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ABSTRACT: Health Canada Safety Code 35 brings Canada's diagnostic imaging radiation output and protection standards to an international level. This Safety Code is comprehensive and will have broad implications for most health care facilities. This Safety Code outlines quality control procedures that will ultimately reduce patient dose while providing the best quality diagnostic images, all within a safe working environment. However, the Safety Code has some important omissions and errors of which radiologists should be aware, especially if they act as radiation safety officers. We hope that highlighting these issues will be the beginning of an ongoing dialogue between Health Canada, radiologists, medical physicists, and technologists that will not only bring awareness of Safety Code 35 but will provide a basis for updating, correcting, and improving future revisions of the Safety Code.
Canadian Association of Radiologists Journal 05/2012; · 0.69 Impact Factor
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ABSTRACT: The close proximity between the interventionalist and patient during catheter-based interventions for cardiac arrhythmia exposes the interventionalist to harmful radiation. A prototype remote catheter navigation system (RCNS) has been developed to reduce occupational dose. The safety, feasibility of this RCNS and a comparison of remote and conventional navigation techniques is investigated in vivo.
Seven anatomical locations in the right side of the heart in porcine models were chosen as navigation targets. Using fluoroscopy and electrogram analysis, an experienced electrophysiology interventionalist manipulated a radiofrequency (RF) ablation catheter to each target using the RCNS and conventional navigation. Success rate, navigation time, exposure, exposure time and procedure time was recorded for all anatomical targets. Time to integrate the RCNS with the procedure suite was also measured.
All targets were successfully reached with the RCNS and conventional navigation. No erratic catheter motion was observed with the RCNS whereas 1 operation failure occurred. The anatomical targets were found to have the largest effect on navigation time (P < 0.05), exposure (P < 0.05), and exposure time (P < 0.01), although the navigation method had little to no effect on the metrics. These results suggest that remote navigation procedures can be performed with navigation times comparable to conventional bedside navigation.
Remote navigation with the RCNS may present a safe method of reducing occupational dose, while providing comparable navigation time with conventional bedside navigation.
Journal of Cardiovascular Electrophysiology 08/2011; 23(1):81-7. · 3.06 Impact Factor
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ABSTRACT: Optimization and standardization of radiographic procedures in a health region minimizes patient exposure while producing diagnostic images. This report highlights the dose variation in common computed radiography (CR) examinations throughout a large health region. The RadChex cassette was used to measure the radiation exposure at the table or wall bucky in 20 CR rooms, in seven hospitals, using CR technology from two vendors. Exposures were made to simulate patient exposure (21 cm polymethyl methacrylate) under standard conditions for each bucky: 81 kVp at 100 cm for anteroposterior abdomen table bucky exposures (180 cm for posteroanterior chest wall bucky exposures), using the left, the right, or the center automatic exposure control (AEC) cells. Protocol settings were recorded. An average of 37% variation was found between AEC chambers, with a range between 4% and 137%. A 60% difference in dose was discovered between manufacturers, which was the result of the manufacture's image processing algorithm and subsequently corrected via software updates. Finally, standardizing AEC cell selection during common chest examinations could reduce patient dose by up to 30%. In a large health region, variation in exam protocols can occur, leading to unnecessary patient dose from the same type of examination. Quality control programs must monitor exam protocols and AEC chamber calibration in CR to ensure consistent, minimal, patient dose, regardless of hospital or CR vendor. Furthermore, this report highlights the need for communication between radiologists, technologists, medical physicist, service engineers, and manufacturers required to optimize CR protocols.
Journal of Digital Imaging 05/2011; 25(1):189-95. · 1.25 Impact Factor
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ABSTRACT: Remote catheter navigation systems are being developed to reduce the occupational risk of the intervening physician. Despite the success of such systems, development has occurred with little fundamental knowledge of the catheter dynamics applied by the interventionalist. This paper characterizes the kinematics of a catheter during manipulation, the minimum applied force/torque during interventional procedures, and the maximum force/torque applied by an operator to overcome vasculature friction. Ten operators manipulated a 6F catheter inside a specialized catheter movement sensor to determine the velocities and accelerations of catheter motion. A mass-spring apparatus was constructed to measure the forces and torques required to overcome introducer sheath and vasculature friction. Results showed the catheter was manipulated at peak velocities and accelerations of (mu +/- sigma): 360 +/-180 mm x s(-1) and 22200 +/-14000 mm x s(- 2), and 19 +/-7 rad x s(- 1) and 900 +/-510 rad x s(- 2), for axial and radial directions of motion, respectively. A minimum force of 0.29 +/- 0.06 N and a torque of 1.15 +/-0.3 mN x m was required to move the catheter through the introducer sheath; while the observed maximum applied torque was 15 mN x m to overcome vasculature friction. The implications of these results for future design optimization of an intuitive remote catheter navigation system are considered.
IEEE transactions on bio-medical engineering 09/2009; 56(8):2140-3. · 2.15 Impact Factor
