Tissue-like phantoms for near-infrared fluorescence imaging system assessment and the training of surgeons

Grand, Alec M. De; Lomnes, Stephen J.; Lee, Deborah S.; Pietrzykowski, Matthew; Ohnishi, Shunsuke; Morgan, Timothy G.; Gogbashian, Andrew; Laurence, Rita G.; Frangioni, John V.

doi:10.1117/1.2170579

Cited by 125 publications

(130 citation statements)

References 36 publications

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“…One approach to solve these problems is to use QDs emitting in the near-infrared window. However, even in the near-infrared range [19], tissue autofluorescence always remains a major and often overlooked problem that reduces the signal-to-background ratio and, therefore, objects detectability. Self-illuminating quantum dots have great potential as an in vivo imaging and sensitive detection probe.…”

Section: Discussionmentioning

confidence: 99%

Improved QD-BRET conjugates for detection and imaging

Xing

Koh

et al. 2008

Biochemical and Biophysical Research Communications

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Self-illuminating quantum dots, also known as QD-BRET conjugates, are a new class of quantum dots bioconjugates which do not need external light for excitation. Instead, light emission relies on the bioluminescence resonance energy transfer from the attached Renilla luciferase enzyme, which emits light upon the oxidation of its substrate. QD-BRET combines the advantages of the QDs (such as superior brightness & photostability, tunable emission, multiplexing) as well as the high sensitivity of bioluminescence imaging, thus holds the promise for improved deep tissue in vivo imaging. Although studies have demonstrated the superior sensitivity and deep tissue imaging potential, the stability of the QD-BRET conjugates in biological environment needs to be improved for long-term imaging studies such as in vivo cell trafficking. In this study, we seek to improve the stability of QD-BRET probes through polymeric encapsulation with a polyacrylamide gel. Results show that encapsulation caused some activity loss, but significantly improved both the in vitro serum stability and in vivo stability when subcutaneously injected into the animal. Stable QD-BRET probes should further facilitate their applications for both in vitro testing as well as in vivo cell tracking studies. Keywordsself-illuminating quantum dots; bioluminescence resonance energy transfer (BRET); polymeric encapsulation; molecular imaging; nanotechnology Semiconductor quantum dots (QDs) have captivated scientists and engineers over the past two decades owing to their fascinating optical and electronic properties, which are not available from either single individual molecules or bulk solids [1]. Compared with organic dyes and fluorescent proteins, semiconductor QDs offer several unique advantages, such as size-and composition-tunable emission from visible to infrared wavelengths, large absorption coefficients across a wide spectral range, and very high levels of brightness and photostability [2]. These properties make them appealing fluorescent probes for bioimaging applications including in situ cell/tissue labeling, live cell imaging and in vivo imaging [3]. However, in vivo imaging using quantum dots still faces challenges such as interferences from tissue autofluorescence [4] and paucity of light available at non-superficial tissue sites [5]. One approach to solve these problems is to use high quality near infrared (NIR) QDs [6], which is an area still under active development. Alternatively, since both problems are related to the

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Section: Discussionmentioning

confidence: 99%

Improved QD-BRET conjugates for detection and imaging

Xing

Koh

et al. 2008

Biochemical and Biophysical Research Communications

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“…Breast-shaped phantoms were produced as described earlier (13,14). For tumorlike agarose inclusions, 2% agarose (Hispanagar) was suspended in Tris-buffered saline and heated to 70°C.…”

Section: Phantom Studymentioning

confidence: 99%

⁸⁹Zr-Bevacizumab PET Imaging in Primary Breast Cancer

et al. 2013

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Vascular endothelial growth factor (VEGF)-A is overexpressed in most malignant and premalignant breast lesions. VEGF-A can be visualized noninvasively with PET imaging and using the tracer 89 Zr-labeled bevacizumab. In this clinical feasibility study, we assessed whether VEGF-A in primary breast cancer can be visualized by 89 Zr-bevacizumab PET. Methods: Before surgery, breast cancer patients underwent a PET/CT scan of the breasts and axillary regions 4 d after intravenous administration of 37 MBq of 89 Zr-bevacizumab per 5 mg. PET images were compared with standard imaging modalities. 89 Zr-bevacizumab uptake was quantified as the maximum standardized uptake value (SUV max ). VEGF-A levels in tumor and normal breast tissues were assessed with enzyme-linked immunosorbent assay. Data are presented as mean 6 SD. Results: Twenty-five of 26 breast tumors (mean size 6 SD, 25.1 6 19.8 mm; range, 4-80 mm) in 23 patients were visualized. SUV max was higher in tumors (1.85 6 1.22; range, 0.52-5.64) than in normal breasts (0.59 6 0.37; range, 0.27-1.69; P , 0.001). The only tumor not detected on PET was 10 mm in diameter. Lymph node metastases were present in 10 axillary regions; 4 could be detected with PET (SUV max , 2.66 6 2.03; range, 1.32-5.68). VEGF-A levels in the 17 assessable tumors were higher than in normal breast tissue in all cases (VEGF-A/mg protein, 184 6 169 pg vs. 10 6 21 pg; P 5 0.001), whereas 89 Zr-bevacizumab tumor uptake correlated with VEGF-A tumor levels (r 5 0.49). Conclusion: VEGF-A in primary breast cancer can be visualized by means of 89 Zr-bevacizumab PET.

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“…In circumstances where a static matrix with limited water mobility or with complex sample structures is desired, hydrogels, such as gelatin gel, are preferred. [18][19][20][21][22][23] Fabrication of such hydrogel phantoms with Intralipid additive is nontrivial-the main variables being the mixing temperature and time. To mix Intralipid thoroughly with hydrogel in the liquid phase, e.g., a gelatin-water solution, the mixture has to be kept warm to prevent the hydrogel matrix from solidifying.…”

Section: Introductionmentioning

confidence: 99%

Dependence of optical scattering from Intralipid in gelatin-gel based tissue-mimicking phantoms on mixing temperature and time

Lai

Wang

2014

J. Biomed. Opt

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Abstract. Intralipid is widely used as an optical scattering agent in tissue-mimicking phantoms. Accurate control when using Intralipid is critical to match the optical diffusivity of phantoms to the prescribed value. Currently, most protocols of Intralipid-based hydrogel phantom fabrication focus on factors such as Intralipid brand and concentration. In this note, for the first time to our knowledge, we explore the dependence of the optical reduced scattering coefficient (at 532 nm optical wavelength) on the temperature and the time of mixing Intralipid with gelatin-water solution. The studied samples contained 1% Intralipid and were measured with oblique-incidence reflectometry. It was found that the reduced scattering coefficient increased when the Intralipid-gelatinwater mixture began to solidify at room temperature. For phantoms that had already solidified completely, the diffusivity was shown to be significantly influenced by the temperature and the duration of the mixing course. The dependence of the measured diffusivity on the mixing conditions was confirmed by experimental observations. Moreover, the mechanism behind the dependence behavior is discussed.

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Tissue-like phantoms for near-infrared fluorescence imaging system assessment and the training of surgeons

Cited by 125 publications

References 36 publications

Improved QD-BRET conjugates for detection and imaging

Improved QD-BRET conjugates for detection and imaging

⁸⁹Zr-Bevacizumab PET Imaging in Primary Breast Cancer

Dependence of optical scattering from Intralipid in gelatin-gel based tissue-mimicking phantoms on mixing temperature and time

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Tissue-like phantoms for near-infrared fluorescence imaging system assessment and the training of surgeons

Cited by 125 publications

References 36 publications

Improved QD-BRET conjugates for detection and imaging

Improved QD-BRET conjugates for detection and imaging

89Zr-Bevacizumab PET Imaging in Primary Breast Cancer

Dependence of optical scattering from Intralipid in gelatin-gel based tissue-mimicking phantoms on mixing temperature and time

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Product

Resources

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⁸⁹Zr-Bevacizumab PET Imaging in Primary Breast Cancer