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Photodynamic therapy: a review.

机译：光动力疗法：综述。

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Photodynamic therapy (PDT) of malignant tumours is a new technique for treating cancers. After intravenous injection, a photosensitiser is selectively retained by the tumour cells so after time there is more sensitiser in the tumour than in the normal adjacent tissue. The photosensitiser must be able to absorb the wavelength of light being delivered to it, and the amount of light getting to the photosensitiser depends on the characteristics of the tissue it passes through. When exposed to light with the proper wavelength, the sensitiser produces an activated oxygen species, singlet oxygen, that oxidises critical elements of neoplastic cells. Because there is less sensitiser in the adjacent normal tissue, less reaction occurs to it. Since this is an entirely different process, the use of chemotherapy, ionising radiation or surgery does not preclude the use of PDT. Also, unlike ionising irradiation, repeated injections and treatments can be made indefinitely. Different molecules and atoms absorb different wavelengths of energy. Since the light energy must be absorbed to start the photochemical reaction, the absorption spectrum of the photosensitiser determines the wavelength used to initiate the reaction. However, this can be qualified by the tissue the light has to travel through to get to the photosensitiser. The photosensitiser porfimer sodium has a peak absorption in the area of 405 nm (blue-violet) and a much lower absorption peak at 630 nm (red). However, because the longer red wavelength penetrates tissue deeper than 405 nm, we use the red wavelength, usually delivered from a laser system. This permits coupling of the red light beam to quartz fibres which can then be used with modifications to treat external surface tumours, inserted interstitially directly into large tumours, passed though any endoscope to treat intraluminal tumours, or inserted behind the retina to treat tumours of the retina. Twenty years after the pioneering work of Dr. Thomas Doherty, the US Food and Drug Administration (FDA) has approved the use of porfimer sodium for photodynamic therapy of endobronchial and oesophageal tumours. Research continues towards approval for management of skin cancers and metastatic cutaneous and subcutaneous breast cancers. The realisation that one of the mechanisms of photodynamic therapy is thrombosis of vessels led to the development of verteporfin to treat macular degeneration. Multiple other areas are being investigated as well as new photosensitisers. Photodynamic therapy is an entirely new treatment modality and its development can be likened to that of the discovery of antibiotics. This is just the beginning, and its possible uses are only limited by the imagination.
机译：恶性肿瘤的光动力疗法（PDT）是一种治疗癌症的新技术。静脉注射后，光敏剂被肿瘤细胞选择性保留，因此一段时间后，肿瘤中的光敏剂比正常的相邻组织中的光敏剂更多。光敏剂必须能够吸收传递给它的光的波长，到达光敏剂的光量取决于它穿过的组织的特性。当暴露于适当波长的光时，敏化剂会产生一种活化的氧，即单线态氧，该氧会氧化肿瘤细胞的关键元素。由于相邻正常组织中的敏化剂较少，因此对其发生的反应也较少。由于这是完全不同的过程，因此化学疗法，电离辐射或手术的使用并不排除PDT的使用。而且，与电离辐射不同，可以无限期进行重复注射和治疗。不同的分子和原子吸收不同波长的能量。由于必须吸收光能才能启动光化学反应，因此光敏剂的吸收光谱决定了用于引发反应的波长。但是，这可以通过光必须传播通过的组织才能到达光敏剂。光敏剂porfimer钠在405 nm区域具有吸收峰（蓝紫色），在630 nm区域具有较低的吸收峰（红色）。但是，由于较长的红色波长穿透的组织比405 nm更深，因此我们使用通常从激光系统发出的红色波长。这样可以将红光束耦合到石英纤维，然后可以对其进行修改以治疗外表面肿瘤，将其间质地直接插入大的肿瘤中，通过任何内窥镜治疗腔内肿瘤，或者插入到视网膜后方以治疗糖尿病。视网膜。在Thomas Doherty博士的开创性工作20年之后，美国食品药品监督管理局（FDA）批准将porfimer钠用于支气管内和食道肿瘤的光动力治疗。研究继续朝着批准治疗皮肤癌以及转移性皮肤癌和皮下乳腺癌的方向发展。光动力疗法的机制之一是血管血栓形成的认识导致verteporfin的发展，以治疗黄斑变性。正在研究其他多个领域以及新型光敏剂。光动力疗法是一种全新的治疗方式，其发展可与发现抗生素相提并论。这仅仅是开始，其可能的用途仅受想象力的限制。

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