Photodynamic therapy (PDT) is a technique used for several tumor types treatment. Light penetration on biological tissue
is one limiting factor for PDT applied to large tumors. An alternative is using interstitial PDT, in which optical fibers are
inserted into tumors. Cylindrical diffusers have been used in interstitial PDT. Light emission of different diffusers depends
on the manufacturing process, size and optical properties of fibers, which make difficult to establish an adequate light
dosimetry, since usually light profile is not designed for direct tissue-fiber contact. This study discusses the relevance of
light distribution by a cylindrical diffuser into a turbid lipid emulsion solution, and how parts of a single diffuser contribute
to illumination. A 2 cm-long cylindrical diffuser optical fiber was connected to a diode laser (630 nm), and the light spatial
distribution was measured by scanning the solution with a collection probe. From the light field profile generated by a 1
mm-long intermediary element of a 20 mm-long cylindrical diffuser, recovery of light distribution for the entire diffuser
was obtained. PDT was performed in rat healthy liver for a real treatment outcome analysis. By using computational tools,
a typical necrosis profile generated by the irradiation with such a diffuser fiber was reconstructed. The results showed that
it was possible predicting theoretically the shape of a necrosis profile in a healthy, homogeneous tissue with reasonable
accuracy. The ability to predict the necrosis profile obtained from an interstitial illumination by optical diffusers has the
potential improve light dosimetry for interstitial PDT.
Photodynamic therapy (PDT) is a treatment modality that can be indicated for several cancer types and pre-cancer lesions. One of the main applications of PDT is the treatment of superficial skin lesions such as basal cell carcinoma, Bowen’s disease and actinic keratosis. Three elements are necessary in PDT, a photosensitizer (PS); light at specific wavelength to be absorbed by the PS, and molecular oxygen. A typical PS used for skin lesion is protoporphyrin IX (PpIX), which is an intrinsic PS; its production is stimulated by a pro-drug, such as 5-aminolevulinic acid (ALA). Before starting a treatment, it is very important to follow up the PpIX production (to ensure that enough PS was produced prior to a PDT application) and, during a PDT session, to monitor its photodegradation (as it is evidence of the photodynamic effect taking place). The aim of this paper is to present a unique device, LINCE (MMOptics - São Carlos, Brazil), that brings together two probes that can, respectively, allow for fluorescence imaging and work as a light source for PDT treatment. The fluorescence probe of the system is optically based on 400 nm LED (light emitting diodes) arrays that allow observing the fluorescence emission over 450 nm. The PDT illumination probe options are constituted of 630 nm LED arrays for small areas and, for large areas, of both 630 nm and 450 nm LED arrays. Joining both functions at the same device makes PDT treatment simpler, properly monitorable and, hence, more clinically feasible. LINCE has been used in almost 1000 PDT treatments of superficial skin lesions in Brazil, with 88.4% of clearance of superficial BCC.
Onychomycosis is a common disease of the nail plate, constituting approximately half of all cases of nail infection. Onychomycosis diagnosis is challenging because it is hard to distinguish from other diseases of the nail lamina such as psoriasis, lichen ruber or eczematous nails. The existing methods of diagnostics so far consist of clinical and laboratory analysis, such as: Direct Mycological examination and culture, PCR and histopathology with PAS staining. However, they all share certain disadvantages in terms of sensitivity and specificity, time delay, or cost.
This study aimed to evaluate the use of infrared and fluorescence imaging as new non-invasive diagnostic tools in patients with suspected onychomycosis, and compare them with established techniques.
For fluorescence analysis, a Clinical Evince (MM Optics®) was used, which consists of an optical assembly with UV LED light source wavelength 400 nm ± 10 nm and the maximum light intensity: 40 mW/cm2 ± 20%. For infrared analysis, a Fluke® Camera FKL model Ti400 was used. Patients with onychomycosis and control group were analyzed for comparison. The fluorescence images were processed using MATLAB® routines, and infrared images were analyzed using the SmartView® 3.6 software analysis provided by the company Fluke®.
The results demonstrated that both infrared and fluorescence could be complementary to diagnose different types of onychomycosis lesions. The simplicity of operation, quick response and non-invasive assessment of the nail patients in real time, are important factors to be consider for an implementation.
Cancer is responsible for about 13% of all causes of death in the world. Over 7 million people die annually of this disease. In most cases, the survival rates are greater when diagnosed in early stages. It is known that tumor lesions present a different temperature compared with the normal tissues. Some studies have been performed in an attempt to establish new diagnosis methods, targeting this temperature difference. In this study, we aim to investigate the use of a handheld thermographic camera to discriminate skin lesions. The patients presenting Basal Cell Carcinoma, Squamous Cell Carcinoma, Actinic Keratosis, Pigmented Seborrheic Keratosis, Melanoma or Intradermal Nevus lesions have been investigated at the Skin Departament of Amaral Carvalho Hospital. Patients are selected by a dermatologist, and the lesion images are recorded using an infrared camera. The images are evaluated taken into account the temperature level, and differences into lesion areas, borders, and between altered and normal skin. The present results show that thermography may be an important tool for aiding in the clinical diagnostics of superficial skin lesions.