YONEZAWA Takumi Research Associate, Faculty of Medicine, The University of Tokyo, 医学部, 助手 (50221677)
ABE Yusuke Research Associate, Faculty of Medicine, The University of Tokyo, 医学部, 助手 (90193010)
|Budget Amount *help
¥6,900,000 (Direct Cost : ¥6,900,000)
Fiscal Year 1991 : ¥3,400,000 (Direct Cost : ¥3,400,000)
Fiscal Year 1990 : ¥3,500,000 (Direct Cost : ¥3,500,000)
Photodynamic therapy(PDT)of cancer with laser and photoreactive dye is very effective because of its high selectivity on damaging cancer tissue. Light source for PDT is not necessary to be laser. Light source with any wave length, which can excite photoreactive dye, will do. Solar light is one of such light source. In this study, we developed equipment which focused solar light to introduce solar ray to patients. With this equipment, westudied on PDT with solar ray.
Solar light, filtered with infrared filter, was reflected with main miffor of 180 mm diameter and was focused to 18 mm spot. On this stage, maximum power of 2.3W, mean power of I. IW was gained. On next stage, it collimated to 0.9 mm diameter optical fiber. Mean light power on output side of optical fiber was 0.26W. This equipment traced sun and maintained its output light power for 5 hours.
Focused solar ray was irradiated to cancer tissue on rat and effect of irradiation was studied pathohistologically. As PDTgroup, 4 mg/kg hematoporphyrin -(HPD)was administrated in abdominal cavity on 24 hours before irradiation. As control group, no HPD was administrated before irradiation. The irradiation was performed to subcutaneous cancer through skin for 30 minutes. Immediate change was not found on both group after irradiation.
Cancer reduction was found at 24 hours after irradiation on PDT group. After 1 week, cancer tissue was reduced by half. Histrogially, necrosis of cancer cell and infiltration of white blood cell were observed.
Usually, dye lasers have been used as PDT light source. The excitive wave length of HPD spread through visible light. In this basic study, solar light which covers this excitation range, causes effective PDT on cancer therapy.