validation of a real-time multispectral endoscopic system for the detection and biopsy of bladder tumors.

Background: Real-time multispectral imaging (rMSI) simultaneously provides white light (WL), photodynamic diagnosis (PDD) images, and a real-time fusion of both. It may improve the detection of bladder tumors. However, rMSI has not been used for transurethral biopsy or resection so far.

Multiparametric Cystoscopy for Detection of Bladder Cancer Using Real-time Multispectral Imaging.

Background: Various imaging modalities can be used in addition to white light (WL) to improve detection of bladder cancer (BC).

Objective: To use real-time multispectral imaging (rMSI) during urethrocystoscopy to combine different imaging modalities to achieve multiparametric cystoscopy (MPC).

Design, Setting, And Participants: The rMSI system consisted of a camera with a spectral filter, a multi-LED light source, a microcontroller, and a computer for display and data acquisition.

Spectral and temporal multiplexing for multispectral fluorescence and reflectance imaging using two color sensors.

Fluorescence imaging can reveal functional, anatomical or pathological features of high interest in medical interventions. We present a novel method to record and display in video rate multispectral color and fluorescence images over the visible and near infrared range. The fast acquisition in multiple channels is achieved through a combination of spectral and temporal multiplexing in a system with two standard color sensors.

Simultaneous real-time multicomponent fluorescence and reflectance imaging method for fluorescence-guided surgery.

Fluorescence-guided surgical procedures are employed in an increasing number of applications such as tumor delineation, blood perfusion, and sentinel lymph node detection. A new generation of fluorescent probes is expected to increase the number of applications and improve efficiency. Yet, there are no available imaging methods to take full advantage of the forthcoming targeting technologies.

Effects of multispectral excitation on the sensitivity of molecular optoacoustic imaging.

Molecular optoacoustic (photoacoustic) imaging typically relies on the spectral identification of absorption signatures from molecules of interest. To achieve this, two or more excitation wavelengths are employed to sequentially illuminate tissue. Due to depth-related spectral dependencies and detection related effects, the multispectral optoacoustic tomography (MSOT) spectral unmixing problem presents a complex non-linear inversion operation.

Usefulness of a Darwinian system in a biotechnological application: evolution of optical window fluorescent protein variants under selective pressure.

With rare exceptions, natural evolution is an extremely slow process. One particularly striking exception in the case of protein evolution is in the natural production of antibodies. Developing B cells activate and diversify their immunoglobulin (Ig) genes by recombination, gene conversion (GC) and somatic hypermutation (SHM).

Deep-tissue reporter-gene imaging with fluorescence and optoacoustic tomography: a performance overview.

Purpose: A primary enabling feature of near-infrared fluorescent proteins (FPs) and fluorescent probes is the ability to visualize deeper in tissues than in the visible. The purpose of this work is to find which is the optimal visualization method that can exploit the advantages of this novel class of FPs in full-scale pre-clinical molecular imaging studies.

Procedures: Nude mice were stereotactically implanted with near-infrared FP expressing glioma cells to from brain tumors.

Fluorescence background subtraction technique for hybrid fluorescence molecular tomography/x-ray computed tomography imaging of a mouse model of early stage lung cancer.

The ability to visualize early stage lung cancer is important in the study of biomarkers and targeting agents that could lead to earlier diagnosis. The recent development of hybrid free-space 360-deg fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) imaging yields a superior optical imaging modality for three-dimensional small animal fluorescence imaging over stand-alone optical systems. Imaging accuracy was improved by using XCT information in the fluorescence reconstruction method.

Fluorescence molecular tomography of brain tumors in mice.

Fluorescence molecular tomography of tissues is a method that three-dimensionally resolves fluorescence biodistribution in vivo, with applications in small-animal research and pre-clinical diagnostics. There are many alternative imaging geometries in optical tomographic experimental systems, but in general, all imaging setups consist of four subsystems: illumination, animal mount, imaging, and automation and data acquisition (i.e.

Vaccinia virus-mediated melanin production allows MR and optoacoustic deep tissue imaging and laser-induced thermotherapy of cancer.

We reported earlier the delivery of antiangiogenic single chain antibodies by using oncolytic vaccinia virus strains to enhance their therapeutic efficacy. Here, we provide evidence that gene-evoked production of melanin can be used as a therapeutic and diagnostic mediator, as exemplified by insertion of only one or two genes into the genome of an oncolytic vaccinia virus strain. We found that produced melanin is an excellent reporter for optical imaging without addition of substrate.

In vivo frequency domain optoacoustic tomography.

Optoacoustic imaging has been primarily implemented in the time domain, i.e., using ultrashort nanosecond laser pulses for illumination.

Deep tissue optical and optoacoustic molecular imaging technologies for pre-clinical research and drug discovery.

For centuries, biological discoveries were based on optical imaging, in particular microscopy but also several chromophoric assays and photographic approaches. With the recent emergence of methods appropriate for bio-marker in vivo staining, such as bioluminescence, fluorescent molecular probes and proteins, as well as nanoparticle-based targeted agents, significant attention has been shifted toward in vivo interrogations of different dynamic biological processes at the molecular level. This progress has been largely supported by the development of advanced tomographic imaging technologies suitable for obtaining volumetric visualization of bio-marker distributions in small animals at a whole-body or whole-organ scale, an imaging frontier that is not accessible by the existing tissue-sectioning microscopic techniques due to intensive light scattering beyond the depth of a few hundred microns.

In vivo tomographic imaging of red-shifted fluorescent proteins.

We have developed a spectral inversion method for three-dimensional tomography of far-red and near-infrared fluorescent proteins in animals. The method was developed in particular to address the steep light absorption transition of hemoglobin from the visible to the far-red occurring around 600 nm. Using an orthotopic mouse model of brain tumors expressing the red-shifted fluorescent protein mCherry, we demonstrate significant improvements in imaging accuracy over single-wavelength whole body reconstructions.

Blind source unmixing in multi-spectral optoacoustic tomography.

Multispectral optoacoustic (photoacoustic) tomography (MSOT) is a hybrid modality that can image through several millimeters to centimeters of diffuse tissues, attaining resolutions typical of ultrasound imaging. The method can further identify tissue biomarkers by decomposing the spectral contributions of different photo-absorbing molecules of interest. In this work we investigate the performance of blind source unmixing methods and spectral fitting approaches in decomposing the contributions of fluorescent dyes from the tissue background, based on MSOT measurements in mice.

Gaussia luciferase variant for high-throughput functional screening applications.

Gaussia luciferase (Gluc) is a sensitive reporter for studying different biological processes such as gene expression, promoter activity, protein-protein interactions, signal transduction, as well as tumor cell growth and response to therapy. Since Gluc is naturally secreted, the kinetics of these processes can be monitored in real-time by measuring an aliquot of conditioned medium in culture or a few microliters of blood in vivo at different time points. Gluc catalyzes light emission with a short half-life which is unfavorable for certain applications.

In-vivo imaging of murine tumors using complete-angle projection fluorescence molecular tomography.

We interrogate the ability of free-space fluorescence tomography to image small animals in vivo using charge-coupled device (CCD) camera measurements over 360-deg noncontact projections. We demonstrate the performance of normalized dual-wavelength measurements that are essential for in-vivo use, as they account for the heterogeneous distribution of photons in tissue. In-vivo imaging is then showcased on mouse lung and brain tumors cross-validated by x-ray microcomputed tomography and histology.

Performance of the red-shifted fluorescent proteins in deep-tissue molecular imaging applications.

The discovery of new fluorescent proteins (FPs) that emit in the far-red part of the spectrum, where light absorption from tissue is significantly lower than in the visible, offers the possibility for noninvasive biological interrogation at the entire organ or small animal level in vivo. The performance of FPs in deep-tissue imaging depends not only on their optical characteristics, but also on the wavelength-dependent tissue absorption and the depth of the fluorescence activity. To determine the optimal choice of FP and illumination wavelength, we compared the performance of five of the most promising FPs: tdTomato, mCherry, mRaspberry, mPlum, and Katushka.