Decreasing radiation exposure in interventional pediatric cardiology: a 10-year European single-center analysis of 3683 procedures.

Because of the higher radiosensitivity of infants and children compared with adults, there is a need to evaluate the doses delivered to pediatric patients who undergo interventional cardiac procedures. However, knowledge of the effective dose in pediatric interventional cardiology is very limited. For an accurate risk estimation, a patient-specific Monte Carlo simulation of the effective dose was set up in 60 patients with congenital heart disease who underwent diagnostic (n=28) or therapeutic (n=32) cardiac catheterization procedures. The dose-saving effect of using extra copper filtration in the x-ray beam was also investigated. For diagnostic cardiac catheterizations, a median effective dose of 4.6 mSv was found. Therapeutic procedures resulted in a higher median effective dose of 6.0 mSv because of the prolonged use of fluoroscopy. The overall effect of inserting extra copper filtration into the x-ray beam was a total effective dose reduction of 18% with no detrimental effect on image quality. An excellent correlation between the dose-area product and effective patient dose was found (r=0.95). Hence, dose-area product is suitable for online estimation of the effective dose with good accuracy. With all procedures included, the resulting median lifetime risk for stochastic effects was 0.08%. Because of the high radiation exposure, it is important to monitor patient dose by dose-area product instrumentation and to use additional beam filtration to keep the effective dose as low as possible in view of the sensitivity of the pediatric patients.

Introduction: Rotational angiography of the left atrium with three-dimensional (3D) reconstruction (3D-ATG) represents a modern method enabling to create computed tomography (CT) like 3D images on a standard X-ray machine. Recently, electroanatomical mapping system can import 3D images reconstructed by 3D-ATG. Hypothesis: We assessed the hypothesis that atrial fibrillation (AF) ablation using 3D-ATG would be feasible with a significant reduction in effective dose without compromising image quality compared with 3D CT image. Methods: 3D-ATG was performed by using the Philips Allura Xper FD 10 system operated at a low-frame pulsed fluoroscopy (7.5 frames per second). Effective radiation dose was calculated from dose area product (DAP) measurements in 103 patients (mean age of 65 years, 71% men) undergoing AF ablation guided by 3D-ATG. Organ dose was measured at 37 points with a radiophotoluminescence glass dosimeter inserted in the position of an anthropomorphic Rando Phantom. Effective dose was calculated by multiplying organ dose by tissue weighting factor. The DAP to effective dose conversion factor was calculated by measurement of DAP at the same time of radiation exposure. Effective dose at CT examination was estimated from dose length product and conversion factor of 0.014. Left atrial dimensions and vertical ostial pulmonary vein (PV) diameters for each imaging method were compared. Results: The DAP to effective dose conversion factor of 3D-ATG was 2.4x10 -4 mSv/mGy•cm 2 by using the Philips Allura Xper FD 10 system in our hospital. Mean DAP for all patients was 7777±1488mGy•cm 2 for rotational angiography of the left atrium. The corresponding effective radiation doses for 3D-ATG were 1.9±0.4mSv. The effective doses for CT examinations were 13.6±4.2mSv (p<0.001). The correlations of left atrial dimension were r=0.73 for sagittal plane, 0.76 for coronal, and 0.80 for vertical (p<0.005). The correlation coefficient between 3D-ATG and 3D-CT for the ostial PV diameters was r=0.72 for left superior PV, 0.88 for left inferior PV, 0.60 for right superior PV, and 0.65 for right inferior PV (p<0.005). Conclusions: AF ablation using 3D-ATG is possible with a significant reduction in effective dose without compromising image quality.

Radiation exposure to neonates and infants during cardiac catheterizations is an important issue. Smaller patient size and higher heart rate in these patients result in a greater need for magnification modes and higher frame rates, all of which contribute to a significant increase in radiation doses. The aims of our study were to evaluate organ and effective doses for neonates and infants during diagnostic cardiac catheterizations on the basis of in-phantom dosimetry and conversion factors from dose-area product (DAP) to the effective dose. Organ doses for 0- and 1-year-old children during diagnostic cardiac catheterizations were measured by radiophotoluminescence glass dosimeters implanted in neonate and infant anthropomorphic phantoms. The effective doses were evaluated according to recommendations of the International Commission on Radiologic Protection (ICRP) publication 103. The mean effective doses evaluated according to ICRP 103 were 7.7 mSv (range, 0.1-18.4 mSv) for a neonate and 7.3 mSv (range, 1.9-18.6 mSv) for an infant. Conversion factors from DAP to the effective dose were 2.2 and 4.0 in posteroanterior and lateral cine angiography, respectively, for a neonate and 1.4 and 2.7 in posteroanterior and lateral cine angiography, respectively, for an infant. The dose data and conversion factors evaluated in this study could be useful for the estimation of radiation exposure in neonates and infants during diagnostic cardiac catheterization.

IntroductionCardiac catheterization procedures result in high radiation doses and often multiple procedures are necessary for congenital heart disease patients. However, diagnostic reference levels (DRL) remain scarce. Our first goal was finding the optimal DRL parameter and determining appropriate DRLs. The second goal was to calculate organ doses (OD), effective doses (ED) and lifetime attributable risks (LAR) per procedure and to provide conversion factors based on dose area product (DAP).Materials and methodsDRLs are calculated for each procedure type, as the 75th percentile of the cumulative value per procedure from the corresponding parameter. All irradiation events in the DICOM Structured Reports were automatically processed and simulated using PCXMC, resulting in OD, ED and LAR. Using a Kruskal Wallis H test and subsequent pairwise comparisons, differences in median values of the DRL parameter between procedure types were assessed.ResultsLinear regression showed a strong correlation and narrow confidence interval between DAP and product of body weight and fluoroscopy time (BWxFT), even when all procedures (diagnostic and interventional) are combined. Only 15% of the pairwise comparisons were statistically significant for DAP normalized to BWxFT (DAPBWxFT). The latter pairs contained less frequent procedure types with significant outliers. For DAP normalized to BW (DAPBW), 38% of the pairwise comparisons showed statistically significant differences. Conversion factors from DAPBW to OD and ED were reported for various weight groups, due to the higher correlation between DAPBW and both OD and ED than between DAP and both OD and ED.ConclusionsThe P75 of DAPBWxFT for all procedures combined serves as an appropriate DRL value. This facilitates local DRL determination in smaller paediatric centres, which often have insufficient data to produce appropriate DRLs for different procedure types. Conversion factors are more reliable starting from DAPBW instead of DAP and should be used according to the appropriate BW group.

1625 DECREASE IN RADIATION EXPOSURE DURING FLUORO URODYNAMICS (FUDS)

The Council Directive of the European Communities 97/43/Euratom requires dose assessment, especially for X-ray examinations of children and if high doses to the patient are involved. Both these aspects apply in cardiac catheterization and angiocardiography of children. Effective doses are a good indicator of radiation risk, particularly for leukaemia. Effective doses have been determined for 2114 infants and children undergoing cardiac catheterization from 1984 to 1996 at the University Hospital in Essen. Conversion factors (effective dose/dose-area product) were calculated based on direct dose-area product measurements for posteroanterior (PA) and lateral (Lat) projections as well as on patient records and examination details. The factors are calculated for eight age groups of children, taking into account the X-ray tube voltage for fluoroscopy and cine-film sequences, with and without zoom mode. Frequency distributions are presented for 2114 patients, for dose-area product, number of angiographic examinations (each combined with one cine-film sequence both PA and Lat) and for calculated effective doses. Highest effective doses are found in newborns (18.0 mSv and 6.5 mSv 90th and 50th percentiles, respectively) compared with adolescents of 15-21 years (8.0 mSv and 3.0 mSv 90th and 50th percentiles, respectively). Effective dose for cardiac catheterization is highest for newborns, in spite of lowest measured dose-area products, because the decreased value of the conversion factors overcompensates for the increase of dose-area product with age. This is especially important because of the higher tumour risk for equal effective dose for young children compared with adults.

OR12-1 | Minimizing Radiation Exposure During Cardiac Catheterization by Utilizing Ultra-Low Fluoroscopy Frame Rate

To provide dose-area-product (DAP) to effective dose (E) conversion factors for complete interventional procedures, based on in-the-field clinical measurements of DAP values and using tabulated E/DAP conversion factors for single projections available from the literature. Nine types of interventional procedures were performed on 84 patients with two angiographic systems. Different calibration curves (with and without patient table attenuation) were calculated for each DAP meter. Clinical and dosimetric parameters were recorded in-the-field for each projection and for all patients, and a conversion factor linking DAP and effective doses was derived for each complete procedure making use of published, Monte Carlo calculated conversion factors for single static projections. Fluoroscopy time and DAP values for the lowest-dose procedure (biliary drainage) were approximately 3-fold and 13-fold lower, respectively, than those for the highest-dose examination (transjugular intrahepatic portosystemic shunt, TIPS). Median E/DAP conversion factors from 0.12 (abdominal percutaneous transluminal angioplasty) to 0.25 (Nephrostomy) mSvGy(-1) cm(-2) were obtained and good correlations between E and DAP were found for all procedures, with R(2) coefficients ranging from 0.80 (abdominal angiography) to 0.99 (biliary stent insertion, Nephrostomy and TIPS). The DAP values obtained in this study showed general consistency with the values provided in the literature and median E values ranged from 4.0 mSv (biliary drainage) to 49.6 mSv (TIPS). Values of E/DAP conversion factors were derived for each procedure from a comprehensive analysis of projection and dosimetric data: they could provide a good evaluation for the stochastic effects. These results can be obtained by means of a close cooperation between different interventional professionals involved in patient care and dose optimization.

European states within the EEC are required to establish and use diagnostic reference levels (DRLs) in X-ray examinations. However, up to now there have been no DRLs for cardiac catheterization in children, nor as a rule is the effective dose estimated. We have evaluated the dose-area products (DAPs) for three different types of angiocardiography systems over a time span of 8 years. For each system DAP increased in proportion to the body weight (BW) over two orders of magnitude. The proportionality constant decreased over the years. To reduce the broad distribution of DAP the doses for cine acquisition (DAPA) and fluoroscopy (DAPF) were indexed with respect to the total numbers of acquired images (AN) and the total times of fluoroscopy (FT). DAPA/AN is directly proportional to BW with a high correlation (r = 0.896, n = 1346). Likewise, DAPF/FT is proportional to BW from 0.1 kg to 100 kg (r = 0.84, n = 2138). Therefore, by normalizing DAP to BW the growth dependent variation of DAP can be eliminated. There are numerous short examinations with very small total DAPs, which were separated from the group of diagnostic examinations. The mean DAP/BW of this group is 0.41 Gycm2 kg(-1) (90th percentile: 0.81 Gycm2 kg(-1), n = 1106). For interventional procedures in congenital heart diseases DAP/BW is significantly higher (p<0.001) (mean: 0.56 Gycm2 kg(-1), 90th percentile: 1.16 Gycm2 kg(-1), n = 883). There are significant differences between different types of interventional procedures, the mean values being between 0.35 Gycm2 kg(-1) (occlusion of patent ductus botalli, n = 165) and 1.30 Gycm2 kg(-1) (occlusion of ventricular septal defect, n = 32). For patients who are catheterized several times over the years, the cumulative effective dose (E) may reach high values, being especially high for patients with hypoplastic left heart syndrome (typically 11 mSv). E is derived from DAP/BW by use of a constant DAP/BW to E conversion factor, independent of the age of the patient. DAP/BW is appropriate to describe paediatric DRLs and is recommended instead of using mean DAP values for age groups.

Interventional cardiologists are exposed to radiation-induced diseases, partly due to patient's scatter radiation. We sought to compare the radiation exposure (RE) of the cardiac catheterization room staff using SEPARPROCATH®, a novel radio-protective drape versus standard shielding equipment. This was a two-step prospective, randomized pilot trial: first, in experimental conditions using a phantom model, and second, during cardiac catheterization. Primary end-point was operator RE corresponding to the ratio between operator cumulative dose (CD) and dose area product (DAP). Secondary end-points were nurse RE, operator and nurse CD, DAP, and fluoroscopy time. A total of 51 patients were included. SEPARPROCATH® was associated with a lower operator RE (0.07 [0-0.19] vs. 0.37 [0.23-0.81] μSv/Gy.cm2 without SEPARPROCATH®, p value <0.0001) and lower nurse RE (0 [0-0.05] vs. 0.13 [0.03-0.28] μSv/Gy.cm2 , p value <0.0001) corresponding to an RE relative risk reduction of 81% and 99%, respectively. Similar reductions were observed for operator and nurse CDs. No difference was found in DAP (19 [11-29] vs. 14 [10-32] Gy.cm2 without SEPARPROCATH®, p value 0.81). SEPARPROCATH® offers significant additional radioprotection to the operator and nurse during cardiac catheterization without affecting patient safety.

The present study evaluated the organ and effective doses in infant diagnostic cardiac catheterisation performed using a modern x-ray imaging unit by in-phantom dosimetry. In addition, conversion factors from dose-area product (DAP) to effective dose were determined. The organ and effective doses in 1-year old during diagnostic cardiac catheterisations were measured using radiophotoluminescence glass dosemeters implanted into an infant anthropomorphic phantom. The mean effective doses, evaluated according to the International Commission on Radiologic Protection Publication 103, were 4.0 mSv (range: 1.5-8.7 mSv). The conversion factors from DAP to effective dose were 2 and 3.5 mSv (Gy cm2)-1 for posteroanterior and lateral fluoroscopy, respectively, and 1.8 and 3.3 mSv (Gy cm2)-1 for posteroanterior and lateral cineangiography, respectively. The dose data and conversion factors evaluated in the present study may be useful for estimating radiation exposure in infants during diagnostic cardiac catheterisation.

Conversion factors for effective dose (CF(E) = effective dose/dose-area product (mSv (Gy cm2)(-1)) in paediatric interventional cardiology were estimated retrospectively for 249 patients using the dose-area product (DAP), irradiation geometry, exposure parameters and tissue-weighting factors (TWFs) from the International Commission on Radiological Protection (ICRP) 60. Two methods for estimating the conversion factors, which differed in the description of the irradiation geometry, were evaluated. The effective doses obtained with the two methods were almost identical. The results showed that irradiation geometry had no significant impact on the CF(E), and a single factor was defined for both diagnostic and interventional examinations. In addition, the effect of the new tissue-weighting factor for breast tissue (TWF(b)) given in ICRP 103 on the effective dose was assessed. The CF(E) was 3.7+/-0.2 mSv (Gy cm2)(-1) (neonate), 1.9+/-0.2 mSv (Gy cm2)(-1) (1 year), 1.0+/-0.1 mSv (Gy cm2)(-1) (5 years), 0.6+/-0.1 mSv (Gy cm2)(-1) (10 years) and 0.4+/-0.1 mSv (Gy cm2)(-1) (15 years). Applying these CFs to the individual DAP values of each patient yielded mean effective doses of 13.0 mSv (neonate), 8.6 mSv (1 year), 6.4 mSv (5 years), 8.6 mSv (10 years) and 12.7 mSv (15 years). The maximum estimated skin dose (15 patients) did not exceed 60 mGy. With the new ICRP value for TWF(b), increases in the CFs in the order of 10-30%, and in the effective dose of 10-20%, were indicated. The results indicated that the effective dose in paediatric interventional cardiology is of much greater concern than the skin dose. Furthermore, age-dependent CF(E) values are required so as not to underestimate the doses to very young patients.

patients are exposed to ionizing radiation during endoscopic retrograde cholangiopancreatography (ERCP). Radiation dose depends on multiple factors. The goal of this study was to assess fluoroscopy time (FT), radiation doses and effective dose (ED) during ERCP according to the condition being treated. a descriptive study was performed of 369 consecutive ERCPs from January 2017 to June 2019. Patient demographic and procedure data were collected. FT, cumulative dose area product (DAP), fluoroscopy DAP, DA fluoroscopy, air kerma, and number of radiographs were assessed. ED was estimated using specific conversion factors. the mean age was 73.34 years and 193 subjects were male. Mean FT was 4.56 ± 0.17 min, cumulative DAP was 2,056.73 ± 188.83 cGycm2, fluoroscopy DAP was 1,722.90 ± 82.26 cGycm2 and air kerma was 85.84 ± 4.93 mGy. The number of radiographs was 2.10 ± 0.07 and the mean ED was 5.34 ± 0.49 mSv. FT was significantly longer for choledocholithiasis (CL), proximal malignant biliary stricture (PMBS) and distal malignant biliary stricture (DMBS) versus others (OT). Cumulative DAP was higher for PMBS (p < 0.002). FT, cumulative DAP, fluoroscopy DAP and air kerma values were significantly higher for complicated CL as compared to simple CL. ED was higher for CL, DMBS and PMBS, but only significantly (p < 0.002) for PMBS. FT for ERCP is variable and increases with exploration difficulty. Thus, it is longer in the case of PMBS, as well as with the amount of radiation received by the patients and ED.

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.

The aim of this work is to estimate organ and effective dose of patients during some selected fluoroscopy guided examinations using monte carlo based code PCXMC and propose conversion factors for dose estimation at the facility. Screening time, number of radiographs were recorded from the fluoroscopy console and the kerma area product (KAP) from a KAP meter for a total of one hundred and seventy-one (171) patients in two different facilities (A and B). Incident air kerma at reference point, organ and effective doses were estimated with PCXMC software. The mean KAP value was 11.0, 10.4 and 81.0 mGycm2 for hysterosalpingography (HSG), retrograde (RUG) and barium swallow (BaS) respectively. The estimated effective dose was 0.8, 1.1, 22.8 mSv for HSG, RUG and BaS respectively. The mean fluoroscopy screening time was 0.89, 1.26, 2.92 minutes for HSG, RUG and BaS respectively. The mean number of radiographs taken was 4.5, 7.0, 13.0 for HSG, RUG and BaS respectively. Bladder (7.96 mGy), testicles (21.89 mGy) and breast (76,77 mGy) received the highest dose for HSG, RUG and BaS respectively. The recorded mean KAP values of this study for BaS was high than that of HSG and RUG by a factor of 7.4 and 7.8 respectively. This was attributed to high number of radiographs taken and fluoroscopy screening time. The mean KAP of this study was more than that of other studies by a maximum factor of 22.0, 7.8 and 23.5 for HSG, RUG and BaS respectively. The fluoroscopy screening of this study was more than that of other studies by a maximum factor of 3.3, 4.7 and 10.3 for HSG, RUG and BaS respectively. Also, the mean number of radiographs taken for this study was more than that of other studies by a maximum factor of 2.0, 2.6 and 1.7 for HSG, RUG and BaS respectively. It was suggested that there are other contributing factors to patient doses in addition to the screening time and radiographs taken during fluoroscopy procedures. A dose conversion factor from measurable quantities to effective dose estimation has been proposed to aid patient dose optimization. Further studies aiming at reporting patient organ doses in fluoroscopy examination and investigate into other patient dose contributing factors has been recommended to strengthen patient dose optimization.