This study reports the results of our recent in vivo study using attenuation-based quantitative OCT for intra-operative mapping of brain cancer in patients. A total of 34 brain cancer patients were recruited, and an optimal optical attenuation threshold of 4.3 mm-1 was established with cancer of lower values. We achieved an excellent specificity of over 98%, with a corresponding sensitivity of over 95% for both high-grade and low-grade cancers. Applying the established optical attenuation threshold to infiltrated tissues, we were able to identify regions of cancers qualitatively matching the neuropathologist’s assessment. The study suggests that optical attenuation-based quantitative OCT represents a promising technology for intraoperative brain cancer detection and
Various algorithms have been proposed to compute attenuation coefficient (AC) based on optical coherence tomography (OCT) signals. The single scattering model has gained widespread application due to its computational efficiency; however, it’s only applicable to thin tissue layers, thus imposing strict requirements on the data length used for calculations. This study compared the algorithms for estimating the AC from OCT data using different data length such as 180 μm , 250 μm , 350 μm , 435 μm acquired from intralipid phantoms. Subsequently, employing various algorithms and utilizing the optimal data length, we calculated the attenuation coefficients of liquid phantoms with different concentrations, and the methodology was applied to homogeneous mouse tissues. The comparative study may provide a reliable basis for parameter configuration for AC extraction algorithm.
High-resolution imaging technologies, such as multiphoton imaging (MPM) and optical coherence tomography (OCT), are capable of high-speed imaging of biological tissues in vivo with subcellular resolution. In brain cancer surgery, it is challenging to distinguish cancer from noncancer intraoperatively. This study shows that MPM can provide label-free images with histological details. Increased cellularity, microvascular proliferation, nuclear pleomorphism and collagen deposition, can be clearly visualized in cancerous human brain tissues. Photodynamic therapy (PDT) is an effective treatment for cancers. The change of tumor vasculatures, including a newly-formed microvascular, in response to PDT, is a key assessment parameter for optimizing the treatment effect. We demonstrated the in vivo imaging of PDT effects on mouse tumor model with an ultrahigh-resolution functional OCT. The technologies have shown significant translational potential for cancer detection and PDT treatment assessment.
Vascular-targeted photodynamic therapy (V-PDT) is known to be an effective therapeutic modality for the treatment of port wine stains (PWS). Monitoring the PWS microvascular response to the V-PDT is crucial for improving the effectiveness of PWS treatment. The objective of this study was to use laser Doppler technique to directly assess the skin perfusion in PWS before and during V-PDT. In this study, 30 patients with PWS were treated with V-PDT. A commercially laser Doppler line scanner (LDLS) was used to record the skin perfusion of PWS immediately before; and at 1, 3, 5, 7, 10, 15 and 20 minutes during V-PDT treatment. Our results showed that there was substantial inter- and intra-patient perfusion heterogeneity in PWS lesion. Before V-PDT, the comparison of skin perfusion in PWS and contralateral healthy control normal skin indicated that PWS skin perfusion could be larger than, or occasionally equivalent to, that of control normal skin. During V-PDT, the skin perfusion in PWS significantly increased after the initiation of V-PDT treatment, then reached a peak within 10 minutes, followed by a slowly decrease to a relatively lower level. Furthermore, the time for reaching peak and the subsequent magnitude of decrease in skin perfusion varied with different patients, as well as different PWS lesion locations. In conclusion, the LDLS system is capable of assessing skin perfusion changes in PWS during V-PDT, and has potential for elucidating the mechanisms of PWS microvascular response to V-PDT.
In this study, the vessel constriction was measured as a biological indicator of acute vascular response after vascular
targeted photodynamic therapy (V-PDT). During V-PDT treatment, the near-infrared (NIR) singlet oxygen (1O2)
luminescence at 1270 nm generated in blood vessels in a dorsal skinfold window chamber model in vivo was directly
monitored using a custom built high-sensitive NIR imaging system. In order to compare the acute vascular response,
various irradiances with the same light dose were utilized for treatments. The obtained results show that the complete
arteriole constriction occurred frequently, while some of the larger veins were constricted partially. For the vessels that
have significant constriction after V-PDT, our preliminary data suggest that the vasoconstriction in the selected ROIs are
roughly correlated with the local cumulative 1O2 luminescence intensities. This study implies that the 1O2 luminescence
dosimetry maybe also effective for evaluating V-PDT efficiency.
Response of port wine stain (PWS) to photodynamic therapy treatment (PDT) is variable and depends on treatment setting used and anatomic sites as well as on size and depth of ectatic vessels. Optical coherence tomography (OCT) is a non-destructive imaging modality which can reveal the layered structure of the upper part of the skin. The structural features of the PWS skin such as the diameter and depth of the blood vessels in different anatomic sites can be showed in the OCT images. In this study, the possible role of PWS skin structure in the response to PDT is assessed. 82 positions from 43 patients with PWS underwent OCT evaluation in cheek, zygomatic aera, preauricular and temporal region before and 3~4 months after the first PDT when treatment outcomes were also evaluated. After analyzing the structural features in different anatomic sites and the therapeutic effect of them, we found that the ectatic vessels diameter was obvious bigger in the cheek which had slightly poorer outcomes than other areas. Some typical structures had poor or good outcomes after first PDT. These can help the clinic doctors predict the response of some patients which have typical structures after PDT treatment. The OCT will be a potential tool for prediction of treatment response for port wine stain after photodynamic therapy.
Singlet oxygen (1O2) is commonly recognized to be a major phototoxic component for inducing the biological damage during photodynamic therapy (PDT). In this study, a novel configuration of a thermoelectrically-cooled near-infrared sensitive InGaAs camera was developed for imaging of photodynamically-generated 1O2 luminescence. The validation of 1O2 luminescence images for solution samples was performed with the model photosensitizer Rose Bengal (RB). Images of 1O2 luminescence generated in blood vessels in vivo in a well-controlled dorsal skinfold window chamber model were also recorded during PDT. This study demonstrated the capacity of the newly-developed imaging system for imaging of 1O2 luminescence, and the first reported images of 1O2 luminescence in blood vessels in vivo. This system has potential for elucidating the mechanisms of vascular targeted PDT.
Singlet oxygen (1O2) is widely considered to be the predominant cytotoxic agent for photodynamic therapy (PDT), and
the 1O2 quantum yield is a key characteristic for the newly developed photosensitizers. In this study, 1O2 generation from
the HiPorfin is monitored indirectly by using the fluorescence probe Singlet Oxygen Sensor Green (SOSG). The good
linear relationship between the concentration of HiPorfin and the initial reaction rate of SOSG is observed, and the 1O2
quantum yield of HiPorfin is determined to be 0.124 ± 0.001, as compared to the standard reference of Rose Bengal. The
results suggest that SOSG can be useful for 1O2 quantum yield determination for the potential photosensitizers in PDT.
Singlet oxygen (1O2) can be generated in a living cell upon focused laser irradiation of an intracellular photosensitizer. In
this study, 1O2 generation from the plasma membrane-targeted protoporphyrin IX (PpIX) in human nasopharyngeal
carcinoma CNE2 cells was monitored indirectly by using the fluorescence probe Singlet Oxygen Sensor Green agent
(SOSG). The confocal images indicate that the fluorescence of SOSG in the vicinity of the cells that incubated with PpIX
was dramatically enhanced with the increased irradiation time, while there is no significant enhancement for the control
cells. Moreover, the fluorescence of SOSG is dramatically enhanced with the increase of the intracellular PpIX in CNE2
cells for the same photoirradiation time. These observations imply that the 1O2 generated from the plasma
membrane-targeted PpIX in the CNE2 cells can be escaped into the extracellular medium and to react with the SOSG to
produce SOSG-EP, and the fluorescence enhancement of SOSG around the cells mainly depends on the intracellular
PpIX. Our findings may be useful for further monitored the 1O2 that can be escaping from the living cells.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.