title: Calibrated breast density methods for full field digital mammography: a system for serial quality control and inter-system generalization.
abstract: OBJECTIVE
  The authors are developing a system for calibrated breast density measurements using full field digital mammography (FFDM). Breast tissue equivalent (BTE) phantom images are used to establish baseline (BL) calibration curves at time zero. For a given FFDM unit, the full BL dataset is comprised of approximately 160 phantom images, acquired prior to calibrating prospective patient mammograms. BL curves are monitored serially to ensure they produce accurate calibration and require updating when calibration accuracy degrades beyond an acceptable tolerance, rather than acquiring full BL datasets repeatedly. BL updating is a special case of generalizing calibration datasets across FFDM units, referred to as cross-calibration. Serial monitoring, BL updating, and cross-calibration techniques were developed and evaluated.
  
  
  METHODS
  BL curves were established for three Hologic Selenia FFDM units at time zero. In addition, one set of serial phantom images, comprised of equal proportions of adipose and fibroglandular BTE materials (50/50 compositions) of a fixed height, was acquired biweekly and monitored with the cumulative sum (Cusum) technique. These 50/50 composition images were used to update the BL curves when the calibration accuracy degraded beyond a preset tolerance of ±4 standardized units. A second set of serial images, comprised of a wide-range of BTE compositions, was acquired biweekly to evaluate serial monitoring, BL updating, and cross-calibration techniques.
  
  
  RESULTS
  Calibration accuracy can degrade serially and is a function of acquisition technique and phantom height. The authors demonstrated that all heights could be monitored simultaneously while acquiring images of a 50/50 phantom with a fixed height for each acquisition technique biweekly, translating into approximately 16 image acquisitions biweekly per FFDM unit. The same serial images are sufficient for serial monitoring, BL updating, and cross-calibration. Serial calibration accuracy was maintained within ±4 standardized unit variation from the ideal when applying BL updating. BL updating is a special case of cross-calibration; the BL dataset of unit 1 can be converted to the BL dataset for another similar unit (i.e., unit 2) at any given time point using the 16 serial monitoring 50/50 phantom images of unit 2 (or vice versa) acquired near this time point while maintaining the ±4 standardized unit tolerance.
  
  
  CONCLUSIONS
  A methodology for monitoring and maintaining serial calibration accuracy for breast density measurements was evaluated. Calibration datasets for a given unit can be translated forward in time with minimal phantom imaging effort. Similarly, cross-calibration is a method for generalizing calibration datasets across similar units without additional phantom imaging. This methodology will require further evaluation with mammograms for complete validation.
authors: Department of Cancer Epidemiology, Division of Population Science, H. Lee Moffitt Cancer Center, Tampa, Florida 33612.
authors: B
authors: B
authors: Lu
authors: Department of Cancer Epidemiology, Division of Population Science, H. Lee Moffitt Cancer Center, Tampa, Florida 33612.
authors: A M
authors: AM
authors: Smallwood
authors: Department of Cancer Epidemiology, Division of Population Science, H. Lee Moffitt Cancer Center, Tampa, Florida 33612.
authors: T A
authors: TA
authors: Sellers
authors: Department of Diagnostic Imaging, H. Lee Moffitt Cancer Center, Tampa, Florida 33612.
authors: J S
authors: JS
authors: Drukteinis
authors: Department of Cancer Imaging and Metabolism, Division of Basic Science, H. Lee Moffitt Cancer Center, Tampa, Florida 33612.
authors: J J
authors: JJ
authors: Heine
authors: Department of Cancer Epidemiology, Division of Population Science, H. Lee Moffitt Cancer Center, Tampa, Florida 33612.
authors: E E E
authors: EE
authors: Fowler
mesh_terms: D001940:Breast / Q000166:cytology*; D002138:Calibration; D006801:Humans; D008327:Mammography / Q000379:methods*; D019047:Phantoms, Imaging; D011786:Quality Control; D011856:Radiographic Image Enhancement / Q000379:methods*
references: ANZ J Surg. 2001 Aug;71(8):453-6
references: 11504287
references: Ann Thorac Surg. 2002 Jan;73(1):S358-62
references: 11834071
references: Int J Qual Health Care. 2002 Jun;14(3):251-8
references: 12108535
references: Anesth Analg. 2002 Aug;95(2):411-6, table of contents
references: 12145063
references: Med Phys. 2002 Aug;29(8):1867-80
references: 12201434
references: Hum Hered. 2002;54(2):99-110
references: 12566741
references: Med Phys. 2003 Mar;30(3):352-64
references: 12674236
references: Ann Thorac Surg. 2003 Sep;76(3):663-7
references: 12963172
references: Stat Med. 2004 Jul 30;23(14):2195-214
references: 15236425
references: J Thorac Cardiovasc Surg. 1994 Mar;107(3):914-23; discussion 923-4
references: 8127123
references: Ann Surg. 2005 Feb;241(2):262-8
references: 15650636
references: MMWR Morb Mortal Wkly Rep. 2004 Sep 24;53 Suppl:79-85
references: 15714634
references: IEEE Trans Med Imaging. 2006 Mar;25(3):273-82
references: 16524084
references: Phys Med Biol. 2006 Jun 7;51(11):2695-713
references: 16723760
references: Int J Epidemiol. 2006 Oct;35(5):1314-21
references: 16926216
references: Med Phys. 2006 Nov;33(11):4350-66
references: 17153414
references: Ultrasound Obstet Gynecol. 2008 Mar;31(3):332-7
references: 18307213
references: Biomed Eng Online. 2008;7:13
references: 18373863
references: Breast Cancer Res. 2008;10(3):209
references: 18598375
references: Prev Vet Med. 2009 Sep 1;91(1):2-10
references: 19539387
references: Int Urogynecol J Pelvic Floor Dysfunct. 2009 Sep;20(9):1119-25
references: 19479177
references: Med Phys. 2009 Dec;36(12):5380-90
references: 20095250
references: Med Phys. 2009 Dec;36(12):5525-36
references: 20095265
references: Biomed Eng Online. 2010;9:73
references: 21080916
references: Acad Radiol. 2011 May;18(5):556-64
references: 21474058
references: Clin Microbiol Infect. 2010 Sep;16(9):1368-74
references: 20041891
references: Ultrasound Obstet Gynecol. 2011 May;37(5):582-7
references: 21520314
references: Med Phys. 2012 May;39(5):2746-53
references: 22559645
references: Anaesthesia. 2012 Jul;67(7):734-40
references: 22420772
references: Breast. 2012 Aug;21(4):503-6
references: 22285387
references: Med Phys. 2012 Aug;39(8):4903-17
references: 22894417
references: Circulation. 2013 Jul 30;128(5):483-91
references: 23804253
references: Int J Inj Contr Saf Promot. 2014;21(2):154-62
references: 23656206
references: Biomed Eng Online. 2013;12:114
references: 24207013