to reduce occupational doses. Interventionalists should not overlook their own personal protection when using new technologies with dose reduction systems.

ADVANCES IN KNOWLEDGE

Dose reduction technology in interventional systems may increase scatter dose for operators. Personal protection should not be overlooked with dose reduction systems.

Radiation doses during cardiac catheterisation procedures in India: a multicentre study: Radiation dose study

AIMS

Established, evidence-based measures of radiation are required to minimise its hazards, while maintaining adequate image quality. The aim of this study is to evaluate radiation data and generate reference radiation levels for commonly performed coronary catheterisation procedures in India.

METHODS AND RESULTS

In this prospective, observational study, all procedures were performed in accordance with the established standards using Innova IGS 520/2100-IQ catheterisation laboratories. Demographic, procedural and radiation data were collected. Dose reference limits (DRL) were established as the 75th percentile of the total distribution. There were 2,906 coronary angiograms (CAG), 750 percutaneous coronary interventions (PCI) and 715 CAG+PCI. DRLs for dose area product were: 19.6 Gy·cm2 for CAG, 49.8 Gy·cm2 for PCI and 72.0 Gy·cm2 for CAG+PCI, respectively. Median cumulative air kerma levels were: 185 mGy for CAG, 533mGy for PCI, and 891 mGy for CAG+PCI. Male gender, higher BMI, combining CAG+PCI, fluoroscopy time, number of cine frames, and image acquisition settings were significant contributors to increased radiation dose.

CONCLUSIONS

This study established reference radiation dose levels for diagnostic and interventional coronary procedures in India, which were comparable to and in the lower range of international standards.

The role of a commercial radiation dose index monitoring system in establishing local dose reference levels for fluoroscopically guided invasive cardiac procedures

PURPOSE

The primary goal was to evaluate local dose level for fluoroscopically guided invasive cardiac procedures in a high-volume activity catheterization laboratory, using automatic data registration with minimal impact on operator workload. The secondary goal was to highlight the relationship between dose indices and acquisition parameters, in order to establish an effective strategy for protocols optimization.

METHODS

From September 2016 to December 2018, a dosimetric survey was conducted in the 2 rooms of the catheterization laboratory of our institution. Data collection burden was minimized using a commercial Radiation Dose Index Monitoring System (RDIMs) that analyzes dicom files automatically sent by the x-ray equipment. Data were combined with clinical information extracted from the HIS records reported by the interventional cardiologist. Local dose levels were established for different invasive cardiac procedures.

RESULTS

A total of 3029 procedures performed for 2615 patients were analyzed. Median KAP were 21 Gycm² for invasive coronary angiography (ICA) procedures, 61 Gycm² for percutaneous coronary intervention (PCI) procedures, 59 Gycm² for combined (ICA+PCI) procedures, 87 Gycm² for structural heart intervention (TAVI) procedures. A significant dose reduction (51% for ICA procedures and 58% for PCI procedures) was observed when noise reduction acquisition techniques were applied.

CONCLUSIONS

RDIMs are effective tools in the establishment of local dose level in interventional cardiology, as they mitigate the burden to collect and register extensive dosimetric data and exposure parameters. Systematic review of data support the multi-disciplinary team in the definition of an effective strategy for protocol management and dose optimization.

Radiation Dose Reduction Using a Novel Fluoroscopy System in Patients Undergoing Diagnostic Invasive Coronary Angiography

BACKGROUND

Invasive coronary angiography (ICA) still causes a significant amount of radiation exposure for patients and operators. In February 2017, the Azurion system was introduced, a new-generation fluoroscopy image acquisition and processing system. Radiation exposure in patients undergoing ICA was assessed comparing the novel Azurion 7 F12 angiography system to its predecessor Allura Xper in a randomized manner.

METHODS

Radiation exposure was prospectively analyzed in 238 patients undergoing diagnostic ICA. Patients were randomly assigned to the novel Azurion system (119 patients) or its predecessor Allura Xper system (119 patients). In each patient, 8 predefined standard projections (5 left coronary artery, 3 right coronary artery) were performed. Image quality was quantified by grading of the images on the basis of a 5-point grading system.

RESULTS

Radiation dose area product was significantly lower in the Azurion group 109 (interquartile range [IQR 75-176] cGy cm) compared with the Allura Xper group 208 [IQR 134-301] cGy cm (P<0.001). Body mass index (26.6 [IQR 23.9-29.7] kg/m vs. 26.2 [IQR 24.2-29.4] kg/m; P=0.607), body surface area (1.96 [IQR 1.81-2.11] m vs. 1.90 [IQR 1.77-20.4] m; P=0.092), and procedure duration (1.5 [IQR 1.2-2.3] min vs. 1.6 [IQR 1.2-2.5] min; P=0.419) were similar in both groups. Images from the Azurion system were at least of equal quality compared with Allura Xper (image quality grade 4.82±0.45 vs. 4.75±0.52, P=0.43).

CONCLUSION

Use of the novel Azurion 7 F12 angiography system resulted in a significant reduction of dose area product in patients undergoing diagnostic ICA by 56%.

Radiation dose reduction and static image quality assessment using a channelized hotelling observer on an angiography system upgraded with clarity IQ

The goal of this paper was the comparison of radiation dose and imaging quality before and after the Clarity IQ technology installation in a Philips AlluraXper FD20/20 angiography system using a Channelized Hotelling Observer model (CHO). The core characteristics of the Allura Clarity IQ technology are its real-time noise reduction algorithms (NRT) combined with state-of-the-art hardware; this technology allows to implement acquisition protocols able to significantly reduce patient entrance dose. To measure the system performances in terms of image quality we used a contrast detail phantom in a clinical scatter condition. A Leeds TO10 phantom has been imaged between two 10 cm thick homogeneous solid water slabs. Fluoroscopy images were acquired using a cerebral protocol at 3 dose levels (low, medium and high) with a field- of view (FOV) of 31 cm. Cineangiography images were acquired using a cerebral protocol at 2 fps. Thus, 4 acquisitions were obtained for the conventional technology and 4 acquisitions were taken after the Clarity IQ upgrade, for a total of 8 different image sets. A validated 40 Gabor channels CHO with an internal noise model compared the image sets. Human observers' studies were carried out to tune the internal noise parameter. We showed that the CHO did not detect any significant difference between any of the image sets acquired using the two technologies. Consequently, this x-ray imaging technology provides a non-inferior image quality with an average patient dose reduction of 57% and 28% respectively in cineangiography and fluoroscopy. The Clarity IQ installation has certainly allowed a considerable improvement in patient and staff safety, while maintaining the same image quality.

Conversion factors to estimate effective doses from kerma area product in interventional cardiology. Impact of added filtration

There is a large variation in the factors used to estimate effective doses from kerma area product (KAP) for interventional cardiology. These factors are required to estimate population doses. This paper presents the results for this conversion factor for cardiac procedures using tissue weighting factors of ICRP-103 and the impact of the added copper filtration in the X-ray beam. The data from 925 cardiac procedures and 75,347 radiation events were collected from two angiography laboratories using the DICOM Radiation Dose Structured Reports (RDSR). Effective doses were calculated with Monte Carlo software and the dosimetric, technical and geometrical information included in the RDSR. In one laboratory, with an X-ray system without Cu filtration for the cine runs, a factor of 0.21 ± 0.05 mSv/(Gy·cm²) was obtained. In other laboratory, incorporating a patient dose reduction technique, and 0.4 mm of Cu filtration for cine runs, the conversion factor was 0.29 ± 0.05 mSv/(Gy·cm²). The analysis of the radiation events for the different Cu filtrations (0.0; 0.1; 0.4 and 0.9 mm) resulted in conversion factors of: 0.16; 0.27; 0.34 and 0.40 mSv/(Gy·cm²) respectively. The estimation of effective and population doses from KAP should take into account the Cu filtration in the X-ray beam. For the X-ray system with patient dose reduction technique, using 0.4 mm Cu for cine runs, the global conversion factor increased by 38%, from 0.21 to 0.29 mSv/(Gy·cm²) in comparison to the standard X-ray system with a protocol that did not include copper filtration for cine acquisitions.

Multicenter Assessment of Radiation Exposure during Pediatric Cardiac Catheterizations Using a Novel Imaging System

Objectives

To quantify radiation exposure during pediatric cardiac catheterizations performed by multiple operators on a new imaging platform, the Artis Q.zen (Siemens Healthcare, Forchheim, Germany), and to compare these data to contemporary benchmark values.

Background

The Artis Q.zen has been shown to achieve significant radiation reduction during select types of pediatric cardiac catheterizations in small single-center studies. No large multicenter study exists quantifying patient dose exposure for a broad spectrum of procedures.

Methods

Retrospective collection of Air Kerma (AK) and dose area product (DAP) for all pediatric cardiac catheterizations performed on this new imaging platform at four institutions over a two-year time period.

Results

A total of 1,127 pediatric cardiac catheterizations were analyzed. Compared to dose data from earlier generation Artis Zee imaging systems, this study demonstrates 70–80% dose reduction (AK and DAP) for similar patient and procedure types. Compared to contemporary benchmark data for common interventional procedures, this study demonstrates an average percent reduction in AK and DAP from the lowest dose saving per intervention of 39% for AK and 27% for DAP for transcatheter pulmonary valve implantation up to 77% reduction in AK and 70% reduction in DAP for atrial septal defect closure.

Conclusion

Use of next-generation imaging platforms for pediatric cardiac catheterizations can substantially decrease patient radiation exposure. This multicenter study defines new low-dose radiation measures achievable on a novel imaging system.

Significant Radiation Dose Reduction Using a Novel Angiography Platform in Patients Undergoing Cryoballoon Pulmonary Vein Isolation

OBJECTIVES

Cryoballoon pulmonary vein isolation (cPVI) in patients with atrial fibrillation requires fluoroscopic guidance, causing a relevant amount of radiation exposure. Strategies to reduce radiation exposure in electrophysiologic procedures and specifically cPVI are of great importance. The aim of this study was to evaluate a possible reduction of radiation dose using the novel Azurion 7 F12 x-ray system compared with its predecessor Allura FD10.

METHODS

In February 2017, the Philips Azurion angiography system was introduced, combining the Allura Clarity radiation dose reduction technology with a more powerful generator, improved image resolution, and a large screen display. In 173 patients undergoing cPVI by a single experienced operator in our institution between December 2016 and April 2018, dose area products (cGy×cm) and image quality were compared using Azurion 7 F12 or Allura FD10 angiography system.

RESULTS

A significant reduction in total radiation dose expressed as a dose area products of 524 (332; 821) cGy×cm on the Allura system compared with 309 (224; 432) cGy×cm on the Azurion system was observed (P<0.001). The number of imaging scenes recorded were 14.7 versus 13.9, and mean overall imaging quality scores (grading 4.85±0.4 with Azurion vs. 4.80±0.4 with Allura, P=0.38) and scores based on specific quality parameters were similar in both groups.

CONCLUSION

Use of the new Azurion 7 F12 angiography system substantially reduced radiation doses compared with the previous generation reference system, Allura Clarity, without compromising imaging quality in patients undergoing cryoballoon pulmonary vein isolation.

Strategies for Minimizing Occupational Radiation Exposure in Cardiac Imaging

PURPOSE OF REVIEW

Radiation safety has been at the center of interest of both researchers and healthcare institutions. This review will summarize and shed light on the various techniques adapted to reduce staff exposure to ionizing radiation (IR) in the field of cardiac imaging.

RECENT FINDINGS

In the last years, with the advance of awareness and the development of new technologies, there have been several tools and techniques adapted. The breakthrough of several technologies to lower radiation dose and shorten the duration of diagnostic tests associated with IR, the use of protection devices by staff members, and mostly the awareness of exposure to IR are the hallmark of these advances. Using all these measures has led to a significant decrease in staff exposure to IR. Reducing staff exposure to meet the "As Low As Reasonably Achievable" principle is feasible. This review introduces the most important strategies applied in cardiac imaging.

Efficacy of radiation dose reduction due to real-time monitoring and visualization of peak skin dose during coronary angiography and percutaneous coronary intervention

OBJECTIVES

This study assessed that the use of real-time monitoring and visualization of peak skin dose could reduce radiation dose during coronary angiography (CAG) and percutaneous coronary intervention (PCI).

BACKGROUND

Exposure to ionizing radiation has dose related effects including skin damage. Reducing the radiation exposure is important during CAG and PCI. The skin dose-tracking system (DTS) has a real-time monitor of radiation peak skin dose.

METHODS

A total of 323 consecutive patients who underwent CAG and PCI between September 2014 and June 2015 were enrolled. Patients were classified into with DTS group (CAG alone in 104 and PCI in 57 patients) or without DTS group (CAG alone in 106 and PCI in 56 patients).

RESULTS

There was no significant difference in reference air kerma between CAG alone with and without DTS groups. Reference air kerma with DTS group during PCI was lower than without DTS group (204.6 ± 141.1 mGy vs. 294.2 ± 237.4 mGy, P = 0.016). Moreover, kerma area product (17.8 ± 13.0 Gycm² vs. 25.2 ± 19.3 Gycm² , P = 0.019) and number of cine runs (12.8 ± 5.0 vs. 15.5 ± 6.5, P = 0.013) with DTS group were lower than without DTS group. Multiple regression analysis showed increased reference air kerma was associated with male gender, body mass index and type B2/C lesion. Conversely, DTS correlated with decreased reference air kerma.

CONCLUSIONS

The use of DTS could reduce radiation dose during PCI. Real-time radiation monitoring and visualization of peak skin dose was effective for the patients with PCI.

Reduction in Radiation Dose in a Pediatric Cardiac Catheterization Lab Using the Philips AlluraClarity X-ray System

The objective of this study was to compare radiation doses and imaging quality using Philips AlluraClarity (Philips Healthcare, Best, The Netherlands) X-ray system and an older generation reference system. AlluraClarity is a new generation fluoroscopy system designed to reduce radiation without compromising image quality, but reports of its use in pediatric patients are limited. Dose area products (DAP, mGy cm²) and DAP/kg were compared in patients catheterized using Allura Xper and AlluraClarity systems over a year of use for each. Randomly selected studies from each system were assessed for image quality. The 430 patients imaged with Clarity were larger than the 332 imaged with Xper (median BSA: 0.74 vs. 0.64 m², p = 0.06), and median total fluoroscopic times (TFT) were similar (15.8 vs. 16.1 min, p = 0.37). Median DAPs were 8661 mGy cm² (IQR: 18,300 mGy cm²) and 4523 mGy cm² (IQR: 11,596 mGy cm²) with Xper and Clarity, respectively (p < 0.001). There was a reduction in median DAP in all procedure categories. After adjustment for BSA, TFT, and procedure type, using Clarity was associated with a 57.5% (95% CI 51.5-62.8%, p < 0.001) reduction in DAP for all procedures. Reductions did not significantly differ by weight (<10 kg, 10-40 kg, ≥ 40 kg). There was an adjusted percent reduction in DAP for each procedure category ranging from 39.0% (95% CI 25.6-50.1%, p < 0.001) for cardiac biopsies with or without coronary angiography to 67.6% (95% CI 61.2-72.8%, p < 0.001) for device occlusions. Mean overall imaging quality scores (4.3 ± 0.8 with Clarity vs. 4.4 ± 0.6 with Xper, p = 0.62) and scores based on specific quality parameters were similar in the two groups. Use of AlluraClarity substantially reduced radiation doses compared to the older generation reference system without compromising imaging quality in a pediatric cardiac catheterization lab.

Image noise reduction technology allows significant reduction of radiation dosage in cardiac device implantation procedures

BACKGROUND

Novel x-ray systems with real-time image noise reduction technology (INRT) to reduce radiation dose during fluoroscopy and cine acquisition have become available. This study evaluated the reduction of radiation dose in device implantation with INRT.

METHODS

Radiation dose data from 132 consecutive new device implantation procedures (102 pacemaker [PM] or implantable cardioverter defibrillator [ICD] and 30 cardiac resynchronization therapy [CRT] devices) performed between January 2015 and December 2015 on an angiography system with INRT (Allura ClarityIQ) were collected. For comparison, radiation dose data from 147 consecutive device implantation procedures (121 PM/ICDs and 26 CRT devices) performed between June 2013 and September 2014 on a C-arm system with continuous and pulsed fluoroscopy option (4 frames/second) were evaluated. Total dose area product (DAP), fluoroscopy DAP, and cine DAP were evaluated.

RESULTS

Patient age, gender and body weight, procedure, and fluoroscopy times were similar between systems. In PM/ICD cases, DAP of INRT and C-arm system was similar (423 ± 381 cGycm²  vs 417 ± 517 cGycm) due to pulsed fluoroscopy with the C-arm system (78% of time) and sparse use of cine. In CRT procedures requiring higher image quality (82% use of continuous fluoroscopy with C-arm system), DAP of INRT was significantly lower (1,544 ± 834 cGycm vs 7,252 ± 6,431 cGycm, P < 0.001) due to less fluoroscopy DAP (1,414 ± 757 cGycm vs 5,854 ± 6,767 cGycm) and less cine DAP (130 ± 106 cGycm vs 1,399 ± 1,342 cGycm). Considering all procedures, total DAP was reduced by 60% using INRT.

CONCLUSION

Novel INRT results in a substantial lowering of radiation dose in device implantation, in particular, in complex CRT implantation procedures requiring high image quality.

Examination of Dose Reduction Using Image Noise Reduction Technology in Cardiovascular X-ray Systems

The aim of this study is to establish radiation exposure dose reduction protocols during cardiac intervention by decreasing the entrance dose at flat panel detector (FPD) with image quality evaluations. For measuring entrance surface dose (ESD), we have used a Radical 9015 dosimeter (6 cc ion chamber) placed under 20 cm thick acrylic plates at the patient's entrance reference point. We performed an image quality assessment based on quantitative as well as visual evaluation of the images obtained via current and dose reduction protocols. The visual evaluation was performed by measuring the signal to noise ratio and contrast using a cine/digital angiography cardiac phantom. The quantitative evaluation was performed by cardiologists and radiological technologists using the five-point scale method. For the dose reduction protocol, we used an image noise reduction technique to prevent the deterioration of image quality. The ESDs for the fluoroscopy and digital cine in the dose reduction protocol were 18.0 mGy/min and 0.18 mGy/frame, respectively, which corresponded to 81% and 49% of the ESD in the current protocol. Our results reveal that the ESD for fluoroscopy was lower than the diagnostic reference level (20 mGy/min) for interventional radiology. We recommend a lower dose setting and the maintenance of image quality using noise reduction techniques. This will ensure use of a lower FPD entrance dose compared to the initial dose setting currently recommended by manufacturers.

Image noise reduction technology reduces radiation in a radial-first cardiac catheterization laboratory

BACKGROUND

Transradial coronary angiography (TRA) has been associated with increased radiation doses. We hypothesized that contemporary image noise reduction technology would reduce radiation doses in the cardiac catheterization laboratory in a typical clinical setting.

METHODS AND RESULTS

We performed a single-center, retrospective analysis of 400 consecutive patients who underwent diagnostic and interventional cardiac catheterizations in a predominantly TRA laboratory with traditional fluoroscopy (N=200) and a new image noise reduction fluoroscopy system (N=200). The primary endpoint was radiation dose (mGy cm²). Secondary endpoints were contrast dose, fluoroscopy times, number of cineangiograms, and radiation dose by operator between the two study periods. Radiation was reduced by 44.7% between the old and new cardiac catheterization laboratory (75.8mGycm²±74.0 vs. 41.9mGycm²±40.7, p<0.0001). Radiation was reduced for both diagnostic procedures (45.9%, p<0.0001) and interventional procedures (37.7%, p<0.0001). There was no statistically significant difference in radiation dose between individual operators (p=0.84). In multivariate analysis, radiation dose remained significantly decreased with the use of the new system (p<0.0001) and was associated with weight (p<0.0001), previous coronary artery bypass grafting (p<0.0007) and greater than 3 stents used (p<0.0004). TRA was used in 90% of all cases in both periods. Compared with a transfemoral approach (TFA), TRA was not associated with higher radiation doses (p=0.20).

CONCLUSIONS

Image noise reduction technology significantly reduces radiation dose in a contemporary radial-first cardiac catheterization clinical practice.