We studied the concentration change of talaporfin sodium in human skin by in silico pharmacokinetics model for quantitative evaluation of skin photosensitivity risk. Talaporfin sodium is clinically applied with light shading in a room of less than 500 lux for two weeks. Although it doesn’t prescribe a hospitalization, basically two weeks of hospitalizations are conducted. In order to reduce patient burden and medical costs, it is necessary to obtain the scientific evidence on the safety of skin photosensitivity. We performed a clinical study of the talaporfin sodium fluorescence measurement in skin tissue using our developed transdermal fluorescence measurement system. This clinical study was conducted at Tokyo Medical University Hospital and Nippon Medical School Hospital. Talaporfin sodium concentration change was evaluated by measuring talaporfin sodium fluorescence using a blue LED (wavelength 409 ± 16 nm) for excitation of the Soret band absorbance peak. We investigated the time range where the skin photosensitivity risk is high after administration, by using an in silico pharmacokinetics model to predict the continuous photosensitizer concentration change in skin tissue.

We conducted objective observations and compared the crushing effects of engineered energy caused by laser radiation according to the irradiation distance to the target as well as the irradiation direction. Observations were carried out in a water bath and the behavior from bubble formation to collapse was observed with a high-speed video camera synchronized with the impact at bubble collapse. Observations of the behavior and impact energy of induced bubbles in the vicinity of the wall clearly indicated that there is an optimal irradiation distance from the target and that it differs depending on the irradiation direction. Experiments were carried out with fibers placed parallel or perpendicular to the solid wall surface. We found that the acquisition of effective energy by laser irradiation has different characteristics depending on the irradiation direction and irradiation environment, and that it is possible to acquire effective energy and avoid influencing the peripheral tissues by adapting the irradiation style to various situations.

Since the 1960’s, basic and clinical research has been conducted regarding the biostimulative effects of photobiomodulation (PBM) by means of low-reactive level laser therapy (LLLT). A number of studies have used low-level diode lasers in near-infrared to infrared wavelengths because of their high degree of tissue penetration. In the dental field, it has been shown that LLLT enhances proliferation, migration, and differentiation of gingival fibroblasts, osteoblasts, periodontal ligament cells, as well as mesenchymal stem cells in vitro. Furthermore, LLLT promoted wound healing and bone formation in vivo. Currently, less invasive and safer procedures are desired for dental treatment, especially for regenerative therapy. It is expected that PBM by means of LLLT will contribute to attaining that goal. Consequently, we have reviewed basic and clinical studies using the diode laser for LLLT, and we discuss the potential of LLLT in promoting periodontal tissue healing and regeneration.

Photodynamic therapy in dental treatment is performed as antimicrobial therapy against bacterium in periodontal pockets and peri-implant sulcus. However, we consider that photodynamic therapy can be applied to hard tissue regenerative therapy by using light emitting diodes. Our current studies on hard tissue formation biology is introduced in this study.

The guidelines for the intended use of dental lasers released by the United States Food and Drug Administration includes “coagulation of extraction sites”. Carbon dioxide lasers is one of the laser technologies recommended for this treatment. However, there are virtually no reports of the biological basic research on carbon dioxide lasers. In this paper, the authors describe some of the biological basic research conducted to elucidate the effects of carbon dioxide laser therapy after tooth extraction on wound healing in the extraction socket, and report the effects on the specific formation of new bone and the cicatrization of the extraction socket mucosa in particular.

The 2.94 μm wavelength Er:YAG laser is strongly absorbed by water and is able to effectively ablate both soft and hard tissues. In periodontal treatment, Er:YAG lasers are used to debride inflammatory granulation tissue and calculus. Recently, we developed a novel bone regenerative procedure, Er:YAG laser-assisted bone regenerative therapy (Er-LBRT), which induces blood clot coagulation in the superficial areas of grafted bone. We have applied this technique in periodontal regenerative therapy. Er-LBRT achieved successful clinical outcomes that are more than equivalent to those seen with conventional periodontal regenerative therapy. Furthermore, Er-LBRT was applied to regenerative therapy in peri-implantitis treatment. In this article, the Er-LBRT procedure is introduced and its effectiveness is discussed based on clinical evidence.

Photodynamic therapy (PDT) using talaporfin sodium (talaporfin-PDT) and laser irradiation (PD-laser) has been applied clinically as a salvage treatment for local failure after chemoradiotherapy (CRT) in patients with esophageal cancer (EC) in Japan since October 2015. Twenty-eight patients were treated by salvage talaporfin-PDT from October 2015 to June 2018 in our hospital. The local complete response rate was 53.6% (15/28) in all patients, especially 60% (12/20) in patients with T1b stage before PDT. Salvage talaporfin-PDT is one of the curative treatment option for local failure after CRT in patients with EC in clinical practice.

Photodynamic therapy (PDT) using talaporfin sodium and PD laser (talaporfin-PDT) has been reported as an effective treatment for malignant diseases due to the high tumor accumulation of talaporfin sodium and the prolonged attainable depth of PD laser (wavelength: 664 nm). Talaporfin-PDT has been clinically applied as treatment for early stage lung cancer, primary malignant brain tumor, and salvage treatment for local failure after chemoradiotherapy (CRT) or radiotherapy (RT) in patients with esophageal cancer in Japan. Skin phototoxicity is the most important complication in PDT. Talaporfin sodium has a lower risk of skin phototoxicity compared with porfimer sodium, and requires shorter sun shade preriod (2 weeks vs 1 month). However, skin phototoxicity has been reported (0–14.8%) in some clinical trials using talaporfin-PDT. Therefore management for skin phototoxicity is essential in the treatment of talaporfin-PDT. In this article, we describe the management method for a skin phototoxicity after talaporfin-PDT in our hospital.

Photodynamic therapy (PDT) by laserphyrin was newly covered by insurance in 2015 for esophageal cancer, following early stage lung cancer and malignant brain tumor. In photodynamic therapy, light hypersensitivity caused by photosensitizer remaining on the skin is a problem. In order to avoid the risk of light hypersensitivity, in the case of laserphyrin, a light shading period of two weeks is prescribed, but the metabolism of the drug has individual differences, and this period is prescribed for patients with slow metabolism. This light shading period does not prescribe hospitalization, but in practice, hospitalization observation is often taken. For this reason, patients with early metabolism may be forcing redundant hospitalization. Therefore, we developed a monitoring system that can quantitatively and time-sequentially measure the amount of laserphyrin remaining on the skin by fluorescence measurement. The current qualitative judgment method is stipulated in the package insert of the medicine and its revision has a high difficulty, but the realization of quantitative evaluation has the merit of both patient quality of life improvement and medical cost reduction.

Laserphyrin PDT (photodynamic therapy) is a treatment using a photosensitizer, laserphyrin, and a diode laser. Laserphyrin PDT requires a certain sunshade period for the prevention of skin phototoxicity. Careful observations of general findings and endoscopical findings are also needed for two months after PDT. Here, we report this patient management of laserphyrin PDT.

We retrospectively analyzed 16 esophageal cancer patients who were treated by repeated photodynamic therapy (PDT) in our hospital from September 2005 to April 2018. All patients had recurrent esophageal cancer after chemoradiotherapy or radiotherapy. T-category before first PDT was T1 in 12 patients and T2 in four patients. After first PDT, seven T1 cancer patients initially achieved complete remission (CR) but later recurred. Five T1 and four T2 cancer patients had residual cancer. T-category before second PDT was T1 in 12 patients and T2 in four patients. After second PDT, nine of 12 T1 (75%) and none of T2 cancer patients achieved CR. The CR rate was 56.3%. Esophageal stricture, which required dilatation, developed in 37.5% (6/16 patients). Based on our experience, CR can be expected by repeated PDT in T1 cancer patients.

Recently, intraoperative fluorescence navigation system by photosensitive substances becomes the focus of attention. Intraoperative fluorescence navigation system is next-generation endoscopic technique. So this technique is necessary for accurate cancer diagnosis in clinical setting. Target lesion show fluorescence and detect accurate lesion and margin in real time. This technique assists our intraoperative diagnosis by color images. We introduce 5-aminolevulinic acid-based photodynamic diagnosis for bladder cancer.

In this review, photodynamic technology for managing prostate cancer is discussed. This treatment approach is divided into diagnostic and therapeutic uses. In cellular-targeted photochemotherapy, antitumor effects are conferred by irradiating cancer cells with photosensitizing substances, while in vascular-targeted photochemotherapy (VTP), these effects are conferred by irradiating vessels and their occlusions with photosensitizing substances. A phase III trial of VTP using WST11 as a focal therapy for prostate cancer has shown significant outcomes, and its clinical application has been anticipated. Regarding photodynamic diagnostics, the use of 5-aminolevulinic acid has been evaluated. However, further investigations are warranted to determine its efficacy in the clinical setting.

Protoporphyrin IX (PPIX) is synthesized from 5-aminolevulinic acid (5-ALA), accumulates at a high concentration in cancer tissue than normal tissue, and emits red fluorescence under blue light. Therefore, 5-ALA is currently used for photodynamic diagnosis (PDD) of bladder carcinoma. It is reported that the intensity of luminescence on the tumor correlate with grade of malignancy of bladder carcinoma. It is also reported that urine porphyrin measurement after 5-ALA administration may be useful for detecting urothelial carcinoma. In this study, we examined the usefulness of 5-ALA in renal cell carcinoma detection.