Is SPECT or CT Based Attenuation Correction More Quantitatively Accurate for Dedicated Breast SPECT Acquired with Non-Traditional Trajectories?

Published

Journal Article

Attenuation correction is necessary for SPECT quantification. There are a variety of methods to create attenuation maps. For dedicated breast SPECT imaging, it is unclear if either SPECT- or CT-based attenuation map would provide the most accurate quantification and whether or not segmenting the different tissue types will have an effect on the qunatification. For these experiments, 99mTc diluted in methanol and water was filled into geometric and anthropomorphic breast phantoms and was imaged with a dedicated dual-modality SPECT-CT scanner. SPECT images were collected using a compact CZT camera with various 3D acquisitions including vertical and 30° tilted parallel beam, and complex sinusoidal trajectories. CT images were acquired using a quasi-monochromatic x-ray source and CsI(T1) flat panel digital detector in a half-cone beam geometry. Measured scatter correction for SPECT and CT were implemented. To compare photon attenuation correction in the reconstructed SPECT images, various volumetric attenuation matrices were derived from 1) uniform SPECT, 2) uniform CT, and 3) segmented CT, populated with different attenuation coefficient values. Comparisons between attenuation masks using phantoms consisting of materials with different attenuation values show that at 140 keV the differences in the attenuation between materials do not affect the quantification as much as the size and alignment of the attenuation map. The CT-based attenuation maps give quantitative values 30% below the actual value, but are consistent. While the SPECT-based attenuation maps can provide within 10% accurate quantitative values, but are less consistent.

Full Text

Duke Authors

Cited Authors

  • Perez, KL; Mann, SD; Pachon, JH; Madhav, P; Tornai, MP

Published Date

  • October 2010

Published In

Volume / Issue

  • 2010 /

Start / End Page

  • 2319 - 2324

PubMed ID

  • 25999683

Pubmed Central ID

  • 25999683

International Standard Serial Number (ISSN)

  • 1095-7863

Digital Object Identifier (DOI)

  • 10.1109/NSSMIC.2010.5874198

Language

  • eng

Conference Location

  • United States