Observer detection limits for a dedicated SPECT breast imaging system.

Journal Article

An observer-based contrast-detail study is performed in an effort to evaluate the limits of object detectability using a dedicated CZT-based breast SPECT imaging system under various imaging conditions. A custom geometric contrast-resolution phantom was developed that can be used for both positive ('hot') and negative contrasts ('cold'). The 3 cm long fillable tubes are arranged in six sectors having equal inner diameters ranging from 1 mm to 6 mm with plastic wall thicknesses of <0.25 mm, on a pitch of twice their inner diameters. Scans of the activity filled tubes using simple circular trajectories are obtained in a 215 mL uniform water filled cylinder, varying the rod:background concentration ratios from 10:1 to 1:10 simulating a large range of biological uptake ratios. The rod phantom is then placed inside a non-uniformly shaped 500 mL breast phantom and scans are again acquired using both simple and complex 3D trajectories for similarly varying contrasts. Summed slice and contiguous multi-slice images are evaluated by five independent readers, identifying the smallest distinguishable rod for each concentration and experimental setup. Linear and quadratic regression is used to compare the resulting contrast-detail curves. Results indicate that in a moderately low-noise 500 mL background, using the SPECT camera having 2.5 mm intrinsic pixels, the mean detectable rod was approximately 3.4 mm at a 10:1 ratio, degrading to approximately 5.2 mm with the 2.5:1 concentration ratio. The smallest object detail was observed using a 45 degrees tilted trajectory acquisition. The complex 3D projected sine wave acquisition, however, had the most consistent combined intra- and inter-observer results, making it potentially the best imaging approach for consistent results.

Full Text

Duke Authors

Cited Authors

  • Cutler, SJ; Perez, KL; Barnhart, HX; Tornai, MP

Published Date

  • April 7, 2010

Published In

Volume / Issue

  • 55 / 7

Start / End Page

  • 1903 - 1916

PubMed ID

  • 20224159

Electronic International Standard Serial Number (EISSN)

  • 1361-6560

Digital Object Identifier (DOI)

  • 10.1088/0031-9155/55/7/008

Language

  • eng

Conference Location

  • England