Program Information
Increased Small Focal Spot Output Capability of Two Novel X-Ray Tube Insert Designs Over Existing Angiographic Tubes Demonstrated by Mueller-Oosterkamp Heat Calculations
E Freund*, D Bednarek , S Rudin , Univ. at Buffalo (SUNY) School of Med., Buffalo, NY
Presentations
SU-K-702-1 (Sunday, July 30, 2017) 4:00 PM - 6:00 PM Room: 702
Purpose: Mueller-Oosterkamp focal spot heat calculations of existing angiographic x-ray tubes by Toshiba, Siemens, and Varian are compared with two novel designs to demonstrate improved small-focal-spot (sfs) output of the proposed designs.
Methods: Two new anode geometries, designated “non-offset” and “offset,” are proposed to reduce heat limitations and make use of existing small field-of-view (FOV) high-resolution microangiographic (MAF) detectors. Both designs include two filaments that correspond to unique anode focal target tracks. The radial length of the medium-focal-spot (mfs) track is 6.81mm with 11° anode angle to be used with a standard FOV flat-panel detector. The filament for the sfs is elongated to produce a 13.6mm radial focal length corresponding to a 1.8° anode angle to be used with an MAF detector. The elongated filament enables the sfs to have comparable x-ray output to the mfs as demonstrated by the Mueller-Oosterkamp equation. The focal spot temperatures for angiographic tubes by Toshiba, Siemens, and Varian are also calculated and compared to the non-offset, and offset designs.
Results: The maximum sfs power rating among the tested existing tubes is 18kW, which produces Mueller-Oosterkamp temperatures ranging from 1550-1700 K. A 45kW sfs output with the non-offset and offset designs yields temperatures of 1710K and 1520 K respectively. Power ratings for mfs range from 40-60kW among presented manufacturers, and calculated temperatures range from 1580-1800K. A 45kW output yields temperatures of 1640K for non-offset and 2960K for offset designs.
Conclusion: The offset design has a sfs output advantage over the non-offset because the sfs has a larger track diameter. However, the mfs track must be reduced in the offset design to enable the larger sfs track; thus mfs heat loading limits the offset design. For comparable Mueller-Oosterkamp temperatures, nearly a threefold increase in sfs output is achievable with the non-offset and offset designs.
Funding Support, Disclosures, and Conflict of Interest: Toshiba Medical Systems Corp.
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