Comprehensive Review of Huffman Encoding Technique for Image Compression

The image processing is used in the every field of life. It is growing field and is used by large number of users. The image processing is used in order to remove the problems present within the image. There are number of techniques which are suggested in order to improve the image. For this purpose image enhancement is commonly used. The space requirements associated with the image is also very important factor. The main aim of the various techniques of image processing is to decrease the space requirements of the image. The space requirements will be minimized by the use of compression techniques. Compression techniques are lossy and lossless in nature. This paper will conduct a comprehensive survey of the lossless compression Huffman coding in detail

Quantitative near-infrared spectroscopy of cervical dysplasia in vivo

The aims of this study were: (i) to quantify near-infrared optical properties of normal cervical tissues and high-grade squamous intra-epithelial lesions (H-SIL); (ii) to assess the feasibility of differentiating normal cervical tissues from H-SIL on the basis of these properties; and (iii) to determine how cervical tissue optical properties change following photodynamic therapy (PDT) of H-SIL in vivo. Using the frequency domain photon migration technique, non-invasive measurements of normal and dysplastic ecto-cervical tissue optical properties, i.e. absorption (μa) and effective scattering coefficients, and physiological parameters, i.e. tissue water and haemoglobin concentration, percentage oxygen saturation (%SO2), were performed on 10 patients scheduled for PDT of histologically-proven H-SIL. Cervix absorption and effective scattering parameters were up to 15% lower in H-SIL sites compared with normal cervical tissue for all wavelengths studied (674, 811, 849, 956 nm). Following PDT, all μa values increased significantly, due to elevated tissue blood and water content associated with PDT-induced hyperaemia and oedema. Tissue total haemoglobin concentration ([TotHb]) and arterio-venous oxygen saturation measured in H-SIL sites were lower than normal sites ([TotHb]: 88.6 ± 35.8 μmol/l versus 124.7 ± 22.6 μmol/l; %SO2: 76.5 ± 14.7% versus 84.9 ± 3.4%

Intrauterine light delivery for photodynamic therapy of the human endometrium

Photodynamic therapy is currently being evaluated as a minimally invasive procedure for endometrial ablation not requiring anaesthesia. Light penetration depths at 630, 660 and 690 nm and the optimal configuration of intrauterine light-diffusing fibres were determined in 14 human uteri to assist in the design of a light intrauterine device. Post-menopausal ex-vivo uteri showed a significantly lower light penetration depth than pre-menopausal uteri. With a single central diffusing fibre inserted, the fluence rate measured in the uterine wall at the most remote point of the cavity decreased to 1.1 ± 0.4% of that measured at closest proximity, whereas it decreased to only 40.0 ± 9.0% with three fibres. Distension of the uterine cavity with 2 ml of an optically clear fluid increased the fluence rate at the fundus between the fibres at a depth of 2 mm by a factor of 4. We conclude that in normal-sized pre-menopausal uterine cavities, three diffusing fibres will deliver an optical dose above the photodynamic threshold level at a depth of 4 mm, even in the most remote areas, in <30 min without causing thermal damage. For distorted and elongated cavities, either slight distension of the cavity or the insertion of a fourth diffusing fibre is require

Photomedicine of the endometrium: experimental concepts

Gynaecological photomedicine offers new diagnostic and therapeutic methods based on the interaction of light with the reproductive organs. One example is photodynamic therapy (PDT) in which photosensitizers are applied systemically or topically for selective endometrial ablation. Several studies describing the potential use of PDT for this application are reviewed. Basic experimental and clinical aspects of PDT, such as photosensitizer types, application modes, irradiation parameters, optical properties of tissues and photodegradation of photosensitizers are discusse

Uterus and endometrium: Regeneration processes in rabbit endometrium: a photodynamic therapy model

The origin and process of regeneration in rabbit endo metrium was evaluated following photodynamic epithelial destruction using topically applied anilnolevulinic acid (ALA). Selective destruction of endometrial epithelium was performed using photodynamic therapy (PDT). ALA was diluted to 200 mg/ml dextran 70 shortly prior to adininistra tion. A volume of 1.2 ml was injected into the left uterus. Intrauterine illumination (wavelength 630 nm, light dose 40-80 J/cm2was performed 3 h after drug administration. Tissue morphology was evaluated by light and scanning electron microscopy 1, 3, 7 and 28 days post-treatment (three animals at each dine-point). Regeneration of the endometriwn following epithelial ablation by PDT was fully activated after 24 h and was completed after 72 h. Endometrial surface generation occurred by proliferation, originating primarily in deeper regions of the glands. Findings from our morphological follow-up study support the origin of endometrial regeneration being mainly from undifferentiated stem cells and residual glandular epitheliu

Optical Properties of Human Uterus at 630 nm

The optical properties of normal and fibriotic human uteri were determined using frequency-domain and steady-state techniques

Minimally-invasive debulking of ovarian cancer in the rat pelvis by means of photodynamic therapy using the pegylated photosensitizer PEG-m-THPC

Interstitial photodynamic therapy (PDT) using the pegylated photosensitizer PEG-m-THPC was evaluated as a minimally-invasive procedure to selectively debulk unrespectable pelvic ovarian cancer (NuTu-19) in immunocompetent rats. To assess tumour selectivity, PEG-m-THPC at dosages of 0.3, 3.0 and 30 mg kg−1 body weight was administered intravenously to 30 rats 4 weeks following tumour induction. Eight days later laser light at 652 nm and optical doses ranging from 100 to 900 J cm−1 diffuser-length was delivered by an interstitial cylindrical diffusing fibre inserted blindly into the pelvis. Three days following light application, the volume of necrosis was measured and the damage to pelvic organs was assessed histologically on cross sections. For analysis of survival, 20 tumour-bearing rats received PDT using drug doses of 3 or 9 mg kg−1 body weight and an optical dose of 900 J cm−1 diffuser-length, whereas ten untreated tumour-bearing rats served as controls. The histological assessment of PDT induced necrosis showed a non-linear dose–response for both the photosensitizer dose and the optical dose. The lowest drug dose activated with the highest optical dose did not induce more necrosis than seen in tumour-bearing control animals. The same optical dose induced necrosis of 17 mm in diameter using 30 mg kg−1 and 11 mm using 3 mg kg−1 photosensitizer. The optical threshold for induction of significant necrosis was between 100 and 300 J cm−1 diffuser-length for 30 mg kg−1 and between 300 and 500 J cm−1 for 3 mg kg−1 PEG-m-THPC. Significant damage to normal pelvic organs was only seen if 30 mg kg−1 photosensitizer was activated with optical doses of 700 J cm−1 or more. In the survival study, all treated animals survived PDT for at least 2 weeks and the intestinal and urinary tract remained functional. No clinical signs of blood vessel or nerve injury were observed. Mean overall survival of untreated tumour-bearing rats was 25.0 ± 4.5 days compared to 38.4 ± 3.8 days and 40.0 ± 3.6 days for rats treated with 3 mg kg−1 or 9 mg kg−1 PEG-m-THPC mediated PDT respectively (P < 0.05). We conclude that PEG-m-THPC mediated PDT has a favourable therapeutic window and that this minimally-invasive procedure can reduce pelvic cancer bulks effectively and selectively. © 1999 Cancer Research Campaig

Rat reproductive performance following photodynamic therapy with topically administered Photofrin

A rat animal model was used for comparing the photodynamic efficacy of two formulations of topically administered Photofrin in the uterus: 0.7 mg/kg Photofrin and 0.7 mg/kg Photofrin + 4% Azone, a penetrationenhancing agent. Uterine structure and reproductive performance were evaluated following illumination with 80 J/cm2 of 630 nm light. Fluorescence microscopy was employed to determine drug localization in frozen uterine sections at various times after drug administration. Functionality studies demonstrated a significant reduction in the number of implantations per treated uterine horn compared to controls. The mean number of implantations decreased systematically on increasing the interval between Photofrin administration and light application. At 72 h, 0.88 ± 0.52 gestational sacs per rat were recorded with Photofrin therapy, compared with 8.1 ± 1.12 (P = 0.01) on the untreated side, indicating nearly complete loss of reproductive capability. Similar results were achieved after only 3 h treatment with Photofrin + Azone (0.38 ± 0.26 sacs per rat versus 7.5 ± 1.07 on the untreated side; P = 0.01). This indicates that the effect of Photofrin can be enhanced either by extending the drug incubation period from 3 to 72 h or by adding the penetration-enhancing drug Azone. Fluorescence pharmacokinetic studies suggest that both forms of topically administered Photofrin are diffusely distributed throughout the endometrium at virtually the same rate. However, Azone may enhance the selectivity of photodynamic therapy by facilitating drug targeting to critical endometrial structure