Assessing the level of radiation experienced by anesthesiologists during transfemoral Transcatheter Aortic Valve Implantation and protection by a lead cap.

OBJECTIVE: Transfemoral Transcatheter Aortic Valve Implantation (TAVI) has become a standard therapy for patients with aortic valve stenosis. Fluoroscopic imaging is essential for TAVI with the anesthesiologist's workplace close to patient's head side. While the use of lead-caps has been shown to be useful for interventional cardiologists, data are lacking for anesthesiologists. METHODS: A protective cap with a 0.35 lead-equivalent was worn on 15 working days by one anesthesiologist. Six detectors (three outside, three inside) were analyzed to determine the reduction of radiation. Literature search was conducted between April and October 2018. RESULTS: In the observational period, 32 TAVI procedures were conducted. A maximum radiation dose of 0.55 mSv was detected by the dosimeters at the outside of the cap. The dosimeters inside the cap, in contrast, displayed a constant radiation dose of 0.08 mSv. CONCLUSION: The anesthesiologist's head is exposed to significant radiation during TAVI and it can be protected by wearing a lead-cap.

Variability in radiation dose and image quality: A comparison across fluoroscopy-system vendors, generations of equipment and institutions.

OBJECTIVES: To evaluate differences in radiation dose and image quality across institutions, fluoroscope vendors and generations of fluoroscopes for pediatric cardiac catheterization. BACKGROUND: Increased recognition of the potentially harmful effects of ionizing radiation has spurred technological advances in fluoroscopes, as well as increased focus on optimizing fluoroscope performance. There is currently little understanding of variability in the dose-image quality relationship across institutions, fluoroscope vendor and/or generation of equipment. METHODS: We evaluated latest generation fluoroscopes from Phillips, Siemens, GE, and Toshiba, and an older generation Phillips fluoroscope (release date 2003) at three different institutions. Radiation dose was measured using an anthropomorphic dose-assessment phantom with effective dose in mSv estimated from Monte Carlo simulations. Image quality phantom images were scored on a 12-point scale by three blinded reviewers. RESULTS: Fluoroscope effective doses ranged from 0.04 to 0.14 mSv/1,000 pulses for fluoroscopy with associated composite image quality scores ranging from 8.0 ± 0.6 to 10.4 ± 1.3. For cineangiography, effective doses ranged from 0.17 to 0.57 mSv/1,000 frames with image quality scores ranging from 10.1 ± 0.3 to 11.1 ± 0.3. There was modest correlation between effective dose and image quality (r = 0.67, P = 0.006). The older generation fluoroscope delivered consistently higher doses than the newer generation systems (2.3- to 3.5-fold higher for fluoroscopy; 1.1- to 3.4-fold higher for cineangiography) without appreciable differences in image quality. CONCLUSION: Technological advances have markedly improved fluoroscope performance. Comparing latest generation systems across vendors and institutions, we found variability in the dose-IQ relationship and speculate that this reflects both equipment and institutional optimization practices.

Noise reduction technology reduces radiation dose in chronic total occlusions percutaneous coronary intervention: a propensity score-matched analysis.

Chronic total occlusions (CTO) percutaneous coronary intervention (PCI) is associated with high radiation dose. Our study aim was to evaluate the impact of the implementation of a noise reduction technology (NRT) on patient radiation dose during CTO PCI. A total of 187 CTO PCIs performed between February 2016 and May 2017 were analyzed according to the angiographic systems utilized: Standard (n = 60) versus NRT (n = 127). Propensity score matching (PSM) was performed to control for differences in baseline characteristics. Primary endpoints were Cumulative Air Kerma at Interventional Reference Point (AK at IRP), which correlates with patient's tissue reactions; and Kerma Area Product (KAP), a surrogate measure of patient's risk of stochastic radiation effects. An Efficiency Index (defined as fluoroscopy time/AK at IRP) was calculated for each procedure. Image quality was evaluated using a 5-grade Likert-like scale. After PSM, n = 55 pairs were identified. Baseline and angiographic characteristics were well matched between groups. Compared to the Standard system, NRT was associated with lower AK at IRP [2.38 (1.80-3.66) vs. 3.24 (2.04-5.09) Gy, p = 0.035], a trend towards reduction for KAP [161 (93-244) vs. 203 (136-363) Gycm2, p = 0.069], and a better Efficiency Index [16.75 (12.73-26.27) vs. 13.58 (9.92-17.63) min/Gy, p = 0.003]. Image quality was similar between the two groups (4.39 ± 0.53 Standard vs. 4.34 ± 0.47 NRT, p = 0.571). In conclusion, compared with a Standard system, the use of NRT in CTO PCI is associated with lower patient radiation dose and similar image quality.

Radiation Protocol for Three-Dimensional Rotational Angiography to Limit Procedural Radiation Exposure in the Pediatric Cardiac Catheterization Lab.

BACKGROUND: Three-dimensional rotational angiography (3DRA) offers more detailed anatomic information than 2D digital acquisition (2DDA). Concerns over potentially higher contrast and radiation doses have limited its routine use. OBJECTIVE: The primary objective of this study was to compare radiation doses required to obtain 3DRA using a customized low dose radiation protocol with 2DDA. The secondary objective was to compare total procedural radiation in pediatric cardiac catheterization procedures utilizing 3DRA to those that do not. STUDY DESIGN: Phantom studies were conducted to establish customized 3DRA protocols for radiation reduction. Comparison of 3DRA and non-3DRA procedures in age-, size- and diagnosis-matched controls was performed. Radiation doses were indexed to body surface area (BSA) to account for differing body habitus as validated from the phantom study. RESULTS: Study (n = 100) and control (n = 100) groups were matched for age (10.2 vs. 9.98 years; P = .239) and BSA (1.23 vs. 1.09 m2 ; P = .103). The dose area product (DAP) to acquire a 3DRA was similar to a 5 s, 15 frames/second 2DDA (278 vs. 241 cGy/cm2 ; P = .14). Despite the 3DRA group consisting of more complex interventions, no difference was found in the total procedural Air Kerma and DAP indexed to BSA (244 vs. 249 mGy/m2 ; P = .79 and 3348 vs. 3176 cGy/cm2 /m2 ; P = .48, respectively). The contrast volume to acquire a 3DRA compared to a 2DDA was greater (1.59 vs. 1.01 mL/kg; P < .001). However, no difference was found for the entire procedure (3.8 vs. 4 mL/kg, P = .494). This could have resulted from the need to obtain multiple 2DDAs to achieve the detail of a single 3DRA (11 vs. 7 per study; P < .001). CONCLUSIONS: When 3DRA, using the proposed protocols is employed, total procedural contrast and radiation doses are comparable with the sole use of biplane cine-angiograms. These protocols may allow for routine use of 3DRA for congenital cardiac catheterizations.

Evaluation of a new very low dose imaging protocol: feasibility and impact on X-ray dose levels in electrophysiology procedures.

AIMS: This study presents and evaluates the impact of a new lowest-dose fluoroscopy protocol (Siemens AG), especially designed for electrophysiology (EP) procedures, on X-ray dose levels. METHODS AND RESULTS: From October 2014 to March 2015, 140 patients underwent an EP study on an Artis zee angiography system. The standard low-dose protocol was operated at 23 nGy (fluoroscopy) and at 120 nGy (cine-loop), the new lowest-dose protocol was operated at 8 nGy (fluoroscopy) and at 36 nGy (cine-loop). Procedural data, X-ray times, and doses were analysed in 100 complex left atrial and in 40 standard EP procedures. The resulting dose-area products were 877.9 ± 624.7 µGym² (n = 50 complex procedures, standard low dose), 199 ± 159.6 µGym² (n = 50 complex procedures, lowest dose), 387.7 ± 36.0 µGym² (n = 20 standard procedures, standard low dose), and 90.7 ± 62.3 µGym² (n = 20 standard procedures, lowest dose), P < 0.01. In the low-dose and lowest-dose groups, procedure times were 132.6 ± 35.7 vs. 126.7 ± 34.7 min (P = 0.40, complex procedures) and 72.3 ± 20.9 vs. 85.2 ± 44.1 min (P = 0.24, standard procedures), radiofrequency (RF) times were 53.8 ± 26.1 vs. 50.4 ± 29.4 min (P = 0.54, complex procedures) and 10.1 ± 9.9 vs. 12.2 ± 14.7 min (P = 0.60, standard procedures). One complication occurred in the standard low-dose and lowest-dose groups (P = 1.0). CONCLUSION: The new lowest-dose imaging protocol reduces X-ray dose levels by 77% compared with the currently available standard low-dose protocol. From an operator standpoint, lowest X-ray dose levels create a different, reduced image quality. The new image quality did not significantly affect procedure or RF times and did not result in higher complication rates. Regarding radiological protection, operating at lowest-dose settings should become standard in EP procedures.

Comparison of radiation dose between different fluoroscopy systems in the modern catheterization laboratory: Results from bench testing using an anthropomorphic phantom.

BACKGROUND: Variations in radiation dose between various X-ray systems have received limited study. OBJECTIVE: We examined the impact of X-ray system type on patient radiation dose during cardiac catheterization. METHODS: An anthropomorphic phantom was used in a series of standardized experiments that involved 15 sec of continuous cineangiography in 7 projections. Three to seven experiments were performed in four commonly used X-ray systems: Innova IGS (GE Healthcare), Integris Allura FD20 (Philips), Allura Clarity (Philips), and Artis one (Siemens). Phantom radiation dose was measured with a dedicated X-ray dosimetry system (Gafchromic radiology film and Film QA XR software, Ashland) that was precalibrated at 0, 1, 2, 3, and 4 Gray, and with the X-ray system built-in functions. RESULTS: Radiation dose was lowest with the Allura Clarity system [average film dose 4.2±0.1 cGray, peak film dose 18.3±1.6 cGray, Air Kerma (AK) dose 0.310±0.002 Gray, Dose Area Product (DAP) dose 23.72±0.84 Gray*cm2], intermediate with the Integris Allura FD20 (average film dose 4.4±1.1 cGray, peak film dose 29.4±15.5 cGray, AK 0.482±0.189 Gray, DAP 45.18±21.90 Gray*cm2), and highest with the Artis one system (average film dose 7.4±0.8 cGray, peak film dose 66.9±0.09 cGray, AK 0.746±0.085 Gray, DAP 75.93±9.11 Gray*cm2) and the Innova IGS system (average film dose 7.2±1.0 cGray, peak film dose 49.3±28.9 cGray, AK 0.874±0.340 Gray, DAP 92.28±14.73 Gray*cm2; P=0.011 for average film dose, P=0.019 for maximum film dose, P=0.033 for AK, and P=0.008 for DAP). CONCLUSIONS: The X-ray system type has significant impact on patient radiation dose during cardiac catheterization.

Three-dimensional rotational X-ray acquisition technique is reducing patients' cancer risk in coronary angiography.

OBJECTIVES: The purpose of this study was to assess patient-specific organ doses and cancer risk with 3D-rotational acquisitions versus the current standard of multiple single-plane coronary angiography (CA). BACKGROUND: Catheter-based CA remains one of the most commonly performed diagnostic invasive procedures delivering a relatively high radiation dose to the patient. With the introduction of flat-panel technology, three-dimensional rotational angiography became an alternative for the conventional two-dimensional angiography. However, limited information is available on the difference in patient radiation exposure with both acquisition techniques. METHODS: Eighty adult patients (45 males, age 38-93 years) were randomly assigned to the rotational or standard angiography group. Exposure parameters were registered and skin dose distribution was measured during the procedure. Patient-specific organ doses and related cancer risks were assessed with dedicated software. RESULTS: Rotational angiograms were associated with 33% lower KAP-values (decrease from 49.99 Gycm(2) to 33.37 Gycm(2), P < 0.001). A significant (P < 0.001) lower peak skin dose was measured with rotational acquisitions (80 mGy, median) versus planar imaging (172 mGy, median). Moreover, the skin dose was smoothed over the whole chest of the patient. Contrast medium consumption decreased from 104 mL to 73 mL (P < 0.001) with the use of 3D-imaging. The reduction in radiation exposure resulted in a corresponding decrease of organ doses. The latter contributed to an overall cancer risk reduction of 21% for males and 50% for females. CONCLUSIONS: The current study demonstrates that in CA radiation risk reduction is feasible by using a rotational acquisition technique.

Direct and indirect measurement of patient radiation exposure during endovascular aortic aneurysm repair.

With the increasing complexity of endovascular procedures, concern has grown regarding patient radiation exposure. Abdominal aortic aneurysm (AAA) repair represents the most common complex endovascular procedure currently performed by vascular specialists. Our study evaluates the patient radiation dose received during endovascular AAA repair. Over a 3-month period we prospectively monitored the radiation dose in a series of consecutive patients undergoing endovascular AAA repair. All patients underwent standard endovascular AAA repair with one of two commercially available grafts using the GE OEC 9800 unit. Direct measurement of maximum radiation dose at skin level (peak skin dose, PSD) was recorded using GAFCHROMIC radiographic dosimetry film. Indirect measurements of radiation dose (fluoroscopy time and dose-area-product [DAP]) were recorded with the C-arm dosimeter. A total of 12 consecutive patients undergoing standard endovascular AAA repair were evaluated. Mean PSD was 0.75 Gy (range 0.27-1.25). Mean total fluoroscopy time was 20.6 min (range 12.6-34.2) with an average of 92% spent in standard fluoroscopy and 8% spent in cinefluoroscopy. Regarding total fluoroscopy time, 49% was spent in normal field of view and 51% in magnified view. Mean DAP was 15,166 cGy x cm(2) (range 5,207-24,536). PSD correlated with DAP (r = 0.9, p < 0.05) but not total fluoroscopy time (r = 0.18, p > 0.05). PSD also correlated with body mass index (BMI; r = 0.82, p < 0.05). Obese patients had a mean PSD of 1.1 Gy compared to 0.5 Gy in nonobese patients. PSD of all patients was well below the accepted 2.0 Gy threshold for skin injury. PSD correlated with DAP but not total fluoroscopy time. PSD also correlated with BMI, and the mean PSD was significantly increased in obese compared to nonobese patients. Despite the complexity and duration of endovascular AAA repair, the procedure can be performed safely without excessive radiation exposure.

Insuficiência renal aguda induzida pelo contraste em pacientes submetidos à cineangiocoronariografia: análise dos métodos de prevenção / Radiocontrast: induced nephropathy in patients undergoing coronary angiography: analysis of protective methods

A insuficiência renal aguda induzida por contraste (IRAIC) é considerada, atualmente, uma importante causa de disfunção renal em pacientes hospitalizados submetidos à cinecorioangiografia (CAG). Este achado adquire maior importância quando se verifica que a IRAIC é responsável por um aumento significativo dos índices de morbidade e mortalidade hospitalar / Radiocontrast-induced nephropathy (RIN) is considered an importante cause of renal failure in patients undergoing coronary. This data becomes more relevant when it presents a positive correlation with higher morbidity and mortality rates...

Radiation exposure to patients undergoing percutaneous coronary interventions: are current reference values too high?

PURPOSE: To determine predictors of patient radiation exposure due to percutaneous coronary interventions (PCI) and to compare our results with the "preliminary reference levels", recently proposed by the European DIMOND research cardiology group: i. e., 75 Gy.cm(2) for dose area kerma product (DAP), 17 min for fluoroscopy time (T(F)), and 1,300 for cinegraphic frames (F). MATERIAL AND METHODS: For 642 PCI-exclusive of the fraction for diagnostic catheterization to avoid statistical confounder effects-we measured total DAP, cinegraphic (DAP(C)) and fluoroscopic (DAP(F)) fractions, the number of cinegraphic frames and runs, and T(F). DAP(C)/F and DAP(F)/s were calculated to indicate the quality of focusing to the region of interest. RESULTS: The mean total patient DAP for elective one-, two-, and three-vessel PCI amounted to 6.7, 11.6, and 19.4 Gy.cm(2), for PCI of focal in-stent restenoses to 4.2 Gy.cm(2), and for excimer laser angioplasty of diffuse in-stent restenoses to 19.4 Gy.cm(2), respectively. Recanalization of chronic occlusions and PCI in acute myocardial infarction occasioned mean levels of 16.0 and 17.3 Gy.cm(2). Implantation of one and > or = two stents during one-vessel PCI significantly increased total mean DAP from a baseline level of 5.7 up to 7.1 and to 13.8 Gy.cm(2). DAP significantly varied according to the various PCI target regions and amounted to 4.0, 4.5, and 5.5 Gy.cm(2) for intermedius, diagonal, and left anterior descending arteries, to 4.9, 5.0, and 7.0 Gy.cm(2) for obtuse marginal, left posterolateral, and circumflex arteries, to 8.3, 9.1, and 9.5 Gy.cm(2) for proximal/mid right coronary segments, posterior descending, and right posterolateral arteries, and to 11.6 Gy.cm(2) for saphenous vein grafts, respectively. CONCLUSION: This study, carried through by consistent use of radiation-reducing techniques, enables a reliable scoring of patient radiation exposure according to complexity and target vessel of the intended PCI. Our 95th percentiles for elective PCI, for recanalizations of chronic occlusions, and for emergency PCI advise reference levels of 22, 32, and 42 Gy.cm(2) for DAP, of 16, 25, and 24 min for T(F), and of 400, 600, and 700 cinegraphic frames, respectively.

Patient dosimetry during coronary interventions: a comprehensive analysis.

BACKGROUND: We performed a detailed analysis of patient radiation during coronary interventions, comparing dose measurements to established dose reference levels, assessing coronary artery doses, and estimating total radiation risk of fatal cancer. METHODS: We prospectively examined 281 patients who were subjected to 307 percutaneous coronary interventions. RESULTS: The mean kerma area product (KAP) per procedure was 82.1 +/- 47.9 Gy x cm2. Corresponding values for fluoroscopy and digital cineangiography were 28.3 +/- 25.5 Gy x cm2 and 53.8 +/- 35.5 Gy x cm2, respectively, and exposure times were 13.1 +/- 6.8 minutes (87%) and 2.0 +/- 1.5 minutes (13%), respectively. The right anterior oblique caudal and left anterior oblique cranial projections accounted for the highest amount of KAP (24.0% and 23.1%, respectively) compared with other projections. The maximum recorded skin-dose was 182 mGy. Performing a representative procedure on a phantom, the effective dose was 14.9 mSv. The mean coronary dose was 61.7 +/- 38.2 mGy, with a highest calculated dose of 220.1 mGy. The third quartile of KAP measurements was 105 Gy x cm2, the 95th percentile was 175 Gy x cm2, and the mean value of KAP measurements was 82 Gy x cm2. The total risk for the development of fatal cancer was calculated as 83 cases for every 100,000 patients subjected to coronary intervention. CONCLUSIONS: A detailed analysis of patient radiation during coronary interventions is presented. Coronary doses and total radiation risk of fatal cancer are also calculated, and a method for establishing dose reference level values is proposed.

[Secondary ionizing radiation generated by digital and analog coronary cineangiographic equipment: influence of external systems of radiologic protection]. / Radiación ionizante secundaria generada en equipos de cineangiografía coronaria digital y analógica: influencia de los sistemas externos de protección radiológica.

BACKGROUND: Exposure to ionizing radiation is a known hazard of radiological procedures. AIM: To compare the emission of secondary ionizing radiation from two coronary angiographic equipment, one with digital and the other with analog image generation. To evaluate the effectiveness of external radiological protection devices. MATERIAL AND METHODS: Environmental and fluoroscopy generated radiation in the cephalic region of the patient was measured during diagnostic coronary angiographies. Ionizing radiation generated in anterior left oblique projection (ALO) and in anterior right oblique projection (ARO) were measured with and without leaded protections. In 19 patients (group 1), a digital equipment was used and in 21 (group 2), an analog equipment. RESULTS: Header radiation for groups 1 and 2 was 1194 +/- 337 and 364 +/- 222 microGray/h respectively (p < 0.001). During fluoroscopy and with leaded protection generated radiation for groups 1 and 2 was 612 +/- 947 and 70 +/- 61 microGray/h respectively (p < 0.001). For ALO projection, generated radiation for groups 1 and 2 was 105 +/- 47 and 71 +/- 192 microGray/h respectively (p < 0.001). During filming the radiation for ALO projection for groups 1 and 2 was 7252 +/- 9569 and 1671 +/- 2038 microGray/h respectively (p = 0.03). Out of the protection zone, registered radiation during fluoroscopy for groups 1 and 2 was 2800 +/- 1741 and 1318 +/- 954 microGray/h respectively (p < 0.001); during filming, the figures were 15,500 +/- 5840 and 18,961 +/- 10,599 microGray/h respectively (NS). CONCLUSIONS: Digital radiological equipment has a lower level of ionizing radiation emission than the analog equipment.

Chronic radiodermatitis following cardiac catheterisation: a report of two cases and a brief review of the literature.

Cardiac angiography produces one of the highest radiation exposures of any commonly used diagnostic x ray procedure. Recently, serious radiation induced skin injuries have been reported after repeated therapeutic interventional procedures using prolonged fluoroscopic imaging. Two male patients, aged 62 and 71 years, in whom chronic radiodermatitis developed one to two years after two consecutive cardiac catheterisation procedures are reported. Both patients had undergone lengthy procedures using prolonged fluoroscopic guidance in a limited number of projections. The resulting skin lesions were preceded, in one case, by an acute erythema and took the form of a delayed pigmented telangiectatic, indurated, or ulcerated plaque in the upper back or below the axilla whose site corresponded to the location of the x ray tube during cardiac catheterisation. Cutaneous side effects of radiation exposure result from direct damage to the irradiated tissue and have known thresholds. The diagnosis of radiation induced skin injury relies essentially on clinical and histopathological findings, location of skin lesions, and careful medical history. Interventional cardiologists should be aware of this complication, because chronic radiodermatitis may result in painful and resistant ulceration and eventually in squamous cell carcinoma.

Occupational exposure in pediatric cardiac catheterization.

Radiation doses to staff involved with pediatric cardiac catheterization were measured using thermoluminescent dosimeters in 18 procedures. The average doses to the lens and thyroid, and the effective dose per procedure to the main operating physicians was 88, 180, and 8 microSv, respectively; to assistant physicians, 23, 51, and 2 microSv; and to technicians, 23, 27, and 2 microSv. In some procedures, the dose to the technician's hand approached 1,500 microSv. The doses received by physicians were proportional to cineangiographic time but with no correlation with integrated currents. The number of procedures which may be performed in a year by individual staff members was estimated to be 430 and 2,780 procedures for physicians and assistants, respectively. It was suggested that the front of the neck is an adequate position for the dosimeter to measure doses during pediatric catheterization.