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MO-D-141-09: An Investigation of the Feasibility of Volumetric Imaging of Fluorescent Bio-Markers Using Optical-ECT.

Publication ,  Journal Article
Oldham, M; Thomas, A; Dewhirst, M
Published in: Med Phys
June 2013

PURPOSE: Toptical-ECT is a technique with potential for high resolution 3D imaging of the distribution of fluoresent biomarkers (including reporter proteins like GFP) in un-sectioned tissue samples. Accurate optical-ECT data is only feasible if the biomarkers survive an optical clearing procedure. This work presents investigates this question, and the feasibility of extracting volume metrics from optical-ECT data. METHODS: 4T1 tumors were grown in window chambers on nude mice, following an approved protocol. Tumor cells constitutively expressed RFP, and endogenously expressed GFP labeling HIF-1 transcription. Microvasculature was labeled by colloidal carbon. When the tumors were ∼5-7mm, they were imaged in-vivo (in the chamber) using conventional epi-fluorescent microspcopy. Tumors were then immediately removed, optically-cleared, and imaged ex-vivo by optical-CT/ECT. Comparison of the in-vivo and ex-vivo images enabled investigation of the stability of the biomarkers through optical clearing. Volume measurements of regions expressing different markers (GFP and RFP) were generated though automatic thresholding. RESULTS: Biomarker expressing regions (GFP and RFP) were generally consistent between comparable optical-ECT projections and in-vivo microscopy. In some tumors, GFP and RFP expression was observed to be partially obscured in in-vivo images, due to absorption in overlying tissue. In optical-ECT views, these regions became visible, due to optical clearing. In one tumor, 31% of the gross tumor was deemed viable, as determined from RFP expression. 13% of the tumor was hypoxic as inferred from HIF-1 expression. Almost all the GFP hypoxic volume was within the viable RFP tumor volume. CONCLUSION: Our preliminary data supports several key concepts: fluorescent biomarkers can survive the optical clearing process representative of in-vivo condition; the cleared tumor revealed new regions of signal that were partially obscured in in-vivo images; and 3D quantitative metrics can be determined from optical-CT/ECT that correspond to their 2D counterparts in standard microscopy (e.g. sub-volume of HIF-1 expression).

Duke Scholars

Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

June 2013

Volume

40

Issue

6Part24

Start / End Page

401

Location

United States

Related Subject Headings

  • Nuclear Medicine & Medical Imaging
  • 5105 Medical and biological physics
  • 4003 Biomedical engineering
  • 1112 Oncology and Carcinogenesis
  • 0903 Biomedical Engineering
  • 0299 Other Physical Sciences
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Oldham, M., Thomas, A., & Dewhirst, M. (2013). MO-D-141-09: An Investigation of the Feasibility of Volumetric Imaging of Fluorescent Bio-Markers Using Optical-ECT. Med Phys, 40(6Part24), 401. https://doi.org/10.1118/1.4815256
Oldham, M., A. Thomas, and M. Dewhirst. “MO-D-141-09: An Investigation of the Feasibility of Volumetric Imaging of Fluorescent Bio-Markers Using Optical-ECT.Med Phys 40, no. 6Part24 (June 2013): 401. https://doi.org/10.1118/1.4815256.
Oldham, M., et al. “MO-D-141-09: An Investigation of the Feasibility of Volumetric Imaging of Fluorescent Bio-Markers Using Optical-ECT.Med Phys, vol. 40, no. 6Part24, June 2013, p. 401. Pubmed, doi:10.1118/1.4815256.

Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

June 2013

Volume

40

Issue

6Part24

Start / End Page

401

Location

United States

Related Subject Headings

  • Nuclear Medicine & Medical Imaging
  • 5105 Medical and biological physics
  • 4003 Biomedical engineering
  • 1112 Oncology and Carcinogenesis
  • 0903 Biomedical Engineering
  • 0299 Other Physical Sciences