Photodiagnosis Photodyn Ther
September 2022
Background: Photodynamic therapy (PDT) has been reported as an excellent option for the treatment of small nodular basal cell carcinomas (nBCC). The standard protocol consists of two sessions, one week apart. Sometimes, returning to the hospital after one week can be impractical for elderly patients, due to comorbidities and mobility issues.
View Article and Find Full Text PDFMelanoma is the most aggressive type of skin cancer and a relevant health problem due to its poor treatment response with high morbidity and mortality rates. This study, aimed to investigate the tissue changes of an improved photodynamic therapy (PDT) response when combined with optical clearing agent (OCA) in the treatment of cutaneous melanoma in mice. Photodithazine (PDZ) was administered intraperitoneally and a solution of OCA was topically applied before PDT irradiation.
View Article and Find Full Text PDFDecreasing incubation time, as well as enhanced PpIX production, are present challenges for topical photodynamic therapy (PDT). There are reports concerning the existence of a strong relationship between site temperature and porphyrin synthesis in biological tissue, that suggest temperature increase in the tissue can improve the formation of PpIX. The main objective of this study is to determine whether the temperature change of the tissue favors the production of PpIX.
View Article and Find Full Text PDFEvaluating the optical properties of biological tissues is needed to achieve accurate dosimetry during photodynamic therapy (PDT). Currently, accurate assessment of the photosensitizer (PS) concentration by fluorescence measurements during PDT is typically hindered by the lack of information about tissue optical properties. In the present work, a hand-held fiber-optic probe instrument monitoring fluorescence and reflectance is used for assessing blood volume, reduced scattering coefficient, and PS concentration facilitating accurate dosimetry for PDT.
View Article and Find Full Text PDFThe limited adoption of photodynamic therapy (PDT) around the medical field may be tied to the unpredicted treatment response that an unmonitored therapy could deliver. Given the high variability in the lesions optical and physiological parameters, it is of fundamental importance to monitor PDT, since different lesions require different therapeutic parameters. We developed a system to treat and online monitor PDT of skin cancer, using protoporphyrin-IX (PpIX) near-infrared fluorescence imaging.
View Article and Find Full Text PDFThe changes in tissue temperature of basal cell carcinoma lesions were investigated during photodynamic therapy in order to better understand the effects and mechanisms of PDT in tissue. In this study, the monitoring of 40 lesions of basal cell carcinoma was performed during photodynamic therapy. The lesion region becomes thermally evident throughout the procedure, and there is an improved contrast of the lesion edges after the end of the irradiation.
View Article and Find Full Text PDFAlong the past years, a national program to implement photodynamic therapy (PDT) for nonmelanoma skin cancer (NMSC) was performed over the Brazilian territory. Using a strategy involving companies, national bank, and medical partners, equipment, medication, and protocols were tested in a multicenter study. With results collected over 6 years, we could reach a great deal of advances concerning the use of PDT for skin cancer.
View Article and Find Full Text PDFNon-melanoma skin cancer is the most prevalent type of cancer in Brazil and worldwide. Topical Photodynamic Therapy is a technique that offers advantages as: excellent aesthetic result, possibility of application for outpatients in ambulatory setting, and presenting a minimum functional impact of the treated anatomic site. Fractionated Photodynamic Therapy is a modification of the usual technique in which the full dose of light is delivered in steps separated by a periods of time ("dark intervals").
View Article and Find Full Text PDFPhotodynamic Therapy (PDT) is a treatment that requires light, a photosensitizing agent, and molecular oxygen. The photosensitizer is activated by light and it interacts with the oxygen that is present in the cellular microenvironment. The molecular oxygen is transformed into singlet oxygen, which is highly reactive and responsible for the cell death.
View Article and Find Full Text PDFUltraviolet (UV) radiation may induce skin alterations as observed in photoaging. Some recognized modifications are epidermal hyperplasia, amorphous deposition of degraded elastic fibers and reduction in the number of collagen fibers. They alter the tissue biochemical properties that can be interrogated by steady state fluorescence spectroscopy (SSFS).
View Article and Find Full Text PDFPhotodynamic therapy (PDT) has been widely used for oncologic indications, especially nonmelanoma skin cancer such as superficial and nodular basal cell carcinoma (BCC). We present a multicenter clinical study conducted between 2012 and 2014 analyzing the adverse reactions during and after PDT with a standardized protocol in 866 lesions. A total of 728 patients with positive clinical and histopathological diagnosis for BCC with up to 2 cm diameter were treated.
View Article and Find Full Text PDFPhotodynamic therapy (PDT) has been used for local treatment of several types of tumors. Light penetration of biological tissue is one limiting factor in PDT, decreasing the success rates of the treatment of invasive and solid tumors. In those cases, a possible solution is to use interstitial PDT, in which both diffuser optical fibers are inserted into the tumor.
View Article and Find Full Text PDFCancer is one of the major challenges for Latin America health services, since the skin cancer is the most frequent lesion. This manuscript addresses an initiative for the treatment of basal cell carcinomas (BCC) by photodynamic therapy (PDT) based on a government-funded national program in Brazil. The program provides clinical training and facilitates access to drugs/equipment and significantly reduces PDT costs.
View Article and Find Full Text PDFMelanoma is the most aggressive skin cancer type. It is characterized by pigmented lesions with high tissue invasion and metastatic potential. The early detection of melanoma is extremely important to improve patient prognosis and survival rate, since it can progress to the deadly metastatic stage.
View Article and Find Full Text PDFPurpose: To evaluate the transdentinal light attenuation of LED at three wavelengths through different dentin thicknesses, simulating cavity preparations of different depths.
Methods: Forty-two dentin discs of three thicknesses (0.2, 0.
Non-melanoma skin cancer is the most prevalent cancer type in Brazil and worldwide. Photodynamic therapy (PDT) is a noninvasive technique with excellent cosmetic outcome and good curative results, when used for the initial stages of skin cancer. A Brazilian program was established to determine the efficacy of methyl aminolevulinate (MAL)-PDT, using Brazilian device and drug.
View Article and Find Full Text PDFThe effects of laser etching on dentin are studied by microenergy-dispersive x-ray fluorescence spectrometry (μ-EDXRF) and scanning electron microscopy (SEM) to establish the correlation of data obtained. Fifteen human third molars are prepared, baseline μ-EDXRF mappings are performed, and ten specimens are selected. Each specimen received four treatments: acid etching (control-CG) or erbium:yttrium-aluminum-garnet (Er:YAG) laser irradiation (I-100 mJ, II-160 mJ, and III-220 mJ), and maps are done again.
View Article and Find Full Text PDFOne of the clinical limitations of the photodynamic therapy (PDT) is the reduced light penetration into biological tissues. Pulsed lasers may present advantages concerning photodynamic response when compared to continuous wave (CW) lasers operating under the same average power conditions. The aim of this study was to investigate PDT-induced response when using femtosecond laser (FSL) and a first-generation photosensitizer (Photogem) to evaluate the induced depth of necrosis.
View Article and Find Full Text PDFThe objective of this work was to evaluate photodynamic therapy (PDT) by using a hematoporphyrin derivative as a photosensitizer and light-emitting diodes (LEDs) as light source in induced mammary tumors of Sprague-Dawley (SD) rats. Twenty SD rats with mammary tumors induced by DMBA were used. Animals were divided into four groups: control (G1), PDT only (G2), surgical removal of tumor (G3), and submitted to PDT immediately after surgical removal of tumor (G4).
View Article and Find Full Text PDFThe aim of this study was to evaluate the apical sealing of dentinal tubules after root-end surface cutting by using Er:YAG and Nd:YAG lasers. After root-canal instrumentation and filling, apices of 50 extracted maxillary canine human teeth were resected by Er:YAG with 400 mJ, 10 Hz, for 30 sec. The samples were randomly assigned to five groups (n = 10): (GI) treated without root-end cavity, but with Nd:YAG (1.
View Article and Find Full Text PDFThe purpose of our investigation is to compare the intrapulpal temperature changes following blue LED system and halogen lamp irradiation at the enamel surface of permanent teeth. The fixation of brackets using composite resin is more comfortable and faster when using a photo-curable composite. Several light sources can be used: halogens, arc plasma, lasers, and recently blue LED systems.
View Article and Find Full Text PDFObjectives: The purpose of this work is to investigate comparative ablation rate between composite resins and dental hard tissues (enamel and dentin) after Er:YAG laser irradiation to verify possible development of an ultra-conservative dentistry to with minimum effect for the teeth tissue.
Methods: We have used 11 extracted or exfoliated primary anterior and posterior teeth and six extracted permanent molar teeth. Three different types of composite resin were chosen (microfiller, hybrid, and condensable) in terms of chemical and structural composition.
Background And Objectives: We have investigated the fundamental aspects of Nd:YAG laser at the picosecond pulse regime interacting with primary teeth. Because little is present in the literature concerning specific laser ablation for primary teeth with respect to enamel and dentin, this work may open perspectives for new investigations.
Study Design/materials And Methods: Using a picosecond Nd:YAG laser, different power levels (200, 300, and 350 mW) and different exposition times (5, 10, and 15 seconds) were considered.