Occupational Risks of Radiation Exposure to Cardiologists.

PURPOSE OF REVIEW: Invasive cardiologists are exposed to large amounts of ionizing radiation. This review aims to summarize the main occupational risks in a radiation-exposed cardiology practice. RECENT FINDINGS: We carried out a literature review on the subject. The studies reviewed allowed us to list six main health risk categories possibly associated with radiation exposure among cardiologists: deoxyribonucleic acid (DNA) and biochemical damages; cancers; ocular manifestations; olfaction, vascular, and neuropsychological alterations; musculoskeletal problems; and reproductive risks. Our descriptive analysis demonstrates higher risks of DNA damage and lens opacities among radiation-exposed cardiology staff. Surveys and questionnaires have demonstrated a higher risk of musculoskeletal disease in exposed workers. Studies reported no difference in cancer frequency between radiation-exposed workers and controls. Changes in olfactory performance, neuropsychological aspects, and vascular changes have also been reported. Limited literature supports the security of continuing radiation-exposed work during pregnancy. Therefore, there is an urgent need to increase knowledge of the occupational risks of radiation exposure and to adopt technologies to reduce them.

Comparison of radiation exposure during transradial diagnostic coronary angiography with single- or multi-catheters approach.

OBJECTIVE: To compare radiation exposure during transradial diagnostic coronary angiography (DCA) using standard single- or multi-catheters with different shapes. BACKGROUND: Transradial DCA can be performed using single- or multi-catheters to canulate left and right coronary ostia. To date, it remains unknown whether there are differences in radiation exposure between the two strategies. METHODS: From November 2012 to June 2014, 3,410 consecutive patients who underwent transradial DCA were recruited. Groups were based on the initial diagnostic catheter used and were dichotomized between single- and multi-catheters approach. All crossovers were excluded. The multi-catheters approach (Multi) group consisted of Judkins left and right catheters, whereas the single-catheter (Single) group included Amplatz, Barbeau, or Multipurpose catheters. Fluoroscopy time (FT) as a surrogate end-point for total radiation exposure and kerma-area product (KAP; patient radiation exposure) were collected as radiation exposure parameters. RESULTS: A single-catheter strategy was used in 439 patients, while 2,971 patients had a multi-catheters approach. There was no significant difference in FT between groups (2.86 ± 1.48 min for Multi vs. 2.87 ± 1.72 min for Single, P = 0.13). The multi-catheters approach was associated with a significant 15% reduction in KAP (3,599 ± 2,214 cGy · cm2 vs. 3,073 ± 1,785 cGy · cm2 , P < 0.0001) compared to the single-catheter approach. When pooling all patients, mean FT was 2.86 ± 1.51 min. Mean KAP was 3,141 ± 1,854 cGy · cm2 . Reference levels in our institution in both groups were below international diagnostic reference levels. Overall both FT and KAP decreased by 15% and 19%, respectively, over the 2-year study period. CONCLUSIONS: Compared to a single-catheter approach, a multi-catheters approach with standard Judkins catheters for DCA significantly reduced patient radiation exposure. Whether single catheter designed for DCA by radial approach can further reduce radiation exposure compared to Judkins catheters remains to be compared in randomized studies. © 2016 Wiley Periodicals, Inc.

PA/Lateral chest X-ray is equivalent to cine-fluoroscopy for the detection of conductor externalization in defibrillation leads.

BACKGROUND: Riata™ and Riata ST defibrillation leads (St. Jude Medical, Sylmar, CA, USA) are susceptible to insulation defects with conductor externalization. Cine-fluoroscopy is considered to be the gold standard for the documentation of insulation defects, but similar detection rates have been reported for posterior-anterior (PA)/lateral chest x-ray (CXR) with zooming. OBJECTIVE: Prospective single-center study to assess the diagnostic equivalence of a PA/lateral CXR with zooming for the detection of Riata insulation defects in a direct comparison to cine-fluoroscopy. METHODS: Seventy-eight consecutive patients underwent 3-view cine-fluoroscopy and a PA/lateral CXR. All CXRs and cine-fluoroscopy images were reviewed by blinded electrophysiologists and staff radiologists. RESULTS: Forty-four of 78 patients had an abnormal cine-fluoroscopy (56%). The diagnostic correlation between PA/lateral CXR and cine-fluoroscopy was excellent (κ = 0.90; 95% confidence interval 0.80-1.00). PA/lateral CXR was equivalent to cine-fluoroscopy for the detection of conductor externalization showing a sensitivity of 97.7% and a specificity of 91.2%. The mean radiation effective dose of CXR was significantly lower compared to cine-fluoroscopy (0.09 millisievert [mSV] vs 0.85 ± 0.47 mSv; P < 0.001). Also, CXR was significantly less expensive. CONCLUSION: PA/lateral CXR with zooming is equivalent to cine-fluoroscopy for the detection of Riata insulation defects and should be considered as the preferred screening method.

Radiation Exposure During Transcatheter Aortic Valve Replacement: Impact of Arterial Approach and Prosthesis Type.

BACKGROUND: The impact of novel alternative access and valve type on radiation exposure during transcatheter aortic valve replacement (TAVR) has not yet been evaluated. This study sought to determine the impact of a transarterial approach and prosthesis type on physician and patient exposure to radiation during TAVR. METHODS: This was a prospective study including 140 consecutive patients undergoing TAVR by transfemoral (n = 102) or transcarotid (TC) (n = 38) access at 2 centers. Implanted valves were the self-expanding Evolut R/PRO system (Medtronic, Minneapolis, MN; n = 38) and the balloon-expandable SAPIEN 3 valve (Edwards Lifesciences, Irvine, CA; n = 102). The primary endpoint was first operator radiation exposure. The secondary endpoint was patient radiation exposure. RESULTS: First operator radiation exposure was 4-fold greater during TC TAVR (P < .001). The use of a self-expanding valve was associated with a longer x-ray time (P = .015) and a 2-fold greater first operator radiation dose (P = .018). Patient radiation dose was not significantly affected by arterial approach (P = .055) or valve type (P = .095). After adjustment for potential confounders, the TC approach remained associated with a 174.8% (95% confidence interval, 80.6-318.3, P < .001) increase in first operator radiation dose, whereas the use of a self-expanding valve no longer influenced the first operator dose (P = .630). CONCLUSIONS: TC access and the use of a self-expanding valve were associated with a 4- and 2-fold greater first operator radiation exposure during TAVR procedures, respectively. Unlike the arterial approach, the effect of bioprosthesis type on radiation exposure was mainly related to x-ray time and was no longer significant after adjustment.

Plastic scintillation dosimetry: optimal selection of scintillating fibers and scintillators.

Scintillation dosimetry is a promising avenue for evaluating dose patterns delivered by intensity-modulated radiation therapy plans or for the small fields involved in stereotactic radiosurgery. However, the increase in signal has been the goal for many authors. In this paper, a comparison is made between plastic scintillating fibers and plastic scintillator. The collection of scintillation light was measured experimentally for four commercial models of scintillating fibers (BCF-12, BCF-60, SCSF-78, SCSF-3HF) and two models of plastic scintillators (BC-400, BC-408). The emission spectra of all six scintillators were obtained by using an optical spectrum analyzer and they were compared with theoretical behavior. For scintillation in the blue region, the signal intensity of a singly clad scintillating fiber (BCF-12) was 120% of that of the plastic scintillator (BC-400). For the multiclad fiber (SCSF-78), the signal reached 144% of that of the plastic scintillator. The intensity of the green scintillating fibers was lower than that of the plastic scintillator: 47% for the singly clad fiber (BCF-60) and 77% for the multiclad fiber (SCSF-3HF). The collected light was studied as a function of the scintillator length and radius for a cylindrical probe. We found that symmetric detectors with nearly the same spatial resolution in each direction (2 mm in diameter by 3 mm in length) could be made with a signal equivalent to those of the more commonly used asymmetric scintillators. With augmentation of the signal-to-noise ratio in consideration, this paper presents a series of comparisons that should provide insight into selection of a scintillator type and volume for development of a medical dosimeter.

Effectiveness of low rate fluoroscopy at reducing operator and patient radiation dose during transradial coronary angiography and interventions.

OBJECTIVES: 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). BACKGROUND: TRA for cardiac catheterization is potentially associated with increased radiation exposure. Low rate fluoroscopy has the potential to reduce radiation exposure. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Plastic scintillation dosimetry: Optimal selection of scintillating fibers and scintillators.

Scintillation dosimetry is a promising avenue for evaluating dose patterns delivered by intensity-modulated radiation therapy plans or for the small fields involved in stereotactic radiosurgery. However, the increase in signal has been the goal for many authors. In this paper, a comparison is made between plastic scintillating fibers and plastic scintillator. The collection of scintillation light was measured experimentally for four commercial models of scintillating fibers (BCF-12, BCF-60, SCSF-78, SCSF-3HF) and two models of plastic scintillators (BC-400, BC-408). The emission spectra of all six scintillators were obtained by using an optical spectrum analyzer and they were compared with theoretical behavior. For scintillation in the blue region, the signal intensity of a singly clad scintillating fiber (BCF-12) was 120% of that of the plastic scintillator (BC-400). For the multiclad fiber (SCSF-78), the signal reached 144% of that of the plastic scintillator. The intensity of the green scintillating fibers was lower than that of the plastic scintillator: 47% for the singly clad fiber (BCF-60) and 77% for the multiclad fiber (SCSF-3HF). The collected light was studied as a function of the scintillator length and radius for a cylindrical probe. We found that symmetric detectors with nearly the same spatial resolution in each direction (2 mm in diameter by 3 mm in length) could be made with a signal equivalent to those of the more commonly used asymmetric scintillators. With augmentation of the signal-to-noise ratio in consideration, this paper presents a series of comparisons that should provide insight into selection of a scintillator type and volume for development of a medical dosimeter.