Arnfield M R, Mathew R P, Tulip J, McPhee M S
Department of Surgery, Cross Cancer Institute, Edmonton, Alberta, Canada.
Phys Med Biol. 1992 Jun;37(6):1219-30. doi: 10.1088/0031-9155/37/6/002.
New photosensitizers activated by longer wavelengths than 630 nm light used with Photofrin II are under evaluation by various groups for the treatment of malignancies. Any increase in tumour volume destroyed by these agents as compared to Photofrin II will be partly determined by tissue penetrance at the longer wavelengths. Attenuation coefficients were measured for various tissues at 630 nm and the more penetrative near infrared wavelength of 789 nm. A new model of light propagation in tissue is shown to be accurate for arbitrary ratios of absorption and scattering, by comparison with a rigorous solution to the transport equation. Absorption and transport scattering coefficients of tissues at 630 and 789 nm were obtained by fitting this model to optical attenuation measurements. In vitro tissues included bovine heart, kidney and tongue, pig liver and fat, and chicken muscle; in vivo tissues included Dunning R3327-AT and R3327-H tumours. The penetration depth was found to be 1.35-2.25 times greater at 789 than 630 nm, depending on tissue type. The greatest differences in penetration between the two wavelengths were in the highly pigmented tissues. These substantial increases in penetration in the infrared may be important in future applications of photodynamic therapy.
多个研究团队正在评估波长大于630nm的新型光敏剂，其与卟吩姆钠联合用于恶性肿瘤的治疗。相较于卟吩姆钠，这些药物破坏肿瘤体积的增加程度，部分取决于较长波长下的组织穿透性。我们测量了630nm以及穿透性更强的近红外波长789nm下各种组织的衰减系数。通过与输运方程的严格解进行比较，我们发现一种新的组织光传播模型对于任意吸收与散射比例均准确无误。通过将该模型与光学衰减测量结果进行拟合，我们获得了630nm和789nm下组织的吸收系数与输运散射系数。体外组织包括牛心、肾、舌、猪肝、猪脂肪以及鸡肌肉；体内组织包括Dunning R3327-AT和R3327-H肿瘤。根据组织类型，789nm处的穿透深度比630nm处深1.35至2.25倍。两种波长穿透性的最大差异存在于色素沉着较高的组织中。红外穿透性的显著增加在光动力疗法的未来应用中可能具有重要意义。
