Comparison of Panitumumab-IRDye800CW and 5-Aminolevulinic Acid to Provide Optical Contrast in a Model of Glioblastoma Multiforme.
Molecular cancer therapeutics
Maximal safe resection of malignant tissue is associated with improved progression-free survival and better response to radiation and chemotherapy for glioblastoma (GBM) patients. 5-aminolevulinic acid (5-ALA) is the current FDA-approved standard for intraoperative brain tumor visualization. Unfortunately, autofluorescence in diffuse areas and high fluorescence in dense tissues significantly limit discrimination at tumor margins. The present study is the first to compare 5-ALA to an investigational new drug, panitumumab-IRDye800CW, in the same animal model. A patient-derived GBM xenograft model was established in 16 nude mice, which later received injections of 5-ALA, panitumumab-IRDye800CW, IRDye800CW, 5-ALA and IRDye800CW, or 5-ALA and panitumumab-IRDye800CW. Brains were prepared for multi-instrument fluorescence imaging, immunohistochemistry, and quantitative analysis of tumor-to-background ratio (TBR) and tumor margin accuracy. Statistical analysis was compared with Wilcoxon rank-sum or paired t-test. Panitumumab-IRDye800CW had a 30% higher comprehensive TBR compared to 5-ALA (p = 0.0079). Standard deviations for core and margin regions of interest in 5-ALA-treated tissues were significantly higher than those found in panitumumab-IRDye800CW-treated tissues (p = 0.0240 and p = 0.0284, respectively). Panitumumab-IRDye800CW specificities for tumor core and margin were over 10% higher than those of 5-ALA. Higher area under the curve for panitumumab-IRDye800CW indicated strong capability to discriminate between normal and malignant brain tissue when compared to 5-ALA. This work demonstrates that panitumumab-IRDye800CW shows potential as a targeting agent for fluorescent intraoperative detection of GBM. Improved margin definition and surgical resection using panitumumab-IRDye800 has the potential to improve surgical outcomes and survival in GBM patients compared to 5-ALA.
View details for DOI 10.1158/1535-7163.MCT-19-0819
View details for PubMedID 32606015
Fluorescently Labeled Cetuximab-IRDye800 for Guided Surgical Excision of Ameloblastoma: A Proof of Principle Study.
Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons
Fluorescently labeled epidermal growth factor receptor (EGFR) antibodies have successfully identified microscopic tumors in multiple in vivo models of human cancers with limited toxicity. The present study sought to demonstrate the ability of fluorescently labeled anti-EGFR, cetuximab-IRDye800, to localize to ameloblastoma (AB) tumor cells in vitro and in vivo.EGFR expression in AB cells was confirmed by quantitative real-time polymerase chain reaction and immunohistochemistry. Primary AB cells were labeled in vitro with cetuximab-IRDye800 or nonspecific IgG-IRDye800. An in vivo patient-derived xenograft (PDX) model of AB was developed. The tumor tissue from 3 patients was implanted subcutaneously into immunocompromised mice. The mice received an intravenous injection of cetuximab-IRDye800 or IgG-IRDye800 and underwent imaging to detect infrared fluorescence using a Pearl imaging system (LI-COR Biosciences, Lincoln, NE). After resection of the overlying skin, the tumor/background ratios (TBRs) were calculated and statistically analyzed using a paired t test.EGFR expression was seen in all AB samples. Tumor-specific labeling was achieved, as evidenced by a positive fluorescence signal from cetuximab-IRDye800 binding to AB cells, with little staining seen in the negative controls treated with IgG-IRDye800. In the animal PDX model, imaging revealed that the TBRs produced by cetuximab were significantly greater than those produced by IgG on days 7 to 14 for AB-20 tumors. After skin flap removal to simulate a preresection state, the TBRs increased with cetuximab and were significantly greater than the TBRs with the IgG control for PDX tumors derived from the 3 patients with AB. The excised tissues were embedded in paraffin and examined to confirm the presence of tumor.Fluorescently labeled anti-EGFR demonstrated specificity for AB cells and PDX tumors. The present study is the first report of tumor-specific, antibody-based imaging of odontogenic tumors, of which AB is one of the most clinically aggressive. We expect this technology will ultimately assist surgeons treating AB by helping to accurately assess the tumor margins during surgery, leading to improved long-term local tumor control and less surgical morbidity.
View details for DOI 10.1016/j.joms.2020.05.022
View details for PubMedID 32554066
- Adjuvant anti-angiogenic therapy enhances chemotherapeutic uptake in a murine model of head and neck cancer(*) JOURNAL OF DRUG TARGETING 2019; 27 (2): 193–200
Adjuvant Anti-angiogenic Therapy Enhances Chemotherapeutic Uptake in a Murine Model of Head and Neck Cancer.
Journal of drug targeting
Intratumoral metabolic demands result in excessive angiogenic cytokine release leading to unorganized vasculature. Resultant fluid dynamics oppose blood flow and drug penetration due to a marked increase in interstitial fluid hydrostatic pressure. It is hypothesized that anti-angiogenic therapy may function to "prune" vasculature and lead to improved chemotherapeutic penetration. Subcutaneous, OSC19 tumor bearing mice (n = 5/dose/agent) were administered varying doses of an anti-mouse VEGFR2 (DC101) or an anti-mouse VEGFR3 (31C1) -3d, -1d, 0d, +1d, and +3d prior to 200μg of cetuximab fluorescently labeled with IRDye800CW. Fluorescence imaging of tumors was performed 10d post cetuximab-IRDye800CW dose to monitor therapeutic uptake. Co-administration of dual anti-angiogenic agents at 50%-50%, 75%-25%, and 25%-75% using optimal dose and time (-1d 10mg/kg anti-VEGFR2 and -1d 40mg/kg anti-VEGFR3) was also evaluated. In order to establish vessel normalization, NG2 (pericyte marker) and CD31 (endothelial cells) ratios were assessed during immunohistochemical staining of tumor sections. Twenty-mg/kg anti-VEGFR3 + 5mg/kg anti-VEGFR2 significantly (p < 0.0005) reduced tumor size (-73%) compared to control (59%). The 20mg/kg anti-VEGFR3 + 5mg/kg anti-VEGFR2 and 30mg/kg anti-VEGFR3 + 2.5mg/kg anti-VEGFR2 significantly (p < 0.0004) improved percent-injected cetuximab-IRDye800CW dose/gram tumor tissue compared to other groups. Adjuvant, dual anti-angiogenic therapy targeting VEGFR2 and VEGFR3 significantly enhances tumor chemotherapeutic uptake compared to control.
View details for PubMedID 29972342
Evaluation of optical imaging agents in a fluorescence-guided surgical model of head and neck cancer.
2018; 27 (2): 225–30
Tumor proliferation often occurs from pathologic receptor upregulation. These receptors provide unique targets for near-infrared (NIR) probes that have fluorescence-guided surgery (FGS) applications. We demonstrate the use of three smart-targeted probes in a model of head and neck squamous cell carcinoma.A dose escalation study was performed using IntegriSense750, ProSense750EX, and ProSense750FAST in mice (n = 5) bearing luciferase-positive SCC-1 flank xenograft tumors. Whole body fluorescence imaging was performed serially after intravenous injection using commercially available open-field (LUNA, Novadaq, Canada) and closed-field NIR systems (Pearl, LI-COR, Lincoln, NE). An ex vivo, whole-body biodistribution was conducted. Lastly, FGS was performed with IntegriSense750 to demonstrate orthotopic and metastatic disease localization.Disease fluorescence delineation was assessed by tumor-to-background fluorescence ratios (TBR). Peak TBR values were 3.3 for 1 nmol ProSense750EX, 5.5 for 6 nmol ProSense750FAST, and 10.8 for 4 nmol IntegriSense750 at 5.5, 3, and 4 d post administration, respectively. Agent utility is unique: ProSense750FAST provides sufficient contrast quickly (TBR: 1.5, 3 h) while IntegriSense750 produces strong (TBR: 10.8) contrast with extended administration-to-resection time (96 h). IntegriSense750 correctly identified all diseased nodes in situ during exploratory surgeries. Ex vivo, whole-body biodistribution was assessed by tumor-to-tissue fluorescence ratios (TTR). Agents provided sufficient fluorescence contrast to discriminate disease from background, TTR>1. IntegriSense750 was most robust in neural tissue (TTR: 64) while ProSense750EX was superior localizing disease against lung tissue (TBR: 13).All three agents appear effective for FGS.
View details for PubMedID 29937175
Laser-Assisted Indocyanine Green Dye Angiography for Postoperative Fistulas After Salvage Laryngectomy.
JAMA otolaryngology-- head & neck surgery
Pharyngocutaneous fistula formation is an unfortunate complication after salvage laryngectomy for head and neck cancer that is difficult to anticipate and related to a variety of factors, including the viability of native pharyngeal mucosa.To examine whether noninvasive angiography with indocyanine green (ICG) dye can be used to evaluate native pharyngeal vascularity to anticipate pharyngocutaneous fistula development.This cohort study included 37 patients enrolled from June 1, 2013, to June 1, 2016, and follow-up was for at least 1 month postoperatively. The study was performed at the University of Alabama at Birmingham, a tertiary care center. Included patients were those undergoing salvage total laryngectomy who were previously treated with chemoradiotherapy or radiotherapy alone.The ICG dye was injected intraoperatively, and laser-assisted vascular imaging was used to evaluate the native pharyngeal mucosa after the ablative procedure. The center of the native pharyngeal mucosa was used as the reference to compare with the peripheral mucosa, and the lowest mean ICG dye percentage of mucosal perfusion was recorded for each patient.The primary outcome was the formation of a postoperative fistula, which was assessed by clinical and radiographic assessment to test the hypothesis formulated before data collection.A total of 37 patients were included (mean [SD] age, 62.3 [8.5] years; 32 [87%] male and 5 [14%] female); 20 had a history of chemoradiotherapy, and 17 had history of radiotherapy alone. Thirty-four patients (92%) had free flap reconstruction, and 3 had primary closure (8%). Ten patients (27%) developed a postoperative fistula. No significant difference was found in fistula rate between patients who underwent neck dissection and those who did not and patients previously treated with chemoradiotherapy and those treated with radiotherapy alone. A receiver operator characteristic curve was generated to determine the diagnostic performance of the lowest mean ICG dye percentage of mucosal perfusion determined by fluorescence imaging, which was found to be a threshold value of 26%. The area under the curve was 0.85 (95% CI, 0.73-0.97), which was significantly greater than the chance diagonal. The overall mean lowest ICG dye percentage of mucosal perfusion was 31.3%. The mean lowest ICG dye percentage of mucosal perfusion was 22.0% in the fistula group vs 34.9% in the nonfistula group (absolute difference, 12.9%; 95% CI, 5.1%-21.7%).Patients who developed postoperative fistulas had lower mucosal perfusion as detected by ICG dye angiography when compared with patients who did not develop fistulas.
View details for DOI 10.1001/jamaoto.2017.0187
View details for PubMedID 28520896
Sensitivity and Specificity of Cetuximab-IRDye800CW to Identify Regional Metastatic Disease in Head and Neck Cancer.
Clinical cancer research : an official journal of the American Association for Cancer Research
Purpose: Comprehensive cervical lymphadenectomy can be associated with significant morbidity and poor quality of life. This study evaluated the sensitivity and specificity of cetuximab-IRDye800CW to identify metastatic disease in patients with head and neck cancer.Experimental Design: Consenting patients scheduled for curative resection were enrolled in a clinical trial to evaluate the safety and specificity of cetuximab-IRDye800CW. Patients (n = 12) received escalating doses of the study drug. Where indicated, cervical lymphadenectomy accompanied primary tumor resection, which occurred 3 to 7 days following intravenous infusion of cetuximab-IRDye800CW. All 471 dissected lymph nodes were imaged with a closed-field, near-infrared imaging device during gross processing of the fresh specimens. Intraoperative imaging of exposed neck levels was performed with an open-field fluorescence imaging device. Blinded assessments of the fluorescence data were compared to histopathology to calculate sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV).Results: Of the 35 nodes diagnosed pathologically positive, 34 were correctly identified with fluorescence imaging, yielding a sensitivity of 97.2%. Of the 435 pathologically negative nodes, 401 were correctly assessed using fluorescence imaging, yielding a specificity of 92.7%. The NPV was determined to be 99.7%, and the PPV was 50.7%. When 37 fluorescently false-positive nodes were sectioned deeper (1 mm) into their respective blocks, metastatic cancer was found in 8.1% of the recut nodal specimens, which altered staging in two of those cases.Conclusions: Fluorescence imaging of lymph nodes after systemic cetuximab-IRDye800CW administration demonstrated high sensitivity and was capable of identifying additional positive nodes on deep sectioning. Clin Cancer Res; 1-9. ©2017 AACR.
View details for DOI 10.1158/1078-0432.CCR-16-2968
View details for PubMedID 28446503
Characterizing the Utility and Limitations of Repurposing an Open-Field Optical Imaging Device for Fluorescence-Guided Surgery in Head and Neck Cancer Patients
JOURNAL OF NUCLEAR MEDICINE
2017; 58 (2): 246-251
The purpose of this study was to assess the potential of U.S. Food and Drug Administration-cleared devices designed for indocyanine green-based perfusion imaging to identify cancer-specific bioconjugates with overlapping excitation and emission wavelengths. Recent clinical trials have demonstrated potential for fluorescence-guided surgery, but the time and cost of the approval process may impede clinical translation. To expedite this translation, we explored the feasibility of repurposing existing optical imaging devices for fluorescence-guided surgery.Consenting patients (n = 15) scheduled for curative resection were enrolled in a clinical trial evaluating the safety and specificity of cetuximab-IRDye800 (NCT01987375). Open-field fluorescence imaging was performed preoperatively and during the surgical resection. Fluorescence intensity was quantified using integrated instrument software, and the tumor-to-background ratio characterized fluorescence contrast.In the preoperative clinic, the open-field device demonstrated potential to guide preoperative mapping of tumor borders, optimize the day of surgery, and identify occult lesions. Intraoperatively, the device demonstrated robust potential to guide surgical resections, as all peak tumor-to-background ratios were greater than 2 (range, 2.2-14.1). Postresection wound bed fluorescence was significantly less than preresection tumor fluorescence (P < 0.001). The repurposed device also successfully identified positive margins.The open-field imaging device was successfully repurposed to distinguish cancer from normal tissue in the preoperative clinic and throughout surgical resection. This study illuminated the potential for existing open-field optical imaging devices with overlapping excitation and emission spectra to be used for fluorescence-guided surgery.
View details for DOI 10.2967/jnumed.115.171413
View details for Web of Science ID 000393360100017
View details for PubMedID 27587708
View details for PubMedCentralID PMC5288741
Oncologic Procedures Amenable to Fluorescence-guided Surgery.
Annals of surgery
Although fluorescence imaging is being applied to a wide range of cancers, it remains unclear which disease populations will benefit greatest. Therefore, we review the potential of this technology to improve outcomes in surgical oncology with attention to the various surgical procedures while exploring trial endpoints that may be optimal for each tumor type.For many tumors, primary treatment is surgical resection with negative margins, which corresponds to improved survival and a reduction in subsequent adjuvant therapies. Despite unfavorable effect on patient outcomes, margin positivity rate has not changed significantly over the years. Thus, patients often experience high rates of re-excision, radical resections, and overtreatment. However, fluorescence-guided surgery (FGS) has brought forth new light by allowing detection of subclinical disease not readily visible with the naked eye.We performed a systematic review of clinicatrials.gov using search terms "fluorescence," "image-guided surgery," and "near-infrared imaging" to identify trials utilizing FGS for those received on or before May 2016.fluorescence surgery for tumor debulking, wide local excision, whole-organ resection, and peritoneal metastases.fluorescence in situ hybridization, fluorescence imaging for lymph node mapping, nonmalignant lesions, nonsurgical purposes, or image guidance without fluorescence.Initial search produced 844 entries, which was narrowed down to 68 trials. Review of literature and clinical trials identified 3 primary resection methods for utilizing FGS: (1) debulking, (2) wide local excision, and (3) whole organ excision.The use of FGS as a surgical guide enhancement has the potential to improve survival and quality of life outcomes for patients. And, as the number of clinical trials rise each year, it is apparent that FGS has great potential for a broad range of clinical applications.
View details for DOI 10.1097/SLA.0000000000002127
View details for PubMedID 28045715
Effects of an Unlabeled Loading Dose on Tumor-Specific Uptake of a Fluorescently Labeled Antibody for Optical Surgical Navigation.
Molecular imaging and biology
Intraoperative optical imaging to guide surgeons during oncologic resections offers a unique and promising solution to the ambiguity of cancer margins to tactile and visual assessment that results in devastatingly high rates of positive margins. Sequestering of labeled antibodies by normal tissues with high expression of the antibody target, or "antigen sinks", diminishes the efficacy of these probes to provide contrast between the tumor and background tissues by decreasing the amount of circulating probe available for uptake by the tumor and by increasing the fluorescence of non-tumor tissues. We hypothesized that administering a dose of unlabeled antibody prior to infusion of the near-infrared (NIR) fluorescently labeled antibody would improve tumor-specific uptake and contrast of the fluorescently labeled probe by occupying extra-tumoral binding sites, thereby increasing the amount of labeled probe available for uptake by the tumor.In this study, we explore this concept by testing two different "pre-load" doses of unlabeled cetuximab (the standard 10-mg test dose, and a larger, experimental 100-mg test dose) in six patients receiving cetuximab conjugated to the fluorescent dye IRDye800CW (cetuximab-IRDye800CW) in a clinical trial, and compared the amount of fluorescent antibody in tumor and background tissues, as well as the tumor-specific contrast of each.The patients receiving the larger preload (100 mg) of unlabeled cetuximab demonstrated significantly higher concentrations (9.5 vs. 0.1 μg) and a longer half-life (30.3 vs. 20.6 days) of the labeled cetuximab in plasma, as well as significantly greater tumor fluorescence (32.3 vs. 9.3 relative fluorescence units) and tumor to background ratios (TBRs) (5.5 vs. 1.7).Administering a preload of unlabeled antibody prior to infusion of the fluorescently labeled drug may be a simple and effective way to improve the performance of antibody-based probes to guide surgical resection of solid malignancies.
View details for PubMedID 27830425
Antiangiogenic antibody improves melanoma detection by fluorescently labeled therapeutic antibodies.
Evaluate if vascular normalization with an antiangiogenic monoclonal antibody improves detection of melanoma using fluorescently labeled antibody-based imaging.Preclinical.Panitumumab and control IgG were covalently linked to a near-infrared fluorescent probe (IRDye800CW). Immunodeficient mice with ear xenografts of melanoma cell lines (A375 and SKMEL5) were systemically injected (200 μg, tail vein) with either IgG-IRDye800CW, panitumumab-IRDye800CW, or a combination (bevacizumab [5mg/kg], administered 72 hours prepanitumumab-IRDye800CW) (n = 5). Primary tumors were imaged with open-field (LUNA, Novadaq, Toronto, Ontario, Canada) and closed-field (Pearl, LI-COR Biosciences, Lincoln, NB) imaging devices. Postresection, the concentration of labeled antibody within the tumor (μg/g) was calculated using normalized standards.The mean fluorescence within the melanoma tumors was greater for the combination group compared to panitumumab alone for both cell lines (P < 0.001). The tumor-to-background ratio (TBR) for the A375 tumors was greater for the combination (3.4-7.1) compared to the panitumumab alone (3.2-5.0) (P = 0.04). The TBR for SKMEL5 tumors was greater for the combination (2.4-6.0) compared to the panitumumab alone (2.2-3.9) (P = 0.02). Within A375 tumors, the concentration was lower for panitumumab (0.51 μg/g) compared to combination group (0.68 μg/g) (P = 0.036). Within SKMEL5 tumors, the concentration was lower for panitumumab (0.0.17 μg/g) compared to combination group (0.35 μg/g) (P = 0.048). Residual tumor (1.0-0.2 mg) could be differentiated from background in both panitumumab and combination groups. For both cell lines, panitumumab and combination groups had greater mean fluorescence of the tumor compared to control IgG.The addition of antiangiogenic therapy improves uptake of fluorescently labeled monoclonal antibodies within melanoma tumors. Clinical translation could improve detection of melanoma intraoperatively, reducing positive margins and sparing normal tissue.NA Laryngoscope, 126:E387-E395, 2016.
View details for DOI 10.1002/lary.26215
View details for PubMedID 27576611
View details for PubMedCentralID PMC5121084
Photoimmunotherapy of residual disease after incomplete surgical resection in head and neck cancer models
2016; 5 (7): 1526-1534
Antibody-based photodynamic therapy, or photoimmunotherapy (PIT), is a novel, targeted cancer therapy, which can serve as both a diagnostic and a therapeutic agent. The primary objective of this study was to evaluate the capacity of panitumumab-IRDye700DX (Pan-IR700) to eliminate microscopic tumor remnants in the postsurgical setting, which was accomplished using novel in vitro and in vivo models of residual disease after incomplete resection. Additionally, PIT was evaluated in fresh human-derived cancer tissue. To determine a threshold for cellular regrowth after PIT, an in vitro assay was performed using a range of cells representing microscopic disease quantities. Long-term growth inhibition was induced after treatment of 5 × 10(3) and 1 × 10(4) cells at 6 J. A novel in vivo mouse model of subtotal tumor resection was used to assess the effectiveness of Pan-IR700 mediated PIT to eliminate residual disease and inhibit recurrence in the post-surgical wound bed. Mice receiving surgical treatment plus adjuvant PIT showed a threefold and fourfold reduction in tumor regrowth at 30 days post PIT in the 50% and 90% subtotal resection groups, respectively (as measured by bioluminescence imaging), demonstrating a significant (P < 0.001) reduction in tumor regrowth. To determine the translatability of epidermal growth factor receptor (EGFR)-targeted PIT, SCCHN human tissues (n = 12) were treated with Pan-IR700. A significant reduction (P < 0.001) in ATP levels was observed after treatment with Pan-IR700 and 100 J cm(-2) (48% ± 5%) and 150 J cm(-2) (49% ± 7%) when compared to baseline. Targeting EGFR with Pan-IR700 has robust potential to provide a tumor-specific mechanism for eliminating residual disease in the surgical setting, thereby increasing therapeutic efficacy, prolonging progression-free survival, and decreasing morbidity.
View details for DOI 10.1002/cam4.752
View details for Web of Science ID 000380048900019
View details for PubMedID 27167827
View details for PubMedCentralID PMC4867660
Fluorescence imaging to localize head and neck squamous cell carcinoma for enhanced pathological assessment.
The journal of pathology. Clinical research
2016; 2 (2): 104-112
Accurately identifying close or positive margins in real-time permits re-excision during surgical procedures. Intraoperative assessment of margins via gross examination and frozen section is a widely used tool to assist the surgeon in achieving complete resection. While this methodology permits diagnosis of freshly resected tissue, the process is fraught with misinterpretation and sampling errors. During fluorescence-guided surgery, an exogenous fluorescent agent specific for the target disease is imaged in order to navigate the surgical excision. As this technique quickly advances into the clinic, we hypothesize that the disease-specific fluorescence inherently contained within the resected tissues can be used to guide histopathological assessment. To evaluate the feasibility of fluorescence-guided pathology, we evaluated head and neck squamous cell carcinoma tumour specimens and margins resected from animals and patients after systemic injection of cetuximab-IRDye800CW. In a preclinical model of luciferase-positive tumour resection using bioluminescence as the gold standard, fluorescence assessment determined by closed-field fluorescence imaging of fresh resected margins accurately predicted the presence of disease in 33/39 positive margins yielding an overall sensitivity of 85%, specificity of 95%, positive predictive value (PPV) of 94%, and a negative predictive value (NPV) of 87%, which was superior to both surgical assessment (54%, 61%, 57%, and 58%) and pathological assessment (49%, 95%, 91%, and 66%), respectively. When the power of the technique was evaluated using human-derived tumour tissues, as little as 0.5mg (1mm(3)) of tumour tissue was identified (tumour-to-background-ratio:5.2). When the sensitivity/specificity of fluorescence-guided pathology was determined using traditional histological assessment as the gold standard in human tissues obtained during fluorescence-guided surgery, the technique was highly accurate with a sensitivity of 91%, specificity of 85%, PPV of 81%, and NPV of 93% for 90 human-derived samples. This approach can be used as a companion to the pathologist, eliminating confounding factors while impacting surgical intervention and patient management.
View details for DOI 10.1002/cjp2.40
View details for PubMedID 27499920
View details for PubMedCentralID PMC4907060
- Standardized model for predicting flap failure using Indocyanine Green Dye SPIE-INT SOC OPTICAL ENGINEERING. 2016
- Near-infrared (NIR) fluorescence imaging of head and neck squamous cell carcinoma for fluorescence-guided surgery SPIE-INT SOC OPTICAL ENGINEERING. 2016