WE-DE-207B-05: Measuring Spatial Resolution in Digital Breast Tomosynthesis: Update of AAPM Task Group 245

Journal Article · Wed Jun 15 00:00:00 EDT 2016 · Medical Physics

DOI:https://doi.org/10.1118/1.4957865· OSTI ID:22669546

Scaduto, DA; Hu, Y-H; Zhao, W ^[1]; Goodsitt, M; Chan, H-P ^[2]; Olafsdottir, H ^[3]; Das, M ^[4]; Fredenberg, E ^[5]; Geiser, W ^[6]; Goodenough, D ^[7]; Heid, P ^[8]; Liu, B ^[9]; Mainprize, J ^[10]; Reiser, I ^[11]; Van Engen, R ^[12]; Varchena, V ^[13]; Vecchio, S ^[14]; Glick, S ^[15]

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1. Stony Brook Medicine, Stony Brook, NY (United States)
2. University Michigan, Ann Arbor, MI (United States)
3. Image Owl, 105 Reykjavik (Iceland)
4. University Houston, Houston, TX (United States)
5. Philips Healthcare, Solna (Sweden)
6. UT MD Anderson Cancer Center, Houston, TX (United States)
7. The George Washington University, Washington, DC (United States)
8. ARCADES, Marseille (France)
9. Massachusetts General Hospital, Boston, MA (United States)
10. Sunnybrook Health Sciences Centre, North York, ON (Canada)
11. The University of Chicago, Chicago, IL (United States)
12. LRCB, Nijmegen (Netherlands)
13. CIRS Inc., Norfolk, VA (United States)
14. I.M.S., Pontecchio Marconi (Italy)
15. Food and Drug Administration, Silver Spring, MD (United States)

Purpose: Spatial resolution in digital breast tomosynthesis (DBT) is affected by inherent/binned detector resolution, oblique entry of x-rays, and focal spot size/motion; the limited angular range further limits spatial resolution in the depth-direction. While DBT is being widely adopted clinically, imaging performance metrics and quality control protocols have not been standardized. AAPM Task Group 245 on Tomosynthesis Quality Control has been formed to address this deficiency. Methods: Methods of measuring spatial resolution are evaluated using two prototype quality control phantoms for DBT. Spatial resolution in the detector plane is measured in projection and reconstruction domains using edge-spread function (ESF), point-spread function (PSF) and modulation transfer function (MTF). Spatial resolution in the depth-direction and effective slice thickness are measured in the reconstruction domain using slice sensitivity profile (SSP) and artifact spread function (ASF). An oversampled PSF in the depth-direction is measured using a 50 µm angulated tungsten wire, from which the MTF is computed. Object-dependent PSF is derived and compared with ASF. Sensitivity of these measurements to phantom positioning, imaging conditions and reconstruction algorithms is evaluated. Results are compared from systems of varying acquisition geometry (9–25 projections over 15–60°). Dependence of measurements on feature size is investigated. Results: Measurements of spatial resolution using PSF and LSF are shown to depend on feature size; depth-direction spatial resolution measurements are shown to similarly depend on feature size for ASF, though deconvolution with an object function removes feature size-dependence. A slanted wire may be used to measure oversampled PSFs, from which MTFs may be computed for both in-plane and depth-direction resolution. Conclusion: Spatial resolution measured using PSF is object-independent with sufficiently small object; MTF is object-independent. Depth-direction spatial resolution may be measured directly using MTF or indirectly using ASF or SSP as surrogate measurements. While MTF is object-independent, it is invalid for nonlinear reconstructions.

• OSTI ID: 22669546
• Journal Information: Medical Physics, Vol. 43, Issue 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
61 RADIATION PROTECTION AND DOSIMETRY
BIOMEDICAL RADIOGRAPHY
MAMMARY GLANDS
NONLINEAR PROBLEMS
QUALITY CONTROL
SPATIAL RESOLUTION
TRANSFER FUNCTIONS