This work was funded by the National Institutes of Health (NIH) Award # R15CA208798 and in part by the National Science Foundation (NSF) Award # 1408007. Funding for the pulsed THz system was obtained through NSF/MRI Award # 1228958. We acknowledge the use of tissues procured by the National Disease Research Interchange (NDRI) with support from the NIH grant U42OD11158. We also acknowledge the collaboration with Oklahoma Animal Disease Diagnostic Laboratory at the Oklahoma State University for conducting the histopathology procedure on all the tissues handled in this work.

This protocol follows all the requirements set by the Environmental Health and Safety department at the University of Arkansas.
1. Set Up the Tissue Handling Area
<ol>
	<li>Take a stainless-steel metal tray and cover it with the biohazard bag as shown in Figure 1. Any handling of the biological tissues will be performed within the tray area (i.e., the tissue handling area).</li>
	<li>Prepare laboratory tweezers, tissue wipes, paper towels, filter paper pack, tis...

<ol>
	<li>Burford, N. M., El-Shenawee, M. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+of+terahertz+photoconductive+antenna+technology.">Review of terahertz photoconductive antenna technology.</a> Optical Engineering. 56 (1), 010901 (2017).</li><li>Sun, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+terahertz+technology+for+biomedical+applications.">Recent advances in terahertz technology for biomedical applications.</a> Quantitative Imaging in Medicine and Surgery. 7 (3), 345-355 (2017).</li><li>Wilmink, G. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+investigation+of+the+biological+effects+associated+with+human+dermal+fibroblasts+exposed+to+2.52+THz+radiation.">In vitro investigation of the biological effects associated with human dermal fibroblasts exposed to 2.52 THz radiation.</a> Lasers in Surgery and Medicine. 43 (2), 152-163 (2011).</li><li>Arbab, M. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+spectroscopy+for+the+assessment+of+burn+injuries+in+vivo.">Terahertz spectroscopy for the assessment of burn injuries in vivo.</a> Journal of Biomedical Optics. 18 (7), 077004 (2013).</li><li>Sy, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+spectroscopy+of+liver+cirrhosis:+investigating+the+origin+of+contrast.">Terahertz spectroscopy of liver cirrhosis: investigating the origin of contrast.</a> Physics in Medicine and Biology. 55 (24), 7587-7596 (2010).</li><li>Yu, C., Fan, S., Sun, Y., Pickwell-Macpherson, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+potential+of+terahertz+imaging+for+cancer+diagnosis:+A+review+of+investigations+to+date.">The potential of terahertz imaging for cancer diagnosis: A review of investigations to date.</a> Quantitative Imaging in Medicine and Surgery. 2 (1), 33-45 (2012).</li><li>El-Shenawee, M., Vohra, N., Bowman, T., Bailey, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cancer+detection+in+excised+breast+tumors+using+terahertz+imaging+and+spectroscopy.">Cancer detection in excised breast tumors using terahertz imaging and spectroscopy.</a> Biomedical Spectroscopy and Imaging. 8 (1-2), 1-9 (2019).</li><li>Yamaguchi, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brain+tumor+imaging+of+rat+fresh+tissue+using+terahertz+spectroscopy.">Brain tumor imaging of rat fresh tissue using terahertz spectroscopy.</a> Scientific Reports. 6 (30124), 1-6 (2016).</li><li>Rong, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+in-line+digital+holography+of+human+hepatocellular+carcinoma+tissue.">Terahertz in-line digital holography of human hepatocellular carcinoma tissue.</a> Scientific Reports. 5 (8445), 1-6 (2015).</li><li>Park, J. Y., Choi, H. J., Nam, G., Cho, K., Son, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+Vivo+Dual-Modality+Terahertz+/+Magnetic+Resonance+Imaging+Using+Superparamagnetic+Iron+Oxide+Nanoparticles+as+a+Dual+Contrast+Agent.">In Vivo Dual-Modality Terahertz / Magnetic Resonance Imaging Using Superparamagnetic Iron Oxide Nanoparticles as a Dual Contrast Agent.</a> IEEE Transactions on Terahertz Science and Technology. 2 (1), 93-98 (2012).</li><li>Ji, Y. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Feasibility+of+terahertz+reflectometry+for+discrimination+of+human+early+gastric+cancers.">Feasibility of terahertz reflectometry for discrimination of human early gastric cancers.</a> Biomedical Optics Express. 6 (4), 1413-1421 (2015).</li><li>Bowman, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Phantom+Study+of+Terahertz+Spectroscopy+and+Imaging+of+Micro-+and+Nano-diamonds+and+Nano-onions+as+Contrast+Agents+for+Breast+Cancer.">A Phantom Study of Terahertz Spectroscopy and Imaging of Micro- and Nano-diamonds and Nano-onions as Contrast Agents for Breast Cancer.</a> Biomedical Physics and Engineering Express. 3 (5), 055001 (2017).</li><li>Chavez, T., Bowman, T., Wu, J., Bailey, K., El-Shenawee, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+Terahertz+Imaging+for+Excised+Breast+Cancer+Tumors+with+Image+Morphing.">Assessment of Terahertz Imaging for Excised Breast Cancer Tumors with Image Morphing.</a> Journal of Infrared, Millimeter, and Terahertz Waves. 39 (12), 1283-1302 (2018).</li><li>Bowman, T. C., El-Shenawee, M., Campbell, L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+Imaging+of+Excised+Breast+Tumor+Tissue+on+Paraffin+Sections.">Terahertz Imaging of Excised Breast Tumor Tissue on Paraffin Sections.</a> IEEE Transactions on Antennas and Propagation. 63 (5), 2088-2097 (2015).</li><li>Bowman, T., El-Shenawee, M., Campbell, L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+transmission+vs+reflection+imaging+and+model-based+characterization+for+excised+breast+carcinomas.">Terahertz transmission vs reflection imaging and model-based characterization for excised breast carcinomas.</a> Biomedical Optics Express. 7 (9), 3756-3783 (2016).</li><li>Bowman, T., Wu, Y., Gauch, J., Campbell, L. K., El-Shenawee, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+Imaging+of+Three-Dimensional+Dehydrated+Breast+Cancer+Tumors.">Terahertz Imaging of Three-Dimensional Dehydrated Breast Cancer Tumors.</a> Journal of Infrared, Millimeter, and Terahertz Waves. 38 (6), 766-786 (2017).</li><li>Bowman, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulsed+terahertz+imaging+of+breast+cancer+in+freshly+excised+murine+tumors.">Pulsed terahertz imaging of breast cancer in freshly excised murine tumors.</a> Journal of Biomedical Optics. 23 (2), 026004 (2018).</li><li>Bowman, T., Vohra, N., Bailey, K., El-Shenawee, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+tomographic+imaging+of+freshly+excised+human+breast+tissues.">Terahertz tomographic imaging of freshly excised human breast tissues.</a> Journal of Medical Imaging. 6 (2), 023501 (2019).</li><li>Vohra, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulsed+Terahertz+Reflection+Imaging+of+Tumors+in+a+Spontaneous+Model+of+Breast+Cancer.">Pulsed Terahertz Reflection Imaging of Tumors in a Spontaneous Model of Breast Cancer.</a> Biomedical Physics and Engineering Express. 4 (6), 065025 (2018).</li><li>Jacobs, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Positive+margins:+the+challenge+continues+for+breast+surgeons.">Positive margins: the challenge continues for breast surgeons.</a> Annals of Surgical Oncology. 15 (5), 1271-1272 (2008).</li><li>Moran, M. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Society+of+Surgical+Oncology--American+Society+for+Radiation+Oncology+Consensus+Guideline+on+Margins+for+Breast-Conserving+Surgery+With+Whole-Breast+Irradiation+in+Stages+I+and+II+Invasive+Breast+Cancer.">Society of Surgical Oncology--American Society for Radiation Oncology Consensus Guideline on Margins for Breast-Conserving Surgery With Whole-Breast Irradiation in Stages I and II Invasive Breast Cancer.</a> International Journal of Radiation Oncology. 88 (3), 553-564 (2014).</li><li>Fitzgerald, A. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+Pulsed+Imaging+of+human+breast+tumors.">Terahertz Pulsed Imaging of human breast tumors.</a> Radiology. 239 (2), 533-540 (2006).</li><li>Ashworth, P. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+pulsed+spectroscopy+of+freshly+excised+human+breast+cancer.">Terahertz pulsed spectroscopy of freshly excised human breast cancer.</a> Optics Express. 17 (15), 12444-12454 (2009).</li><li>Doradla, P., Alavi, K., Joseph, C., Giles, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+colon+cancer+by+continuous-wave+terahertz+polarization+imaging+technique.">Detection of colon cancer by continuous-wave terahertz polarization imaging technique.</a> Journal of Biomedical Optics. 18 (9), 090504 (2013).</li><li>Reid, C. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+pulsed+imaging+of+freshly+excised+human+colonic+tissues.">Terahertz pulsed imaging of freshly excised human colonic tissues.</a> Physics in Medicine and Biology. 56 (1), 4333-4353 (2011).</li><li>. Teraview.com Available from: <a target="_blank" href="https://teraview.com">https://teraview.com</a> (2019)</li><li>Orosco, R. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Positive+Surgical+Margins+in+the+10+Most+Common+Solid+Cancers.">Positive Surgical Margins in the 10 Most Common Solid Cancers.</a> Scientific Reports. 8 (1), 1-9 (2018).</li><li>Bowman, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Statistical+signal+processing+for+quantitative+assessment+of+pulsed+terahertz+imaging+of+human+breast+tumors.">Statistical signal processing for quantitative assessment of pulsed terahertz imaging of human breast tumors.</a> 2017 42nd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz). , 1-2 (2017).</li><li>Gavdush, A. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Terahertz+spectroscopy+of+gelatin-embedded+human+brain+gliomas+of+different+grades:+a+road+toward+intraoperative+THz+diagnosis.">Terahertz spectroscopy of gelatin-embedded human brain gliomas of different grades: a road toward intraoperative THz diagnosis.</a> Journal of Biomedical Optics. 24 (2), 027001 (2019).</li></ol>

The authors declare that they have no conflict of interest.

Effective THz reflection imaging of fresh tissue is primarily dependent on two critical aspects: 1) the proper consideration of tissue handling (sections 2 and 4.15); and 2) the stage setup (primarily section 4.11). Insufficient drying of the tissue can result in increased reflection and inability to visualize regions due to high reflections of DMEM and other fluids. Meanwhile, poor tissue contact with the imaging window creates rings or spots of low reflection in the THz reflection image that obscure the results. Extra ...

Terahertz (THz) imaging and spectroscopy has been a rapidly growing area of research in the past decade. The continued development of more efficient and consistent THz emitters in the range of 0.1&#8211;4 THz has made their applications grow significantly1. One area where THz has shown promise and significant growth is the biomedical field2. THz radiation has been shown to be nonionizing and biologically safe at the power levels generally used to analyze fixed tissues3. As a result, THz imaging and spectroscopy has been used to classify and differentiate various tissue features such as water content to indicate burn damage and healing4, liver cirrhosis5, and cancer in excised tissues6,7. Cancer assessment in particular covers a broad range of potential clinical and surgical applications, and has been investigated for cancers of the brain8, liver9, ovaries10, gastrointestinal tract11, and breast7,12,13,14,15,16,17,18,19.
THz applications for breast cancer are primarily focused on supporting breast conserving surgery, or lumpectomy, via margin assessment. The objective of a lumpectomy is to remove the tumor and a small layer of surrounding healthy tissue, in contrast to full mastectomy, which removes the entire breast. The surgical margin of the excised tissue is then assessed via pathology once the sample has been fixed in formalin, sectioned, embedded in paraffin, and mounted in 4 &#181;m&#8211;5 &#181;m slices on microscope slides. This process can be time-consuming and requires a secondary surgical procedure at a later time if a positive margin is observed20. Current guidelines by the American Society of Radiation Oncology define this positive margin as having cancer cells contacting the surface-level margin ink21. THz imaging for high-absorption hydrated tissue is primarily limited to surface imaging with some varying penetration based on tissue type, which is sufficient for meeting the surgical needs of rapid margin assessment. A quick analysis of margin conditions during the surgical setting would greatly decrease surgical costs and follow-up procedure rate. To date, THz has proven effective in differentiating between cancer and healthy tissue in formalin-fixed, paraffin-embedded (FFPE) tissues, but additional investigation is needed to provide reliable detection of cancer in freshly excised tissues7.
This protocol details the steps for performing THz imaging and spectroscopy on freshly excised human tissue samples obtained from a biobank. THz applications built on freshly excised human breast cancer tissues have seldom been used in published research7,18,22,23, especially by research groups not integrated with a hospital. The use of freshly excised tissues is likewise rare for other cancer applications, with most non-breast human cancer examples being reported for colonic cancer24,25. One reason for this is that FFPE tissue blocks are far easier to access and handle than freshly excised tissue unless the THz system being used for the study is part of the surgical workflow. Similarly, most commercial laboratory THz systems are not prepared to handle fresh tissue, and those that do are still in the stages of using cell line growth or have only started to look at excised tissue from animal models. To apply THz to an intraoperative setting requires that imaging and characterization steps be developed for fresh tissue in advance so that the analysis does not interfere with the ability to perform standard pathology. For applications that are not inherently meant to be intraoperative, the characterization of fresh tissue is still a challenging step that must be addressed to work towards in vivo applications and differentiation.
The objective of this work is to provide a guideline for THz application for freshly excised tissue using a commercial THz system. The protocol was developed on a THz imaging and spectroscopy system26 for murine breast cancer tumors13,17,19 and was extended to human surgical tissue obtained from biobanks7,18. While the protocol was generated for breast cancer, the same concepts can be applied to similar THz imaging systems and other types of solid-tumor cancers that are treated with surgery where success depends on margin assessment27. Due to a fairly small amount of published THz results on freshly excised tissues, this is the first work to the authors&#8217; knowledge to focus on the protocol of fresh tissue handling for THz imaging and characterization.

<table>
	<tbody>
		<tr>
			<td>70% isopropyl alcohol</td>
			<td>VWR</td>
			<td>89108-162</td>
			<td>Contains 70% USP grade isopropanol and 30% USP grade deionized water</td>
		</tr>
		<tr>
			<td>Alconox powder detergent</td>
			<td>VWR</td>
			<td>21835-032</td>
			<td>Concentrated detergent to remove organic contaminants from glass, metal, stainless steel, porcelain, ceramic, plastic, rubber, and fiberglass</td>
		</tr>
		<tr>
			<td>Bio Hazard Bags</td>
			<td>Fisher Scientific</td>
			<td>19-033-712</td>
			<td>Justrite FM-Approved Biohazard Waste Container Replacement Bags</td>
		</tr>
		<tr>
			<td>Cardboard holder</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Scrap cardboard to keep tissue imaging face intact when immersed in formalin</td>
		</tr>
		<tr>
			<td>Centrifuge Tubes</td>
			<td>VWR</td>
			<td>10026-078</td>
			<td>Centrifuge Tubes with Flat Caps, Conical-Bottom, Polypropylene, Sterile, Standard Line</td>
		</tr>
		<tr>
			<td>Cotton Swabs</td>
			<td>Walmart</td>
			<td>551398298</td>
			<td>Q-tips Original Cotton Swabs used to dye the tissue</td>
		</tr>
		<tr>
			<td>Ethyl Alcohol</td>
			<td>VWR</td>
			<td>71002-426</td>
			<td>KOPTECH Pure (undenatured) anhydrous (200 proof/100%) ethyl alcohol</td>
		</tr>
		<tr>
			<td>Eye protection goggles</td>
			<td>VWR</td>
			<td>89130-918</td>
			<td>Kimberly-clark professional safety glasses</td>
		</tr>
		<tr>
			<td>Face Mask</td>
			<td>VWR</td>
			<td>95041-774</td>
			<td>DUKAL Corporation surgical masks</td>
		</tr>
		<tr>
			<td>Filter paper</td>
			<td>Sigma Aldrich</td>
			<td>Z240087</td>
			<td>Whatman grade 1 cellulose filters</td>
		</tr>
		<tr>
			<td>Formalin solution</td>
			<td>Sigma Aldrich</td>
			<td>HT501128-4L</td>
			<td>10% neutral buffered formalin</td>
		</tr>
		<tr>
			<td>Human freshly excised tumors (Infilterating Ductal Carcinoma (IDC))</td>
			<td>National Disease Research Interchange (NDRI biobank</td>
			<td>N/A</td>
			<td>A protocol is signed with the NDRI for the type of tumors required</td>
		</tr>
		<tr>
			<td>IRADECON Bleach solution</td>
			<td>VWR</td>
			<td>89234-816</td>
			<td>Pre-diluted Sodium Hypochlorite Bleach solution</td>
		</tr>
		<tr>
			<td>KIMTECH SCIENCE wipes</td>
			<td>VWR</td>
			<td>21905-026</td>
			<td>Kimberly-clark professional Kim wipes</td>
		</tr>
		<tr>
			<td>Laboratory Coat</td>
			<td>VWR</td>
			<td>10141-342</td>
			<td>This catalog number is for medium size coat</td>
		</tr>
		<tr>
			<td>Laboratory tweezers/Forceps</td>
			<td>VWR</td>
			<td>82027-388</td>
			<td>Any laboratory tweezers can be used as long as it does not damage the tissue</td>
		</tr>
		<tr>
			<td>Liquid sample holder (two quartz windows with a 0.1 mm teflon spacer)</td>
			<td>TeraView, Ltd</td>
			<td>N/A</td>
			<td>1&#34; diameter, and 0.1452&#34; thick quartz windows</td>
		</tr>
		<tr>
			<td>Nitrile hand gloves</td>
			<td>VWR</td>
			<td>82026-426</td>
			<td>This catalog number is for medium size gloves</td>
		</tr>
		<tr>
			<td>Nitrogen cylinder</td>
			<td>Airgas</td>
			<td>NI UHP300</td>
			<td>NITROGEN UHP GR 5.0 SIZE 300</td>
		</tr>
		<tr>
			<td>Paper towel</td>
			<td>VWR</td>
			<td>14222-321</td>
			<td>11 x 8.78&#34; Sheets, 1 Ply</td>
		</tr>
		<tr>
			<td>Parafilm</td>
			<td>VWR</td>
			<td>52858-076</td>
			<td>Flexible thermoplastic. Rolled, waterproof sheet interwound with paper to prevent self-adhesion.</td>
		</tr>
		<tr>
			<td>Petri Dish</td>
			<td>VWR</td>
			<td>470210-568</td>
			<td>VWR Petri Dish, Slippable, Mono Plate (undivided bottom)</td>
		</tr>
		<tr>
			<td>Polystyrene Plate</td>
			<td>Home Depot</td>
			<td>1S11143A</td>
			<td>~ 10 x 10 cm square piece cut from a 11&#34; x 14&#34; x 0.05&#34; Non-glare styrene sheet</td>
		</tr>
		<tr>
			<td>ScanAcquire Software</td>
			<td>TeraView, Ltd</td>
			<td>N/A</td>
			<td>System Software for THz reflection imaging measurements</td>
		</tr>
		<tr>
			<td>Stainless steel low-profile blade (#4689)</td>
			<td>VWR</td>
			<td>25608-964</td>
			<td>Tissue-Tek Accu-Edge Disposable Microtome Blades</td>
		</tr>
		<tr>
			<td>Stainless steel metal tray</td>
			<td>Quick Medical</td>
			<td>10F</td>
			<td>Polar Ware Stainless Steel Medical Instrument Trays</td>
		</tr>
		<tr>
			<td>Tissue Marking Dyes</td>
			<td>Ted Pella, Inc</td>
			<td>Yellow Dye #27213-1 
			Red Dye #27213-2 
			Blue Dye #27213-4</td>
			<td>Used to orient excised tissue samples 
			sent to the histopathology laboratory</td>
		</tr>
		<tr>
			<td>TPS Spectra 3000</td>
			<td>TeraView, Ltd</td>
			<td>N/A</td>
			<td>THz imaging and spectroscopy system</td>
		</tr>
		<tr>
			<td>TPS Spectra Software</td>
			<td>TeraView, Ltd</td>
			<td>N/A</td>
			<td>System Software for THz transmission spectroscopy measurements</td>
		</tr>
	</tbody>
</table>

terahertz imaging and characterization protocol for freshly excised breast cancer tumors

This manuscript presents a protocol to handle, characterize, and image freshly excised human breast tumors using pulsed terahertz imaging and spectroscopy techniques. The protocol involves terahertz transmission mode at normal incidence and terahertz reflection mode at an oblique angle of 30&#176;. The collected experimental data represent time domain pulses of the electric field. The terahertz electric field signal transmitted through a fixed point on the excised tissue is processed, through an analytical model, to extract the refractive index and absorption coefficient of the tissue. Utilizing a stepper motor scanner, the terahertz emitted pulse is reflected from each pixel on the tumor providing a planar image of different tissue regions. The image can be presented in time or frequency domain. Furthermore, the extracted data of the refractive index and absorption coefficient at each pixel are utilized to provide a tomographic terahertz image of the tumor. The protocol demonstrates clear differentiation between cancerous and healthy tissues. On the other hand, not adhering to the protocol can result in noisy or inaccurate images due to the presence of air bubbles and fluid remains on the tumor surface. The protocol provides a method for surgical margins assessment of breast tumors.

The THz imaging results18 obtained following the abovementioned protocol of human breast cancer tumor specimen #ND14139 received from the biobank are presented in Figure 9. According to the pathology report, the #ND14139 tumor was a I/II grade infiltrating ductal carcinoma (IDC) obtained from a 49-year-old woman via a left breast lumpectomy surgery procedure. The photograph of the tumor is shown in Figure 9A, the pathology image in <stron...

Watch this Scientific Journal Video about Terahertz Imaging and Characterization Protocol for Freshly Excised Breast Cancer Tumors at JoVE.com

Terahertz Imaging and Characterization Protocol for Freshly Excised Breast Cancer Tumors

Freshly excised human breast cancer tumors are characterized with terahertz spectroscopy and imaging following fresh tissue handling protocols. Tissue positioning is taken into consideration to enable effective characterization while providing analysis in a timely manner for future intraoperative applications.

This manuscript presents a protocol to handle, characterize, and image freshly excised human breast tumors using pulsed terahertz imaging and spectroscopy ...

This protocol uses Terahertz imaging and spectroscopy to evaluate the surgical margins of breast tumors with the aim of substantially decreasing the need for a second surgery. Terahertz imaging can be used to distinguish between cancerous and non-cancerous tissues based on their optical properties, in a non-ionizing and biologically safe manner processes. This technique was developed for breast cancer margin assessment, but it's applicable to other solid tumors that require surgical excision and margin assessment.This method allows imaging of the inside of FFPE tissue blocks without the need for physical slicing, facilitating the identification of tumor margins at any depth precise. This protocol requires the performance of critical steps such as tissue handling and stage balancing that can be difficult to understand without visual demonstration. Before handling the tissue cover stainless steel metal tray with a biohazard bag and place all of the appropriate lab materials within easy reach of the covered tray.Next, transfer the fresh tumor sample into a petri dish on the tray and use gross inspection to select a side of the tumor that is sufficiently flat and has little blood and few blood vessels. Then, place the side to be imaged on grade one filter paper to remove any excess demand medium and to clear the tissue of fluid or secretions, repositioning the tumor to a dry spot as the paper saturates. While keeping the tumor drying for five minutes, place a 1.2 millimetre thick polystyrene plate onto the scanning window within an approximately 37 millimetre diameter and place the scanning window and the polystyrene plate onto the sample stage of the Terahertz imager.In the main window click the Fixed Point Scan icon to activate the Terahertz antennas and to start sending and receiving the reflected Terahertz signal from a single point on the polystyrene plate. Click the Motor Stage dialog icon. The Motor Control window will open up.To center the reflected pulse from the polystyrene in the main window, click the optical delay axis arrows to adjust the optical delay axis. Click the Data Acquisition Settings button to open the Data Acquisition Settings Dialogue window and change the optical delay value from five to four volts. Adjust the vertical position of the scanning stage with the micrometre scale, until the minimum of the secondary pulse is the strongest and adjust the optical delay the axis in the Motor Control window to put the primary reflection outside of the range of the reflected signal being measured.To level the sample stage and record the reference signal, click the motor control dialogue button to open the motor control window and reposition the motor control and main software windows so that the time domain signal is visible while adjusting the motor positions. To level the A axis using the following steps in the motor control window, change the value of the x axis from zero to negative 10 and hit Enter. The stage will move to the minus 10 millimetre position of the A axis and a shift in the signal position will be observed in the main window.Use the adjustable micrometre scale to move the minimum peak of the signal back to the previous vertical position and change the A axis value to plus 10. Click Enter. The stage will move to the plus 10 millimetre position on the A axis and a shift in the signal will be observed again.Note that the direction and distance that the signal shifted from its previous position and change the A axis value back to minus 10. The signal will return to the original vertical position. Rotate the leveling screw on the A axis of the scanning stage and shift the signal to double the distance in the same direction, the stage moved from the original position.Use the micrometer on the scanning stage to shift the signal back to the original position and repeat the adjustment until the signal at plus 10 and minus 10 are equal in the peak for both positions is focused at the original position. Once the leveling of the A axis has been achieved, change the A axis value to zero and repeat the same procedure for the B axis. Once both axes have been leveled, return both the A and B axes to zero millimeters, enclose the motor control window, then verify that the signal is in its original position in case it has shifted a little.To record this signal as the reference in the Data Acquisition Properties window, change the averaging value to five and leave all of the other parameters at their default settings. Then click new reference. The averaging counter will count from zero to 20.Once the counter reaches 20, change the averaging value to one and click OK.The reflected signal from the polystyrene will be saved as the reference for any subsequent scans. When all of the parameters have been set, transfer the imaging window from the scanning stage to the tissue handling area and mount the tumor onto the polystyrene plate. Remove any air bubbles within the tumor with tweezers or gently roll the sample onto the polystyrene until the air gaps are minimized.Place absorptive spacers at regular intervals around the test sample and place another polystyrene plate above the tumor. Gently press the tumor surface as flat as possible and tape down the tumor and polystyrene plate arrangement in the sample window. A flat tissue surface and a good contact with the polystyrene plate are vital as air bubbles, excess fluid and an uneven surface can ruin the tumor tissue imaging.Flip the sample window and take photos of the tumor to keep a record of its orientation. Return the sample window to the scanning stage and click the image parameter dialogue button to open the image acquisition parameters window. Set the values of axis one minimum, axis one maximum, axis two minimum and axis two maximum to fully enclose the position of the tumor in the imaging window.Set axis one step and axis two step to 0.2 millimeters for the imaging scan. Then, under the Measure menu, select Flyback 2D scan and create a folder and file name under which to save the scan data in the pop up window. In this analysis, a grade one to two infiltrating ductal carcinoma obtained from a 49 year old woman via left breast lumpectomy surgery procedure was assessed.Upon correlating the Terahertz image with the pathology image, it was clear that the cancer region exhibited a higher reflection than the fat region. Tomographic imaging revealed that as the frequency increased the calculated absorption coefficient values for the cancer in fat pixels increased with the cancer pixels showing higher values than the fat at both frequencies. In contrast, the refractive index of both tissues decreased as the frequency increased.Transmission spectroscopy analysis of the same tumor reveals a good agreement for the frequency range of both the extracted absorption coefficient and refractive index for both sections extracted from the tumor. Note that insufficient handling of the tissue can lead to misleading imaging results, resulting for example in suggesting a larger presence of cancer in the tumor due to the presence of excess liquid within the undried tumor sample. Additional characterization can be performed on the Terahertz image data to obtain information about the frequency dependent properties of the tissue and statistical analysis can be performed for automated image segmentation.This technique has led to the development of imaging and spectroscopy algorithms for investigating the signatures of ductal carcinoma in situ, to differentiate low grade tumors from deadly high grade tumors. Remember, to handle cancerous tissues and the formalin solution with caution and that any system elements or tools that contacts the tumor tissue must be cleaned or discarded appropriately.

terahertz-imaging-characterization-protocol-for-freshly-excised

Research

JoVE Journal

Engineering

10.6K vues.  University of Arkansas. Ce protocole utilise l’imagerie térahertz et la spectroscopie pour évaluer les marges chirurgicales des tumeurs mammaires dans le but de réduire considérablement le besoin d’une deuxième chirurgie. L’imagerie térahertz peut être utilisée pour distinguer les tissus cancéreux des tissus non cancéreux en fonction de leurs propriétés optiques, d’une manière non ionisante et biologiquement sûre. Cette technique a été développée pour l’évaluation de marge de cancer du s...