1
|
Arias A, Anastasopoulou M, Gorpas D, Ntziachristos V. Using reflectometry to minimize the dependence of fluorescence intensity on optical absorption and scattering. BIOMEDICAL OPTICS EXPRESS 2023; 14:5499-5511. [PMID: 37854563 PMCID: PMC10581795 DOI: 10.1364/boe.496599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 09/11/2023] [Indexed: 10/20/2023]
Abstract
The total diffuse reflectance RT and the effective attenuation coefficient µeff of an optically diffuse medium map uniquely onto its absorption and reduced scattering coefficients. Using this premise, we developed a methodology where RT and the slope of the logarithmic spatially resolved reflectance, a quantity related to µeff, are the inputs of a look-up table to correct the dependence of fluorescent signals on the media's optical properties. This methodology does not require an estimation of the medium's optical property, avoiding elaborate simulations and their errors to offer accurate and fast corrections. The experimental demonstration of our method yielded a mean relative error in fluorophore concentrations of less than 4% over a wide range of optical property variations. We discuss how the method developed can be employed to improve image fidelity and fluorochrome quantification in fluorescence molecular imaging clinical applications.
Collapse
Affiliation(s)
- Augusto Arias
- Chair of Biological Imaging at the Central Institute for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, 81675, Germany
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, 85764, Germany
| | - Maria Anastasopoulou
- Chair of Biological Imaging at the Central Institute for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, 81675, Germany
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, 85764, Germany
| | - Dimitris Gorpas
- Chair of Biological Imaging at the Central Institute for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, 81675, Germany
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, 85764, Germany
| | - Vasilis Ntziachristos
- Chair of Biological Imaging at the Central Institute for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, 81675, Germany
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, 85764, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, 81675, Germany
| |
Collapse
|
2
|
Abstract
The present chapter summarizes progress with optical methods that go beyond human vision. The focus is on two particular technologies: fluorescence molecular imaging and optoacoustic (photoacoustic) imaging. The rationale for the selection of these two methods is that in contrast to optical microscopy techniques, both fluorescence and optoacoustic imaging can achieve large fields of view, i.e., spanning several centimeters in two or three dimensions. Such fields of views relate better to human vision and can visualize large parts of tissue, a necessary premise for clinical detection. Conversely, optical microscopy methods only scan millimeter-sized dimensions or smaller. With such operational capacity, optical microscopy methods need to be guided by another visualization technique in order to scan a very specific area in tissue and typically only provide superficial measurements, i.e., information from depths that are of the order of 0.05-1 mm. This practice has generally limited their clinical applicability to some niche applications, such as optical coherence tomography of the retina. On the other hand, fluorescence molecular imaging and optoacoustic imaging emerge as more global optical imaging methods with wide applications in surgery, endoscopy, and non-invasive clinical imaging, as summarized in the following. The current progress in this field is based on a volume of recent review and other literature that highlights key advances achieved in technology and biomedical applications. Context and figures from references from the authors of this chapter have been used here, as it reflects our general view of the current status of the field.
Collapse
Affiliation(s)
- Daniel Razansky
- Faculty of Medicine and Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Department of Information Technology and Electrical Engineering, Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland
| | - Vasilis Ntziachristos
- Technical University of Munich, Ismaningerstr. 22, 81675, Munich, Germany.
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany.
| |
Collapse
|
3
|
Non-destructive evaluation of watermelon seeds germination by using Delayed Luminescence. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2018; 187:126-130. [PMID: 30145462 DOI: 10.1016/j.jphotobiol.2018.08.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/06/2018] [Accepted: 08/13/2018] [Indexed: 11/21/2022]
Abstract
The evaluation of optical properties of biological samples is gaining increasing interests both in scientific and commercial fields concerning agriculture and food processing. The optical techniques can indeed be able to provide information on quality assessment in a fast and non-destructive way. This feature makes them suitable for automatic management of control processes. In this paper, we propose to use the Delayed Luminescence, a ultra-weak and photo-induced emission of optical photons, as a tool for a rapid evaluation of germination performance, the principal index reflecting seed quality. Two lots of 'Mirella' F1 watermelon dried seeds, of 96 seeds each, were considered. The seeds were analyzed in the conditions as provided by seed/breeding company. Characteristics of Delayed Luminescence emission from each single seed were correlated to the different germination levels as assessed by International Seed Testing Procedures. Parametric differences in the two lots were determined, based on the relaxation kinetics of some spectral components. A control test, with the aim to construct a calibration model, was conceived and successfully tested. Time decays of Delayed Luminescence spectral components at central wavelengths 450 nm, 550 nm and 650 nm, corresponding to spectrum region where natural biomarkers as NADH, flavins and lipopigments, protoporphyrin and ROS respectively emit, have been evaluated. The results show that such time decays are strictly connected to the biological state of the system under analysis and allow also proposing Delayed Luminescence measurement as a quick, cheap and non-destructive test for seed viability analysis.
Collapse
|
4
|
Huang Z, Shi S, Qiu H, Li D, Zou J, Hu S. Fluorescence-guided resection of brain tumor: review of the significance of intraoperative quantification of protoporphyrin IX fluorescence. NEUROPHOTONICS 2017; 4:011011. [PMID: 28097209 PMCID: PMC5227178 DOI: 10.1117/1.nph.4.1.011011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 12/20/2016] [Indexed: 05/07/2023]
Abstract
Surgical removal of tumor mass is a common approach in the management of brain tumors. However, the precise delineation of normal tissue from tumor tissue for a complete resection of tumor mass in brain tumor surgery remains a difficult task for neurosurgeons. Aminolevulinic acid (ALA)-mediated exgogenous fluorescence of protoporphyrin IX (PpIX) is a sensitive approach for tumor imaging. Recent studies suggest that the use of ALA/PpIX-mediated fluorescence-guided resection (FGR) or fluorescence-guided surgery can enable more accurate and complete resection of brain tumors, especially when used in quantitative fashion. This review will highlight the current progress in PpIX-mediated FGR and discuss technical challenges in intraoperative quantification of intracellular PpIX fluorescence during FGR of brain tumor.
Collapse
Affiliation(s)
- Zheng Huang
- Fujian Normal University, MOE Key Laboratory of OptoElectronic Science and Technology for Medicine, 8 Shangsan Road, Fuzhou 350007, China
- Address all correspondence to: Zheng Huang, E-mail:
| | - Songsheng Shi
- Fujian Medical University, Union Hospital, Department of Neurosurgery, 29 Xinquan Road, Fuzhou 350001, China
| | - Haixia Qiu
- Chinese PLA General Hospital, Department of Laser Medicine, 28 Fuxing Road, Beijing 100039, China
| | - Desheng Li
- Affiliated Hospital of Academy of Military Medical Sciences, Department of Neurosurgery, 8 Dongda Avenue, Beijing 100071, China
| | - Jian Zou
- Fujian Normal University, MOE Key Laboratory of OptoElectronic Science and Technology for Medicine, 8 Shangsan Road, Fuzhou 350007, China
| | - Shaoshan Hu
- The Second Affiliated Hospital of Harbin Medical University, Department of Neurosurgery, 246 Xuefu Road, Harbin 150001, China
| |
Collapse
|
5
|
Xie H, Svenmarker P, Axelsson J, Gräfe S, Kyriazi M, Bendsoe N, Andersson-Engels S, Svanberg K. Pharmacokinetic and biodistribution study following systemic administration of Fospeg®--a Pegylated liposomal mTHPC formulation in a murine model. JOURNAL OF BIOPHOTONICS 2015; 8:142-152. [PMID: 24375973 DOI: 10.1002/jbio.201300133] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 11/01/2013] [Accepted: 11/15/2013] [Indexed: 06/03/2023]
Abstract
Fospeg® is a newly developed photosensitizer formulation based on meso-tetra(hydroxyphenyl)chlorin (mTHPC), with hydrophilic liposomes to carry the hydrophobic photosensitizer to the target tissue. In this study the pharmacokinetics and biodistribution of Fospeg® were investigated by high performance liquid chromatography at various times (0.5-18 hours) following systemic i.v. administration. As a model an experimental HT29 colon tumor in NMRI nu/nu mice was employed. Our study indicates a higher plasma peak concentration, a longer circulation time and a better tumor-to-skin ratio than those of Foslip®, another liposomal mTHPC formulation. Data from ex vivo tissue fluorescence and reflectance imaging exhibit good correlation with chemical extraction. Our results have shown that optical imaging provides the potential for fluorophore quantification in biological tissues.
Collapse
Affiliation(s)
- Haiyan Xie
- Department of Physics, Lund University, P.O. Box 118, 22100, Lund, Sweden.
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Quantitative detection of drug dose and spatial distribution in the lung revealed by Cryoslicing Imaging. J Pharm Biomed Anal 2015; 102:129-36. [DOI: 10.1016/j.jpba.2014.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 08/06/2014] [Accepted: 09/01/2014] [Indexed: 12/21/2022]
|
7
|
Singh S, Nagpal R, Manuja N, Tyagi SP. Photodynamic therapy: An adjunct to conventional root canal disinfection strategies. AUST ENDOD J 2014; 41:54-71. [PMID: 25404404 DOI: 10.1111/aej.12088] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Although chemical-based root canal disinfectants are important to reduce microbial loads and remove infected smear layer from root dentin, they have only a limited ability to eliminate biofilm bacteria, especially from root complexities. This paper explores the novel photodynamic therapy (PDT) for antimicrobial disinfection of root canals. The combination of an effective photosensitizer, the appropriate wavelength of light and ambient oxygen is the key factor in PDT. PDT uses a specific wavelength of light to activate a non-toxic dye (photosensitizer), leading to the formation of reactive oxygen species. These reactive oxygen molecules can damage bacterial proteins, membrane lipids and nucleic acids, which promote bacterial cell death. In, addition PDT may enhance cross-linking of collagen fibrils in the dentin matrix and thereby improving dentin stability. The concept of PDT is plausible and could foster new therapy concepts for endodontics. The available knowledge should enable and encourage steps forward into more clinical-oriented research and development. This article discusses PDT as related to root canal disinfection, including its components, mechanism of action, reviews the current endodontic literature and also highlights the shortcomings and advancements in PDT techniques.
Collapse
Affiliation(s)
- Shipra Singh
- Department of Conservative Dentistry and Endodontics, Kothiwal Dental College and Research Centre, Moradabad, India
| | - Rajni Nagpal
- Department of Conservative Dentistry and Endodontics, Kothiwal Dental College and Research Centre, Moradabad, India
| | - Naveen Manuja
- Department of Pediatric Dentistry, Kothiwal Dental College and Research Centre, Moradabad, India
| | - Sashi Prabha Tyagi
- Department of Conservative Dentistry and Endodontics, Kothiwal Dental College and Research Centre, Moradabad, India
| |
Collapse
|
8
|
Yang C, Hou VW, Girard EJ, Nelson LY, Seibel EJ. Target-to-background enhancement in multispectral endoscopy with background autofluorescence mitigation for quantitative molecular imaging. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:76014. [PMID: 25027002 PMCID: PMC4098034 DOI: 10.1117/1.jbo.19.7.076014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 06/25/2014] [Indexed: 05/05/2023]
Abstract
Fluorescence molecular imaging with exogenous probes improves specificity for the detection of diseased tissues by targeting unambiguous molecular signatures. Additionally, increased diagnostic sensitivity is expected with the application of multiple molecular probes. We developed a real-time multispectral fluorescence-reflectance scanning fiber endoscope (SFE) for wide-field molecular imaging of fluorescent dye-labeled molecular probes at nanomolar detection levels. Concurrent multichannel imaging with the wide-field SFE also allows for real-time mitigation of the background autofluorescence (AF) signal, especially when fluorescein, a U.S. Food and Drug Administration approved dye, is used as the target fluorophore. Quantitative tissue AF was measured for the ex vivo porcine esophagus and murine brain tissues across the visible and nearinfrared spectra. AF signals were then transferred to the unit of targeted fluorophore concentration to evaluate the SFE detection sensitivity for sodium fluorescein and cyanine. Next, we demonstrated a real-time AF mitigation algorithm on a tissue phantom, which featured molecular probe targeted cells of high-grade dysplasia on a substrate containing AF species. The target-to-background ratio was enhanced by more than one order of magnitude when applying the real-time AF mitigation algorithm. Furthermore, a quantitative estimate of the fluorescein photodegradation (photobleaching) rate was evaluated and shown to be insignificant under the illumination conditions of SFE. In summary, the multichannel laser-based flexible SFE has demonstrated the capability to provide sufficient detection sensitivity, image contrast, and quantitative target intensity information for detecting small precancerous lesions in vivo.
Collapse
Affiliation(s)
- Chenying Yang
- University of Washington, Department of Bioengineering, Seattle, Washington 98195, United States
| | - Vivian W. Hou
- University of Washington, Department of Biology, Seattle, Washington 98195, United States
| | - Emily J. Girard
- Fred Hutchinson Cancer Research Center, Clinical Research Division, Seattle, Washington 98109, United States
| | - Leonard Y. Nelson
- University of Washington, Department of Mechanical Engineering, Seattle, Washington 98195, United States
| | - Eric J. Seibel
- University of Washington, Department of Mechanical Engineering, Seattle, Washington 98195, United States
- Address all correspondence to: Eric J. Seibel,
| |
Collapse
|
9
|
Keereweer S, Van Driel PBAA, Snoeks TJA, Kerrebijn JDF, Baatenburg de Jong RJ, Vahrmeijer AL, Sterenborg HJCM, Löwik CWGM. Optical image-guided cancer surgery: challenges and limitations. Clin Cancer Res 2013; 19:3745-54. [PMID: 23674494 DOI: 10.1158/1078-0432.ccr-12-3598] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Optical image-guided cancer surgery is a promising technique to adequately determine tumor margins by tumor-specific targeting, potentially resulting in complete resection of tumor tissue with improved survival. However, identification of the photons coming from the fluorescent contrast agent is complicated by autofluorescence, optical tissue properties, and accurate fluorescent targeting agents and imaging systems. All these factors have an important influence on the image that is presented to the surgeon. Considering the clinical consequences at stake, it is a prerequisite to answer the questions that are essential for the surgeon. What is optical image-guided surgery and how can it improve patient care? What should the oncologic surgeon know about the fundamental principles of optical imaging to understand which conclusions can be drawn from the images? And how do the limitations influence clinical decision making? This article discusses these questions and provides a clear overview of the basic principles and practical applications. Although there are limitations to the intrinsic capacity of the technique, when practical and technical surgical possibilities are considered, optical imaging can be a very powerful intraoperative tool in guiding the future oncologic surgeon toward radical resection and optimal clinical results.
Collapse
Affiliation(s)
- Stijn Keereweer
- Department of Otorhinolaryngology Head and Neck Surgery; Center of Optical Diagnostics and Therapy, Erasmus Medical Center, Rotterdam, the Netherlands.
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Liu L, Nie Y, Lin L, Li W, Huang Z, Xie S, Li B. Pattern recognition of multiple excitation autofluorescence spectra for colon tissue classification. Photodiagnosis Photodyn Ther 2013; 10:111-9. [DOI: 10.1016/j.pdpdt.2012.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 07/20/2012] [Accepted: 07/23/2012] [Indexed: 10/28/2022]
|
11
|
Saager RB, Cuccia DJ, Saggese S, Kelly KM, Durkin AJ. Quantitative fluorescence imaging of protoporphyrin IX through determination of tissue optical properties in the spatial frequency domain. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:126013. [PMID: 22191930 PMCID: PMC3253591 DOI: 10.1117/1.3665440] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 11/09/2011] [Accepted: 11/10/2011] [Indexed: 05/17/2023]
Abstract
The ability to quantitatively determine tissue fluorescence is of interest for the purpose of better understanding the details of photodynamic therapy of skin cancer. In particular, we are interested in quantifying protoporphyrin IX (PpIX) in vivo. We present a method of correcting fluorescence for effects of native tissue absorption and scattering properties in a spatially resolved manner that preserves the resolution of the fluorescence imaging system, based off a homogeneous representation of tissue. Validation was performed using a series of liquid turbid phantoms having varying concentrations of absorber, scatterer, and fluorophore (PpIX). Through the quantification of tissue optical properties via spatial frequency domain imaging, an empirical model based on Monte Carlo simulations was deployed to successfully decouple the effects of absorption and scattering from fluorescence. From this we were able to deduce the concentration of the PpIX to within 0.2 μg/ml of the known concentration. This method was subsequently applied to the determination of PpIX concentration from in vivo normal skin where the model-based correction determined a concentration of 1.6 μg/ml, which is in agreement with literature.
Collapse
Affiliation(s)
- Rolf B Saager
- University of California Irvine, Beckman Laser Institute, 1002 Health Sciences Road, Irvine, California 92612, USA.
| | | | | | | | | |
Collapse
|
12
|
Xie H, Liu H, Svenmarker P, Axelsson J, Xu CT, Gräfe S, Lundeman JH, Cheng HPH, Svanberg S, Bendsoe N, Andersen PE, Svanberg K, Andersson-Engels S. Drug quantification in turbid media by fluorescence imaging combined with light-absorption correction using white Monte Carlo simulations. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:066002. [PMID: 21721803 DOI: 10.1117/1.3585675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Accurate quantification of photosensitizers is in many cases a critical issue in photodynamic therapy. As a noninvasive and sensitive tool, fluorescence imaging has attracted particular interest for quantification in pre-clinical research. However, due to the absorption of excitation and emission light by turbid media, such as biological tissue, the detected fluorescence signal does not have a simple and unique dependence on the fluorophore concentration for different tissues, but depends in a complex way on other parameters as well. For this reason, little has been done on drug quantification in vivo by the fluorescence imaging technique. In this paper we present a novel approach to compensate for the light absorption in homogeneous turbid media both for the excitation and emission light, utilizing time-resolved fluorescence white Monte Carlo simulations combined with the Beer-Lambert law. This method shows that the corrected fluorescence intensity is almost proportional to the absolute fluorophore concentration. The results on controllable tissue phantoms and murine tissues are presented and show good correlations between the evaluated fluorescence intensities after the light-absorption correction and absolute fluorophore concentrations. These results suggest that the technique potentially provides the means to quantify the fluorophore concentration from fluorescence images.
Collapse
Affiliation(s)
- Haiyan Xie
- Lund University, Department of Physics, P.O. Box 118, SE-221 00, Lund, Sweden.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
In vivo quantification of photosensitizer fluorescence in the skin-fold observation chamber using dual-wavelength excitation and NIR imaging. Lasers Med Sci 2011; 26:789-801. [PMID: 21279401 PMCID: PMC3183248 DOI: 10.1007/s10103-011-0888-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Accepted: 01/05/2011] [Indexed: 10/24/2022]
Abstract
A major challenge in biomedical optics is the accurate quantification of in vivo fluorescence images. Fluorescence imaging is often used to determine the pharmacokinetics of photosensitizers used for photodynamic therapy. Often, however, this type of imaging does not take into account differences in and changes to tissue volume and optical properties of the tissue under interrogation. To address this problem, a ratiometric quantification method was developed and applied to monitor photosensitizer meso-tetra(hydroxyphenyl) chlorin (mTHPC) pharmacokinetics in the rat skin-fold observation chamber. The method employs a combination of dual-wavelength excitation and dual-wavelength detection. Excitation and detection wavelengths were selected in the NIR region. One excitation wavelength was chosen to be at the Q band of mTHPC, whereas the second excitation wavelength was close to its absorption minimum. Two fluorescence emission bands were used; one at the secondary fluorescence maximum of mTHPC centered on 720 nm, and one in a region of tissue autofluorescence. The first excitation wavelength was used to excite the mTHPC and autofluorescence and the second to excite only autofluorescence, so that this could be subtracted. Subsequently, the autofluorescence-corrected mTHPC image was divided by the autofluorescence signal to correct for variations in tissue optical properties. This correction algorithm in principle results in a linear relation between the corrected fluorescence and photosensitizer concentration. The limitations of the presented method and comparison with previously published and validated techniques are discussed.
Collapse
|
14
|
Non-homogeneous liver distribution of photosensitizer and its consequence for photodynamic therapy outcome. Photodiagnosis Photodyn Ther 2010; 7:189-200. [PMID: 20728844 DOI: 10.1016/j.pdpdt.2010.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 07/01/2010] [Accepted: 07/03/2010] [Indexed: 11/24/2022]
Abstract
BACKGROUND Photodynamic therapy is mainly used for treatment of malignant lesions, and is based on selective location of a photosensitizer in the tumor tissue, followed by light at wavelengths matching the photosensitizer absorption spectrum. In molecular oxygen presence, reactive oxygen species are generated, inducing cells to die. One of the limitations of photodynamic therapy is the variability of photosensitizer concentration observed in systemically photosensitized tissues, mainly due to differences of the tissue architecture, cell lines, and pharmacokinetics. This study aim was to demonstrate the spatial distribution of a hematoporphyrin derivative, Photogem, in the healthy liver tissue of Wistar rats via fluorescence spectroscopy, and to understand its implications on photodynamic response. METHODS Fifteen male Wistar rats were intravenously photosensitized with 1.5mg/kg body weight of Photogem. Laser-induced fluorescence spectroscopy at 532 nm-excitation was performed on ex vivo liver slices. The influence of photosensitizer surface distribution detected by fluorescence and the induced depth of necrosis were investigated in five animals. RESULTS Photosensitizer distribution on rat liver showed to be greatly non-homogeneous. This may affect photodynamic therapy response as shown in the results of depth of necrosis. CONCLUSIONS As a consequence of these results, this study suggests that photosensitizer surface spatial distribution should be taken into account in photodynamic therapy dosimetry, as this will help to better predict clinical results.
Collapse
|
15
|
Sunar U, Rohrbach D, Rigual N, Tracy E, Keymel K, Cooper MT, Baumann H, Henderson BH. Monitoring photobleaching and hemodynamic responses to HPPH-mediated photodynamic therapy of head and neck cancer: a case report. OPTICS EXPRESS 2010; 18:14969-78. [PMID: 20639983 PMCID: PMC2964147 DOI: 10.1364/oe.18.014969] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We present initial results obtained during the course of a Phase I clinical trial of 2-1[hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH)-mediated photo-dynamic therapy (PDT) in a head and neck cancer patient. We quantified blood flow, oxygenation and HPPH drug photobleaching before and after therapeutic light treatment by utilizing fast, non-invasive diffuse optical methods. Our results showed that HPPH-PDT induced significant drug photobleaching, and reduction in blood flow and oxygenation suggesting significant vascular and cellular reaction. These changes were accompanied by cross-linking of the signal transducer and activator of transcription 3 (STAT3), a molecular measure for the oxidative photoreaction. These preliminary results suggest diffuse optical spectroscopies permit non-invasive monitoring of PDT in clinical settings of head and neck cancer patients.
Collapse
Affiliation(s)
- Ulas Sunar
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, NY, 14263, USA.
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Tyrrell J, Campbell S, Curnow A. Validation of a non-invasive fluorescence imaging system to monitor dermatological PDT. Photodiagnosis Photodyn Ther 2010; 7:86-97. [DOI: 10.1016/j.pdpdt.2010.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 03/09/2010] [Accepted: 03/14/2010] [Indexed: 12/29/2022]
|
17
|
Abstract
A 3-chip CCD imaging system has been developed for quantitative in vivo fluorescence imaging. This incorporates a ratiometric algorithm to correct for the effects of tissue optical absorption and scattering, imaging “geometry” and tissue autofluorescence background. The performance was characterized, and the algorithm was validated in tissue-simulating optical phantoms for quantitative measurement of the fluorescent molecule protoporphyrin IX (PpIX). The technical feasibility to use this system for fluorescence-guided surgical resection of malignant brain tumor tissue was assessed in an animal model in which PpIX was induced exogenously in the tumor cells by systemic administration of aminolevulinic acid (ALA).
Collapse
|
18
|
Bogaards A, Sterenborg HJCM, Trachtenberg J, Wilson BC, Lilge L. In vivo quantification of fluorescent molecular markers in real-time by ratio imaging for diagnostic screening and image-guided surgery. Lasers Surg Med 2008; 39:605-13. [PMID: 17868102 DOI: 10.1002/lsm.20525] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Future applications of "molecular diagnostic screening" and "molecular image-guided surgery" will demand images of molecular markers with high resolution and high throughput (~ > or =30 frames/second). MRI, SPECT, PET, optical fluorescence tomography, hyper-spectral fluorescence imaging, and bioluminescence imaging do not offer such high frame rates. 2D optical fluorescence imaging can provide surface images with high resolution and high throughput. The ability to accurately quantify the fluorescence in vivo is critical to extract functional information of the disease state, however few methods are available. Here, a ratiometric 2D quantification method is introduced. Through mathematical modeling the performance was evaluated using optical properties that resembled biological tissues with the fluorescent marker Protoporhyrin IX. Experimentally the performance was evaluated in optical phantoms with different optical properties employing a novel prototype clinical imaging system. The clinical feasibility of real-time, image-guided surgery was demonstrated in patients undergoing prostatectomy. Discussed are the reasons why the introduced method leads to an increased quantification performance followed by modifications so it can be applied to novel fluorescent molecular markers as phthalocyanine 4 and dual-fluorescent markers. These offer additional advantages as these can provide a linear response to marker concentration and further minimize the dependence on autofluorescence and optical properties, as demonstrated through modeling.
Collapse
Affiliation(s)
- A Bogaards
- University Health Network, Division of Biophysics and Bioimaging, Toronto, Ontario, Canada.
| | | | | | | | | |
Collapse
|