波長980 nm の高出力ダイオードレーザーおよびTwister<sup>TM</sup> Large Fiber を用いた接触式前立腺蒸散術（CVP）

Abstract

High power 980 nm diode laser vaporization of the prostate was introduced since 2007 to the western countries and has proven its efficiency and safety. Using TwisterTM Fiber instead of side-firing fibers, the procedure can be done in the contact manner with higher efficacy and durability. In Japan, the clinical trial for PMDA approval was performed from April 2013 and proved its safety and non-inferiority of IPSS to TURP. Since the absorption coefficients of 980 nm laser to the major chromophores of prostate (hemoglobin and water) are not so high as those of 532 nm (KTP laser or LBO laser) to hemoglobin and of 2100 nm (Ho:YAG laser) to water, the absorption depth to prostatic tissue is higher. Thus, the high efficiency of vaporization and hemostasis are assumed to be achieved when the high energy is applied. It was shown in ex vivo experiment of bovine prostate using 300W that the vaporization depth was about 3 mm and the coagulation depth was 1.2 mm after 1 sec irradiation. Clinically, the heat affected depth of prostate from urethral cavity was about 5 mm which was recognized as a low signal zone in the T2 image of MRI at two weeks after operation. Considering comparatively larger coagulation depth, on the counter side of high efficiency of vaporization and hemostasis, this modality is quite efficient and user-friendly.