Publications [#157107] of G. Allan Johnson
- MD Lin, E Samei, CT Badea, TT Yoshizumi, GA Johnson, Optimized radiographic spectra for small animal digital subtraction angiography.,
Medical physics, United States, vol. 33 no. 11
pp. 4249-57, ISSN 0094-2405
(last updated on 2009/03/13)
The increasing use of small animals in basic research has spurred interest in new imaging methodologies. Digital subtraction angiography (DSA) offers a particularly appealing approach to functional imaging in the small animal. This study examines the optimal x-ray, molybdenum (Mo) or tungsten (W) target sources, and technique to produce the highest quality small animal functional subtraction angiograms in terms of contrast and signal-difference-to-noise ratio squared (SdNR2). Two limiting conditions were considered-normalization with respect to dose and normalization against tube loading. Image contrast and SdNR2 were simulated using an established x-ray model. DSA images of live rats were taken at two representative tube potentials for the W and Mo sources. Results show that for small animal DSA, the Mo source provides better contrast. However, with digital detectors, SdNR2 is the more relevant figure of merit. The W source operated at kVps >60 achieved a higher SdNR2. The highest SdNR2 was obtained at voltages above 90 kVp. However, operation at the higher potential results in significantly greater dose and tube load and reduced contrast quantization. A reasonable tradeoff can be achieved at tube potentials at the beginning of the performance plateau, around 70 kVp, where the relative gain in SdNR2 is the greatest.
Algorithms* • Angiography, Digital Subtraction • Animals • Image Enhancement • Image Interpretation, Computer-Assisted • Rats • Reproducibility of Results • Sensitivity and Specificity • Spectrometry, X-Ray Emission • instrumentation • methods* • veterinary*