Molecular Imaging 

About: Molecular Imaging is an academic journal published by SAGE Publishing. The journal publishes majorly in the area(s): In vivo & Positron emission tomography. It has an ISSN identifier of 1535-3508. It is also open access. Over the lifetime, 688 publications have been published receiving 23513 citations.

AMIDE: a free software tool for multimodality medical image analysis.

Abstract: Amide's a Medical Image Data Examiner (AMIDE) has been developed as a user-friendly, open-source software tool for displaying and analyzing multimodality volumetric medical images. Central to the package's abilities to simultaneously display multiple data sets (e.g., PET, CT, MRI) and regions of interest is the on-demand data reslicing implemented within the program. Data sets can be freely shifted, rotated, viewed, and analyzed with the program automatically handling interpolation as needed from the original data. Validation has been performed by comparing the output of AMIDE with that of several existing software packages. AMIDE runs on UNIX, Macintosh OS X, and Microsoft Windows platforms, and it is freely available with source code under the terms of the GNU General Public License.

Image-Guided Surgery Using Invisible Near-Infrared Light: Fundamentals of Clinical Translation:

Abstract: The field of biomedical optics has matured rapidly over the last decade and is poised to make a significant impact on patient care. In particular, wide-field (typically > 5 cm), planar, near-infrared (NIR) fluorescence imaging has the potential to revolutionize human surgery by providing real-time image guidance to surgeons for tissue that needs to be resected, such as tumors, and tissue that needs to be avoided, such as blood vessels and nerves. However, to become a clinical reality, optimized imaging systems and NIR fluorescent contrast agents will be needed. In this review, we introduce the principles of NIR fluorescence imaging, analyze existing NIR fluorescence imaging systems, and discuss the key parameters that guide contrast agent development. We also introduce the complexities surrounding clinical translation using our experience with the Fluorescence-Assisted Resection and Exploration (FLARE™) imaging system as an example. Finally, we introduce state-of-the-art optical imaging techniques that might someday improve image-guided surgery even further.

Selection of Quantum Dot Wavelengths for Biomedical Assays and Imaging

Abstract: Fluorescent semiconductor nanocrystals (quantum dots [QDs]) are hypothesized to be excellent contrast agents for biomedical assays and imaging. A unique property of QDs is that their absorbance increases with increasing separation between excitation and emission wavelengths. Much of the enthusiasm for using QDs in vivo stems from this property, since photon yield should be proportional to the integral of the broadband absorption. In this study, we demonstrate that tissue scatter and absorbance can sometimes offset increasing QD absorption at bluer wavelengths, and counteract this potential advantage. By using a previously validated mathematical model, we explored the effects of tissue absorbance, tissue scatter, wavelength dependence of the scatter, water-to-hemoglobin ratio, and tissue thickness on QD performance. We conclude that when embedded in biological fluids and tissues, QD excitation wavelengths will often be quite constrained, and that excitation and emission wavelengths should be selected carefully based on the particular application. Based on our results, we produced near-infrared QDs optimized for imaging surface vasculature with white light excitation and a silicon CCD camera, and used them to image the coronary vasculature in vivo. Taken together, our data should prove useful in designing fluorescent QD contrast agents optimized for specific biomedical applications.

Toxicity of organic fluorophores used in molecular imaging: literature review.

Abstract: Fluorophores are potentially useful for in vivo cancer diagnosis. Using relatively inexpensive and portable equipment, optical imaging with fluorophores permits real-time detection of cancer. However, fluorophores can be toxic and must be investigated before they can be administered safely to patients. A review of published literature on the toxicity of 19 widely used fluorophores was conducted by searching 26 comprehensive biomedical and chemical literature databases and analyzing the retrieved material. These fluorophores included Alexa Fluor 488 and 514, BODIPY FL, BODIPY R6G, Cy 5.5, Cy 7, cypate, fluorescein, indocyanine green, Oregon green, 8-phenyl BODIPY, rhodamine 110, rhodamine 6G, rhodamine X, rhodol, TAMRA, Texas red, and Tokyo green. Information regarding cytotoxicity, tissue toxicity, in vivo toxicity, and mutagenicity was included. Considerable toxicity-related information was available for the Food and Drug Administration (FDA)-approved compounds indocyanine green and fluorescein, but published information on many of the non-FDA-approved fluorophores was limited. The information located was encouraging because the amounts of fluorophore used in molecular imaging probes are typically much lower than the toxic doses described in the literature. Ultimately, the most effective and appropriate probes for use in patients will be determined by their fluorescent characteristics and the safety of the conjugates.

Quantitative Comparison of the Sensitivity of Detection of Fluorescent and Bioluminescent Reporters in Animal Models

Abstract: Bioluminescent and fluorescent reporters are finding increased use in optical molecular imaging in small animals. In the work presented here, issues related to the sensitivity of in vivo detection are examined for standard reporters. A highsensitivity imaging system that can detect steady-state emission from both bioluminescent and fluorescent reporters is described. The instrument is absolutely calibrated so that animal images can be analyzed in physical units of radiance allowing more quantitative comparisons to be performed. Background emission from mouse tissue, called autoluminescence and autofluorescence, is measured and found to be an important limitation to detection sensitivity of reporters. Measurements of dual-labeled (bioluminescent/fluorescent) reporter systems, including PC-3M-luc/DsRed2-1 and HeLaluc/PKH26, are shown. The results indicate that although fluorescent signals are generally brighter than bioluminescent signals, the very low autoluminescent levels usually results in superior signal to background ratios for bioluminescent imaging, particularly compared with fluorescent imaging in the green to red part of the spectrum. Fluorescence detection sensitivity improves in the far-red to near-infrared, provided the animals are fed a low-chlorophyll diet to reduce autofluorescence in the intestinal region. The use of blue-shifted excitation filters is explored as a method to subtract out tissue autofluorescence and improve the sensitivity of fluorescent imaging. Mol Imaging (2004) 3, 9 – 23.