Operator Radiation Dose Research Articles

Efficacy of RADPAD protective drape during coronary angiography

Ionizing radiation is an integral part of percutaneous coronary angiographies. Chronic exposure to low-dose radiation confers arisk for skin damage, eye lens opacities or cataracts, and malignant diseases to staff in the catheter laboratory. The RADPAD is asterile surgical drape that reduces the effect of scatter radiation on the operator. We sought to assess the efficacy of RADPAD shields in reducing radiation dose experienced by operators during routine diagnostic coronary angiography. Sixty consecutive patients due to undergo elective coronary angiography were randomized in a1:1 pattern to have their procedures performed with and without the RADPAD drape in situ. Dosimetry was performed on the left arm of the primary operator. There was no significant difference in the two main determents of radiation exposure in both groups: the screening times (102± 86 s for the RADPAD group vs. 105± 36 s for the control group, p= 0.9) and body mass index (BMI; 27.7± 4.2 kg/m2 for the RADPAD group vs. 27.9± 5.5 kg/m2 for the control group, p= 0.8). Moreover, there was no difference in the dose-area ratio (1337± 582 cGy/cm2 for the RADPAD group vs. 1541± 804 cGy/cm2 for the control group, p= 0.3) between the two patient groups. The primary operator radiation dose was significantly lower in the RADPAD group at 8.0 µSv (Q1: 3.2, Q3: 20.1) compared with 19.6 µSv (Q1: 7.1, Q3: 37.7) for the control group (p= 0.02). The RADPAD significantly reduces radiation exposure to primary operators during routine diagnostic coronary angiography in patients with aBMI> 25 kg/m2. It reduces total radiation exposure toprimary operators by 59%, and the radiation exposure rate by 47%.

Radiation Exposure and Vascular Access in Acute Coronary Syndromes: The RAD-Matrix Trial

BackgroundIt remains unclear whether radial access increases the risk of operator or patient radiation exposure compared to transfemoral access when performed by expert operators. ObjectivesThis study sought to determine whether radial access increases radiation exposure. MethodsA total of 8,404 patients, with or without ST-segment elevation acute coronary syndrome, were randomly assigned to radial or femoral access for coronary angiography and percutaneous intervention, and collected fluoroscopy time and dose-area product (DAP). RAD-MATRIX is a radiation sub-study of the MATRIX (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of AngioX) trial. We anticipated that 13 or more operators, each wearing a thorax (primary endpoint), wrist, and head (secondary endpoints) lithium fluoride thermoluminescent dosimeter, and randomizing at least 13 patients per access site, were needed to establish noninferiority of radial versus femoral access. ResultsAmong 18 operators, performing 777 procedures in 767 patients, the noninferiority primary endpoint was not achieved (p value for noninferiority = 0.843). Operator equivalent dose at the thorax (77 μSv) was significantly higher with radial than femoral access (41 μSv; p = 0.02). After normalization of operator radiation dose by fluoroscopy time or DAP, the difference remained significant. Radiation dose at wrist or head did not differ between radial and femoral access. Thorax operator dose did not differ for right radial (84 μSv) compared to left radial access (52 μSv; p = 0.15). In the overall MATRIX population, fluoroscopy time and DAP were higher with radial compared to femoral access: 10 min versus 9 min (p < 0.0001) and 65 Gy·cm2 versus 59 Gy·cm2 (p = 0.0001), respectively. ConclusionsCompared to femoral access, radial access is associated with greater operator and patient radiation exposure when performed by expert operators in current practice. Radial operators and institutions should be sensitized towards radiation risks and adopt adjunctive radioprotective measures. (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of AngioX; NCT101433627)

Determinants of operator radiation exposure during percutaneous coronary procedures

Radiation exposure is an important issue for interventional cardiologists that is often underevaluated. Our aim was to evaluate determinants of operator radiation exposure during percutaneous coronary procedures. The RADIANT (NCT01974453) is a prospective, single-center observational study involving 4 expert operators and 2 fellows performing percutaneous coronary procedures. The operator radiation dose was evaluated using dedicated electronic dosimeters in 2,028 procedures: 1,897 transradial access (TRA; 1,120 right and 777 left TRA) and 131 transfemoral access (TFA). In the whole population, operator radiation dose at the thorax did not differ between TFA (9μSv [interquartile range 5-18μSv]) and TRA (9μSv [4-21μSv]), but after propensity score matching analysis, TFA showed lower dose (9μSv [5-18μSv]) compared with TRA (17μSv [9-28μSv], P<.001). In the whole transradial group, left TRA (5μSv [2-12μSv]) was associated with significant lower operator dose compared with right TRA (13μSv [6-26μSv], P<.001).The use of adjunctive protective pelvic drapes was significantly associated with lower radiation doses compared with procedures performed without drapes (P<.001). Among the operators, an inverse relation between height and dose was observed. Finally, left projections and the use of angiographic systems not dedicated for coronary and high frame rates were all associated with a significant higher operator radiation exposure. In a high-volume center for transradial procedures, TFA is associated with lower operator radiation dose compared with TRA. The use of adjunctive anti-rx drapes seems a valuable tool to reduce the higher operator radiation exposure associated with TRA.

Mini C-arm: faster, cheaper, safer?

Mini C-arm image intensifiers (IIs) are promoted to permit lower radiation dose than traditional IIs with a lower purchase price and without the need for a radiographer, saving time. In real-world usage, radiation dose is not always lower. A retrospective review of prospectively collected data for 620 children undergoing forearm fracture reduction in theatre was undertaken. Imaging was performed with the Fluoroscan mini C-arm or a comparison traditional II. Radiation dose and theatre time were recorded. There was no significant difference in radiation dose as measured by dose-area product (0.013 versus 0.014 Gy.cm2 , P = 0.22). We noted an inverse association between operator experience and radiation dose. The mini C-arm allowed a shorter procedure time (26 versus 30 min, P < 0.001) and theatre time (13 versus 16 min, P < 0.001). Re-displacement rates were similar (1.3 versus 2.2%). The Fluoroscan is AU$120 000 cheaper to purchase and AU$35 283 cheaper to run per year than the comparison II. Consultants had a 14% lower dose-area product (0.012 versus 0.014 Gy.cm2 , P < 0.001) and 18% shorter screening time (8 versus 9.8 s, P < 0.001) than registrars. The Fluoroscan mini C-arm II does not demonstrate a radiation saving during closed reductions of paediatric forearm fractures but allows shorter procedures and theatre time with similar re-displacement rates. The purchase price is lower than a traditional II. We noted that operator experience reduces radiation dose.

New image-processing and noise-reduction software reduces radiation dose during complex endovascular procedures

A new proprietary image-processing system known as AlluraClarity, developed by Philips Healthcare (Best,The Netherlands) for radiation-based interventional procedures, claims to lower radiation dose while preserving image quality using noise-reduction algorithms. This study determined whether the surgeon and patient radiation dose during complex endovascular procedures (CEPs) is decreased after the implementation of this new operating system. Radiation dose to operators, procedure type, reference air kerma, kerma area product, and patient body mass index were recorded during CEPs on two Philips Allura FD 20 fluoroscopy systems with and without Clarity.Operator dose during CEPs was measured using optically stimulable, luminescent nanoDot (Landauer Inc, Glenwood, Ill) detectors placed outside the lead apron at the left upper chest position. nanoDots were read using a microStar ii (Landauer Inc) medical dosimetry system. For the CEPs in the Clarity group, the radiation dose to surgeons was also measured by the DoseAware (Philips Healthcare) personal dosimetry system. Side-by-side measurements of DoseAware and nanoDots allowed for cross-calibration between systems. Operator effective dose was determined using a modified Niklason algorithm. To control for patient size and case complexity, the average fluoroscopy dose rate and the dose per radiographic frame were adjusted for body mass index differences and then compared between the groups with and without Clarity by procedure. Additional factors, for example, physician practice patterns, that may have affected operator dose were inferred by comparing the ratio of the operator dose to procedural kerma area product with and without Clarity. Aone-sided Wilcoxon rank sum test was used to compare groups for radiation doses, reference air kermas, and operating practices for each procedure type. The analysis included 234 CEPs; 95 performed without Clarity and 139 with Clarity. Practice patterns of operators during procedures with and without Clarity were not significantly different. For all cases, procedure radiation dose to the patient and the primary and assistant operators were significantly decreased in the Clarity group by 60% compared with the non-Clarity group. By procedure type, fluorography dose rates decreased from 44% for fenestrated endovascular repair and up to 70% with lower extremity interventions. Fluoroscopy dose rates also significantly decreased, from about 37% to 47%, depending on procedure type. The AlluraClarity system reduces the patient and primary operator's radiation dose by more than half duringCEPs. This feature appears to be an effective tool in lowering the radiation dose while maintaining image quality.

The effects of device position on the operator's radiation dose when using a handheld portable X-ray device.

Handheld X-ray devices are now offered in dental practice. Handheld X-ray units challenge the concept of a restricted access to the "controlled area" as they are held by the operator. Although an integral lead shield is provided, the distance from the body is variable, dependent on how the device is held. The aim of this article was to investigate the level of operator dose when using a handheld X-ray device in various positions. A NOMAD Pro™ Handheld X-ray system (Aribex Inc., Charlotte, NC) fitted with a remote control and mounted on a tripod was used in this study. A maxillofacial phantom ATOM(®) Max Dental and Diagnostic Phantom, model 711 HN (CIRS Inc., Norfolk, VA) was used to simulate the patient's head position. A mannequin was used to represent the operator. Pre-calibrated thermoluminescent dosemeters (TLDs) (Qados, Agar Scientific, Stansted, UK) were placed on the mannequin close to the eyes and at the level of thyroid, trunk, waist, hand (right finger + left palm) and feet, and three TLDs were used for background radiation. Three test scenarios were investigated; Position 1, close to operators' body and parallel to the ground; Position 2, away from the body with the arms fully extended (approximately 40 cm distance) and parallel to the ground; Position 3, perpendicular to the ground while the arms are partially extended. 30 exposures each of 1 s were performed in each test. Background radiation was measured at 0.0110 mGy. The highest exposure after subtracting background radiation was recorded on the palm of the left hand (0.0310 mGy) at Position 3. The estimated dose to the operator was calculated based on an average workload of 100 intraoral radiographs weekly for a dental practitioner working 46 weeks a year. There is a negligible increase in operator exposure levels using handheld X-ray devices which remain well below the recommended levels of the Ionizing Radiation Regulations 1999. They could however represent an increase from what should be a nil exposure when using a wall-mounted machine. The position of the device relative to the operator has a significant effect on the overall operator's radiation exposure. The use of personal dosemeters is highly recommended to ensure a continuity of low radiation dose exposure. Furthermore, guidance, training and protocols on usage must be in place, strictly adhered to and regular audits are necessary to ensure compliance.

Near zerO fluoroscopic exPosure during catheter ablAtion of supRavenTricular arrhYthmias: the NO-PARTY multicentre randomized trial.

AimsAim of this study was to compare a minimally fluoroscopic radiofrequency catheter ablation with conventional fluoroscopy-guided ablation for supraventricular tachycardias (SVTs) in terms of ionizing radiation exposure for patient and operator and to estimate patients' lifetime attributable risks associated with such exposure.Methods and resultsWe performed a prospective, multicentre, randomized controlled trial in six electrophysiology (EP) laboratories in Italy. A total of 262 patients undergoing EP studies for SVT were randomized to perform a minimally fluoroscopic approach (MFA) procedure with the EnSiteTMNavXTM navigation system or a conventional approach (ConvA) procedure. The MFA was associated with a significant reduction in patients' radiation dose (0 mSv, iqr 0–0.08 vs. 8.87 mSv, iqr 3.67–22.01; P < 0.00001), total fluoroscopy time (0 s, iqr 0–12 vs. 859 s, iqr 545–1346; P < 0.00001), and operator radiation dose (1.55 vs. 25.33 µS per procedure; P < 0.001). In the MFA group, X-ray was not used at all in 72% (96/134) of cases. The acute success and complication rates were not different between the two groups (P = ns). The reduction in patients' exposure shows a 96% reduction in the estimated risks of cancer incidence and mortality and an important reduction in estimated years of life lost and years of life affected. Based on economic considerations, the benefits of MFA for patients and professionals are likely to justify its additional costs.ConclusionThis is the first multicentre randomized trial showing that a MFA in the ablation of SVTs dramatically reduces patients' exposure, risks of cancer incidence and mortality, and years of life affected and lost, keeping safety and efficacy.Trial registrationclinicaltrials.gov Identifier: NCT01132274.

Radiation exposure in relation to the arterial access site used for diagnostic coronary angiography and percutaneous coronary intervention: a systematic review and meta-analysis

Transradial access for cardiac catheterisation results in lower bleeding and vascular complications than the traditional transfemoral access route. However, the increased radiation exposure potentially associated with transradial access is a possible drawback of this method. Whether transradial access is associated with a clinically significant increase in radiation exposure that outweighs its benefits is unclear. Our aim was therefore to compare radiation exposure between transradial access and transfemoral access for diagnostic coronary angiograms and percutaneous coronary interventions (PCI). We did a systematic review and meta-analysis of the scientific literature by searching the PubMed, Embase, and Cochrane Library databases with relevant terms, and cross-referencing relevant articles for randomised controlled trials (RCTs) that compared radiation parameters in relation to access site, published from Jan 1, 1989, to June 3, 2014. Three investigators independently sorted the potentially relevant studies, and two others extracted data. We focused on the primary radiation outcomes of fluoroscopy time and kerma-area product, and used meta-regression to assess the changes over time. Secondary outcomes were operator radiation exposure and procedural time. We used both fixed-effects and random-effects models with inverse variance weighting for the main analyses, and we did confirmatory analyses for observational studies. Of 1252 records identified, we obtained data from 24 published RCTs for 19 328 patients. Our primary analyses showed that transradial access was associated with a small but significant increase in fluoroscopy time for diagnostic coronary angiograms (weighted mean difference [WMD], fixed effect: 1·04 min, 95% CI 0·84-1·24; p<0·0001) and PCI (1·15 min, 95% CI 0·96-1·33; p<0·0001), compared with transfemoral access. Transradial access was also associated with higher kerma-area product for diagnostic coronary angiograms (WMD, fixed effect: 1·72 Gy·cm(2), 95% CI -0·10 to 3·55; p=0·06), and significantly higher kerma-area product for PCI (0·55 Gy·cm(2), 95% CI 0·08-1·02; p=0·02). Mean operator radiation doses for PCI with basic protection were 107 μSv (SD 110) with transradial access and 74 μSv (68) with transfemoral access; with supplementary protection, the doses decreased to 21 μSv (17) with transradial access and 46 μSv (9) with transfemoral. Meta-regression analysis showed that the overall difference in fluoroscopy time between the two procedures has decreased significantly by 75% over the past 20 years from 2 min in 1996 to about 30 s in 2014 (p<0·0001). In observational studies, differences and effect sizes remained consistent with RCTs. Transradial access was associated with a small but significant increase in radiation exposure in both diagnostic and interventional procedures compared with transfemoral access. Since differences in radiation exposure narrow over time, the clinical significance of this small increase is uncertain and is unlikely to outweigh the clinical benefits of transradial access. None.

Operator Radiation Dose Reduction During Fluoroscopic Interventional Procedures

Training in interventional radiology (IR) is an essential part of radiology residency programs, and care must be taken to ensure that appropriate safety measures are in place to reduce resident radiation exposure. IR training of residents at our primary teaching hospital consists of 4 consecutive months of training for each resident, with 4 residents on the service each month. During the course of training, each resident often completes more than 400 procedures as either primary operator or first assistant operator.

Radiation Safety in Vascular Surgery

Modern vascular surgeons perform an ever-increasing number of complex endovascular procedures, largely based on patient preference, decreased length of stay, and improved outcome. With the upsurge of endovascular cases, concern has grown regarding the harmful effects of radiation exposure delivered to the patient and the operator. Surgeon education on the appropriate use of fluoroscopic operating factors coupled with appropriate training in radiation safety has been shown to decrease radiation dose. This review elucidates dose terminology and metrics, possible radiation-induced injuries, risk factors for deterministic injury, and radiation safety principles and techniques. Tables provide practical tips to lower patient and operator radiation dose during fluoroscopically guided intervention, and National Council on Radiation Protection &amp; Measurements recommended dose limits for occupational exposure. Figures illustrate reference air kerma, radiation-induced skin injury, effects of image receptor and table position, and operator exposure. This review contains 4 figures, 3 tables, and 53 references.

Abstract No. 451 - A modified abdominal compression device to facilitate CT fluoroscopy-guided percutaneous interventions

1.Provide indications for the use of an abdominal compression device to improve access to a target during CT fluoroscopy-guided interventions.2.Describe a modified commercially available fluoroscopic compression device.3.Provide cased-based-examples in which the abdominal compression device was used. CT-guided percutaneous abdominal interventions including biopsies and catheter drainages are common procedures in any interventional practice. While most targets, i.e. masses, lymph nodes, and fluid collections are readily accessible, many can be technically challenging due to intervening critical structures or may have a skin to target distance greater than the length of available needles. For structures that are relatively mobile, predominantly digestive and vascular organs, an abdominal compression device can be utilized to displace these structures, thereby creating a clear pathway to the intended target. Such a device can also employed to decrease the skin to target distance thereby allowing access to deeper targets. Abdominal compression devices have been described in the past, however have used materials which may not be readily available, require recreation of the device with every patient, or make manipulating the access needle relatively difficult. 1.Using an F-Spoon device, a slit and hole can be cut using a drill and saw into the spoon portion of the device.2.Intraprocedurally, the device is covered with a sterile ultrasound transducer cover and rubber bands making it sterile and reusable.3.The modified spoon portion can be employed as a compression device and to steer the needle without exposing the operator’s hand to the CT beam.4.After the procedure, the sterile cover is removed, the device cleaned, and reused for subsequent procedures.5.Provide several case examples illustrating the use of the abdominal compression device. 1.A fluoroscopic compression paddle can be easily modified into a device that facilitates CT fluoroscopy-guided percutaneous abdominal interventions.2.This device can be used to displace critical structures, shorten skin to target distance, and steer access needles while minimizing operator radiation dose.

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.

Surgeon Radiation Dose During Complex Endovascular Procedures

Surgeon radiation dose during complex endovascular procedures (CEPs) has not been well studied. We sought to characterize radiation exposure to surgeons during CEPs based on procedure type, operator position, level of operator training, upper vs lower body exposure, and the addition of protective shielding. Optically stimulable, luminescent nanoDot (Landauer Inc) detectors were used to measure radiation dose prospectively to surgeons during CEPs. NanoDot dosimeters were placed outside the lead apron of the primary and assistant operator at the left upper chest and left lower pelvis positions. For each case, procedure type, reference air kerma (RAK), kerma area product (KAP), the relative position of the operator, level of training of the fellow, and presence or absence of external additional shielding devices were recorded. Three positions were assigned on the right hand side of the patient in decreasing relative proximity to the flat panel detector (FPD) as A, B, and C, respectively. Position A (main operator) was closest to the FPD. Position D was on the left side of the patient at the brachial access site. NanoDots were read using a Microstar II medical dosimetry system (Landauer Inc) after every procedure. The nanoDot dosimetry system was calibrated for scattered radiation in an endovascular suite with a NIST-traceable solid state radiation detector (Piranha T20, RTI). Comparative statistical analyses of nanoDot dose levels between categories was performed using analysis of variance with Tukey pairwise comparisons. Bonferroni correction was used for multiple comparisons. There were 415 nanoDot measurements with the following case distribution: 16 thoracic endovascular aortic repairs or endovascular aneurysm repairs, 18 fenestrated endovascular aneurysm repairs (FEVARs), 13 embolizations, 41 lower extremity, 10 fistulograms, and 13 viscerals. The mean operator dose for FEVARs was statistically higher than for other case types (P < .03), 15 μSv at position A and 11 μSv at position B. For all case types, positions A (8.7 ± 2.7 μSv) and D (14.4 ± 7.8 μSv) received statistically higher effective doses than B (3.9 ± 2.7 μSv; P < .001 or C (0 mGy). However, the mean operator dose for position D was not statistically different from position A. The addition of the lead skirt significantly decreased the lower body dose (33 ± 3.4 μSv to 6.3 ± 3.3 μSv) but not the upper body dose (6.5 ± 3.3 μSv to 5.7 ± 2.2 μSv). The use of ceiling-mounted shielding did not affect the nanoDot dose. There was no difference in the operator dose observed based on level of training when the fellow was in position A. KAP was the better predictor of operator radiation dose compared with RAK. The mean KAP for all cases was 330 Gycm2, and the regression coefficient for operator dose to KAP was 0.021 ± 0.003 μSv/Gycm2 for position A and 0.015 ± 0.003 μSv/Gycm2 for B. Surgeon radiation dose during CEPs depends on case type, operator position, and table skirt use, but not on the level of fellow training. On the basis of this data, the primary operator could perform ∼12 FEVARs per week and have an annual dose of <10 mSv, which would not exceed lifetime occupational dose limits during a 35-year career. Excluding FEVARs with the above case mix, the primary operator could perform ∼40 CEPs per week and stay within regulatory limits. With practical case loads, operator doses are relatively low and unlikely to exceed occupational limits.

Effectiveness of Low Rate Fluoroscopy at Reducing Operator and Patient Radiation Dose During Transradial Coronary Angiography and Interventions

This study sought to determine the efficacy of low rate fluoroscopy at 7.5 frames/s (FPS) versus conventional 15 FPS for reduction of operator and patient radiation dose during diagnostic coronary angiography (DCA) and percutaneous coronary intervention (PCI) via the transradial approach (TRA). TRA for cardiac catheterization is potentially associated with increased radiation exposure. Low rate fluoroscopy has the potential to reduce radiation exposure. Patients undergoing TRA diagnostic angiography ± ad-hoc PCI were randomized to fluoroscopy at 7.5 FPS versus 15 FPS prior to the procedure. Both 7.5 and 15 FPS fluoroscopy protocols were configured with a fixed dose per pulse of 40 nGy. Primary endpoints were operator radiation dose (measured with dosimeter attached to the left side of the thyroid shield in μSievert [μSv]), patient radiation dose (expressed as dose-area product in Gy·cm(2)), and fluoroscopy time. From October 1, 2012 to August 30, 2013, from a total of 363 patients, 184 underwent DCA and 179 underwent PCI. Overall, fluoroscopy at 7.5 FPS compared with 15 FPS was associated with a significant reduction in operator dose (30% relative reduction [RR], p < 0.0001); and in patient's dose-area product (19% RR; p = 0.022). When stratified by procedure type, 7.5 FPS compared with 15 FPS was associated with significant reduction in operator dose during both DCA (40% RR; p < 0.0001) and PCI (28% RR; p = 0.0011). Fluoroscopy at 7.5 FPS, compared with 15 FPS, was also associated with substantial reduction in patients' dose-area product during DCA (26% RR; p = 0.0018) and during PCI (19% RR; p = 0.13). Fluoroscopy time was similar in 7.5 FPS and 15 FPS groups for DCA (3.4 ± 2.0 min vs. 4.0 ± 4.7 min; p = 0.42) and PCI (11.9 ± 8.4 min vs. 13.3 ± 9.7 min; p = 0.57), respectively. Fluoroscopy at 7.5 FPS, compared with 15 FPS, is a simple and effective method in reducing operator and patient radiation dose during TRA DCA and PCI.

Percutaneous Bone Biopsies: Comparison between Flat-Panel Cone-Beam CT and CT-Scan Guidance

This study was designed to compare the accuracy of targeting and the radiation dose of bone biopsies performed either under fluoroscopic guidance using a cone-beam CT with real-time 3D image fusion software (FP-CBCT-guidance) or under conventional computed tomography guidance (CT-guidance). Sixty-eight consecutive patients with a bone lesion were prospectively included. The bone biopsies were scheduled under FP-CBCT-guidance or under CT-guidance according to operating room availability. Thirty-four patients underwent a bone biopsy under FP-CBCT and 34 under CT-guidance. We prospectively compared the two guidance modalities for their technical success, accuracy, puncture time, and pathological success rate. Patient and physician radiation doses also were compared. All biopsies were technically successful, with both guidance modalities. Accuracy was significantly better using FP-CBCT-guidance (3 and 5 mm respectively: p = 0.003). There was no significant difference in puncture time (32 and 31 min respectively, p = 0.51) nor in pathological results (88 and 88 % of pathological success respectively, p = 1). Patient radiation doses were significantly lower with FP-CBCT (45 vs. 136 mSv, p < 0.0001). The percentage of operators who received a dose higher than 0.001 mSv (dosimeter detection dose threshold) was lower with FP-CBCT than CT-guidance (27 vs. 59 %, p = 0.01). FP-CBCT-guidance for bone biopsy is accurate and reduces patient and operator radiation doses compared with CT-guidance.

Reduction of Operator Radiation Dose by an Extended Lower Body Shield

PurposeTo quantify the reduction in operator exposure to scatter radiation by using an extension component in addition to a commonly used lower body radiation shield attached to an interventional radiology procedure table. Materials and MethodsAn anthropomorphic pelvis phantom was exposed to fluoroscopy at varying C-arm angles to simulate a standard interventional procedure. A MAVIG UT60 lower body shield (MAVIG, Munich, Germany) (48 cm × 78 cm, 0.5 mm lead equivalent), with an attachable extension component (48 cm × 36 cm), was suspended from the edge of the table adjacent to the pelvic phantom. Using a handheld Geiger counter, scatter radiation exposure rates were measured at the level of an operator’s eye, chest, waist, and knee, with various C-arm angles both with and without the attachable extension component. Mean exposure rates for each experimental setup were calculated and compared. ResultsOverall, scatter radiation exposures were lower with the addition of the extension component, with the largest reductions (> 80%) measured at the operator’s waist and knee levels, for all C-arm angles. The highest reduction in scatter radiation exposure was measured at knee level, at 0 degrees left posterior oblique projection, where the use of the lower body shield extension component reduced the exposure rate from 4.80 mR/h to 0.44 mR/h (90.8% reduction, P < .001). Reductions in scatter radiation were less at eye and chest levels. ConclusionsThe use of the additional extension component to the lower body radiation shield can result in large (> 80%) reductions in operator scatter radiation exposure, particularly to the lower body.

A Randomized Comparison of the Transradial and Transfemoral Approaches for Coronary Artery Bypass Graft Angiography and Intervention: The RADIAL-CABG Trial (RADIAL Versus Femoral Access for Coronary Artery Bypass Graft Angiography and Intervention)

This study sought to compare and contrast use and radiation exposure using radial versus femoral access during cardiac catheterization of patients who had previously undergone coronary artery bypass graft (CABG) surgery. Limited information is available on the relative merits of radial compared with femoral access for cardiac catheterization in patients who had previously undergone CABG surgery. Consecutive patients (N= 128) having previously undergone CABG surgery and referred for cardiac catheterization were randomized to radial or femoral access. The primary study endpoint was contrast volume. Secondary endpoints included fluoroscopy time, procedure time, patient and operator radiation exposure, vascular complications, and major adverse cardiac events. Analyses were by intention-to-treat. Compared with femoral access, diagnostic coronary angiography via radial access was associated with a higher mean contrast volume (142 ± 39 ml vs. 171 ± 72 ml, p < 0.01), longer procedure time (21.9 ± 6.8 min vs. 34.2 ± 14.7 min, p < 0.01), greater patient air kerma (kinetic energy released per unit mass) radiation exposure (1.08 ± 0.54 Gy vs. 1.29 ± 0.67 Gy, p= 0.06), and higher operator radiation dose (first operator: 1.3 ± 1.0 mrem vs. 2.6 ± 1.7 mrem, p < 0.01; second operator 0.8 ± 1.1 mrem vs. 1.8 ± 2.1 mrem, p= 0.01). Fewer patients underwent ad hoc percutaneous coronary intervention (PCI) in the radial group (37.5% vs. 46.9%, p= 0.28) and radial PCI procedures were less complex. The incidences of the primary and secondary endpoints was similar with femoral and radial access among PCI patients. Access crossover was higher in the radial group (17.2% vs. 0.0%, p< 0.01) and vascular access site complications were similar in both groups (3.1%). In patients who had previously undergone CABG surgery, transradial diagnostic coronary angiography was associated with greater contrast use, longer procedure time, and greater access crossover and operator radiation exposure compared with transfemoral angiography. (RADIAL Versus Femoral Access for Coronary Artery Bypass Graft Angiography and Intervention [RADIAL-CABG] Trial; NCT01446263).

Comparison of Fluoroscopic Operator Eye Exposures When Working from Femoral Region, Side, or Head of Patient

Operator radiation exposure is an important occupational hazard compounded over the course of an interventional radiologist's career. This study compared operator radiation dose to the eye and head for different positions around the patient. Compared with cases performed from the femoral region, exposures were 1.8 times higher at the side, and 1.6 times higher at the head, using conventional aprons, table shields, and mobile suspended shields. Exposures were 99% lower when using a suspended personal radiation protection system in all positions. In conclusion, standing at the side or head results in higher head exposures in a conventional setup.

Abstract No. 379 - Comparison of patient radiation doses from digital subtraction and fluoro save acquisitions of femoral access sites prior to use of vascular closure devices

Purpose Prior to use of femoral closure devices, evaluation of the femoral artery access and the suitability of the vessel for use of a vascular closure device is routinely performed. Digital subtraction angiography (DSA) and digital flouroscopic loop (DFL) technology both provide a means to acquire and store angiographic images. We sought to evaluate the image quality and radiation dose associated with each of these modalities. Materials and Methods Using a phantom we simulated angiographic acquisitions of the femoral artery in the AP and 35 degree oblique projections and measured the dose during DSA and DFL acquisitions. We retrospectively selected 60 adult patients from the radiology database who had undergone elective outpatient cerebral angiography using the three different DFL acquisition protocols (15 fps, 7.5 fps and 4 fps). We selected 20 patients who had DSA documentation of the femoral access site and 60 who had DFL documentation of the femoral access site. We then reviewed the images for diagnostic quality to determine if a femoral closure device could be safely employed. We subsequently looked up the dose parameters recorded for the acquisitions and compared the dose for the acquisitions. Results For the phantom studies we found that the dose on the AP acquisitions was lower than the Oblique acquisitions. The DSA dose was higher than the DFL dose. The image quality was diagnostic for evaluation of the femoral artery with regards to access site suitability for use of the femoral closure device on all the clinical studies. The average dose to the patient was 57.9 mGy for DSA acquisitions versus 6.5 mGy, 2.8 mGy and 2.4 mGy for 15 fps, 7.5 fps and 4 fps respectively (p Conclusion Use of the Fluoro save feature on modern angiography equipment yields adequate images for the evaluation of femoral access sites for suitability of femoral closure devices and decreases both patient and operator radiation doses.

Differences between left and right radial approach

Results of the studies showed, that in the hands of expert operators, there were no differences in overall success rate, procedure total duration time, number of catheters used and amount of contrast used in coronary procedures used left or right radial approach. Similarly, in a series of patients undergoing PCI for acute myocardial infarction, no significant difference between right and left radial approaches was found in procedure success rate, procedure duration, room-to-balloon time, and safety profile. However, the left radial artery route offers a few advantages over the right radial approach. In TALENT trial (Left Versus Right Transradial Approach for Percutaneous Coronary Procedures) 1,540 patients were randomized to either right or left radial routes. The study found that among trainees, the left radial approach was associated with a significantly shorter learning curve, reductions in cannulation and fluoroscopy times. This difference may be explained by the anatomical variations between the right and left vasculature. Right radial artery has the higher incidence of loops and the right subclavian artery is often more tortuous than the left, especially in short and elderly patients. Additionally, in the right radial approach, the catheter has to traverse two bifurcations at the right subclavian and brachiocephalic arteries, making catheter manipulation more challenging. Sub study of TALENT trail shown that both approaches are related with similar radiation dose for operators at the body, shoulder, or thyroid level, with a possible significant lower radiation at the wrist with right radial approach. In conclusion use of the right radial approach should be avoided in patients older than 70 years when trainee practitioners are on the learning curve.