Position:  Associate Professor
Degree:   Doctor of Engineering
Laboratory:       Medical Beam Physics
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Development of safe and less invasive optical diagnosis and therapy

We are developing, in collaboration with medical doctors and manufacturers of medical devices, medical devices that use light, including a laser for safe diagnosis and therapy of various diseases such as cancer, benign prostatic hyperplasia, varicose veins, and gallstones. We are developing methods to quickly apply novel optical technologies to clinical diagnosis and therapy, using not only experimental evaluation but also molecular-level understanding of the mechanisms and computer simulation models for accurate estimation. For example, the photograph shows an animal experiment to evaluate a laser device for safe endoscopic treatment of early digestive cancers (e.g., esophagus, stomach, and colon cancers). In addition, it was recently found that cancer treatment using photodynamic therapy (PDT) can be performed not only with a laser, but also with a light-emitting diode (LED). A compact and low-cost device using an LED is very attractive as it would enable PDT to be more widely used in clinical treatment.

Development of techniques for laser ionization mass spectrometry

Using a laser, large labile molecules with molecular weights exceeding 10000  can be ionized without decomposition, and various molecules such as proteins and pharmaceutical drugs can be analyzed with mass spectrometry (MS). Biological samples are often analyzed by a combination of liquid chromatography (LC) and MS, because enormous numbers and types of molecules exist in biological samples. However, it is not possible to directly connect LC and MS, since laser ionization is usually performed in a vacuum chamber. Therefore, we are developing an atmospheric ionization technique using an infrared laser for high-throughput analysis of biological samples by directly connecting LC and MS. In addition, we are developing a molecular imaging technique by combining MS and microscopic imaging. Images of various molecules can be obtained simultaneously by separating the molecules according to their molecular weights. A device for cellular-scale, high-resolution MS imaging is also under development.

Publication

1. Ryuji Hiraguchi, Hisanao Hazama, Katsuyoshi Masuda, and Kunio Awazu: “Atmospheric pressure laser desorption/ionization using a novel 6–7 µm-band mid-infrared tunable laser and liquid water matrix,” Journal of Mass Spectrometry 50(1), 65–70 (2015).
2. Junya Takada, Norihiro Honda, Hisanao Hazama, and Kunio Awazu: “Ex vivo efficacy evaluation of laser vaporization for treatment of benign prostatic hyperplasia using a 300-W high-power laser diode with a wavelength of 980 nm,” Laser Therapy 23(3), 165–172 (2014).
3. Hiroki Kannen, Hisanao Hazama, Yasufumi Kaneda, Tatsuya Fujino, and Kunio Awazu: “Development of laser ionization techniques for evaluation of the effect of cancer drugs using imaging mass spectrometry,” International Journal of Molecular Sciences 15(7), 11234–11244 (2014).
4. Masaya Yamauchi, Norihiro Honda, Hisanao Hazama, Shoji Tachikawa, Hiroyuki Nakamura, Yasufumi Kaneda, and Kunio Awazu: “A novel photodynamic therapy for drug-resistant prostate cancer cells using porphyrus envelope as a novel photosensitizer,” Photodiagnosis and Photodynamic Therapy 11(1), 48–54 (2014).
5. 間久直, 守口直輝, 藤野竜也, 粟津邦男: “マトリックス支援レーザー脱離イオン化を用いた薬剤のイメージング質量分析に向けたゼオライトによるイオン化効率の向上,” 電気学会論文誌C 134(5), 657–663 (2014).