title: Generation of a suite of 3D computer-generated breast phantoms from a limited set of human subject data.
abstract: OBJECTIVE
  The authors previously reported on a three-dimensional computer-generated breast phantom, based on empirical human image data, including a realistic finite-element based compression model that was capable of simulating multimodality imaging data. The computerized breast phantoms are a hybrid of two phantom generation techniques, combining empirical breast CT (bCT) data with flexible computer graphics techniques. However, to date, these phantoms have been based on single human subjects. In this paper, the authors report on a new method to generate multiple phantoms, simulating additional subjects from the limited set of original dedicated breast CT data. The authors developed an image morphing technique to construct new phantoms by gradually transitioning between two human subject datasets, with the potential to generate hundreds of additional pseudoindependent phantoms from the limited bCT cases. The authors conducted a preliminary subjective assessment with a limited number of observers (n = 4) to illustrate how realistic the simulated images generated with the pseudoindependent phantoms appeared.
  
  
  METHODS
  Several mesh-based geometric transformations were developed to generate distorted breast datasets from the original human subject data. Segmented bCT data from two different human subjects were used as the "base" and "target" for morphing. Several combinations of transformations were applied to morph between the "base' and "target" datasets such as changing the breast shape, rotating the glandular data, and changing the distribution of the glandular tissue. Following the morphing, regions of skin and fat were assigned to the morphed dataset in order to appropriately assign mechanical properties during the compression simulation. The resulting morphed breast was compressed using a finite element algorithm and simulated mammograms were generated using techniques described previously. Sixty-two simulated mammograms, generated from morphing three human subject datasets, were used in a preliminary observer evaluation where four board certified breast radiologists with varying amounts of experience ranked the level of realism (from 1 = "fake" to 10 = "real") of the simulated images.
  
  
  RESULTS
  The morphing technique was able to successfully generate new and unique morphed datasets from the original human subject data. The radiologists evaluated the realism of simulated mammograms generated from the morphed and unmorphed human subject datasets and scored the realism with an average ranking of 5.87 ± 1.99, confirming that overall the phantom image datasets appeared more "real" than "fake." Moreover, there was not a significant difference (p > 0.1) between the realism of the unmorphed datasets (6.0 ± 1.95) compared to the morphed datasets (5.86 ± 1.99). Three of the four observers had overall average rankings of 6.89 ± 0.89, 6.9 ± 1.24, 6.76 ± 1.22, whereas the fourth observer ranked them noticeably lower at 2.94 ± 0.7.
  
  
  CONCLUSIONS
  This work presents a technique that can be used to generate a suite of realistic computerized breast phantoms from a limited number of human subjects. This suite of flexible breast phantoms can be used for multimodality imaging research to provide a known truth while concurrently producing realistic simulated imaging data.
authors.affiliation: Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA. christina.hsu@duke.edu
authors.forename: Christina M L
authors.initials: CM
authors.lastname: Hsu
authors.forename: Mark L
authors.initials: ML
authors.lastname: Palmeri
authors.forename: W Paul
authors.initials: WP
authors.lastname: Segars
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Veress
authors.forename: James T
authors.initials: JT
authors.lastname: Dobbins
mesh_terms: D001940:Breast / Q000502:physiology*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008327:Mammography / Q000295:instrumentation* / Q000379:methods*; D008953:Models, Anatomic; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods*
references.citation: IEEE Trans Med Imaging. 1997 Apr;16(2):187-98
references.pmid: 9101328
references.citation: N Engl J Med. 2005 Oct 27;353(17):1773-83
references.pmid: 16169887
references.citation: Proc IEEE Inst Electr Electron Eng. 2009 Dec;97(12):1954-1968
references.pmid: 26472880
references.citation: Phys Med. 2006;21 Suppl 1:39-43
references.pmid: 17645992
references.citation: J Clin Oncol. 2005 Nov 20;23(33):8469-76
references.pmid: 16293877
references.citation: JAMA. 2008 May 14;299(18):2151-63
references.pmid: 18477782
references.citation: CA Cancer J Clin. 2007 Mar-Apr;57(2):75-89
references.pmid: 17392385
references.citation: Phys Med Biol. 2009 Jul 21;54(14):4533-45
references.pmid: 19556683
references.citation: Radiol Clin North Am. 2010 Sep;48(5):1043-54
references.pmid: 20868899
references.citation: Radiology. 2011 Jan;258(1):89-97
references.pmid: 21062924
references.citation: Med Phys. 2006 Apr;33(4):1041-52
references.pmid: 16696481
references.citation: Med Phys. 2005 Jun;32(6):1647-59
references.pmid: 16013724
references.citation: AJR Am J Roentgenol. 2009 Aug;193(2):586-91
references.pmid: 19620460
references.citation: IEEE Trans Med Imaging. 2003 Aug;22(8):986-1004
references.pmid: 12906253
references.citation: Comput Biol Med. 1994 Jan;24(1):11-8
references.pmid: 7515775
references.citation: Med Phys. 2010 Sep;37(9):4902-15
references.pmid: 20964209
references.citation: Radiology. 2008 Feb;246(2):376-83
references.pmid: 18227537
references.citation: Med Phys. 2002 Sep;29(9):2140-51
references.pmid: 12349936
references.citation: J Mammary Gland Biol Neoplasia. 2006 Apr;11(2):103-11
references.pmid: 17053979
references.citation: Med Image Anal. 1998 Mar;2(1):1-36
references.pmid: 10638851
references.citation: Med Phys. 2002 Sep;29(9):2131-9
references.pmid: 12349935
references.citation: Med Phys. 2010 Mar;37(3):1004-16
references.pmid: 20384236
references.citation: Annu Rev Biomed Eng. 2007;9:501-26
references.pmid: 17506654
references.citation: N Engl J Med. 2004 Jul 29;351(5):427-37
references.pmid: 15282350
references.citation: IEEE Trans Med Imaging. 1999 Aug;18(8):712-21
references.pmid: 10534053
references.citation: Acad Radiol. 2007 Aug;14(8):945-50
references.pmid: 17659240
references.citation: IEEE Trans Med Imaging. 1997 Jun;16(3):317-28
references.pmid: 9184894
references.citation: Med Phys. 2009 Jul;36(7):3122-31
references.pmid: 19673211
references.citation: Med Phys. 2008 Aug;35(8):3800-8
references.pmid: 18777939
references.citation: Radiat Prot Dosimetry. 2005;114(1-3):406-9
references.pmid: 15933147
references.citation: Phys Med Biol. 2003 Nov 21;48(22):3699-719
references.pmid: 14680268
references.citation: Neuroimage. 2004;23 Suppl 1:S19-33
references.pmid: 15501089
references.citation: Med Biol Eng Comput. 2007 Jul;45(7):661-9
references.pmid: 17551761
references.citation: Radiology. 2008 Mar;246(3):725-33
references.pmid: 18195383
references.citation: Med Biol Eng Comput. 2006 Mar;44(1-2):15-26
references.pmid: 16929917
references.citation: Med Image Comput Comput Assist Interv. 2006;9(Pt 2):718-25
references.pmid: 17354836
references.citation: Med Phys. 2011 Jun;38(6):3165-76
references.pmid: 21815391
references.citation: Med Phys. 2011 Oct;38(10):5756-70
references.pmid: 21992390
references.citation: Acad Radiol. 2011 May;18(5):536-46
references.pmid: 21397528
references.citation: Semin Ultrasound CT MR. 2011 Aug;32(4):266-72
references.pmid: 21782116
references.citation: Annu Int Conf IEEE Eng Med Biol Soc. 2007;2007:1335-8
references.pmid: 18002210
references.citation: Med Phys. 2010 Nov;37(11):5604-17
references.pmid: 21158272
references.citation: J Am Coll Radiol. 2010 Jan;7(1):18-27
references.pmid: 20129267
references.citation: Med Phys. 2003 Jul;30(7):1914-25
references.pmid: 12906210
references.citation: Phys Med Biol. 2009 Jun 21;54(12):3659-76
references.pmid: 19478374