Photodynamic therapy (PDT), which utilizes laser light and photosensitizer (PS), is now arising as a potential modality for minimally invasive prostate cancer therapy due to its cancer selectivity. However, cancer selectivity and drug accumulation efficiency have to be enhanced to eliminate unwanted side effects and to shorten the time requirement for shielding from light. Therefore, to accomplish high accumulation and selective delivery, we have focused on the drug delivering system of replication-deficient Sendai virus particle, hemagglutinating virus of Japan envelope (HVJ-E). We are currently investigating the therapeutic effectiveness of PDT with a novel photosensitizer named porphyrus envelope, which can be created by combining HVJ-E and PS called protoporphyrin IX (PpIX). This paper will discuss about the drug delivering mechanism of this novel photosensitizer.

Verruca vulgaris is a benign proliferative disease of the skin and mucosal tissue, which is caused by an infection of human papillomavirus. A cryotherapy using liquid nitrogen is commonly considered to be a standard treatment ; however the clinicians occasionally experience some cases which are resistant for the standard therapy. In this time, we tried a treatment with a long-pulsed dye laser mainly for the recalcitrant cases. Consequently, of the ten patients treated, six (60.0%) patients were cleared. We found that treatment using pulsed dye laser is effective for recalcitrant verruca vulgaris. In addition, side effects, such as a scar formation or post-inflammatory pigmentation, were hardly observed. Therefore, we consider that a long-pulsed dye laser therapy can be one of the useful options of the treatment for an intractable verruca vulgaris.

Since 2013, novel picosecond duration lasers (ps-lasers) have become commercially available and the subsequent clinical trials have reported the safety and efficacy in treating multicolored and recalcitrant tattoos. It is considered that irradiation of targets with the ultra-short picosecond pulses can induce almost instantaneous heating of chromophores in the skin and greater fragmentation of the targets in an almost nonlinear fashion, with even less damage to adjacent structures than was achieved with the ns-domain lasers. These laser-tissue interaction caused by picosecond duration laser irradiation is named photoacoustic or photomechanical effect, not photothermal effect.Application of the ps-laser for the treatment of unwanted tattoos was started in authors’ clinic from December 2013. From our experience of the great success of tattoo removal with the ps-laser, we have also started the treatment of epidermal or dermal benign pigmented lesions with ps-lasers, and have obtained good clinical results without persistent adverse effects such as post-inflammatory hyper-pigmentation, hypo-pigmentation and scarring.These novel laser devices, which have been developed based on the theory of ps-laser tissue interaction, might set the fashion for the new approach to treat the cutaneous pigmented lesions.

Picosecond lasers for tattoo removal which were available from the year 2012, and they have been distributed from 3 manufactures. Even though the pulse duration for those lasers all have their distinctive characteristics, it could be applicable for nanosecond lasers target treatment lesions such as benign pigmented dermatosis since wavelengths are utilizing 532, 755, 1064 nm. This study investigated picosecond laser efficacy for treatments of solar lentigo and acquired dermal melanosis using 532 nm wavelength and 750 ps pulse duration.

A series of picosecond lasers, having shorter pulse durations within less than 1 ns, are newly being used in the field of dermatologic laser surgery. Stress relaxation theory is considered to be involved in the actual setting, enabling higher efficiency in tattoo removal using picosecond lasers compared to conventional nanosecond Q-switched lasers. Furthermore, picosecond lasers are increasingly being anticipated to be used for aesthetic skin treatment. However, evidence for this aesthetic effect remains scarce thus far. Therefore, future studies on development of the technique are warranted.

Though firefly bioluminescence is utilized as a luciferase reporter assay in cell imaging and in vivo imaging technologies, the maximum emission spectrum circa 560 nm of the wild bioluminescence is not suited for deep tissue imaging. We innovated an artificial luciferin with an NIR emission ca. 675 nm, marketed as an “Aka Lumine”. “Tokeoni,” with an NIR emission ca. 675 nm, is a next generation artificial luciferin will be put on the market soon. It will be used for optical imaging of a miniature pig.

With advancements in bioimaging research and developments of model animals for it, we can detect various stress, activation of some molecules, and dynamics of specific bioactive substances non - or less- invasively in vivo in these days. Here I would like to introduce several transgenic animal models that generated for imaging in vivo in Japan.

We share our experience of developing a fiber-bundle based micro-endoscope system which can be inserted into deep brain area and can provide cellular imaging in freely moving animals. We built it using commercially available optic components which enabled easy modification according to each experiment with minimal costs. Tips for choosing optical configuration and for recording in freely moving animal were discussed.

PET (Positron Emission Tomography) is a less-invasive molecular imaging method that is used for clinical diagnosis and evaluation of drug candidates at the early stage of drug development. This article reviews recent achievements on PET chemistry with a focus on the development of PET probes, particularly for small molecules labeled with a short-lived positron-emitting radionuclide such as carbon-11 or fluorine-18.

PET (positron emission tomography) is a technology to make image by detection of gamma ray emitted from molecules chemically introduced with positron-emitting short-half-life radionuclides. Thus, PET can give us information of distribution and dynamics of molecules inside the body of animals and humans, while CT and MRI visualize the structural information of that. In this paper, we introduce a basic PET study with [¹⁸F]FDG which is most frequently used in the clinical field, and recent PET studies with another molecular probe which can be used for visualizing brain neuroinflammation in animals and also in humans, in addition to the technological principle of PET study.