Detection of Melanoma Metastases in Resected Human Lymph Nodes by Noninvasive Multispectral Photoacoustic Imaging

Objective. Sentinel node biopsy in patients with cutaneous melanoma improves staging, provides prognostic information, and leads to an increased survival in node-positive patients. However, frozen section analysis of the sentinel node is not reliable and definitive histopathology evaluation requires days, preventing intraoperative decision-making and immediate therapy. Photoacoustic imaging can evaluate intact lymph nodes, but specificity can be hampered by other absorbers such as hemoglobin. Near infrared multispectral photoacoustic imaging is a new approach that has the potential to selectively detect melanin. The purpose of the present study is to examine the potential of multispectral photoacoustic imaging to identify melanoma metastasis in human lymph nodes. Methods. Three metastatic and nine benign lymph nodes from eight melanoma patients were scanned ex vivo using a Vevo LAZR multispectral photoacoustic imager and were spectrally analyzed per pixel. The results were compared to histopathology as gold standard. Results. The nodal volume could be scanned within 20 minutes. An unmixing procedure was proposed to identify melanoma metastases with multispectral photoacoustic imaging. Ultrasound overlay enabled anatomical correlation. The penetration depth of the photoacoustic signal was up to 2 cm. Conclusion. Multispectral three-dimensional photoacoustic imaging allowed for selective identification of melanoma metastases in human lymph nodes

Seeing it through: translational validation of new medical imaging modalities

Medical imaging is an invaluable tool for diagnosis, surgical guidance, and assessment of treatment efficacy. The Network for Translational Research (NTR) for Optical Imaging consists of four research groups working to “bridge the gap” between lab discovery and clinical use of fluorescence- and photoacoustic-based imaging devices used with imaging biomarkers. While the groups are using different modalities, all the groups face similar challenges when attempting to validate these systems for FDA approval and, ultimately, clinical use. Validation steps taken, as well as future needs, are described here. The group hopes to provide translational validation guidance for itself, as well as other researchers

Novel Diagnostic Tools for Skin and Periorbital Cancer - Exploring Photoacoustic Imaging and Diffuse Reflectance Spectroscopy

The eyelids are susceptible to a number of skin cancers which are challenging to excise radically without sacrificing excessive healthy tissue. The way in which a tumor is delineated preoperatively has not changed significantly over the past century. The aims of the work presented in this thesis were to investigate two novel non-invasive techniques for diagnosing and delineating skin tumors.Extended-wavelength diffuse reflectance spectroscopy (EWDRS) was evaluated to determine its ability to differentiate between and classify different skin and tissue types in an in vivo pig model, with the aid of machine learning methods.The recordings were used to train a support vector machine, and it was possible to perform classifications with an overall accuracy of over 98%. The ability of EWDRS to identify the borders of pigmented skin lesions in an in vivo pig model was also evaluated. Using a thin probe, it was possible to detect the border with a median discrepancy of 70 μm, compared to the border found on histological examination.Photoacoustic imaging (PAI), a biomedical imaging modality that combines laser irradiation and ultrasound, was used to examine basal cell carcinomas (BCCs) and human eyelids ex vivo. Typical photoacoustic spectra were observed for BCCs as well as for the different layers of the healthy eyelid, and these structures could be visualized in three-dimensional images. A case was described in which PAI showed that the pentagonal excision of an eyelid BCC was non-radical, as was later confirmed by histological examination.In conclusion, both EWDRS and PAI are capable of differentiating between different kinds of tissue and, following further development and studies, could potentially be used to diagnose and delineate skin and eyelid tumors prior to surgical excision

Combination oral immunotherapy with IL-10 and IL-12 effectively treats colon tumors via synergistic effects on IL-17 producing T cells and colon epithelial barrier integrity.

In this dissertation, the relationship between colon cancer and inflammation, the utility of novel imaging modalities for diagnosis of colitis and cancer, and the therapeutic efficacy of orally delivered, particle-based immunotherapy for the treatment of colon cancer are evaluated. In Chapters One and Two, multispectral optoacoustic tomography (MSOT) is demonstrated to effectively detect colon inflammation without the use of exogenous contrast prior to detection using conventional colonoscopy. Oral particle uptake is demonstrated in the distal small intestine and proximal colon, confirming site-specific delivery. In Chapter Three, administration of IL-10 and IL-12 containing particles is shown to act synergistically to significantly reduce tumor burden in the setting of established colon tumors. Cellular mechanisms deriving from effects on CD8+ T cells and T17 cells as well as a physiologic mechanism stemming from combination therapy’s strengthening of colon epithelial barrier integrity are described. In Chapter Four, the lack of efficacy of orally administered anti-PD1 therapy is demonstrated. IL-17 and γδ T cells, but not CD4+ T cells, are shown to be critical mediators of treatment failure. The significant anti-tumor effect of combination treatment with either anti-IL-17A or anti- γδ TCR and anti-PD1 demonstrate exciting therapeutic targets for future clinical trials. Finally, in Chapter Five, a clinically relevant model of colon cancer is described. This mutationally-driven model recapitulates the clinical scenario of single adenoma development, adenoma to carcinoma transition, carcinoma progression, and eventual metastasis to the liver. Such a model provides an excellent platform for preclinical evaluation of many different aspects of colon cancer

Goggle Augmented Imaging and Navigation System for Fluorescence-Guided Surgery

Surgery remains the only curative option for most solid tumors. The standard-of-care usually involves tumor resection and sentinel lymph node biopsy for cancer staging. Surgeons rely on their vision and touch to distinguish healthy from cancer tissue during surgery, often leading to incomplete tumor resection that necessitates repeat surgery. Sentinel lymph node biopsy by conventional radioactive tracking exposes patients and caregivers to ionizing radiation, while blue dye tracking stains the tissue highlighting only superficial lymph nodes. Improper identification of sentinel lymph nodes may misdiagnose the stage of the cancer. Therefore there is a clinical need for accurate intraoperative tumor and sentinel lymph node visualization. Conventional imaging modalities such as x-ray computed tomography, positron emission tomography, magnetic resonance imaging, and ultrasound are excellent for preoperative cancer diagnosis and surgical planning. However, they are not suitable for intraoperative use, due to bulky complicated hardware, high cost, non-real-time imaging, severe restrictions to the surgical workflow and lack of sufficient resolution for tumor boundary assessment. This has propelled interest in fluorescence-guided surgery, due to availability of simple hardware that can achieve real-time, high resolution and sensitive imaging. Near-infrared fluorescence imaging is of particular interest due to low background absorbance by photoactive biomolecules, enabling thick tissue assessment. As a result several near-infrared fluorescence-guided surgery systems have been developed. However, they are limited by bulky hardware, disruptive information display and non-matched field of view to the user. To address these limitations we have developed a compact, light-weight and wearable goggle augmented imaging and navigation system (GAINS). It detects the near-infrared fluorescence from a tumor accumulated contrast agent, along with the normal color view and displays accurately aligned, color-fluorescence images via a head-mounted display worn by the surgeon, in real-time. GAINS is a platform technology and capable of very sensitive fluorescence detection. Image display options include both video see-through and optical see-through head-mounted displays for high-contrast image guidance as well as direct visual access to the surgical bed. Image capture options from large field of view camera as well high magnification handheld microscope, ensures macroscopic as well as microscopic assessment of the tumor bed. Aided by tumor targeted near-infrared contrast agents, GAINS guided complete tumor resection in subcutaneous, metastatic and spontaneous mouse models of cancer with high sensitivity and specificity, in real-time. Using a clinically-approved near-infrared contrast agent, GAINS provided real-time image guidance for accurate visualization of lymph nodes in a porcine model and sentinel lymph nodes in human breast cancer and melanoma patients with high sensitivity. This work has addressed issues that have limited clinical adoption of fluorescence-guided surgery and paved the way for research into developing this approach towards standard-of-care practice that can potentially improve surgical outcomes in cancer

Multimodal image-guided interventions using oncological biomarkers

This thesis consists of two parts addressing novel imaging technologies to improve the treatment of cancer patients. In part I, the additional value of real time image guidance during surgery is discussed and the research described in this part of the thesis showed that imaging performed during surgery can be of great value. Nevertheless, the success rate is highly dependent on the choice of imaging modality and biomarker to be targeted. In part II, a necrosis avid probe was successfully evaluated as novel method for early neoadjuvant treatment response monitoring.department of Radiology iThera Medical GmbH MiLabs ChipsoftLUMC / Geneeskund

Advances in Diagnostic and Intraoperative Molecular Imaging of Pancreatic Cancer

Surgical oncolog

Video-Rate Fluorescence Molecular Tomography for Hand-held and Multimodal Molecular Imaging

In the United States, cancer is the second leading cause of death following heart disease. Although, a variety of treatment regimens are available, cancer management is complicated by the complexity of the disease and the variability, between people, of disease progression and response to therapy. Therefore, advancements in the methods and technologies for cancer diagnosis, prognosis and therapeutic monitoring are critical to improving the treatment of cancer patients. The development of improved imaging methods for early diagnosis of cancer and of near real-time monitoring of tumor response to therapy may improve outcomes as well as the quality of life of cancer patients. In the last decade, imaging methods including ultrasound, computed tomography: CT), magnetic resonance imaging: MRI), single photon emission computed tomography: SPECT), and positron emission tomography: PET), have revolutionized oncology. More recently optical techniques, that have access to unique molecular reporting strategies and functional contrasts, show promise for oncologic imaging This dissertation focuses on the development and optimization of a fiber-based, video-rate fluorescence molecular tomography: FMT) instrument. Concurrent acquisition of fluorescence and reference signals allowed the efficient generation of ratio-metric data for 3D image reconstruction. Accurate depth localization and high sensitivity to fluorescent targets were established to depths of \u3e10 mm. In vivo accumulation of indocyanine green dye was imaged in the region of the sentinel lymph node: SLN) following intradermal injection into the forepaw of rats. These results suggest that video-rate FMT has potential as a clinical tool for noninvasive mapping of SLN. Spatial and temporal co-registration of nuclear and optical images can enable the fusion of the information from these complementary molecular imaging modalities. A critical challenge is in integrating the optical and nuclear imaging hardware. Flexible fiber-based FMT systems provide a viable solution. The various imaging bore sizes of small animal nuclear imaging systems can potentially accommodate the FMT fiber imaging arrays. In addition FMT imaging facilitates co-registering the nuclear and optical contrasts in time. In this dissertation, the feasibility of integrating the fiber-based, video-rate FMT system with a commercial preclinical NanoSPECT/CT platform was established. Feasibility of in vivo imaging is demonstrated by tracking a monomolecular multimodal-imaging agent: MOMIA) during transport from the forepaw to the axillary lymph nodes region of a rat. These co-registered FMT/SPECT/CT imaging results with MOMIAs may facilitate the development of the next generation preclinical and clinical multimodal optical-nuclear platforms for a broad array of imaging applications, and help elucidate the underlying biological processes relevant to cancer diagnosis and therapy monitoring. Finally, I demonstrated that video-rate FMT is sufficiently fast to enable imaging of cardiac, respiratory and pharmacokinetic induced dynamic fluorescent signals. From these measurements, the image-derived input function and the real-time uptake of injected agents can be deduced for pharmacokinetic analysis of fluorescing agents. In a study comparing normal mice against mice liver disease, we developed anatomically guided dynamic FMT in conjunction with tracer kinetic modeling to quantify uptake rates of fluorescing agents. This work establishes fiber-based, video-rate FMT system as a practical and powerful tool that is well suited to a broad array of potential imaging applications, ranging from early disease detection, quantifying physiology and monitoring progression of disease and therapies

Diagnostic and intraoperative targeted molecular imaging for pancreatic cancer

For years, pancreatic cancer had a dismal prognosis with a long term survival of around 5%. Since the centralization of pancreatic cancer surgery and the introduction of systemic chemotherapy with FOLFIRINOX, the median overall survival increased to around 20%. Radical tumor-margin free resection provides the patient with the best potential chance for cure. However, due to late onset of symptoms, the majority of patients present with inoperable disease. These patients can benefit from neoadjuvant therapy, or palliative chemotherapy. During clinical practice, this means that decision-making before and during surgery is critical to select the most optimal primary treatment modality. Currently, conventional imaging modalities lack sensitivity to detect small metastatic lesions, and are unable to visualize treatment response on neoadjuvant therapy. Tumor-specific molecular imaging in the form of fluorescence and photoacoustic imaging aids the surgeon to accurately recognize and resect malignant tissues in real-time during surgery. This thesis focuses on the challenges a surgeon faces during pancreatic cancer treatment, and the potential improvements that could be achieved by the use of tumor-specific imaging. In addition, the regulatory aspects of clinical translation of tumor-specific optical imaging agents are addressed. Intuitive Surgical, Inc. LI-COR Biosciences, Surgvision, Quest Medical Imaging, LUMC, MSB Gouda, Chipsoft, Curadel, Groene Hart ZiekenhuisLUMC / Geneeskund

A Genetically-Encoded Reporter for In Vivo Imaging in Deep Tissues

Introduction. The ability to track cells in living organisms with sensitivity, accuracy and high spatial resolution would revolutionize the way we study disease. Reporter genes are valuable tools as they encode detectible products, allowing for quantitative “reporting” of cells that express them. Previously, a gene encoding Organic anion-transporting polypeptide 1a1 (Oatp1a1) was established as a magnetic resonance imaging (MRI) reporter based on its ability to take up the paramagnetic contrast agent gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA). Our objective was to assess, characterize and further develop this system for whole-body tracking of cells in vivo. Methods. Cancer cells were engineered to synthetically express Oatp1a1, or Oatp1b3, a closely related human transporter protein. In our first study, T1-weighted images of Oatp1a1-expressing primary tumours in preclinical animals were acquired before and after administration of 0.1-mmol/kg Gd-EOB-DTPA at 3-Tesla. At endpoint, heterogenous contrast enhancement patterns within the primary tumour architecture were compared to whole-tumour fluorescent histology. In the next study, T1-weighted images of Oatp1b3-expressing primary tumours, and their spontaneous metastases to the lymph nodes and lungs, were acquired before and after administration of 1-mmol/kg Gd-EOB-DTPA at 3-Tesla. In the final study, the feasibility of Oatp1b3 as a photoacoustic reporter gene was assessed by acquiring full-spectrum near infrared photoacoustic images of primary tumours in preclinical animals before and after administration of 8-mg/kg indocyanine green. Results. We were able to demonstrate the feasibility of imaging cancer cells with Oatp1a1 at 3-Tesla and 0.1 mmol/kg Gd-EOB-DTPA. Importantly, as primary tumours grew over time, heterogeneous contrast enhancement patterns that emerged near-endpoint strongly correlated to viable cell distributions on whole-tumour histology. Oatp1b3 was also shown to operate as a MRI reporter gene at 3-Tesla, based on the same principle as Oatp1a1. Impressively, single lymph node metastases and the formation of micrometastases in the lungs of preclinical animals were detected with Oatp1b3-MRI. Finally, we also demonstrated the ability of Oatp1b3 to operate as a photoacoustic reporter gene based on its ability to take up indocyanine green. Conclusion. The Oatp1 reporter gene system is a versatile imaging tool for longitudinal tracking of engineered cells in vivo with sensitivity, high resolution, and 3-dimensional spatial information