ヒト下垂体腺腫に対する新しい治療法を開発する基礎実験として, pheophorbide-a(Ph-a)を用いた光化学療法の効果を培養ラット下垂体腫瘍細胞(GH3) で検討した。Ph-aの溶解はアルカリ溶解法により行い. 光源は白色光を用いた。
1)Ph-a濃度: 前処理は120分間, 光照射は15分で検討した。殺細胞効果はPh-a濃度依存性に見られ, その生存細胞率は. 100.000lux照射群では125×10^-6M54%, 2.50×10^-6M19%, 5.00×10^-6Mでは2%であった。
2)光照射強度: 殺細胞効果は光照射強度に応じて見られ. その細胞生存率はPh-a濃度5.0×10^-6Mでは50,000lux: 16%, 100,000lux: 2%であった。
3) 前処理時間: 光照射は50.000lux, 15分間で検討した。前処理時間に応じ殺細胞効果がみられ. Ph-a濃度2.5×10^-6Mでは前処理時間60分で生存細胞率は86%. 90分で71%, 120分で54%であった。
4) vitamin E の光化学効果防御作用: Ph-a濃度5.0×10^-6M, 前処理120分, 光照射50,0001uxの条件下で検討した。Ph-a+光照射では生存細胞率は18%に低下したが, Ph-a+Vitamin E (1.0μg/ml)+光照射では. 35%と有意に上昇し, Vitamin Eによる光化学効果防御作用がみられた。

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Laser treatment has originally been regarded as a non-contact method, but the so called contact method, in which Quartz fiber is brought into direct contact with the tissue, was developed in 1983. Furthermore, with the introduction of new ceramics (Al₂O₃) into laser treatment in 1985, indications of laser surgery have been remarkably expanded.
Advantages of the contact method are: (1) The depth of tissue destruction can be adjusted according to the objectives of the treatment. (2) Hemostasis in deep tissues is possible. (3) Effects similar to those of the non-contact method can be obtained at a lower power (50%). (4) Good cutting ability. (5) High safety.
Laser treatment has recently been applied to new areas such as laser thermia and photo-dynamic therapy and is considered to be a highly promising medical technique.

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医療レーザー, 特にレーザーメスと呼ばれる装置は, 近年日本をはじめとしてUSA, ヨーロッパでもNd: YAG. 特にコンタクトメソッドが主流となってきた。これは.
1.多くの臨床応用性 2. ポータブル性 3. 操作性 4. 価格 5. 安全性
これらの面で他に比し, 大変優れていることによる。85以来 Nd: YAGを利用したレーザーミア(レーザー温熱)による癌冶療, 光化学冶療(感光剤フェオフォーバイドA),コンタクトレーザーアンジオプラスティーなど高度医療への応用も倹討されている。

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Since middle of 1970s, endoscopic laser treatment had been applied hemostasis in the upper GI tract by Frülimorgen P. et al., Dwyer R. M. et al., Kiefhaber P. et al. and so on. At the beginning of 1980s,. Nd: YAG laser endoscopy was applied clinically for the treatment of the GI tumors. From 1984 we have been developing the Nd: YAG laser contact method with several contact probes and a computer-controlled Ncl: YAG laser hyperthermia (Laserthermia) system in cooperation with Surgical Laser Technologies Japan Co.. The experimental studies and technical developments of Nd: YAG laser endoscopy in our hospital were discussed in this paper.
Nd: YAG laser contact method with various kinds of contact probes could treat every type of lesions as endoscopic photocoagulation, vaporization, mucosal cutting, Laserthermia. Actually clinical effects by contact method had been risen about 15-25%, higher than those by the conventional non-contact method. However, it was difficult treating all of the cases concering GI tumors by laser endoscopy alone. Therefore many patterns of the combination therapy of the contact laser methods and the other endoscopic therapeutics and general treatments should be necessary. According to the experimental studies on the ENNG induced gastric tumor in beagle dogs and the transplanted human gastric cancer in nude mice, mucosal GI cancer could be treat by Laserthermia only. On the other hand, the stimulation in the interstitial tissue of the canine stomach and the transplanted human gastric cancer in nude mice as a increase of active collagenase and marked increase of collagen fiber may suggest specific reaction by Laserthermia. We have continuously to study whether these tissue stimulation could be benefit or not in the treatment of GI tumors.^15,16)
The contact method with various contact probes made endoscopic laser therapy easy and safe. Then it is possible to treat endoscopically not only photocoagulation and varporization but also mucosal cutting, interstitial irradiation and Laserthermia. Now we are going to study the Laserthermia by a single channel method using the newly developed Hybrid probe and therapeutic UGI fiberscope (GIF-WT; Olympus).¹⁷⁾

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In 1983 we developed a contact method of Nd: YAG laser irradiation using microprobes made of artificial sapphire. Clinical study of this method has yielded excellent results except in depressed typed early gastric cancer.
We pursued a new method of Nd: YAG laser irradiation for the depressed typed early gastric cancer by applying through an interstitial probe for local hyperthertnia using prolonged, low-powerd contact laser irradiation. Since 1984 we have investigated this method in experimental and clinical studies. We obtained the following results: 1) Initial alteration of cancer tissue after laserthermia treatment observed with light microscopy was dominated by the damage of tumor vessels. 2) Mitochondria may by the primary target in the cell destruction process induced by laserthermia in the electron microscopy. 3) Pathlogical change of the gastric wall after lasertherrnia treatments for 18 preoperative patients indicated the satisfactory penetration and safety of lasertherrnia. 4) Expect for 2 patients with depressed undifferenciated cancer, no local recurrence was found on 13 inoperable patients aiming for complete eradication of cancer cells by lasertherrnia. We propose that laserthermia is the safest and most effective form of treatment for deperssed cancer.

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接触照射法の利点は, (1)煙の発生が少なく, 観察中の視野を確保しやすい, (2)目的部位に蔦現性のある照射が行える, (3)プロープの燃焼破損が少ない, (4)アシストガスの代りにアシスト水を用いて照射可能であることから患者の苦痛を軽減させうる, などの点があげられる。早期霄癌の治療に際しては, 病巣の大きさ, 存在部位に応じて非接触照射法も適宜用いるが, とくに幽門前部や胃体中～上部の病変では正面視での照射が困難で不確実になるため, 接触照射法が選択される。また, 病巣の範囲を正確に把握して治療を行うことは重要な点であるが, われわれは接触照射法で初めに境界部をマーキングしてから照射を進めている。以上のような接触照射法の利点を取り入れて当センターではこれまでに早期胃癌83例89病変のレーザー内視鏡治療を行ってきた。そのうち42病変は接触照射法あるいは両者の併用により治療してきた。
特に2cm以下のIIa, 胃炎類似型およびfocal cancer in adenomaのものは100%の有効率である。

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We applied the Nd: YAG laser to 75 patients with advanced cancer in the upper G. I. tract for improving the stricture. In the 75 patients, 27 were treated by the noncontact irradiation method and 48 were by the contact method. For evaluating an effect of the stricture improvement, we studied from two points of view. One was the frequency of the laser treatment until making an endoscope passed through the stricture, and the other was the time occupied for the improvement of diet.
The former in the contact method was lower than that in the non-contact method (P<0.05). The latter in the contact method was more rapid than that in the non-contact method (P<0.05).
The findings resulted from the contact method to be superior to the non-contact in view of as follows: 1) shorter time occupied for the improvement of diet, 2) less difficulty of treatment of the stricture in the pyloric region, that in the post-operative stoma, and linitis plastica type of cardiac region, 3) accuracy in the target irradiation, and 4) occasionally minor bleeding, a field lens little covered with soot, and visual field keeping clear, in the contact method.

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The development of hyperthermia therapy to cancer has been highly reputed by its good results. Effectiveness of fever for a malignant tumor was reported firstly by Dr. W. Busch, 1866. He had experienced a patient with high fever by erysipelas, which caused the disappearance of a sarcoma at the: face.
As well known, hyperthermia therapy combined with radiotherapy for cancer has been performed, clinically. It has been well known that living cancer cell and a cancerous lesion are more fragile to higher temperature as: 42 to 45 degrees than the normal. This principle has been applied to hyperthermia therapy, of which energy ultrasonic wave and radio: frequency have been: adopted.
Recent few years, contact irradiation of Nd: YAG laser using ceramics tip is performing increasingly for treating cancer of GI tract, compared to its non-contact irradiation. The tip can be injected into a cancerous lesion of GI tract and increase its temperature up to 42-45 degree at a lower power: level (3-5w) of Nd: YAG laser irradiation for: 15-30 minutes, causing its destruction. This range of the temperature is controlled by control system using a computer. This effect is called laserthermis, laser hyperthermia or local interstitial laser hyperthermia.
Clinically, laserthermis is able to applied more safely than ordinary laser irradiation, not only to radical treatment of early cancer, but also recanalization of obstruction due to the advanced cancer of GI tract. Balloon laserthermia using Nd: YAG laser has been studied for this purpose. The effect of laserthermia is used to be increased in combination therapy with cancer chemotherapy or radiotherapy. There is one of the significances: of laserthermia in the meaning of the endoscopic treatment for residual carcinoma after the other endoscopic treatments.

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