In this study, Cylindrical Diffusing Optical Fiber Probe (CDOFP) is used for tumor treatment using Photolon-based photodynamic therapy induced apoptosis and necrosis in thyroid papillary carcinoma (BCPAP) cells. In conclusion, owing to multiple advantageous properties of Photolon as a PDT agent, including preferential accumulation in tumor, biodegradability and unprecedented photosensitizer packing, we evaluate Photolon mediated PDT as a minimally invasive, tumor specific treatment for thyroid cancer. the Photolon-PDT inhibited the growth of human papilloma thyroid cancer cells and effectively decreased xenograft tumor progression in both 10mm and 15mm diffusing length probe. Therefore, this study preliminarily suggests the use of CDOFP and Photolon-PDT for more effective treatment of human thyroid cancer.
Subglottic stenosis (SGS) is a challenging disease to diagnose in neonates. Long-range optical coherence tomography (OCT) is an optical imaging modality that has been described to image the subglottis in intubated neonates. A major challenge associated with OCT imaging is the lack of an automated method for image analysis and micrometry of large volumes of data that are acquired with each airway scan (1 to 2 Gb). We developed a tissue segmentation algorithm that identifies, measures, and conducts image analysis on tissue layers within the mucosa and submucosa and compared these automated tissue measurements with manual tracings. We noted small but statistically significant differences in thickness measurements of the mucosa and submucosa layers in the larynx (p < 0.001), subglottis (p = 0.015), and trachea (p = 0.012). The automated algorithm was also shown to be over 8 times faster than the manual approach. Moderate Pearson correlations were found between different tissue texture parameters and the patient’s gestational age at birth, age in days, duration of intubation, and differences with age (mean age 17 days). Automated OCT data analysis is necessary in the diagnosis and monitoring of SGS, as it can provide vital information about the airway in real time and aid clinicians in making management decisions for intubated neonates.
This paper describes RTBioT, one of the first Internet of Things (IoT) healthcare platforms based on spatially resolved near infrared (NIR) spectroscopy to support non-invasively quantify chromophores in biological tissue. Bluetooth Low Energy (BLE) is used as the primary communication protocol, an IR-enhanced Si PIN photodiode is for a light-receiving element, and a compact fiber-stub type beam combiner is employed as a multiple wavelengths light-emitting source. Most of all, a lock-in amplifier is to retrieve the low noise signal from photodiode which enables accurate measurement of small modulated signals in the presence of noise interference orders of magnitude greater than the signal amplitude by using phase-sensitive detection technique (PSD). The sampling rate of the RTBioT is up to 33Hz, so that it can directly measure mayer wave oscillation, respiration, and cardiac cycle from the raw data. However, it is necessary to approach to the statistical analysis to quantify the concentration of tissue chromophores. First, we determine the optical absorption and scattering properties in the tissue from the locked-in received signal by using the algorithm composed of least square method and diffusion equation. Then, inverse-matrix equation with absorption, reduced scattering and extinction coefficients is solved by the algorithm with respect to chromophores. We conducted an experiment through phantoms simulating human tissue and human subjects to demonstrate its feasibility for the IoT healthcare platform. The experimental results show that it is possible to monitor the biological signals and the concentrations of chromophores in a human subject in near real time fashion.
Gentamicin, which is still used in modern medicine, is a known vestibular toxic agent, and various degrees of balance problems have been observed after exposure to this pharmacologic agent. Photobiomodulation is a candidate therapy for vertigo due to its ability to reach deep inner ear organs such as the cochlea. Previous reports have suggested that photobiomodulation can improve hearing and cochlea function. However, few studies have examined the effect of photobiomodulation on balance dysfunction. We used a rat model to mimic human vestibulopathy resulting from gentamicin treatment and evaluated the effect of photobiomodulation on vestibular toxicity. Slow harmonic acceleration (SHA) rotating platform testing was used for functional evaluation and both qualitative and quantitative epifluorescence analyses of cupula histopathology were performed. Animals were divided into gentamicin only and gentamicin plus laser treatment groups. Laser treatment was applied to one ear, and function and histopathology were evaluated in both ears. Decreased function was observed in both ears after gentamicin treatment, demonstrated by low gain and no SHA asymmetry. Laser treatment minimized the damage resulting from gentamicin treatment as shown by SHA asymmetry and recovered gain in the treated ear. Histology results reflected the functional results, showing increased hair cell density and epifluorescence intensity in laser-treated cupulae.
Laser-induced therapies include laser ablation to remove or cut target tissue by irradiating high-power focused laser beam. These laser treatments are widely used tools for minimally invasive surgery and retinal surgical procedures in clinical settings. In this study, we demonstrate laser tissue interaction images of various sample tissues using high resolution Fourier-domain optical coherence tomography (Fd-OCT). We use a Q-switch diode-pumped Nd:YVO4 nanosecond laser (532nm central wavelength) with a 4W maximum output power at a 20 kHz repetition rate to ablate in vitro and in vivo samples including chicken breast and mouse ear tissues. The Fd-OCT system acquires time-series Bscan images at the same location during the tissue ablation experiments with 532nm laser irradiation. The real-time series of OCT cross-sectional (B-scan) images compare structural changes of 532nm laser ablation using same and different laser output powers. Laser tissue ablation is demonstrated by the width and the depth of the tissue ablation from the B-scan images.
Young patients with dense breasts have a relatively low-positive biopsy rate for breast cancer (∼1 in 7). South Korean women have higher breast density than Westerners. We investigated the benefit of using a functional and metabolic imaging technique, diffuse optical spectroscopic imaging (DOSI), to help the standard of care imaging tools to distinguish benign from malignant lesions in premenopausal Korean women. DOSI uses near-infrared light to measure breast tissue composition by quantifying tissue concentrations of water (ctH2O), bulk lipid (ctLipid), deoxygenated (ctHHb), and oxygenated (ctHbO2) hemoglobin. DOSI spectral signatures specific to abnormal tissue and absent in healthy tissue were also used to form a malignancy index. This study included 19 premenopausal subjects (average age 41±9), corresponding to 11 benign and 10 malignant lesions. Elevated lesion to normal ratio of ctH2O, ctHHb, ctHbO2, total hemoglobin (THb=ctHHb+ctHbO2), and tissue optical index (ctHHb×ctH2O/ctLipid) were observed in the malignant lesions compared to the benign lesions (p<0.02). THb and malignancy index were the two best single predictors of malignancy, with >90% sensitivity and specificity. Malignant lesions showed significantly higher metabolism and perfusion than benign lesions. DOSI spectral features showed high discriminatory power for distinguishing malignant and benign lesions in dense breasts of the Korean population.
Aim: to investigate effectiveness of Low level laser therapy (LLLT) in rescueing ouabain induced spiral ganglion cell damage using Mongolian gerbils. Methods: Animals were divided into 3 groups; Control, Ouabain, Ouabain + LLLT group. Auditory neuropathy was induced by topical application of ouabain (1 mmol/L, 3uL) on the round window membrane in gerbils. Transmeatal LLLT was irradiated into the right ear for 1h (200mW, 720 J) daily for 7d in Ouabain + LLLT group. Before and 7 days after ouabain application, hearing was evaluated using both ABR and distortion product otoacoustic emissions (DPOAE). Seven days after ouabain application, animals were sacrificed to evaluate the morphological changes of cochlea using cochlear section image and whole mount Immunofluorescent staining. Results: DPOAE tests were normal in all animals after ouabain topical treatment indicating intact outer hair cells. Ouabain group showed ABR threshold increase compared with control group. Ouabain+LLLT group showed significant improvement of ABR threshold compared to ouabain only group. H and E stains of mid-modiolar section of cochlear showed spiral ganglion cells, neurofilaments, and post synaptic receptor counts were decreased while inner and outer hair cells were preserved in ouabain group. Ouabain +LLLT group showed higher numbers of spiral ganglion cells, density of neurofilaments and post synaptic receptor counts compared to ouabain group. Conclusions: The results demonstrated that LLLT was effective to rescue ouabain-induced spiral ganglion neuropathy.
We report on development of optical parametric oscillator (OPO) based mid-infrared laser system, which utilizes periodically poled nonlinear crystal that was pumped by near-infrared (NIR) laser. We have obtained 8 W of mid-infrared average output at the injection current of 20A from a quasi-phase-matched OPO using external cavity configuration. The laser tissue ablation efficiency was investigated which is substantially affected by several parameters such as, optical fluence rate, wavelength of the laser source and the optical properties of target tissue. Wavelength and radiant exposure dependent tissue ablation dimension were quantified by using SD-OCT (spectral domain optical coherence tomography) and the ablation efficiency was compared to that of non-converted NIR- laser system.
One of the most common factors that cause hearing disorders is noise trauma. Noise is an increasing hazard and it is pervasive, which makes it difficult to take precautions and prevent noise-induced hearing loss (NIHL). The prevalence of hearing loss among factory workers to be 42 %[1]. Ocupational noise induced hearing loss (ONIHL) continues to be a significant occupational hazard. ONIHL is permanent and may cause significant disability, for which there currently exists no cure, but is largely preventable. More than 30 million Americans are potentially exposed to hazardous noise levels in occupations such as transportation, construction, and coal mining, as well as recreationally. In the mainstream setting, exposure avoidance strategies aimed to reduce the incidence of ONIHL remain the focus of public health and occupational medicine approaches[2]. In military conditions this is most often caused by such things as explosions, blasts, or loud noises from vehicles ranging from 100 to 140 dB[3] and military weapons generating approximately 140–185 dB peak sound pressure levels[4].
Many biomedical applications require an efficient combination and localization of multiple discrete light sources. In this paper, we present a compact six-channel combiner of optical sub-assembly type that couples the output of independent solid-state light sources into a single 400 μm diameter optical fiber. It is equipped with six discrete laser diodes, 658, 690, 705, 785, 830, and 850 nm for the measurement of the tissue optical properties from optical spectroscopy and imaging. We demonstrate coupling efficiencies ≥ 77% and output optical power ≥ 20 mW for each of the 6 laser diodes installed into the prototype. The design supports the use of continuous wave and intensity modulated laser diodes (with bandwidth ≥ 3 GHz). The developed light source could be used to construct custom multi-wavelength sources for tissue oximeters, diffuse optical imaging, and molecular imaging technologies.
Low-level light irradiation (LLLI) reported to stimulate the proliferation or differentiation of a variety of cell types. However, very little is known about the effect of light therapy on stem cells. The aim of the present study was to evaluate the effect of LLLI on the molecular physiological change of human bone marrow derived stem cells (hBMSC) by wavelength (470, 630, 660, 740 and 850, 50mW). The laser diode was performed with different time interval (0, 7.5, 15, 30J/cm2, 50mW) on hBMSC. To determine the molecular physiological changes of cellular level of hBMSC, the clonogenic assay, ATP assay, reactive oxygen species (ROS) detection, mitochondria membrane potential (MMPΦ) staining and calcium efflux assay were assessed after irradiation. There was a difference between with and without irradiation on hBMSCs. An energy density up to 30 J/cm² improved the cell proliferation in comparison to the control group. Among these irradiated group, 630 and 660nm were significantly increased the cell proliferation. The cellular level of ATP and calcium influx was increased with energy dose-dependent in all LLLI groups. Meanwhile, ROS and MMPΦ were also increased after irradiation except 470nm. It can be concluded that LLLI using infrared light and an energy density up to 30 J/cm² has a positive stimulatory effect on the proliferation or differentiation of hBMSCs. Our results suggest that LLLI may influence to the mitochondrial membrane potential activity through ATP synthesis and increased cell metabolism which leads to cell proliferation and differentiation.
Low-level laser therapy (LLLT) is a non-thermal phototherapy used in several medical applications, including wound healing, reduction of pain and amelioration of oral mucositis. Nevertheless, the effects of LLLT upon cancer or dysplastic cells have been so far poorly studied. Here we report that the effects of laser irradiation on anaplastic thyroid cancer cells leads to hyperplasia. 650nm of laser diode was performed with a different time interval (0, 15, 30, 60J/cm2 , 25mW) on anaplastic thyroid cancer cell line FRO in vivo. FRO was orthotopically injected into the thyroid gland of nude mice and the irradiation was performed with the same method described previously. After irradiation, the xenograft evaluation was followed for one month. The thyroid tissues from sacrificed mice were undergone to H&E staining and immunohistochemical staining with HIF-1α, Akt, TGF-β1. We found the aggressive proliferation of FRO on thyroid gland with dose dependent. In case of 60 J/ cm2 of energy density, the necrotic bodies were found in a center of the thyroid. The phosphorylation of HIF-1α and Akt was detected in the thyroid gland, which explained the survival signaling of anaplastic cancer cell was turned on the thyroid gland. Furthermore, TGF-β1 expression was decreased after irradiation. In this study, we demonstrated that insufficient energy density irradiation occurred the decreasing of TGF-β1 which corresponding to the phosphorylation of Akt/ HIF-1α. This aggressive proliferation resulted to the hypoxic condition of tissue for angiogenesis. We suggest that LLLT may influence to cancer aggressiveness associated with a decrease in TGF-β1 and increase in Akt/HIF-1α.
Aim: The LLLT was found to recover NIHL and ototoxicity induced hearing loss in rats but the optimal LLLT laser
dosage to treat NIHL needs to be determined. The aim of this study was to find the optimal laser dosage to recover a
NIHL with transmeatal-LLLT. Methods: Bilateral ears of rats were exposed to noise (narrow band noise, 120 dB, 16
kHz, 6 h). Left ears of the rats were irradiated with transmeatal-LLLT (830 nm) of 50, 100, 150, 200, 250, 300 mW for
60 minutes per day for 12 days, starting 1 day post induction of NIHL. Right ears were not irradiated and used as control
ears. The hearing levels were measured at each frequency of 8, 12, and 32 kHz before the noise exposure, 1, 3, 8, and 12
days post noise exposure. The differences of hearing levels between left treated ear and right controlled ear at each
frequency of different laser dosages (50 – 300 mW) were compared to see the most effective laser dosages to treat NIHL.
Results: Hearing levels were most improved by 150 mW, slightly improved by 200 mW, not improved by 50 and 250
mW, and became worse by 300 mW. Conclusion: The results of this study suggest that most effective therapeutic laser
dosage window to treat NIHL with transmeatal-LLLT was 150 mW for 12 days and it was not effective by 50, 250, and
300 mW.
The studies on microstructured optical fibers (MOF) have drawn considerable interest and played an important role in
many applications. MOFs provide unique optical properties and controllable modal properties because of their
flexibilities on manipulation of the transmission spectrum and the waveguide dispersion properties. MOFs are especially
useful for optical sensing applications because the micro-structured air channels in MOF can host various types of
analytes such as liquids, gases, and chemical molecules. Recently, many studies have focused on the development of
MOF-based optical sensors for various gases and chemical molecules. We propose a compact, and highly sensitive
optical micro-cavity chemical sensor using microstructured fiber. The sensor probe is composed of a hollow optical fiber
and end cleaved microstructured fiber with a solid core. The interference spectrum resulting from the reflected light at
the silica and air interfaces changes when the micro-cavity is infiltrated with external chemical molecules. This structure
enables the direct detection of chemical molecules such as volatile organic compounds (VOCs) without the introduction
of any permeable material.
Adipose-derived stromal cells (ASCs) are attractive cell source for tissue engineering. However, one
obstacle to this approach is that the transplanted ASC population can decline rapidly in the recipient
tissue. The aim of this study was to investigate the effects of low-level laser therapy (LLLT) on
transplanted human ASCs (hASCs) spheroid in a hindlimb ischemia animal model. LLLT, hASCs
spheroid and hASCs spheroid transplantation with LLLT (spheroid + LLLT) were applied to the
ischemic hindlimbs in athymic mice. The survival, differentiation and secretion of vascular
endothelial growth (VEGF) of spheroid ASCs were evaluated by immunohistochemistry. The
spheroid + LLLT group enhanced the tissue regeneration, including angiogenesis, compared with
other groups. The spheroid contributed tissue regeneration via differentiation and secretion of
growth factors. In the spheroid + LLLT group, the survival of spheroid hASCs was increased by the
decreased apoptosis of spheroid hASCs in the ischemic hindlimb. The secretion of growth factors
was stimulated in the spheroid + LLLT group compared with the ASCs group and spheroid group.
These data suggest that LLLT is an effective biostimulator of spheroid hASCs in tissue regeneration
that enhances the survival of ASCs and stimulates the secretion of growth factors in the ischemic
hindlimb.
The primary cause of hearing loss includes damage to cochlear hair cells. Low-level laser therapy (LLLT) has become a popular treatment for damaged nervous systems. Based on the idea that cochlea hair cells and neural cells are from same developmental origin, the effect of LLLT on hearing loss in animal models is evaluated. Hearing loss animal models were established, and the animals were irradiated by 830-nm diode laser once a day for 10 days. Power density of the laser treatment was 900 mW/cm 2 , and the fluence was 162 to 194 J. The tympanic membrane was evaluated after LLLT. Thresholds of auditory brainstem responses were evaluated before treatment, after gentamicin, and after 10 days of LLLT. Quantitative scanning electron microscopic (SEM) observations were done by counting remaining hair cells. Tympanic membranes were intact at the end of the experiment. No adverse tissue reaction was found. On SEM images, LLLT significantly increased the number of hair cells in middle and basal turns. Hearing was significantly improved by laser irradiation. After LLLT treatment, both the hearing threshold and hair-cell count significantly improved.
We investigated the effect of low-level laser radiation on rescuing hair cells of the cochlea after acute acoustic trauma and hearing loss. Nine rats were exposed to noise. Starting the following day, the left ears (NL ears) of the rats were irradiated at an energy output of 100 to 165 mW / cm2 for 60 min for 12 days in a row. The right ears (N ears) were considered as the control group. Frequency-specific hearing levels were measured before the noise exposure and also after the 1st, 3rd to 5th, 8th to 10th and 12th irradiations. After the 12th treatment, hair cells were observed using a scanning electron microscope. Compared to initial hearing levels at all frequencies, thresholds increased markedly after noise exposure. After the 12th irradiation, hearing threshold was significantly lower for the NL ears compared to the N ears. When observed using an electron microscope, the number of hair cells in the middle turn of the NL ears was significantly larger than that of the N ears. Our findings suggest that low-level laser irradiation promotes recovery of hearing thresholds after acute acoustic trauma.
Objectives: Laser cordectomy is very popular nowadays and become one of the treatments of choice for early glottis
carcinoma. Transoral laser microsurgery has many advantages comparing conventional open surgery or radiation therapy.
In this study, we examined the oncologic results of laser cordectomy for early glottic cancer and analyzed the prognostic
impact on the survival of the several tumor-related and treatment-related factors. Methods: Patients who were diagnosed
as early glottic squamous cell carcinoma, treated by laser cordectomy with curative intent were analyzed. Patients with
preivous radiation therapy were included. From June 1988 to March 2005, 202 patients from five hospitals were
analyzed (174 T1, 28 T2). Results: Five-year overall survival and disease-free survival were 98.4% and 84.9%. Twenty
two patients developed local recurrence. Total laryngectomy was done in 6 patients and laryngeal preservation rate was
97%. Recurrence was higher in the patients with anterior commissure involvement (9/39) than without anterior
commissure involvement (13/163). Recurrence was higher in T1b (4/15) than T1a (13/159). Previous radiation was also
highly related to the recurrence (7/20 vs 15/182). Twenty patients with local recurrence after radiation therapy were
treated by salvage laser cordectomy. Of them, 7 patients developed local recurrence and 5 year disease-free survival was 57%. Complication was rare with one case of hemorrhage. Tracheotomy was not necessary in all patients. Conclusions:
Laser cordectomy for early glottic carcinoma showed high survival, laryngeal preservation rate and low complication
rate. The prognostic factors were anterior commissure involvement, both vocal fold involvement and previous
radiotherapy.
The transcanal LLLT was found to recover noise induced hearing loss (NIHL) but the LLLT was performed
immediately after the induction of NIHL. The aim of this study was to find an optimal window time to treat and
recover a NIHL with LLLT. Bilateral ears of 6SD rats (12ears) were exposed to noise. Left ears of the rats were
irradiated with a LLLT (830 nm, 594 J/cm2 per day) for 12 days, starting 3 days and 7 days post exposure to noise.
Right ears were used as control ears. The hearing levels were measured at each frequency of 4, 8, 12, 16, and 32 kHz
before and after the noise exposure and post 12th irradiations. The initial hearing levels in all frequencies before and
after the noise exposure were 26.5, 24.5, 24.0, 24.0 and 24.5 dB SPL and 63.5, 64, 71.5, 73.5 and 67.5 dB SPL in 4,
8, 12, 16 and 32 kHz, respectively in 6 ears. After 12th irradiation, the thresholds of the LLLT treated left ears of the
3-day group recovered significantly compared to those of the untreated right. However, for the 7 day group, the
recovery of the LLLT treated left ears was not significantly improved compared to that of the untreated right. The
results of this study suggest that the optimal window time to treat NIHL with LLLT was within 3 days from the
exposure to noise but the hearing failed to recover if the LLLT was started 7 days post exposure to noise.
The aim of this study was to evaluate antibacterial effects of PDT on common bacteria causing otitis media with effusion (OME).
In vitro study was carried out using a hematoporphyrin derivative sensitizer (photogem) and 632 nm diode laser on H. influenzae, M. catarrhalis, and S. pneumoniae. One ml of each bacterial suspension was incubated for 3 hours and various concentrations of photogem were administered into the suspension. The suspensions were irradiated with 632 diode laser (15 J/cm2). The presence of colony forming units of the bacteria was examined, microscopic structures of bacteria were examined by TEM, and cytometry of bacteria was performed. The PDT was effective in killing all 3 kinds of bacteria. TEM showed damaged bacterial cell membrane and cytoplasmic structures and the flow cytometry showed lower number of viable bacteria in PDT group comparing to the control group.
In vivo PDT study was performed using gerbil. S. pneumoniae or H. influenzae was injected into bullae. Photogem was injected into bullae in 2 days by when OME was developed and transcanal irradiation of 632 nm diode laser (90 J) was performed with a fiber perforated through an ear drum into a middle ear cavity and bulla. Four days after PDT, middle ear and bulla were washed with DPBS and the washed DPBS was cultured. The presence of bacterial colonies was examined. PDT was effective in killing S. pneumoniae in 87 % of the infected bullae with OME while it was effective to eradicate H. influenzae in 50 % of the infected bullae with OME.
The results of these studies demonstrated that PDT may be effective to treat otitis media. It may have clinical implication to treat otitis media that is resistant to antibiotic therapy.
Backgrounds and Objectives: The styryl pyridinium dye FM1-43 is nontoxic, fluorescent, cationic dye whose
fluorescence markedly increases after partitioning into membrane. Rapid entry of FM1-43 is inhibited by drugs that
block the mechanically gated transduction channels, suggesting the dye can itself act as a permanent blocker of the
channels. In this study, the effects of low level laser (LLL) and FM1-43 on gentiamicin induced ototoxicity in
postnatal organotypic culture of rat utricles were investigated. Materials and Methods: An organotypic culture of 2-
7-day-old rat utricular maculae was established. In a series of experiments utricles were exposed to either irradiation
of low level laser(LG group)or 10 ?M FM1-43(FG group) or both(LFG group) followed by 1mM of gentamicin
treatment for 12 hrs. The results of experimental groups were compared with the control group by confocal laser
scanning and scanning electron microscopy. Results: LLL prevented vestibular hair cells ototoxicity. Rapid
incubation with FM1-43 dye protected vestibular hair cell damage induced by gentamicin treatment. Substantial
additive effect of LLL on ototoxicity prevention was noted in combination therapy with FM1-43. There were
statistical significant differences among all groups but between control and LFG group by both confocal laser
scanning and scanning electron microscopy. In addition, caspase-3 activity was hardly found in LFG group after
double staining with Phalloidin-FITC by confocal laser scanning microscopy. Conclusion: These results suggest that
there is an additive protection effect of LLL and FM1-43 against gentamicin ototoxicity in postnatal organotypic
culture of rat utricles. LLL may have clinical preventive and therapeutic implications on ototoxicity.
Tumor hypoxia, either pre-existing or as a result of oxygen bleaching during Photodynamic Therapy (PDT) light irradiation, can significantly reduce the effectiveness of PDT induced cell killing. To overcome the effect of tumor hypoxia and improve tumor cell killing, we propose using supplemental hyperoxygenation during Photofrin PDT. Our previous study has demonstrated that, in an in vivo model, tumor control can be improved by normobaric or hyperbaric 100% oxygen supply. The mechanism for the tumor cure enhancement of the hyperoxygenation-PDT combined therapy is investigated in this study by using an in vivo/in vitro technique. A hypoxic tumor model was established by implanting mammary adenocarcinoma (MCA) in hind legs of C3H mice. Light irradiation (200 J/cm2 at either 75 or 150 mW/cm2), under various oxygen supplemental conditions (room air or carbogen or 100% normobaric or hyperbaric 100% oxygen), was delivered through an optical fiber with a microlens to animals who received 12.5 mg/kg Photofrin 24 hours prior to light irradiation. Tumors treated with PDT were harvested and grown in vitro for colony formation analysis. Treated tumors were also analyzed histologically. The results show that, when combined with hyperoxygenation, the cell killing rate immediately after a PDT treatment is significantly improved over that treated without hyperoxygenation, suggesting an enhanced direct cell killing. This study further confirms our earlier observation that when a PDT treatment is combined with hyperoxygenation, it can be more effective in controlling hypoxic tumors. H&E stain revealed that PDT induced tumor necrosis and hemorrhage. In conclusion, by using an in vivo/in vitro assay, we have shown that PDT combined with hyper-oxygenation can enhance direct cell killing and improve tumor cure.
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