Biophotonics Laboratory, Centre for Earth Science Studies, Akkulam, Thuruvikkal PO, Trivandrum 695031, Kerala, India.
Photodiagnosis Photodyn Ther. 2010 Sep;7(3):162-75. doi: 10.1016/j.pdpdt.2010.06.006. Epub 2010 Jul 24.
The focal goal of this study is to identify optimal accumulation periods for ALA-induced PpIX in different healthy anatomical sites of human oral cavity and different types of abnormal mucosa to improve the accuracy of the clinical applications such as photodiagnosis and tissue grading.
Laser-induced fluorescence (LIF) emission spectra, with excitation at 404 nm from a diode laser, were recorded with a miniature fiber-optics spectrometer from 13 anatomical sites of oral mucosa in 15 healthy volunteers and 30 suspicious sites in 15 patients after topical application of 0.4% 5-ALA solution for 15 min. The optimal accumulation time in different anatomical sites of healthy subjects and abnormal tissues were determined by studying the temporal variation in normalized fluorescence intensities (NFI) at 635, 685 and 705 nm.
In masticatory anatomical locations such as (gingival and hard palate) and in lining mucosa (inner lip, soft palate, floor of mouth, transition to floor of mouth, alveolus and ventral tongue) except vermillion border of lip (VBL) of healthy subjects (designated as group I), it was observed that optimum time for maximum accumulation of PpIX is 90 min. In comparison, for lateral side of tongue (LST) and dorsal side of tongue (DST) tissues (designated as group II), maximum accumulation of PpIX was observed in 150 min of ALA application. For diverse grade lesions of group I mucosa in patients, maximum accumulation of PpIX was observed in 90 min, whereas, in group II mucosa the optimum accumulation time was 150 min as in the case of healthy mucosa. Further, between different grades oral mucosa, maximum variation in NFI take place at these optimal time periods.
The determination of the optimum accumulation time of ALA in oral mucosa based on NFI helps to improve the diagnostic contrast and accuracy of oral cancer diagnosis, and to plan appropriate timing for ensuing PDT.
本研究的焦点目标是确定 ALA 在人体口腔不同健康解剖部位和不同类型异常黏膜中的最佳积累时间，以提高光诊断和组织分级等临床应用的准确性。
激光诱导荧光（LIF）发射光谱，用二极管激光器在 404nm 激发，从 15 名健康志愿者的 13 个口腔黏膜解剖部位和 15 名患者的 30 个可疑部位记录经皮应用 0.4% 5-ALA 溶液 15 分钟后的微型光纤光谱仪。通过研究 635、685 和 705nm 处归一化荧光强度（NFI）的时变来确定健康受试者和异常组织中不同解剖部位的最佳积累时间。
在咀嚼解剖部位（如牙龈和硬腭）和衬里黏膜（内唇、软腭、口底、口底过渡区、牙槽和舌腹）中，除唇红缘（VBL）外（指定为 I 组），观察到 PpIX 最大积累的最佳时间为 90 分钟。相比之下，对于舌外侧（LST）和舌背（DST）组织（指定为 II 组），ALA 应用 150 分钟时观察到 PpIX 的最大积累。对于患者 I 组黏膜的不同等级病变，PpIX 的最大积累在 90 分钟时观察到，而在 II 组黏膜中，最佳积累时间与健康黏膜一样为 150 分钟。此外，在不同等级的口腔黏膜之间，NFI 的最大变化发生在这些最佳时间段。
基于 NFI 确定口腔黏膜中 ALA 的最佳积累时间有助于提高口腔癌诊断的诊断对比度和准确性，并为随后的 PDT 计划适当的时间。
