PMID- 28986933
OWN - NLM
STAT- MEDLINE
DCOM- 20180724
LR  - 20181201
IS  - 2473-4209 (Electronic)
IS  - 0094-2405 (Print)
IS  - 0094-2405 (Linking)
VI  - 44
IP  - 12
DP  - 2017 Dec
TI  - Liquid tissue surrogates for X-ray and CT phantom studies.
PG  - 6251-6260
LID - 10.1002/mp.12617 [doi]
AB  - PURPOSE: To develop a simple method for producing liquid-tissue-surrogate (LTS) 
      materials that accurately represent human soft tissues in terms of density and 
      X-ray attenuation coefficient. METHODS AND MATERIALS: We evaluated hypothetical 
      mixtures of water, glycerol, butanol, methanol, sodium chloride, and potassium 
      nitrate; these mixtures were intended to emulate human adipose, blood, brain, 
      kidney, liver, muscle, pancreas, and skin. We compared the hypothetical 
      densities, effective atomic numbers (Z(eff) ), and calculated discrete-energy CT 
      attenuation [Hounsfield Units (HU)] of the proposed materials with those of human 
      tissue elemental composition as specified in International Commission on 
      Radiation Units (ICRU) Report 46. We then physically produced the proposed LTS 
      materials for adipose, liver, and pancreas tissue, and we measured the 
      polyenergetic CT attenuation (also expressed as HU) of these materials within a 
      32 cm phantom using a 64-slice clinical CT scanner at 80 kVp, 100 kVp, 120 kVp, 
      and 140 kVp. RESULTS: The predicted densities, Z(eff) , and calculated 
      discrete-energy CT attenuation of our proposed formulations generally agreed with 
      those of ICRU within < 1% or < 10 HU. For example, the densities of our 
      hypothetical materials agreed precisely with ICRU's reported values and were 
      0.95 g/mL for adipose tissue, 1.04 g/mL for pancreatic tissue, and 1.06 g/mL for 
      liver tissue; the discrete-energy CT attenuation at 60 keV of our hypothetical 
      materials (and ICRU-specified compositions) were -107 HU (-113 HU) for adipose 
      #3, -89 HU (-90 HU) for adipose #2, 56 HU (55 HU) for liver tissue, and 31 HU 
      (31 HU) for pancreatic tissue. The densities of our physically produced materials 
      (compared to ICRU-specified compositions) were 0.947 g/mL (0.0%) for adipose #2, 
      1.061 g/mL (+2.0%) for pancreatic tissue, and 1.074 g/mL (+1.3%) for liver 
      tissue. The empirical polyenergetic CT attenuation measurements of our LTS 
      materials (and the discrete-energy HU of the ICRU compositions at the mean energy 
      of each spectrum) at 80 kVp were -104 HU (-113 HU) for adipose #3, -87 HU 
      (-90 HU) for adipose #2, 59 HU (55 HU) for liver tissue, and 33 HU (31 HU) for 
      pancreatic tissue; at 120 kVp, these were -83 HU (-83 HU) for adipose #3, -68 HU 
      (-63 HU) for adipose #2, 55 HU (52 HU) for liver tissue, and 35 HU (33 HU) for 
      pancreatic tissue. CONCLUSION: Our method for formulating tissue surrogates 
      allowed straightforward production of solutions with CT attenuation that closely 
      matched the target tissues' expected CT attenuation values and trends with kVp. 
      The LTSs' inexpensive and widely available constituent chemicals, combined with 
      their liquid state, should enable rapid production and versatile use among 
      different phantom and experiment types. Further study is warranted, such as the 
      inclusion of contrast agents. These liquid tissue surrogates may potentially 
      accelerate development and testing of advanced CT imaging techniques and 
      technologies.
CI  - (c) 2017 American Association of Physicists in Medicine.
FAU - FitzGerald, Paul F
AU  - FitzGerald PF
AD  - Imaging, GE Global Research, 1 Research Circle, Niskayuna, NY, 12309, USA.
FAU - Colborn, Robert E
AU  - Colborn RE
AD  - Imaging, GE Global Research, 1 Research Circle, Niskayuna, NY, 12309, USA.
FAU - Edic, Peter M
AU  - Edic PM
AD  - Imaging, GE Global Research, 1 Research Circle, Niskayuna, NY, 12309, USA.
FAU - Lambert, Jack W
AU  - Lambert JW
AD  - Department of Radiology and Biomedical Imaging, University of California, San 
      Francisco, CA, 94143, USA.
FAU - Bonitatibus, Peter J Jr
AU  - Bonitatibus PJ Jr
AD  - Imaging, GE Global Research, 1 Research Circle, Niskayuna, NY, 12309, USA.
FAU - Yeh, Benjamin M
AU  - Yeh BM
AD  - Department of Radiology and Biomedical Imaging, University of California, San 
      Francisco, CA, 94143, USA.
LA  - eng
GR  - R01 EB015476/EB/NIBIB NIH HHS/United States
PT  - Journal Article
DEP - 20171031
PL  - United States
TA  - Med Phys
JT  - Medical physics
JID - 0425746
SB  - IM
MH  - Image Processing, Computer-Assisted
MH  - *Phantoms, Imaging
MH  - Tomography, X-Ray Computed/*instrumentation
PMC - PMC5734616
MID - NIHMS911239
OTO - NOTNLM
OT  - CT
OT  - X-ray
OT  - computed tomography
OT  - phantoms
OT  - tissue equivalents
COIS- The authors declare that they do not have any conflict of interest.
EDAT- 2017/10/08 06:00
MHDA- 2018/07/25 06:00
PMCR- 2018/12/01
CRDT- 2017/10/08 06:00
PHST- 2017/06/12 00:00 [received]
PHST- 2017/09/01 00:00 [revised]
PHST- 2017/09/28 00:00 [accepted]
PHST- 2017/10/08 06:00 [pubmed]
PHST- 2018/07/25 06:00 [medline]
PHST- 2017/10/08 06:00 [entrez]
PHST- 2018/12/01 00:00 [pmc-release]
AID - MP12617 [pii]
AID - 10.1002/mp.12617 [doi]
PST - ppublish
SO  - Med Phys. 2017 Dec;44(12):6251-6260. doi: 10.1002/mp.12617. Epub 2017 Oct 31.