Looking at the socioeconomic trends (demographics, real economy, healthcare finance, etc.) surrounding the medical care field, it is becoming increasingly important to accumulate and utilize evidence from healthcare economics, such as cost-effectiveness evaluation, for the further development of medical care provision and R&D in Japan. In particular, in order to promote medical innovation and appropriate patient access, it is desirable to discuss the state of health economic evaluation in medical ethics and practice guidelines, while promoting the visualization of medical values, etc.

In recent research for cancer therapy, L-type amino acid transporter 1 (LAT1), which is highly expressed on many cancer cells, has been recognized as a promising target molecule. Indeed, the utility of targeting LAT1 has already been demonstrated in clinical studies of boron neutron capture therapy (BNCT). We utilized the knowledge gained from BNCT research, developed drug delivery systems (DDSs) that target LAT1, and extended its application to photosensitizer delivery. This article introduces our recent research for LAT1-targeted photodynamic therapy (PDT).

Recurrence of glioblastoma is often seen at the margins of the resection space and is attributed to the involvement of residual tumor cells, particularly highly infiltrative glioma stem cells (GSCs), in the same area. Although recent reports indicate that glioblastoma requires supra-total resection of the area surrounding the T1 gadolinium-enhancing lesion, it remains to be determined whether GSCs are present in this area. Therefore, if the location of GSCs can be accurately identified preoperatively and intraoperatively, tumor removal including GSCs, i.e., “true supra-total resection”, would be possible. Therefore, the development of new surgical assistance technology is needed. We evaluated 108 glioblastoma surgery cases from April 2017 to March 2025, and reported on the usefulness of the methionine accumulation rate assessment using 11C-Met-positron emission tomography (PET) and metabolic analysis using magnetic resonance spectroscopy (MRS) utilizing the LC-model as a method to identify the residual GSCs in the tumor margins. More recently, in addition to the conventional 5-aminolevulinic acid photodynamic diagnosis (ALA-PDD), we have quantitatively evaluated the 5-ALA fluorescence intensity at the margin of the resection cavity by spectroscopy using purple laser light to identify the extent of the GSC invasion intraoperatively in real time. We established three parameters for determining the extent of the resection: Tumor-to-normal contralateral ratio (TNR) >1.4 on 11C-Met-PET, lactate/creatin ratio >0.66 on MRS, and fluorescence intensity >1,000 a.u. on intraoperative 5-ALA-PDD quantitative assessment. In our current presentation, we discuss the advantages and disadvantages of tumor resection using conventional surgical instruments and present the efforts currently underway at our institution to identify tumor invasion sites using 5-ALA-PDD.

The emergence of multidrug-resistant bacteria has become a serious concern, highlighting the urgent need to promote the appropriate use of antibiotics and to develop new treatment strategies. Photodynamic antimicrobial chemotherapy (PACT), which is expected to be effective against a wide range of pathogenic microorganisms, including multidrug-resistant bacteria, is gaining attention, and related research on PACT is being actively conducted in human medicine. However, in veterinary medicine, research on PACT remains limited, and comprehensive reports are lacking. This review summarizes recent studies on PACT in veterinary medicine, categorized by disease, and discusses the potential and significance of its application in veterinary medicine.