1
|
Zhang XU, van der Zee P, Atzeni I, Faber DJ, van Leeuwen TG, Sterenborg HJCM. Multidiameter single-fiber reflectance spectroscopy of heavily pigmented skin: modeling the inhomogeneous distribution of melanin. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-11. [PMID: 31820596 PMCID: PMC7006040 DOI: 10.1117/1.jbo.24.12.127001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 10/28/2019] [Indexed: 05/05/2023]
Abstract
When analyzing multidiameter single-fiber reflectance (MDSFR) spectra, the inhomogeneous distribution of melanin pigments in skin tissue is usually not accounted for. Especially in heavily pigmented skins, this can result in bad fits and biased estimation of tissue optical properties. A model is introduced to account for the inhomogeneous distribution of melanin pigments in skin tissue. In vivo visible MDSFR measurements were performed on heavily pigmented skin of type IV to VI. Skin tissue optical properties and related physiological properties were extracted from the measured spectra using the introduced model. The absorption of melanin pigments described by the introduced model demonstrates a good correlation with the co-localized measurement of the well-known melanin index.
Collapse
Affiliation(s)
- Xu U. Zhang
- Amsterdam UMC, University of Amsterdam, Department of Biomedical Engineering and Physics, Amsterdam, The Netherlands
- Amsterdam UMC, Cancer Center Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
- Address all correspondence to Xu U. Zhang, E-mail:
| | | | - Isabella Atzeni
- University of Groningen, University Medical Center Groningen, Division of Vascular Medicine, Department of Internal Medicine, Groningen, The Netherlands
| | - Dirk J. Faber
- Amsterdam UMC, University of Amsterdam, Department of Biomedical Engineering and Physics, Amsterdam, The Netherlands
- Amsterdam UMC, Cancer Center Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Ton G. van Leeuwen
- Amsterdam UMC, University of Amsterdam, Department of Biomedical Engineering and Physics, Amsterdam, The Netherlands
- Amsterdam UMC, Cancer Center Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Henricus J. C. M. Sterenborg
- Amsterdam UMC, University of Amsterdam, Department of Biomedical Engineering and Physics, Amsterdam, The Netherlands
- Amsterdam UMC, Cancer Center Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
- The Netherlands Cancer Institute, Department of Surgery, Amsterdam, The Netherlands
| |
Collapse
|
2
|
Makarov NS, Ramasamy K, Jackson A, Velarde A, Castaneda C, Archuleta N, Hebert D, Bergren MR, McDaniel H. Fiber-Coupled Luminescent Concentrators for Medical Diagnostics, Agriculture, and Telecommunications. ACS NANO 2019; 13:9112-9121. [PMID: 31291097 DOI: 10.1021/acsnano.9b03335] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
While luminescent concentrators (LCs) are mainly designed to harvest sunlight and convert its energy into electricity, the same concept can be advantageous in alternative applications. Examples of such applications are demonstrated here by coupling the edge-guided light of high-performance LCs based on CuInSexS2-x/ZnS quantum dots into optical fibers with emission covering visible-to-NIR spectral regions. In particular, a cost-efficient, miniature broadband light source for medical diagnostics, a spectral-conversion and light-guiding device for agriculture, and a large-area broadband tunable detector for telecommunications are demonstrated. Various design considerations and performance optimization approaches are discussed and summarized. Prototypes of the devices are manufactured and tested. Individual elements of the broadband light source show coupling efficiencies up to 1%, which is sufficient to saturate typical fiber-coupled spectrometers at a minimal integration time of 1 ms using 100 mW blue excitation. Agricultural devices are capable of delivering ∼10% of photosynthetically active radiation (per device) converted from absorbed sunlight to the lower canopy of plants, which boosted the tomato yield in a commercial greenhouse by 7% (fresh weight). Finally, large-scale prototype detectors can be used to discern time-modulated unfocused signals with an average power as low as 1 μW, which would be useful for free-space telecommunication systems. Fully optimized devices are expected to make significant impacts on speed and bandwidth of free-space telecommunication systems, medical diagnostics, and greenhouse crop yields.
Collapse
Affiliation(s)
| | | | - Aaron Jackson
- UbiQD, Inc. , Los Alamos , New Mexico 87544 , United States
| | - Andres Velarde
- UbiQD, Inc. , Los Alamos , New Mexico 87544 , United States
| | | | - Nic Archuleta
- UbiQD, Inc. , Los Alamos , New Mexico 87544 , United States
| | - Damon Hebert
- UbiQD, Inc. , Los Alamos , New Mexico 87544 , United States
| | | | | |
Collapse
|
3
|
Rohrbach DJ, Rigual N, Arshad H, Tracy EC, Cooper MT, Shafirstein G, Wilding G, Merzianu M, Baumann H, Henderson BW, Sunar U. Intraoperative optical assessment of photodynamic therapy response of superficial oral squamous cell carcinoma. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:18002. [PMID: 26780226 PMCID: PMC5996863 DOI: 10.1117/1.jbo.21.1.018002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 12/11/2015] [Indexed: 06/05/2023]
Abstract
This study investigated whether diffuse optical spectroscopy (DOS) measurements could assess clinical response to photodynamic therapy (PDT) in patients with head and neck squamous cell carcinoma (HNSCC). In addition, the correlation between parameters measured with DOS and the crosslinking of signal transducer and activator of transcription 3 (STAT3), a molecular marker for PDT-induced photoreaction, was investigated. Thirteen patients with early stage HNSCC received the photosensitizer 2-[1-hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH) and DOS measurements were performed before and after PDT in the operating room (OR). In addition, biopsies were acquired after PDT to assess the STAT3 crosslinking. Parameters measured with DOS, including blood volume fraction, blood oxygen saturation (StO2), HPPH concentration (cHPPH), HPPH fluorescence, and blood flow index (BFI), were compared to the pathologic response and the STAT3 crosslinking. The best individual predictor of pathological response was a change in cHPPH (sensitivity=60%, specificity=100%), while discrimination analysis using a two-parameter classifier (change in cHPPH and change in StO2) classified pathological response with 100% sensitivity and 100% specificity. BFI showed the best correlation with the crosslinking of STAT3. These results indicate that DOS-derived parameters can assess the clinical response in the OR, allowing for earlier reintervention if needed.
Collapse
Affiliation(s)
- Daniel J. Rohrbach
- Roswell Park Cancer Institute, Department of Cell Stress Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
- Wright State University, Department of Biomedical, Industrial and Human Factors Engineering, 207 Russ Center, Dayton, Ohio 45435, United States
| | - Nestor Rigual
- Roswell Park Cancer Institute, Department of Head and Neck Surgery, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Hassan Arshad
- Roswell Park Cancer Institute, Department of Head and Neck Surgery, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Erin C. Tracy
- Roswell Park Cancer Institute, Department of Cellular and Molecular Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Michelle T. Cooper
- Roswell Park Cancer Institute, Department of Cell Stress Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Gal Shafirstein
- Roswell Park Cancer Institute, Department of Cell Stress Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Gregory Wilding
- Roswell Park Cancer Institute, Department of Biostatistics and Bioinformatics, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Mihai Merzianu
- Roswell Park Cancer Institute, Department of Pathology and Laboratory Medicine, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Heinz Baumann
- Roswell Park Cancer Institute, Department of Cellular and Molecular Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Barbara W. Henderson
- Roswell Park Cancer Institute, Department of Cell Stress Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Ulas Sunar
- Roswell Park Cancer Institute, Department of Cell Stress Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
- Wright State University, Department of Biomedical, Industrial and Human Factors Engineering, 207 Russ Center, Dayton, Ohio 45435, United States
- State University of New York at Buffalo, Department of Biomedical Engineering, 332 Bonner Hall, Buffalo, New York 14228, United States
| |
Collapse
|
4
|
Nichols BS, Schindler CE, Brown JQ, Wilke LG, Mulvey CS, Krieger MS, Gallagher J, Geradts J, Greenup RA, Von Windheim JA, Ramanujam N. A Quantitative Diffuse Reflectance Imaging (QDRI) System for Comprehensive Surveillance of the Morphological Landscape in Breast Tumor Margins. PLoS One 2015; 10:e0127525. [PMID: 26076123 PMCID: PMC4468201 DOI: 10.1371/journal.pone.0127525] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 04/16/2015] [Indexed: 11/18/2022] Open
Abstract
In an ongoing effort to address the clear clinical unmet needs surrounding breast conserving surgery (BCS), our group has developed a next-generation multiplexed optical-fiber-based tool to assess breast tumor margin status during initial surgeries. Specifically detailed in this work is the performance and clinical validation of a research-grade intra-operative tool for margin assessment based on diffuse optical spectroscopy. Previous work published by our group has illustrated the proof-of-concept generations of this device; here we incorporate a highly optimized quantitative diffuse reflectance imaging (QDRI) system utilizing a wide-field (imaging area = 17cm2) 49-channel multiplexed fiber optic probe, a custom raster-scanning imaging platform, a custom dual-channel white LED source, and an astronomy grade imaging CCD and spectrograph. The system signal to noise ratio (SNR) was found to be greater than 40dB for all channels. Optical property estimation error was found to be less than 10%, on average, over a wide range of absorption (μa = 0–8.9cm-1) and scattering (μs’ = 7.0–9.7cm-1) coefficients. Very low inter-channel and CCD crosstalk was observed (2% max) when used on turbid media (including breast tissue). A raster-scanning mechanism was developed to achieve sub-pixel resolution and was found to be optimally performed at an upsample factor of 8, affording 0.75mm spatially resolved diffuse reflectance images (λ = 450–600nm) of an entire margin (area = 17cm2) in 13.8 minutes (1.23cm2/min). Moreover, controlled pressure application at the probe-tissue interface afforded by the imaging platform reduces repeated scan variability, providing <1% variation across repeated scans of clinical specimens. We demonstrate the clinical utility of this device through a pilot 20-patient study of high-resolution optical parameter maps of the ratio of the β-carotene concentration to the reduced scattering coefficient. An empirical cumulative distribution function (eCDF) analysis is used to reduce optical property maps to quantitative distributions representing the morphological landscape of breast tumor margins. The optimizations presented in this work provide an avenue to rapidly survey large tissue areas on intra-operative time scales with improved sensitivity to regions of focal disease that may otherwise be overlooked.
Collapse
Affiliation(s)
- Brandon S. Nichols
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
- * E-mail:
| | - Christine E. Schindler
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Jonathon Q. Brown
- Zenalux Biomedical, Research Triangle Park, NC, United States of America
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, United States of America
| | - Lee G. Wilke
- Department of Surgery, The University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Christine S. Mulvey
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Marlee S. Krieger
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
- Zenalux Biomedical, Research Triangle Park, NC, United States of America
| | - Jennifer Gallagher
- Department of Surgery, Duke University Medical Center, Durham, NC, United States of America
| | - Joseph Geradts
- Department of Pathology, Duke University Medical Center, Durham, NC, United States of America
| | - Rachel A. Greenup
- Department of Surgery, Duke University Medical Center, Durham, NC, United States of America
| | - Jesko A. Von Windheim
- Zenalux Biomedical, Research Triangle Park, NC, United States of America
- The Division of Environmental Sciences and Policy, Duke University, Durham, NC, United States of America
| | - Nirmala Ramanujam
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
- Zenalux Biomedical, Research Triangle Park, NC, United States of America
| |
Collapse
|
5
|
Correction for tissue optical properties enables quantitative skin fluorescence measurements using multi-diameter single fiber reflectance spectroscopy. J Dermatol Sci 2015; 79:64-73. [PMID: 25911633 DOI: 10.1016/j.jdermsci.2015.03.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 02/18/2015] [Accepted: 03/23/2015] [Indexed: 11/21/2022]
Abstract
BACKGROUND AND OBJECTIVE Fluorescence measurements in the skin are very much affected by absorption and scattering but existing methods to correct for this are not applicable to superficial skin measurements. STUDY DESIGN/MATERIALS AND METHODS The first use of multiple-diameter single fiber reflectance (MDSFR) and single fiber fluorescence (SFF) spectroscopy in human skin was investigated. MDSFR spectroscopy allows a quantification of the full optical properties in superficial skin (μa, μs' and γ), which can next be used to retrieve the corrected - intrinsic - fluorescence of a fluorophore Qμa,x(f). Our goal was to investigate the importance of such correction for individual patients. We studied this in 22 patients undergoing photodynamic therapy (PDT) for actinic keratosis. RESULTS The magnitude of correction of fluorescence was around 4 (for both autofluorescence and protoporphyrin IX). Moreover, it was variable between patients, but also within patients over the course of fractionated aminolevulinic acid PDT (range 2.7-7.5). Patients also varied in the amount of protoporphyrin IX synthesis, photobleaching percentages and resynthesis (>100× difference between the lowest and highest PpIX synthesis). The autofluorescence was lower in actinic keratosis than contralateral normal skin (0.0032 versus 0.0052; P<0.0005). CONCLUSIONS Our results clearly demonstrate the importance of correcting the measured fluorescence for optical properties, because these vary considerably between individual patients and also during PDT. Protoporphyrin IX synthesis and photobleaching kinetics allow monitoring clinical PDT which facilitates individual-based PDT dosing and improvement of clinical treatment protocols. Furthermore, the skin autofluorescence can be relevant for diagnostic use in the skin, but it may also be interesting because of its association with several internal diseases.
Collapse
|
6
|
Yohan D, Kim A, Korpela E, Liu S, Niu C, Wilson BC, Chin LCL. Quantitative monitoring of radiation induced skin toxicities in nude mice using optical biomarkers measured from diffuse optical reflectance spectroscopy. BIOMEDICAL OPTICS EXPRESS 2014; 5:1309-20. [PMID: 24876997 PMCID: PMC4026905 DOI: 10.1364/boe.5.001309] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/15/2013] [Accepted: 12/15/2013] [Indexed: 05/08/2023]
Abstract
Monitoring the onset of erythema following external beam radiation therapy has the potential to offer a means of managing skin toxicities via biological targeted agents - prior to full progression. However, current skin toxicity scoring systems are subjective and provide at best a qualitative evaluation. Here, we investigate the potential of diffuse optical spectroscopy (DOS) to provide quantitative metrics for scoring skin toxicity. A DOS fiberoptic reflectance probe was used to collect white light spectra at two probing depths using two short fixed source-collector pairs with optical probing depths sensitive to the skin surface. The acquired spectra were fit to a diffusion theory model of light transport in tissue to extract optical biomarkers (hemoglobin concentration, oxygen saturation, scattering power and slope) from superficial skin layers of nude mice, which were subjected to erythema inducing doses of ionizing radiation. A statistically significant increase in oxygenated hemoglobin (p < 0.0016) was found in the skin post-irradiation - confirming previous reports. More interesting, we observed for the first time that the spectral scattering parameters, A (p = 0.026) and k (p = 0.011), were an indicator of erythema at day 6 and could potentially serve as an early detection optical biomarker of skin toxicity. Our data suggests that reflectance DOS may be employed to provide quantitative assessment of skin toxicities following curative doses of external beam radiation.
Collapse
Affiliation(s)
- Darren Yohan
- Department of Physics, Ryerson University, Ontario, Canada
- These authors contributed equally to this work
| | - Anthony Kim
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre Canada
- These authors contributed equally to this work
| | - Elina Korpela
- Department of Medical Biophysics, University of Toronto and Ontario Cancer Institute / Campbell Family Institute for Cancer Research Canada
| | - Stanley Liu
- Department of Medical Biophysics, University of Toronto and Ontario Cancer Institute / Campbell Family Institute for Cancer Research Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - Carolyn Niu
- Department of Medical Biophysics, University of Toronto and Ontario Cancer Institute / Campbell Family Institute for Cancer Research Canada
| | - Brian C Wilson
- Department of Medical Biophysics, University of Toronto and Ontario Cancer Institute / Campbell Family Institute for Cancer Research Canada
| | - Lee CL Chin
- Department of Physics, Ryerson University, Ontario, Canada
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
7
|
Sunar U. Monitoring photodynamic therapy of head and neck malignancies with optical spectroscopies. World J Clin Cases 2013; 1:96-105. [PMID: 24303476 PMCID: PMC3845916 DOI: 10.12998/wjcc.v1.i3.96] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/02/2013] [Accepted: 05/08/2013] [Indexed: 02/05/2023] Open
Abstract
In recent years there has been significant developments in photosensitizers (PSs), light sources and light delivery systems that have allowed decreasing the treatment time and skin phototoxicity resulting in more frequent use of photodynamic therapy (PDT) in the clinical settings. Compared to standard treatment approaches such as chemo-radiation and surgery, PDT has much reduced morbidity for head and neck malignancies and is becoming an alternative treatment option. It can be used as an adjunct therapy to other treatment modalities without any additive cumulative side effects. Surface illumination can be an option for pre-malignant and early-stage malignancies while interstitial treatment is for debulking of thick tumors in the head and neck region. PDT can achieve equivalent or greater efficacy in treating head and neck malignancies, suggesting that it may be considered as a first line therapy in the future. Despite progressive development, clinical PDT needs improvement in several topics for wider acceptance including standardization of protocols that involve the same administrated light and PS doses and establishing quantitative tools for PDT dosimetry planning and response monitoring. Quantitative measures such as optical parameters, PS concentration, tissue oxygenation and blood flow are essential for accurate PDT dosimetry as well as PDT response monitoring and assessing therapy outcome. Unlike conventional imaging modalities like magnetic resonance imaging, novel optical imaging techniques can quantify PDT-related parameters without any contrast agent administration and enable real-time assessment during PDT for providing fast feedback to clinicians. Ongoing developments in optical imaging offer the promise of optimization of PDT protocols with improved outcomes.
Collapse
|
8
|
Rohrbach DJ, Rigual N, Tracy E, Kowalczewski A, Keymel KL, Cooper MT, Mo W, Baumann H, Henderson BW, Sunar U. Interlesion differences in the local photodynamic therapy response of oral cavity lesions assessed by diffuse optical spectroscopies. BIOMEDICAL OPTICS EXPRESS 2012; 3:2142-53. [PMID: 23024908 PMCID: PMC3447556 DOI: 10.1364/boe.3.002142] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/27/2012] [Accepted: 08/10/2012] [Indexed: 05/04/2023]
Abstract
Photodynamic therapy (PDT) efficacy depends on the local dose deposited in the lesion as well as oxygen availability in the lesion. We report significant interlesion differences between two patients with oral lesions treated with the same drug dose and similar light dose of 2-1[hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH)-mediated photodynamic therapy (PDT). Pre-PDT and PDT-induced changes in hemodynamic parameters and HPPH photosensitizer content, quantified by diffuse optical methods, demonstrated substantial differences between the two lesions. The differences in PDT action determined by the oxidative cross-linking of signal transducer and activator of transcription 3 (STAT3), a molecular measure of accumulated local PDT photoreaction, also showed >100-fold difference between the lesions, greatly exceeding what would be expected from the slight difference in light dose. Our results suggest diffuse optical spectroscopies can provide in vivo metrics that are indicative of local PDT dose in oral lesions.
Collapse
Affiliation(s)
- Daniel J. Rohrbach
- Department of Cell Stress Biology & PDT Center, Roswell Park Cancer Institute, Elm & Carlton St, Buffalo, NY 14263, USA
| | - Nestor Rigual
- Department of Head and Neck Surgery, Roswell Park Cancer Institute, Elm & Carlton St, Buffalo, NY 14263, USA
| | - Erin Tracy
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Elm & Carlton St, Buffalo, NY 14263, USA
| | - Andrew Kowalczewski
- Department of Cell Stress Biology & PDT Center, Roswell Park Cancer Institute, Elm & Carlton St, Buffalo, NY 14263, USA
| | - Kenneth L. Keymel
- Department of Cell Stress Biology & PDT Center, Roswell Park Cancer Institute, Elm & Carlton St, Buffalo, NY 14263, USA
| | - Michele T. Cooper
- Department of Cell Stress Biology & PDT Center, Roswell Park Cancer Institute, Elm & Carlton St, Buffalo, NY 14263, USA
| | - Weirong Mo
- Department of Cell Stress Biology & PDT Center, Roswell Park Cancer Institute, Elm & Carlton St, Buffalo, NY 14263, USA
| | - Heinz Baumann
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Elm & Carlton St, Buffalo, NY 14263, USA
| | - Barbara W. Henderson
- Department of Cell Stress Biology & PDT Center, Roswell Park Cancer Institute, Elm & Carlton St, Buffalo, NY 14263, USA
| | - Ulas Sunar
- Department of Cell Stress Biology & PDT Center, Roswell Park Cancer Institute, Elm & Carlton St, Buffalo, NY 14263, USA
| |
Collapse
|
9
|
Middelburg TA, Kanick SC, de Haas ERM, Sterenborg HJCM, Amelink A, Neumann MHAM, Robinson DJ. Monitoring blood volume and saturation using superficial fibre optic reflectance spectroscopy during PDT of actinic keratosis. JOURNAL OF BIOPHOTONICS 2011; 4:721-730. [PMID: 21842485 DOI: 10.1002/jbio.201100053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 07/08/2011] [Accepted: 07/25/2011] [Indexed: 05/31/2023]
Abstract
Optically monitoring the vascular physiology during photodynamic therapy (PDT) may help understand patient-specific treatment outcome. However, diffuse optical techniques have failed to observe changes herein, probably by optically sampling too deep. Therefore, we investigated using differential path-length spectroscopy (DPS) to obtain superficial measurements of vascular physiology in actinic keratosis (AK) skin. The AK-specific DPS interrogation depth was chosen up to 400 microns in depth, based on the thickness of AK histology samples. During light fractionated aminolevulinic acid-PDT, reflectance spectra were analyzed to yield quantitative estimates of blood volume and saturation. Blood volume showed significant lesion-specific changes during PDT without a general trend for all lesions and saturation remained high during PDT. This study shows that DPS allows optically monitoring the superficial blood volume and saturation during skin PDT. The patient-specific variability supports the need for dosimetric measurements. In DPS, the lesion-specific optimal interrogation depth can be varied based on lesion thickness.
Collapse
Affiliation(s)
- Tom A Middelburg
- Department of Dermatology, Erasmus MC, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
10
|
Karakullukcu B, Kanick SC, Aans JB, Sterenborg HJ, Tan IB, Amelink A, Robinson DJ. Clinical feasibility of monitoring m-THPC mediated photodynamic therapy by means of fluorescence differential path-length spectroscopy. JOURNAL OF BIOPHOTONICS 2011; 4:740-751. [PMID: 21861297 DOI: 10.1002/jbio.201100051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 07/12/2011] [Accepted: 07/12/2011] [Indexed: 05/31/2023]
Abstract
The objective quantitative monitoring of light, oxygen, and photosensitizer is challenging in clinical photodynamic therapy settings. We have previously developed fluorescence differential path-length spectroscopy (FDPS), a technique that utilizes reflectance spectroscopy to monitor microvascular oxygen saturation, blood volume fraction, and vessel diameter, and fluorescence spectroscopy to monitor photosensitizer concentration. In this paper the clinical feasibility of the technique is tested on eight healthy volunteers and on three patients undergoing PDT of oral cavity cancers. Model-based analysis of the measured spectra provide quantitative tissue parameters that are corrected for background tissue absorption, autofluorescence, and the transmission of the optical system; this method allows comparison of intra- and inter-subject parameters. The FDPS correctly estimated the absence of m-THPC in volunteers and detected photobleaching in the areas receiving treatment light in patients undergoing PDT treatment. This study demonstrates the feasibility of monitoring clinical photodynamic therapy treatments using optical spectroscopy.
Collapse
Affiliation(s)
- Baris Karakullukcu
- The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Department of Head and Neck Oncology and Surgery, 121 Plesmanlaan, 1066CX Amsterdam, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
11
|
Yu B, Fu HL, Ramanujam N. Instrument independent diffuse reflectance spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:011010. [PMID: 21280897 PMCID: PMC3041242 DOI: 10.1117/1.3524303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Diffuse reflectance spectroscopy with a fiber optic probe is a powerful tool for quantitative tissue characterization and disease diagnosis. Significant systematic errors can arise in the measured reflectance spectra and thus in the derived tissue physiological and morphological parameters due to real-time instrument fluctuations. We demonstrate a novel fiber optic probe with real-time, self-calibration capability that can be used for UV-visible diffuse reflectance spectroscopy in biological tissue in clinical settings. The probe is tested in a number of synthetic liquid phantoms over a wide range of tissue optical properties for significant variations in source intensity fluctuations caused by instrument warm up and day-to-day drift. While the accuracy for extraction of absorber concentrations is comparable to that achieved with the traditional calibration (with a reflectance standard), the accuracy for extraction of reduced scattering coefficients is significantly improved with the self-calibration probe compared to traditional calibration. This technology could be used to achieve instrument-independent diffuse reflectance spectroscopy in vivo and obviate the need for instrument warm up and post∕premeasurement calibration, thus saving up to an hour of precious clinical time.
Collapse
Affiliation(s)
- Bing Yu
- Duke University, Department of Biomedical Engineering, Durham, North Carolina 27708, USA.
| | | | | |
Collapse
|
12
|
Nachabé R, Hendriks BHW, van der Voort M, Desjardins AE, Sterenborg HJCM. Estimation of biological chromophores using diffuse optical spectroscopy: benefit of extending the UV-VIS wavelength range to include 1000 to 1600 nm. BIOMEDICAL OPTICS EXPRESS 2010; 1:1432-1442. [PMID: 21258560 PMCID: PMC3018130 DOI: 10.1364/boe.1.001432] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 10/28/2010] [Accepted: 11/16/2010] [Indexed: 05/19/2023]
Abstract
With an optical fiber probe, we acquired spectra from swine tissue between 500 and 1600 nm by combining a silicon and an InGaAs spectrometer. The concentrations of the biological chromophores were estimated by fitting a mathematical model derived from diffusion theory. The advantage of our technique relative to those presented in previous studies is that we extended the commonly-used wavelength ranges of 500 and 1000 nm to include the range of 1000 to 1600 nm, where additional water and lipid absorption features exist. Hence, a more accurate estimation of these two chromophores is expected when spectra are fitted between 500 and 1600 nm than between 500 and 1000 nm. When extending the UV-VIS wavelength range, the estimated total amount of chromophores approached 100% of the total as present in the probed volume. The confidence levels of the water and lipid related parameters increases by a factor of four.
Collapse
Affiliation(s)
- Rami Nachabé
- Department of Minimally Invasive Healthcare, Philips Research, 5656 AE Eindhoven,The Netherlands
| | - Benno H. W. Hendriks
- Department of Minimally Invasive Healthcare, Philips Research, 5656 AE Eindhoven,The Netherlands
| | - Marjolein van der Voort
- Department of Minimally Invasive Healthcare, Philips Research, 5656 AE Eindhoven,The Netherlands
| | - Adrien E. Desjardins
- Department of Minimally Invasive Healthcare, Philips Research, 5656 AE Eindhoven,The Netherlands
| | - Henricus J. C. M. Sterenborg
- Department of Radiation Oncology,Center of Optical Diagnostics and Therapy,Erasmus Medical Center,3008 AE Rotterdam,The Netherlands
| |
Collapse
|
13
|
Amelink A, Haringsma J, Sterenborg HJCM. Differential path-length spectroscopy: a tool for quantitative assessment of blood oxygen saturation in microvessels. Gastrointest Endosc 2010; 71:1100. [PMID: 20438902 DOI: 10.1016/j.gie.2009.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Accepted: 08/23/2009] [Indexed: 02/08/2023]
|
14
|
Kruijt B, van der Snoek EM, Sterenborg HJCM, Amelink A, Robinson DJ. A dedicated applicator for light delivery and monitoring of PDT of intra-anal intraepithelial neoplasia. Photodiagnosis Photodyn Ther 2010; 7:3-9. [PMID: 20230986 DOI: 10.1016/j.pdpdt.2010.01.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Revised: 01/24/2010] [Accepted: 01/25/2010] [Indexed: 12/17/2022]
Abstract
The objective of this study was to develop an applicator for delivery of light and monitoring of photodynamic therapy (PDT) in the anal cavity for treatment of anal intraepithelial neoplasia grade III (AIN III), which can progress to invasive anal cancer. Forty-eight hours before treatment, patients participating in the study were injected with 0.03 (n=2) or 0.075 (n=2) mg kg(-1) m-THPC. For light delivery and monitoring of PDT, an applicator based on standard anoscopy equipment was developed which facilitates, in addition to a light treatment fiber, fiber optic probes to monitor blood saturation, blood volume, fluorescence and fluence (rate) at two different locations in situ. Patients were given a light dose of 10-17 J cm(-2) at a fluence rate of 45-50 mW cm(-2) based on in situ measured light treatment parameters. We demonstrate that the applicator does not influence the fluence rate profile of the light treatment fiber. Furthermore this study shows the possibility of monitoring blood saturation, blood volume, fluorescence and fluence (rate) during therapeutic illumination without changing the light treatment protocol.
Collapse
Affiliation(s)
- Bastiaan Kruijt
- Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Erasmus MC, Rotterdam, The Netherlands.
| | | | | | | | | |
Collapse
|
15
|
Kanick SC, Robinson DJ, Sterenborg HJCM, Amelink A. Monte Carlo analysis of single fiber reflectance spectroscopy: photon path length and sampling depth. Phys Med Biol 2009; 54:6991-7008. [PMID: 19887712 DOI: 10.1088/0031-9155/54/22/016] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Single fiber reflectance spectroscopy is a method to noninvasively quantitate tissue absorption and scattering properties. This study utilizes a Monte Carlo (MC) model to investigate the effect that optical properties have on the propagation of photons that are collected during the single fiber reflectance measurement. MC model estimates of the single fiber photon path length (L(SF)) show excellent agreement with experimental measurements and predictions of a mathematical model over a wide range of optical properties and fiber diameters. Simulation results show that L(SF) is unaffected by changes in anisotropy (g epsilon [0.8, 0.9, 0.95]), but is sensitive to changes in phase function (Henyey-Greenstein versus modified Henyey-Greenstein). A 20% decrease in L(SF) was observed for the modified Henyey-Greenstein compared with the Henyey-Greenstein phase function; an effect that is independent of optical properties and fiber diameter and is approximated with a simple linear offset. The MC model also returns depth-resolved absorption profiles that are used to estimate the mean sampling depth (Z(SF)) of the single fiber reflectance measurement. Simulated data are used to define a novel mathematical expression for Z(SF) that is expressed in terms of optical properties, fiber diameter and L(SF). The model of sampling depth indicates that the single fiber reflectance measurement is dominated by shallow scattering events, even for large fibers; a result that suggests that the utility of single fiber reflectance measurements of tissue in vivo will be in the quantification of the optical properties of superficial tissues.
Collapse
Affiliation(s)
- S C Kanick
- Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
| | | | | | | |
Collapse
|
16
|
Gill KRS, Wolfsen HC, Preyer NW, Scott MV, Gross SA, Wallace MB, Jones LR. Pilot study on light dosimetry variables for photodynamic therapy of Barrett's esophagus with high-grade dysplasia. Clin Cancer Res 2009; 15:1830-6. [PMID: 19240171 DOI: 10.1158/1078-0432.ccr-08-2317] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Photodynamic therapy (PDT) is used to treat Barrett's esophagus with high-grade dysplasia and mucosal carcinoma. Outcomes are variable with some patients having persistent disease, whereas others develop strictures. The aims of this study were (a) to compare porfimer sodium tissue uptake, light dose, and esophageal thickness with clinical outcomes and (b) to determine the selectivity of porfimer sodium uptake in diseased and normal epithelium. EXPERIMENTAL DESIGN Forty-eight hours after porfimer sodium infusion, patients underwent mucosal biopsy for quantification of the porfimer sodium. Laser light was delivered at 48 hours and again 24 or 48 hours later. Porfimer sodium was extracted from the biopsy samples and quantified using fluorescence spectroscopy. The enhanced photodynamic dose was determined as [porfimer sodium content * light dose/esophageal thickness]. PDT efficacy was determined 6 to 8 weeks later based on persistence or complete ablation of dysplasia or carcinoma. RESULTS Mean porfimer sodium content of 6.2 mg/kg (range, 2.6-11.2 mg/kg) and mean total light dose of 278 J/cm (range, 225-360 J/cm) resulted in a complete treatment. Mean porfimer sodium tissue content of 3.9 mg/kg (range, 2.1-8.1 mg/kg) and mean total light dose of 268 J/cm (range, 250-350 J/cm) resulted in an incomplete treatment. The total esophageal thickness (range, 1.7-6.0 mm) and enhanced photodynamic dose were correlated with treatment outcome. CONCLUSIONS Esophageal thickness is the strongest predictor of treatment outcome. The porfimer sodium content of Barrett's and normal tissue is not significantly different. "Photodynamic dose" for esophageal PDT should incorporate the esophageal thickness.
Collapse
Affiliation(s)
- Kanwar R S Gill
- Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Jacksonville, Florida, USA
| | | | | | | | | | | | | |
Collapse
|
17
|
Kanick SC, Sterenborg HJCM, Amelink A. Empirical model of the photon path length for a single fiber reflectance spectroscopy device. OPTICS EXPRESS 2009; 17:860-71. [PMID: 19158901 DOI: 10.1364/oe.17.000860] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A reflectance spectroscopic device that utilizes a single fiber for both light delivery and collection has advantages over classical multi-fiber probes. This study presents a novel empirical relationship between the single fiber path length and the combined effect of both the absorption coefficient, mua (range: 0.1-6 mm-1), and the reduced scattering coefficient, micro's (range: 0.3 - 10 mm-1), for different anisotropy values (0.75 and 0.92), and is applicable to probes containing a wide range of fiber diameters (range: 200-2000 microm). The results indicate that the model is capable of accurately predicting the single fiber path length over a wide range (r = 0.995; range: 180-3940 microm) and predictions do not show bias as a function of either microa or micro's .
Collapse
Affiliation(s)
- S C Kanick
- Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
| | | | | |
Collapse
|
18
|
Kanick SC, Sterenborg HJCM, Amelink A. Empirical model description of photon path length for differential path length spectroscopy: combined effect of scattering and absorption. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:064042. [PMID: 19123688 DOI: 10.1117/1.3050424] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Differential path length spectroscopy (DPS) is a method of reflectance spectroscopy that utilizes a specialized fiber geometry to make the photon path length (tau) insensitive to variations in tissue optical properties over a wide range of absorption (mu(a)) and total scattering (mu(s)) coefficients, which are common within the ultraviolet/visible (UV/VIS) wavelength region. This study extends the description of tau to larger mu(a) and smaller mu(s) values, optical properties that are representative of the near-infrared region (NIR), a region where the DPS path length may be dependent on both coefficients. This study presents a novel empirical relationship between tau and the combined effect of both mu(a) (range: 0.1-12 mm(-1)) and mu(s) (range: 1.5-42 mm(-1)), anisotropy of 0.8, and is applicable to DPS probes containing a wide range of fiber diameters (range: 100-1000 microm). The results indicate that the simple empirical formula, including only one fitted parameter, is capable of accurately predicting tau over a wide range (r=0.985; range: 80-940 microm) and predictions are not biased versus mu(a) or mu(s). This novel relationship is applicable to analysis of DPS measurements of tissue in both the UV/VIS and NIR wavelength regions and may provide information about the wavelength-specific tissue volume optically sampled during measurement.
Collapse
Affiliation(s)
- Stephen C Kanick
- Erasmus Medical Center, Department of Radiation Oncology, Center for Optical Diagnostics and Therapy, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands.
| | | | | |
Collapse
|
19
|
Amelink A, Kruijt B, Robinson DJ, Sterenborg HJCM. Quantitative fluorescence spectroscopy in turbid media using fluorescence differential path length spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:054051. [PMID: 19021431 DOI: 10.1117/1.2992132] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We have developed a new technique, fluorescence differential path length spectroscopy (FDPS), that enables the quantitative investigation of fluorophores in turbid media. FDPS measurements are made with the same probe geometry as differential path length spectroscopy (DPS) measurements. Phantom measurements are performed for two fiber diameters (400 microm and 800 microm) and for a wide range of optical properties (mu(s)': 0 to 10 mm(-1); mu(a): 0 to 2 mm(-1)) to investigate the influence of the optical properties on the measured differential fluorescence signal. The differential fluorescence signal varies by a factor of 1.4 and 2.2 over the biologically relevant scattering range (0.5 to 5 mm(-1)) for a given fluorophore concentration for 400 microm and 800 microm fibers, respectively. The differential fluorescence signal is attenuated due to absorption at the excitation wavelength following Lambert-Beer's law with a path length equal to the differential path length.
Collapse
Affiliation(s)
- Arjen Amelink
- Erasmus Medical Centre Rotterdam, Department of Radiation Oncology, Center for Optical Diagnostics and Therapy, Rotterdam, The Netherlands 3000 CA.
| | | | | | | |
Collapse
|
20
|
Kruijt B, de Bruijn HS, van der Ploeg-van den Heuvel A, de Bruin RWF, Sterenborg HJCM, Amelink A, Robinson DJ. Monitoring ALA-induced PpIX photodynamic therapy in the rat esophagus using fluorescence and reflectance spectroscopy. Photochem Photobiol 2008; 84:1515-27. [PMID: 18557821 DOI: 10.1111/j.1751-1097.2008.00379.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The presence of phased protoporphyrin IX (PpIX) bleach kinetics has been shown to correlate with esophageal response to 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) in animal models. Here we confirm the existence of phased PpIX photobleaching by increasing the temporal resolution of the fluorescence measurements using the therapeutic illumination and long wavelength fluorescence detection. Furthermore fluorescence differential pathlength spectroscopy (FDPS) was incorporated to provide information on the effects of PpIX and tissue oxygenation distribution on the PpIX bleach kinetics during illumination. ALA at a dose of 200 mg kg(-1) was orally administered to 15 rats, five rats served as control animals. PDT was performed at an in situ measured fluence rate of 75 mW cm(-2) using a total fluence of 54 J cm(-2). Forty-eight hours after PDT the esophagus was excised and histologically examined for PDT-induced damage. Fluence rate and PpIX photobleaching at 705 nm were monitored during therapeutic illumination with the same isotropic probe. A new method, FDPS, was used for superficial measurement on saturation, blood volume, scattering characteristics and PpIX fluorescence. Results showed two-phased PpIX photobleaching that was not related to a (systematic) change in esophageal oxygenation but was associated with an increase in average blood volume. PpIX fluorescence photobleaching measured using FDPS, in which fluorescence signals are only acquired from the superficial layers of the esophagus, showed lower rates of photobleaching and no distinct phases. No clear correlation between two-phased photobleaching and histologic tissue response was found. This study demonstrates the feasibility of measuring fluence rate, PpIX fluorescence and FDPS during PDT in the esophagus. We conclude that the spatial distribution of PpIX significantly influences the kinetics of photobleaching and that there is a complex interrelationship between the distribution of PpIX and the supply of oxygen to the illuminated tissue volume.
Collapse
Affiliation(s)
- Bastiaan Kruijt
- Department of Radiation Oncology, Centre for Optical Diagnostics and Therapy, Erasmus MC, Rotterdam, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
21
|
Woodhams JH, Macrobert AJ, Bown SG. The role of oxygen monitoring during photodynamic therapy and its potential for treatment dosimetry. Photochem Photobiol Sci 2007; 6:1246-56. [PMID: 18046479 DOI: 10.1039/b709644e] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding of the biology of photodynamic therapy (PDT) has expanded tremendously over the past few years. However, in the clinical situation, it is still a challenge to match the extent of PDT effects to the extent of the disease process being treated. PDT requires drug, light and oxygen, any of which can be the limiting factor in determining efficacy at each point in a target organ. This article reviews techniques available for monitoring tissue oxygenation during PDT. Point measurements can be made using oxygen electrodes or luminescence-based optodes for direct measurements of tissue pO2, or using optical spectroscopy for measuring the oxygen saturation of haemoglobin. Imaging is considerably more complex, but may become feasible with techniques like BOLD MRI. Pre-clinical studies have shown dramatic changes in oxygenation during PDT, which vary with the photosensitizer used and the light delivery regimen. Better oxygenation throughout treatment is achieved if the light fluence rate is kept low as this reduces the rate of oxygen consumption. The relationship between tissue oxygenation and PDT effect is complex and remarkably few studies have directly correlated oxygenation changes during PDT with the final biological effect, although those that have confirm the value of maintaining good oxygenation. Real time monitoring to ensure adequate oxygenation at strategic points in target tissues during PDT is likely to be important, particularly in the image guided treatment of tumours of solid organs.
Collapse
Affiliation(s)
- Josephine H Woodhams
- National Medical Laser Centre, Royal Free and University College Medical School, University College London, Charles Bell House, 67-73 Riding House Street, London, UKW1W 7EJ
| | | | | |
Collapse
|
22
|
van Veen RLP, Nyst H, Rai Indrasari S, Adham Yudharto M, Robinson DJ, Tan IB, Meewis C, Peters R, Spaniol S, Stewart FA, Levendag PC, Sterenborg HJCM. In vivo fluence rate measurements during Foscan-mediated photodynamic therapy of persistent and recurrent nasopharyngeal carcinomas using a dedicated light applicator. JOURNAL OF BIOMEDICAL OPTICS 2006; 11:041107. [PMID: 16965135 DOI: 10.1117/1.2338009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The objective of this study was to evaluate the performance of a dedicated light applicator for light delivery and fluence rate monitoring during Foscan-mediated photodynamic therapy of nasopharyngeal carcinoma in a clinical phase I/II study. We have developed a flexible silicone applicator that can be inserted through the mouth and fixed in the nasopharyngeal cavity. Three isotropic fibers, for measuring of the fluence (rate) during therapy, were located within the nasopharyngeal tumor target area and one was manually positioned to monitor structures at risk in the shielded area. A flexible black silicon patch tailored to the patient's anatomy is attached to the applicator to shield the soft palate and oral cavity from the 652-nm laser light. Fourteen patients were included in the study, resulting in 26 fluence rate measurements in the risk volume (two failures). We observed a systematic reduction in fluence rate during therapy in 20 out of 26 illuminations, which may be related to photodynamic therapy-induced increased blood content, decreased oxygenation, or reduced scattering. Our findings demonstrate that the applicator was easily inserted into the nasopharynx. The average light distribution in the target area was reasonably uniform over the length of the applicator, thus giving an acceptably homogeneous illumination throughout the cavity. Shielding of the risk area was adequate. Large interpatient variations in fluence rate stress the need for in vivo dosimetry. This enables corrections to be made for differences in optical properties and geometry resulting in comparable amounts of light available for Foscan absorption.
Collapse
Affiliation(s)
- R L P van Veen
- Erasmus Medical Center, Center of Optical Diagnosis and Therapy, Rotterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|